2012 NOVEMBER
Supplement To:
Magazine
Circle 101 on Reader Service Card for more information
Features 2 GM Gen IV The key to cataloging GM’s popular Gen IV engines is an understanding of the changes that GM made to the Gen III engines to make them more suitable for truck applications, says Contributing Editor Doug Anderson. The 4.8L, 5.3L, 6.0L and the 6.2L each came with a number of variations over the years and now total nearly 30 different models. Our detailed analysis offers information not available anywhere else in the aftermarket.
12 CAT C7 Caterpillar’s C7 common rail diesel engine has been used in applications from Bluebird Buses to Freightliner Trucks. Diesel columnist and contributor Bob McDonald, in conjunction with Jasper Engines and IPD, explores the differences between early and late model C7s, and the opportunities that these engines present.
22 Ford Stroker The mighty Blue Oval offers opportunities to engine builders to create a stroker motor ranging from tame to wild. Editor Doug Kaufman discusses some of the details of what it takes to build a top notch Ford stroker motor with noted “displacement” expert John Nijssen.
Advertiser Information Center ADVERTISER
CIRCLE #
PAGE#
CLOYES DURA-BOND ENGINE & PERFORMANCE WAREHOUSE HOT ROD & RESTORATION SHOW IPD MAHLE CLEVITE INC. RACE & PERFORMANCE EXPO
129 101 130 125 118,119 113 115
3C 2C 4C 25 18,19 13 15 EngineBuilderMag.com 1
CONTRIBUTING EDITOR Doug Anderson danderson@enginebuildermag.com
S
hortly after GM introduced the LS1 in the ’97 Corvette, they created a whole new family of small block truck engines based on the LS1, including the 4.8L, 5.3L, 6.0L and the 6.2L that each came with a number of variations over the years. In fact, GM built nearly 30 different versions of these truck engines during the past ten years. They all share a common architecture and quite a few common parts, but there are significant differences between the Generation III (Gen III) and Generation IV (Gen IV) engines along with plenty of variations from year to year. Just to put it all in perspective, there were seven different 5.3L engines in 2005 – along with the 4.8L and a couple of 6.0L motors. Sorting them out has been a challenge, but after six months of research along with a bunch of cores, some take-out motors and a pile of new parts, we think we have figured out most of the combinations and where they were used, but we may have missed something, so let us know if you have some information to share. The key to cataloging the Gen IV engines is an understanding of the changes that GM made to the Gen III engines to make them more suitable for truck applications. They needed more torque, more power and better fuel economy along with lower emissions, so they modified the block and several other components to accommodate cylinder deactivation (they call it active fuel management or AFM) and variable valve timing (VVT). Here’s an overview of the technology and what’s involved: •AFM: The Gen IV blocks were cast with eight oil ports in the valley to accommodate the lifter oil management assembly (LOMA) that deactivates the lifters for every second cylinder in the firing order under light loads. The 2 November 2012 | EngineBuilder
PHOTOGRAPHY BY NS Photography Pro
knock sensors and cam sensor were moved to make room for the LOMA, because it was bolted on top of the valley. A powerful new ECM was added in ’07, so the crank reluctor wheel was upgraded to 58 teeth and the cam gear had four notches instead of one so the sensors
could provide more immediate and accurate information to the computer. And, the special “De-Ac” collapsible lifters were added for the four cylinders that were going to be deactivated. This is amazing technology, because the four cylinders are deactivated in 45 milliseconds, in firing order sequence, when the exhaust valves are closed…at the same time the injectors are turned off and the position of the throttle blade is changed. This process is reversed during reactivation except that the torque converter is momentarily unlocked to allow it to absorb the torque spike that occurs when the four cylinders come back on line. That’s why AFM is only available with an automatic transmission. AFM improves fuel economy up to 20% depending on the application,
because operating the engine on four cylinders reduces pumping losses and increases thermal efficiency. As amazing as it is, AFM is not without problems that can affect engine builders. We’ll talk about noisy lifters and oil consumption later. • VVT: The use of variable valve timing (VVT) required modifications to the cams along with the timing components and the front covers, but there were no changes to the block itself, so we’ll note the differences when we discuss the individual components. Here’s how it works: • Variable valve timing or “cam phasing” as it’s sometimes called, “eliminates the compromise inherent in conventional fixed valve timing and allows a mix of low rpm torque over a broad range of engine speed and free breathing, high-rev horsepower, when needed,” according to GM. In other words, VVT lets the engine breathe better across the full spectrum of rpm and loads, while creating a wide, smooth, power band. The cam phaser can advance or retard the cam by up to 62 crankshaft degrees, depending on driving requirements. It’s advanced for a smoother idle and better low-end torque, or retarded for more horsepower at higher rpm and better fuel economy under light loads. VVT improves fuel economy when its used in conjunction with AFM because it helps maintain maximum torque when the engine is operating on four cylinders so the engine stays in the AFM mode as long as possible. And, it eliminates the need for an EGR system, because cam overlap is used for internal EGR instead of having an external EGR valve along with the passages from the exhaust ports to the intake manifold. Although all of the Gen IV engines can accommodate both AFM and VVT, GM has used both of these technologies selectively, depending on the en-
Circle 103 on Reader Service Card for more information
There are three front covers for the Gen IV engines including the FWD (left), RWD (center) and RWD with VVT (right). Note the location of the sensors and the extra hole for the VVT solenoid.
gine and the application: • The 4.8L engines never came with AFM and didn’t get VVT until 2010. • All of the 5.3L engines had AFM from ’05 through ’11 with the following exceptions: • The LH8 and LH9 engines that were used in the small pickups and the H3 Hummer didn’t have AFM. • The ’08-’09 LMF motor that was used in the vans didn’t have AFM. • All of the 5.3L engines got VVT in ’10, but the LH9 and LMF engines still came without AFM in ’10 and ’11. • The Gen IV 6.0L engines all got VVT beginning in ’07, but the ’07-’09 L76, the ’08-’09 LFA, and the ’10-’11 LZ1 were the only ones that had both AFM and VVT. •All of the 6.2L engines came with VVT, but AFM was only used on the 1st design L92 in ’07 and on the L94 in ’10-’11. Now that you have a better understanding of what GM was trying to accomplish when they upgraded the Gen IV engines, it’s a lot easier to understand the changes that they made. Let’s begin with the blocks by noting the differences between the Gen III and Gen IV castings.
GEN III Blocks The LS1 that was installed in the ’97 Corvette was the first Gen III motor (the 265 was Gen I and the LT1 was Gen II). GM says it’s part of the small block family, but the only thing it has in common with the earlier engines is the bore spacing and the shape of the bell housing. Soon after the car motors were introduced, GM replaced the old 305 and 350 truck motors with the new 4.8L, 5.3L and 6.0L engines that all used the LS architecture. There were both cast iron and aluminum blocks used from ’99 through ’08, but the cast iron blocks were usually found in 2WD pickups and the aluminum blocks were used in 4 November 2012 | EngineBuilder
the 4WD pickups and SUVs along with the Chevy SSR. They can all be identified by the two knock sensors in the valley and the cam sensor that’s located in the back of the block near the bell housing.
GEN IV Blocks
1900, a 12569513 or a 12568573 casting that has three more bolt holes on the sides. Based on the cores we’ve seen, one or more of these holes are used for some applications, so you can’t replace an aluminum block with an iron one, but you can replace an iron block with an aluminum casting. We suspect that the extra bolt holes on the aluminum 5.3L blocks were used for a differential support of some kind for the Trailblazer/Envoy chassis, because the aluminum block was the only one that was used in these small SUVs. The 6.0L engines came with a cast iron block that’s a 12576181 casting or an aluminum block that’s a 12568952 casting. We don’t know if they’re interchangeable because we haven’t seen them side-by-side, but we suspect that they’re all the same because they were both used in the same trucks, vans and big SUVs, and they were never installed in the Trailblazer or Envoy chassis. There’s also a FWD 5.3L block with
The first Gen IV truck engine was introduced in ’05 in the mid-sized SUVs including the Trailblazer and Envoy along with some other models that shared the same platform. The new 5.3L came with AFM and an aluminum block that incorporated several changes. The most noticeable difference was the addition of the eight oil ports in the valley that supplied oil from the LOMA to the “De-Ac” lifters, so the two knock sensors were moved from the valley to the sides of the block and the cam sensor was moved up to the front cover in order to make room for the oil ports and the lifter There’s one bolt hole on the rear cover for the FWD (right) oil management as- that’s relieved to clear the smaller Buick bell housing. sembly. The cast iron Gen IV block for the 4.8L/5.3L showed up in ’07, along with the cast iron 6.0L that was followed by an aluminum version of the 6.0L in ’08. The 4.8L/5.3L cast iron block is a 12576177, a 12576178 or a The cam gear was held on The Gen IV motors came with 12589779 casting. with one big bolt beginning the chain guide in ’05 and The aluminum in ’07. If the engine had VVT, ’06, but they all got the block is either a the bolt had an actuator blade-style tensioner begin12571048, a 1260valve in the center. ning in ’07.
The three bolt gear with a 1X sensor was replaced by the 1 bolt gear or phaser that had a 4X sensor in ’07.
The late FWD cars used the shortened 12552216 casting with the 58X reluctor wheel. • 6.0L Gen IV ’07-’11 Trucks, Vans and SUVs The 6.0L engines all used the 12552216 casting with the 58X reluctor wheel. This is the same casting that’s used in the 5.3L motors, but it’s balanced with a different bob weight, because of the heavier pistons. However, there are some rebuilders who say they mix and match them and get away with it.
Rods
Note the difference in the shape of the teeth on the cam gear. This asymmetrical design reduces chain noise.
The VVT motors have an electric solenoid that modulates the oil to the phaser so it can advance or retard the cam.
a 12569004 casting number on it. It’s unique, because it has on the 231 Buick bell housing and several different bolt bosses on both sides that are used for the transverse FWD applications.
Cranks and Sensors
All of the Gen IV engines came with the same crank castings that were used in the Gen III motors, but there were a couple of important differences. • 4.8 L Gen IV ’07-’11 Trucks and Vans All of the 4.8L engines used the 12553482 casting with the narrow (0.857˝) flange, but it had the 58X reluctor wheel (p/n 12586768) instead of the 24X reluctor wheel that was found on all the Gen III motors. • 5.3L Gen IV ’05-’06 Trucks, Vans and SUVs These early Gen IV motors came with the 12552216 casting that had the 24X reluctor wheel, just like all the 5.3L Gen III motors, because they still used the early ECM. • 5.3L Gen IV ’07-’11 Trucks, Vans and SUVs Beginning in ’07, all of the 5.3L truck engines came with the 12552216 casting that had the 58X reluctor wheel, because they all had the new ECM that needed more accurate information than they could provide with a 24X reluctor wheel. • 5.3L Gen IV ’05-’07 (1st design) FWD Cars The early FWD cars used the 12552216 casting, just like the trucks, but it was 13.0mm, or about a half an inch, shorter according to GM, so the flange measures 0.750˝ instead of about 0.850˝ and the front snout is shorter, too. This crank had the 24X reluctor wheel. • 5.3L Gen IV (’07-’09 2nd design) FWD Cars
There are long and short LS rods that came with and without pin bushings, but all of the Gen IV rods are bushed. It’s easy to tell them apart because the Gen III press-fit rods have rounded edges on one side of the beam and there’s no bushing. • 4.8L: These engines all have the long rod that measures about 4.70˝ from bore-to-bore. They’re powdered metal with a cracked cap and no identification. • 5.3L and 6.0L: All of these engines use the short, bushed rod that measures about 4.520˝ from bore-to-bore. They’re all powdered metal and most of them have “GKN” and “3847” on the big end of the rod. Rebuilders need to be aware that the bushed rods weigh 30 grams more and the pin bore in the press-fit rods is about .002˝ larger than the one for the bushed rods, so you can’t play mix and match if you’re short of the bushed rods.
Pistons Installing the right pistons in the right motor can be a challenge, because there are flat tops and dished pistons that came with and without the valve reliefs that are required for the engines that have variable valve timing (VVT), so it’s easy to make a mistake. Here’s our cheat sheet for the Gen IV motors:
Engine 4.8L
5.3L
6.0L
Year ’07- ’09 ’10-’11
Piston Flat Tops Flat Tops with 2 reliefs ’05-’09 Flat Tops ’10- ’11 Flat Tops with 2 reliefs ’05-’09 LS2 Flat Tops ’07-’11 Dished (Ex Hybrids) w/2 reliefs ’08-’09 LFA Flat Tops (Hybrid) w/2 reliefs ’10-’11 LZ1 Flat Tops (Hybrid) w/ 2 reliefs
GM P/N 89060486 19208675 89060486 19208675 19178305 89017849 19209286 19209286
Rings The rings for these engines are petty straightforward, because there haven’t been many changes made since the adEngineBuilderMag.com 5
The Gen IV engines without AFM had a flat cover (left) that sealed off the valley and the oil ports. The lifter oil management assembly (right) was used on the engines with AFM.
The perimeter gasket on the left is used for the cover without AFM and the one on the right is used for the one with AFM.
There are four solenoids on the lifter oil management assembly that are connected to the eight oil ports that control the “De-Ac” lifters.
vent of the Gen III truck engines in ’99. • 4.8L: One set covers all the 4.8L engines from ’99-’11. The rings are 1.5mm/1.5mm/3.0mm. • 5.3L: The same set covers all of the 5.3L engines from ’99-’11, because the bore is the same as the 4.8L and the rings are still 1.5mm/1.5mm/3.0mm. • 6.0L: There have been two ring sets for the 6.0L from ’99-’11. • The rings in the first set that fits from ’99-’04 are 1.5mm/1.5mm/3.0mm. • The rings in the second set that fits from ’05-’11 are 1.2mm/1.5mm/2.5mm. Be sure to match the pistons and rings for each application.
Oil Pumps The Gen IV engines have used two different oil pumps that have three different springs for the relief valve. • The 12586665 pump that was carried over from the Gen III applications pumped 0.96 cubic inches per revolution. It was used on all the cast iron Gen IV motors and on a few of the alu6 November 2012 | EngineBuilder
minum ones like the LS2 and LH8 that came without AFM or VVT. The replacement pump is the Melling M295. • GM introduced a new pump beginning in ’05 with 33% more capacity that pumped 1.26 cubic inches per revolution. There were two versions of this pump, but the only difference between them was the spring for the relief valve. The original 12571885 pump that was used for a couple of applications in ’05-’07 had a red spring that relieved the oil pressure at 43 lbs. Based on our research, we believe that GM originally intended to build these early 5.3L Gen IV engines with both AFM and VVT, so they increased the pressure and the volume to make sure the pump could supply enough oil for both of them, but they apparently decided they didn’t need the higher oil pressure because this pump was replaced by the 12612289 that had a 33 lbs. relief valve in ’08. The original high-pressure pump is available from Melling as the M355, but we prefer to use the M365 that has the lower pressure instead.
• The 12612289 is the latest version of the big pump. It has the bigger housing with the extra capacity, but it has the yellow spring that reduces the maximum oil pressure from 43 lbs. down to 33 lbs. It’s used on all of the truck engines with an aluminum block that have AFM or VVT or both. It’s the Melling M365. • The LFA and LZ1 Hybrids came with a variable displacement oil pump that supposedly saves two horsepower. It’s available under p/n 12625823 for the LFA and p/n 12623423 for the LZ1. We recommend replacing all the factory oil pumps with aftermarket pumps because the original design has several flaws that can lead to problems. • The clearance between the rotor and the backing plate is so tight (.000˝ to .003˝) that most of the covers are badly scored by the time we see them. In fact, GM is having problems with them scoring and seizing while they’re still under warranty. • The thin steel backing plate warps, leaks, and bleeds off oil pressure constantly. • The OEM relief spring starts bypassing oil at 6#, which aggravates the problem if the engine has low oil pressure at hot idle, and the constant fluctuation of the relief valve tends to wear the bore in the aluminum housing so the oil bypasses the relief valve and the engine has low oil pressure. The replacement pumps address all of these problems, so we suggest using new ones instead of trying to rebuild the OEM pumps. The chart on page 10 explains the application by RPO and VIN code. You will note that we super-
The shield that fits over the AFM relief valve in the pan deflects the oil down and away from the crank so it doesn’t end up on the walls.
The oil pump for the aluminum engines with AFM and/or VVT had 33% more volume. Note the difference in the width of the gerotor on the right.
seded the 43 lbs. 12571885 with the 33 lbs. 12612289, but you can run the 43 lbs. pump on the ’05-’07 LH6 and LS4 engines if you prefer.
Timing Components There have been several changes made to the timing components over the years. This can create a problem for rebuilders, because the chains, gears and tensioners are not interchangeable even though they may fit several different applications. Here are the correct gear and sensor combinations: • All of the Gen III motors had the cam sensor located on the back of the cam so they used a “plain” gear with lots of holes in it that was bolted to the front of the cam with three small capscrews. Note: GM and most vendors have consolidated their timing gears/sets by replacing the “plain” gear with the ’05’06 Gen IV gear that has a single notch in it and three capscrews. It works fine. • The cam sensor was moved to the cam gear and front cover in ’05 in order to make room for the oil ports that were required for AFM. The cam gear had a single notch (1X) on it through ’06, because these engines still used the old ECM, and it was bolted to the cam with three small capscrews, just like the Gen III motors. • When GM switched to the
new ECM in ’07, they changed the cam gear on the 4.8L and 5.3L. It was held on with one large bolt and it had four notches (4X) on it so it could provide a more accurate signal to the computer. It also provided a backup signal and limp-home capability in case the crank sensor failed. This gear was used up through ’09 on all of these engines, because none of them had VVT and the phaser with the 4X sensor attached to it. • The cam gear on the 6.0L engines was changed in ’07, too, but all of these engines came with VVT, so the cam gear was an integral part of the cam phaser assembly that had a stampedsteel plate with four notches (4X) attached to the front of it. This same assembly was used on all the 4.8L and 5.3L motors when they got VVT in 2010. Here’s a recap of the cam gears and sensors for the Gen IV motors: 4.8L
’07-’09 ’10-’11
4X 4X
One Bolt Phaser P/N 12606358
5.3L
’05-’06 (LH6) 1X ’07-’09 4X ’10-’11 4X
3 Bolts One Bolt Phaser P/N 12606358
6.0L
’05-’06 (LS2) 1X ’07-’09 (LS2) 4X ’07-’11 (ex. LS2 and Hybrids) 4X ’08-‘11 (LFA & LZ1 Hybrids) 4X
3 Bolts One Bolt
The intake rockers had to be offset by 6.0mm to clear the large, rectangular ports on the 823/ 5364 heads that were installed on the 6.0L Gen IV engines beginning in ’07.
Most of the 6.0L Gen IV engines came with either flat top or dished pistons that had valve reliefs for VVT, but the ones for the LS2 didn’t have reliefs because it didn’t have VVT.
ing the tooth profile so the chain sat deeper in the gear, but that created a noise problem, so the powdered metal gears have an asymmetrical pattern on the teeth that reduces the noise by eliminating the common harmonic frequency. Look at the picture of the 4X
Phaser P/N 12606358 Phaser P/N 12602699
Tensioners
GM has used either a chain damper or a tensioner on all the GEN IV engines, depending on the application. They both fit all the Gen IV blocks, but they’re not interchangeable. • The 12588670 is the wedge shaped guide that was used on the ’05-’06 LH6 and the LS2 along with ’05-’07 1st design LS4, because they all had 1X cam gear with the three bolt cam. • The 12585997 is a blade style, spring- loaded tensioner that was used for all ’07 and up Gen IV motors that had the 58X crank relucThe miniature AFM lifter has two tor wheel and the 4X spring-loaded pins that ride up on cam gear or the phaser. a ledge inside the roller body This tensioner must be until they are depressed by the used on all of these enoil pressure that deactivates the gines because GM crelifter and allows it to drop down ated some initial slack inside the roller body. in the chain by modify-
The cam for the ’05-’06 Gen IV engines had three bolts for the cam gear, the ’07-’09 engines without VVT had a single bolt and the all of the engines with VVT had the single bolt along with the two “ears” that supplied oil to the phaser.
The second journal was grooved and had a hole that fed oil into the hollow core for the engines with VVT.
EngineBuilderMag.com 7
The original Delphi “De-Ac” lifter is on the left and the Eaton with the three “windows” is on the right. Neither one should be reused. Unfortunately, you can’t tell the difference between a Delphi I and Delphi II externally. The lifter guides for the AFM engines have one notch that indexes on a tab in the block to ensure that it’s installed in the right location. The ones for the engines without AFM have two notches because the lifters are all the same so they can fit in any location.
gear that’s on page 5 and you will see that the teeth aren’t symmetrical because they all vary in size and width. The bottom line is that you must use the correct chain/gear/tensioner combination for each application or you will have a noisy timing set that will fail prematurely.
Camshafts Getting the right cam in each particular engine can be a challenge, because there have been 12 different cams used in the Gen IV motors and they’re not usually interchangeable because they’re varied, unique and specific to each application in most cases. There are two different bolt patterns for the cam gear and some had AFM or VVT, or both or neither. Here’s what you need to know: • You have to use the three bolt cam in the ’05-’06 Gen IV 5.3L motors in order to use the 1X cam gear.
Notice the difference in the size of the holes for the lifters and the location of the notches in each lifter guide. 8 November 2012 | EngineBuilder
• You must use an AFM cam in the AFM motors, because the ramps on the AFM cylinders are longer so they can take up the locking lash that The early “De-Ac” exists between lifters have a small the ledge in hole in both the body the outer and the plunger. The body and the latest version- the two pins in “Delphi II” -has sevthe lifter when eral large holes that refill the lifter immedi- the cam is on base circle. ately and eliminate • All of the lifter noise at start-up. VVT cams are drilled back to the second journal that’s grooved and there’s a hole in it that feeds oil into the hollow core so the actuator valve can regulate the position of the cam phaser by applying oil into either side of the phaser through the two “ears” in the front of the cam. You can use a cam that’s machined for VVT in a non-VVT motor, because the large bolt for the gear will plug the hole and block off the oil, but you must have a VVT cam with the groove and the ears in order to make the VVT work. GM has chosen to machine all their late cams for VVT whether the engine has it or not, so it can be confusing, but just remember that you can’t use a single bolt cam without the groove and the two ears in a VVT motor. • We have combined a few applications when GM has superseded them and we hope to consolidate a few more because the specs appear to be pretty
close, but we’re concerned about how the computer will react to any changes so we’re sneaking up on it. • The last four digits of the OEM part number are always etched on the back of the rear journal, so it’s easy to identify the cam unless it’s a superseded number, and there are a couple of them, so that makes it more difficult. The good news is that we have figured out the complete part numbers for the superseded cams and included them on the chart on page 10.
Lifters Here’s where the fun starts. • GM changed the location of the oil hole on the Gen IV lifters that are used in the cylinders that aren’t deactivated on the AFM motors. The oil hole is on the same side as the flat instead of 90° away from the flat. We’re told that it has to do with limiting the amount of oil that can leak out of the lifter when the engine is shut off and that this change helps eliminate noisy lifters at start-up, so rebuilders should probably use the correct lifters for the Gen IV engines, even though they cost more. • There are three different “De-Ac” lifters. The early ones were made by either Eaton or Delphi. The latest one, that’s made exclusively by Delphi (we call it the “Delphi II”), was designed to
The Gen III, oval port heads (bottom) were replaced by the ones with “Dee” shaped exhaust ports and bigger valves on all the 4.8L/5.3L Gen IV motors.
The 24X crank sensor wheel (left) was replaced by the 58X on all Gen IV motors beginning in ’07. The 6.0L Gen IV motors got the 823/5364 castings with the big rectangular intake ports instead of the ones with the smaller cathedral ports that were used on all the rest of the Gen IV engines.
eliminate the problem GM had with noisy lifters at start-up with both of the early designs. If you take a “De-Ac” lifter apart, you will see why there’s a problem, because there’s a complete miniature lifter assembly inside the outer roller body where the plunger used to be, so there’s not enough oil in the downsized upper chamber to refill the lower chamber after the engine has been shut off long enough to let the lifter leak down. GM couldn’t change the physical size of the lifter to fix this problem because it had to fit inside the roller body, so they reduced the leak down rate of the lifter and opened up the oil holes in both the lifter and the plunger to make sure they could refill the upper and lower chambers immediately after start-up. These changes eliminated the problem they had with noisy lifters, so we recommend installing all new “Delphi II De-Ac” lifters in every AFM engine. Its not worth taking a chance on the original Eaton or Delphi lifters if you have to replace them under warranty when the engine gets 30,000 or 40,000 miles on it. The “Delphi II” lifters are available from GM for about $50 apiece or for a little less from at least one supplier in the aftermarket. Be sure to specify the latest “Delphi II” lifters when you order new ones wherever you get them. The correct GM part number is 12639516, according to our Chevy dealer.
four regular lifters and fits in any location because it has two notches on the guide that match any of the locator tabs on the block. It has the part number, 12595365, molded right on it. The AFM engines have two different lifter guides that have two big holes for the “De-Ac” lifters and two small holes for regular lifters. The 12571596 is for the front cylinders on both sides and the 12571608 is for the back two cylinders on both sides. GM designed them so you can’t physically interchange them because they each have a single notch that fits over the single raised tab in the block which locates the guide and the lifters correctly.
Heads There have been several different head castings used on the Gen III and Gen 1V motors. The intake and exhaust ports have been changed along with the valve sizes and springs. The chart on page 46 lists all the truck heads we have seen by year, RPO and VIN code, including the ones for the Gen III motors, and describes each one by part number, casting number, port configuration and valve size. Once you see them all together, the patterns become more obvious.
heads with “Dee” shaped exhaust ports, so be sure to use the latest design on the Gen III L33/VIN B and all of the 4.8L/5.3L Gen IV engines that came with these heads.
Springs GM has used two different valve springs for the truck engines. • The original spring that was used on the trucks from ’99 through ’04 had less tension than the later one. The actual specifications will vary depending on the checking height specified by the vendor, but we have found that 75 lbs at 1.800˝ and 180 lbs. at 1.420˝ are acceptable numbers for our use. • GM introduced a new, stronger spring in’05 that was designed to extend the operating range of the engine a little bit higher because the new heads had bigger valves and better ports that flowed more air. We check them at 85 lbs. at 1.800˝ and 245 lbs. at 1.320˝.
Rocker Arms and Supports
GM made a slight modification to the coolant passages in the head gaskets that were used on the 799/12564243
• All of the Gen III and Gen IV 4.8L and 5.3L motors came with straight intake and exhaust rockers along with all the Gen III 6.0L engines and the Gen IV LS2 that was used in some trucks. They were bolted to a rocker support that was mounted on the square pedestals that were machined on the heads. • When GM installed the 823/5343 heads on the Gen IV 6.0L engine in ’07, they had to offset the intake rockers by 6.0mm so the pushrods would clear the big, rectangular intake ports found on these castings. The rocker support (p/n 12569167) was modified to fit the
The chamber for the rectangular port heads (left) was modified to incorporate two quench areas and bigger valves.
The rectangular port heads (left) have round bolt pads instead of the square ones, so there are two different rocker supports.
Head Gaskets
Lifter Guides There have been three different lifter guides used for the Gen IV engines and they’re unique to each application so they’re not interchangeable. All the engines without AFM have a universal guide that accommodates
EngineBuilderMag.com 9
The Gen IV aluminum blocks have one extra bolt hole on the passenger side.
round pedestals that were machined on these heads.
Pushrods The Gen IV engines use the same pushrods that were used for all the Gen III engines.
The LOMA and Valley Covers The “lifter oil management assembly”(LOMA) that contains the solenoids that control the “De-Ac” lifters covers up the valley on the engines with AFM. The early ones were bolted together as an assembly, but the later ones are riveted so they can’t be disassembled. GM offers a perimeter gasket (p/n 89017690) to service the LOMA, but that means you have to cut the gasket and reuse the existing inner portion that seals the oil ports and that’s pretty suspect based on the limited number of samples we’ve seen on cores. The only alternative is to install a new LOMA as-
The Gen IV aluminum blocks have two extra bolt holes on the driver’s side.
sembly or tell the installer that he has to put a new one on in order to validate the warranty. They cost about $200 apiece, but it may be money well spent if it avoids a problem with the AFM lifters, because you will be blamed even though it’s not your fault. If the engine comes without AFM, there’s a plain cover (c/n 12598833) and a perimeter gasket (p/n 12610141) plus eight “O” rings that seal off the valley and the oil ports. There’s no provision for the PCV used on the trucks, but some of the cars use one that has a PCV baffle, so be sure to use the right one for the application.
Front Covers The Gen IV motors have used three different front covers, two for the trucks and one for the cars. • All the Gen IV truck engines, except those with VVT, use a 12600326 casting with a hole for the cam sensor that’s offset toward the driver’s side.
• The Gen IV motor with VVT still has the hole for the cam sensor offset to the driver’s side, but it also has a large hole in the center for the solenoid that regulates the oil pressure for the cam phaser. Our sample has a 12594939 casting number which is the same as the OEM part number. • The FWD cars have a unique front cover that has the hole for the cam sensor offset to the passenger side. We have seen two different versions, but the latest one (p/n 12611880) supersedes the earlier 12580288 casting, so they appear to be interchangeable. The later one has an unusual casting number that’s “CDCG/A,” whatever that means.
Rear Covers These engines have two different rear covers. • The RWD trucks (and cars) have either a 12556105, a 12587100, a 12598301 or a 12572014 casting. They are all very similar to the Gen III rear cover (c/n 12559287) and appear to be interchangeable. • The FWD cars use the 12587100 casting. It’s similar to the RWD cover, but it was modified to provide more
CHEVY GM IV Engines Chart LITERS
YEAR
RPO
VIN
BLOCK
OIL PUMP
MAT'L 4.8L 4.8L 5.3L 5.3L 5.3L 5.3L 5.3L 5.3L 5.3L 5.3L 5.3L 5.3L 5.3L 6.0L 6.0L 6.0L 6.0L 6.0L 6.0L 6.0L 6.0L
2007-09 2010-11 2005-06 2007-09 2007-09 2007-09 2007-09 2008-09 2008-09 2010-11 2010-11 2010-11 2010-11 2005-06 2007-08 2007-09 2007-09 2008-09 2010-11 20102010-11
LY2 L20 LH6 LH6 LY5 LMG LC9 LMF LH8 LH9 LMF LMG LC9 LS2 LS2 LY6 L76 LFA LZ1 LY6 L96
C A M M J O 3 4 L P 4 0 3 H H K Y 5 J K G
CI CI AL AL CI CI AL CI AL AL CI CI AL AL AL CI AL AL AL CI CI
10 November 2012 | EngineBuilder
M295 M295 M365 M365 M295 M295 M365 M295 M295 M365 M295 M295 M365 M295 M295 M295 M365 VARIABLE VARIABLE M295 M295
AFM VVT CRANK SENSOR
° ° ° ° °
° °
° ° °
° ° ° °
° ° ° ° ° °
58X 58X 24X 58X 58X 58X 58X 58X 58X 58X 58X 58X 58X 24X 58X 58X 58X 58X 58X 58X 58X
CAM SENSOR
CAM P/N
4X GEAR/1-BOLT 4X GEAR/1-BOLT 1X GEAR/3-BOLT 4X GEAR/1-BOLT 4X GEAR/1-BOLT 4X GEAR/1-BOLT 4X GEAR/1-BOLT 4X GEAR/1-BOLT 4X GEAR/1-BOLT 4X PHASER 4X PHASER 4X PHASER 4X PHASER 1X GEAR/3-BOLT 4X GEAR/1-BOLT 4X PHASER 4X PHASER 4X PHASER 4X PHASER 4X PHASER 4X PHASER
12593205 - 12625437 12625437 12569525 12593207 - 12625436 12593207 - 12625436 12593207 - 12625436 12593207 - 12625436 12625437 12625437 12625437 12625437 12625436 12625436 12574519 12593206 12612274 - 12625439 12629698/ 12625438 (09) 12629698 12629698 12625439 12625439/ 12625440 (11)
• Lifter noise after a two-hour shutdown can be an issue with the engines that have The Gen IV blocks have 8 oil ports in the valley for AFM inAFM. If the ticking stead of the two knock sensors that were located in the vallasts more than 10 ley on the Gen III motors. seconds after startup and it’s diagclearance around one of the bolt bosses nosed as lifter noise, GM is replacing the for the smaller FWD bell housing. lifters with the latest “Delphi II” lifters (p/n 12639516) that we described earlier. Problems With The LS Motor We recommend using all new “Delphi II” There are a couple of problems with the “De-Ac” lifters in these engines to avoid Gen IV motors that may affect how you the possibility of a warranty 30,000 or rebuild the AFM motors, especially the 40,000 miles later, because you have to reones with aluminum blocks. move the heads in order to replace the
GEN III AND GEN IV LS TRUCK HEADS 4.8L
4.8L/GEN-III 99-07
RPO LR4
VIN V
GM PN 12578925
CN 12559862 12561706
VALVES I 1.890” E 1.55”
PORTS Cathedral Oval
4.8L
4.8L/ GEN-IV RPO 07-09 LY2 10-11 L20
VIN C A
GM PN 12629049
CN 799 12564243
VALVES I 2.00” E 1.55”
PORTS Cathedral “Dee”
5.3L
5.3L/GEN-III 99-07 02-07 03-04 5.3L/GEN-III 05-07
RPO VIN LM7 T L59 Z LM4 P
GM PN 12578925
CN 12559862 12561706
VALVES I 1.890” E 1.55”
PORTS Cathedral Oval
L33
B
12629049
799 12564243
I 2.00” E 1.55
Cathedral “Dee”
5.3L
5.3L/GEN-IV 05-09 07-09 07-11 07-11 08-11 08-09 10-11 05-09
RPO LH6 LY5 LC9 LMG LMF LH8 LH9 LS4
VIN M J 3 0 4 L P C
GM PN 12629049
CN 799 12564243
VALVES I 2.00” E 1.55”
PORTS Cathedral “Dee”
6.0L
6.0L/GEN-III 99-00 CAST IRON 01-08 02-07 ALUMINUM
RPO LQ4
VIN U
GM PN 12568175
CN 12567173
LQ4 LQ9
U N
12562319
12562317
VALVES I 2.00” E 1.55” I 2.00” E 1.55”
PORTS Cathedral Oval Cathedral “Dee”
6.0L/GEN-IV 05-09
RPO LS2
VIN H
GM PN
CN 12564243
07-10 07-09 08-09 10-11 10-12 11
LY6 L76 LFA LZ1 L96 LC8
K Y 5 J G ?
12629051
823 5364 823 5364 823 5364
VALVES I 2.00” E 1.55” I 2.165” E 1.590” I 2.00” E 1.55” I 2.165” E 1.590”
PORTS Cathedral “Dee” Rectangular “Big Dee” Rectangular “Big Dee” Rectangular “Big Dee”
6.2L/GEN-IV 07-08 09-11 10-11
RPO L92 L9H L94
VIN 8 2 F
GM PN 12629091
CN 823 5364
VALVES I 2.165” E 1.590”
PORTS Rectangular “Big Dee”
6.0L
6.2L
lifters, and that gets really expensive! • Some of the aluminum engines with AFM have experienced oil consumption, too. GM says that the oil spray that is discharged from the AFM pressure relief valve in the crankcase may result in carbon deposits in the ring grooves that stick the rings and cause oil consumption. They have modified the rocker cover to change the calibration for the PCV for some applications, but the real fix is the installation of a shield (p/n 12639759) over the AFM relief valve to deflect the oil down into the pan instead of allowing it to hit the crank that throws it up on the cylinder walls. Rebuilders should include this shield with the LC9, L76, L96, LS4, LFA and LZ1 along with a picture and instructions so the installer knows where it goes and why it must be installed before putting the pan on the engine. • The cam phaser hasn’t created any problems for GM, but it probably should be replaced when the engine is rebuilt for a couple of reasons. The cam gear is a part of the phaser, so if the gear is worn, the phaser will have to be replaced. There are some internal parts that wear, too, and there’s no easy way to get the phaser apart to inspect them. So, the only real alternative is to try to clean it and pressure test it to see if it’s okay – or replace it every time to make sure it will go the distance without a comeback. By the way, there are two different phasers. The one for the LFA and LZ1 Hybrids is a p/n 12602699, and the one for all the rest of the VVT applications is p/n 12606358.
Conclusion
12629051 12629051
That’s pretty much the story about the Gen IV engines. It’s interesting to see how GM has taken a building-block approach to this family that has allowed them to mix and match a variety of castings and components to create 28 engines that are all tailored to different needs and applications. Unfortunately, that means there are 28 different truck engines that we all need to rebuild, so it’s going to be real complicated for everyone in the industry, but it can be done if we identify each RPO and rebuild it exactly the way GM built it in the first place. Hopefully this information will make it easier for everyone to do that, but the moral of the LS story is, “Don’t guess EngineBuilderMag.com 11
CONTRIBUTOR Robert McDonald rmcdonald@enginebuildermag.com
E
ven in today’s struggling economy, there are still creative ways to make an income, and the same is true with the transportation industry. I am sure there are plenty of automotive and diesel engine shops finding new areas in which to direct their expertise. I believe society naturally directs the outcome of its environment: if someone manages a quality independent automotive repair shop, they will always be looking for ways to increase their education and specialty tools as technology changes. In order to take care of their customers when the warranty runs out and they no longer visit the dealership, shops need to adapt. A quality independent automotive repair facility that keeps up with technological advances is no different than any other competitive industry. Look at the automotive manufacturers themselves. Today’s society has directed them to make more power, use less fuel and offer more features. The same can be said about the heavy-duty industry as well. Heavyduty diesels that transport goods across the country along with the ones that are used to excavate highways are all using the same competitive strategies to stay on top. In addition, the EPA has raised standards and lowered emissions in response to or as a cause of technological advances. The Caterpillar C7 engine is no exception. Another popular Cat engine, they’re now seeing rebuilding opportunities, so we thought we would take a look at how things have changed to get to where we are today. This popular engine was released in 2003, and now has a total production of over 300,000 units. With a 12 November 2012 | EngineBuilder
range from 190hp to 360hp, this midrange six cylinder engine is very versatile. It can often be found in on-highway trucks, and also in offhighway applications such as loaders, skidders, excavators, motor graders, and industrial and marine units. It is actually a 7.2 liter
(439 cu. in.) engine with a 4.33” bore (110mm) and 5.0” stroke (127mm). From 2003 to 2009, the C7 was Caterpillar’s primary engine for medium-duty trucks with a GVWR of 18,000 to 33,000 lbs. from GMC, Ford, Freightliner and Paccar. The Cat C7 is an inline 6-cylinder diesel engine with a displacement of 7.2 liters or 441 cubic inches. At the end of its production cycle, the engine included a number of features including turbocharging, common rail fuel injection system, full electronic control system and Caterpillar’s ACERT fuel/air management system. To meet regulations, advanced emission solutions include a closed crankcase breather and a diesel particulate filter using Cat’s proprietary regenera-
tion system. Of course, to understand where we are, it’s often necessary to take a look back. The C7 was Caterpillar’s answer to growing demands for emissions reductions and was derived from its older engine brother, the Cat 3126. The 3126 was, in fact, the replacement for the Cat 3116 and that’s where this story REALLY starts. The 3116 engine was used up until the mid ’90s until society demanded more. The 3116 caused strong reactions in many people, to say the least. Not too many 3116 owners were proud of Cat’s reputation behind the engine and, while the engine did prove reliable, it didn’t offer enough power for most users and was not very fuel-efficient. To counter its poor reputation and meet tightening emissions demands, Cat released the 3126 in 1997 as its first midrange electronic diesel engine. The 3126 could be found in GMC, Ford and Freightliner trucks, Thomas and other school buses, recreational vehicles and smaller emergency vehicles. It was also offered in off-road applications as well in excavators, skidders, motor graders, industrial, and marine. Depending on application, the 3126 ranged from 175 to 300 hp. It was a part of the “gear fast, run slow” strategy from Cat, which allows the engine to run slower at cruise speeds, translating into potential reduced fuel consumption. The 300 horsepower version produced peak power at 2,200 rpm with the torque peaking at 800 ft.lbs. at 1440 rpm. To achieve its electronic advancement the 3126 engine utilized HEUI (Hydraulic Electronic Unit Injector).
Circle 113 on Reader Service Card for more information
All HEUI designs work in the same fashion. The components include an ECU (Electronic Control Unit), electronic injectors, and various sensors placed on the engine and vehicle. This same technology is also found in the Ford Power Stroke and was used by International in several different applications with their inline six-cylinder engines in the DT series trucks, but HEUI is a trademark of Caterpillar. Caterpillar used high-pressure oil to make even higher injection pressures, effectively squeezing fuel out of the injector nozzle. In a HEUI system, the oil pump inside the engine supplies oil to a high-pressure oil pump or HPOP. The HPOP is geardriven by the engine and sends pressurized oil to a galley in the cylinder head that surrounds the injector.
When the ECU commands the injector to open, the high-pressure oil enters the injector and pushes down on an intensifier piston inside the injector body which in turn pushes down on a plunger. The intensifier piston is generally seven times greater in size than the plunger. At idle, the HPOP supplies approximately 500 psi of pressure to the injector. Caterpillar used high pressure oil to squeeze fuel out of the injector nozzle. The injector has two compartments in the lower portion of the injectors body. One for high pressure oil to enter the injector and the other is to store incoming fuel which is provided by a pump at 80 psi. When the injector is commanded to open, the 500 psi oil enters and then sends fuel out of the tip at 3,500 psi (7 x 500 because of the intensifier
piston). At wide open throttle, the HPOP can supply the injector with up to 3,000 psi of oil pressure. So, the fuel being ejected from the injector tip can reach as high as 21,000 psi. The volume of oil that is supplied by the HPOP is controlled by an electronic regulator. The various sensors monitor HPOP pressure in relation to engine parameters from coolant temperature, oil temperature, cam position sensor, throttle position, manifold pressure, and barometric pressure. Utilizing these electronic controls along with high-pressure oil brought about more precise engine control as well as more economy. This engine design also increased power and reduced emissions. One thing that really set the 3126 apart was the design of its cylinder head. The inline-six cylinder head in-
This chart provides engine and market information on 17 different configurations of Caterpillar C-series engines, from the C7 to the C280-16 model. Chart courtesy of IPD LLC. 14 November 2012 | EngineBuilder
Circle 115 on Reader Service Card for more information
The one-piece steel piston design is produced by (center) inertia/friction welding a steel crown to a steel piston skirt. This design creates a piston with an internal oil cooling gallery in the crown (right), and increased structural strength and resistance to fatigue.
corporated three valves per cylinder: one exhaust valve and two intake valves. The head was named “crossflow” and revolutionized the airflow of the engine. Incoming air entered the engine from the right hand side through the intake valves and exited through the exhaust valve on the left hand side. This cross-flow design changed the swirl characteristics of the cylinder head and was a big factor in improving power and combustion on this diesel engine. With all of these changes in the 3126, the power was almost double that of the 3116.
In 1998, after one year, Caterpillar released the 3126B, basically the same engine configuration with improved electronics. The ECU was upgraded from a 40 pin to a 70 pin connection. This advanced ECU was used to gain more engine control, as Caterpillar sought less smoke even upon cold start as emissions demands increased. Another concern was to lower the operating decibels of the engine. The previous 3126 was considered to be “too loud,” so by controlling the engine with advanced electronics, fuel delivery strategies
The base of Caterpillar’s rear seal installer is bolted to the rear of the crankshaft. 16 November 2012 | EngineBuilder
were also changed, lowering the decibels and making the engine more efficient. As emissions tightened even further, Caterpillar released the 3126E in 2002. The 3126E was the same engine platform with even more advanced electronics and redesigned HPOP. The HPOP gave higher injection pressures and a new leak-free design. If the HPOP did leak, it would leak into the engine, unlike older designs that tended to leak to the exterior of the engine. The HPOP will only leak when there is an internal
The rear seal is installed over the installer base. An outer sleeve will be used with an impact wrench to install the seal into its proper position.
Rod caps and rods are color coded so that they can be matched during installation and assure correct tolerances for a smooth running engine.
seal problem, which is an indicator of an upcoming HPOP failure. This new design of HPOP also incorporated a different regulator system, however, this style of new pump was more costly to replace and could not be interchanged with older 3126 versions. In the second half of 2003, Cat released the replacement for the 3126 version, known as the C7. Once again, you can see the trend as demand rises. Whether the circumstance involves making more power or keeping compliant with growing emissions standards; in order to compete, things must change. The C7 was Caterpillar’s answer to the Tier 4 standard that would be required for 2004. The engine used the same configuration as the 3126 version, but the fuel system was changed, utilizing a new style of HEUI injector. The electronics were also more intense to offer further fuel control and electronic additions to the engine. The controller was upgraded to a 120 pin connection with much faster processing speeds. One of the electronic additions is known as the Cat
To ensure that the block is salvageable it should be measured with a digital disc brake caliper to determine if the wall thickness can accept a repair sleeve. Circle 118 for more information 18 November 2012 | EngineBuilder
Camshaft end play is inspected with a dial indicator and recorded on a Quality Control Card.
ACERT System – Advanced Combustion Emissions Reduction Technology – involves the precise control of the combustion cycle by controlling incoming air and fuel, as well as exhaust aftertreatment. The new HEUI injector and electronics allow for multiple injections, different fuel rate strategies which help improve combustion. In 2007, the C7 would change again, this time to adjust to the fuel, not just to market demands. You have to remember that in 2007, diesel fuel would change to ULSD (Ultra-Low Sulfur Diesel). With this change, Caterpillar changed the fuel system of the C7 to common-rail injection. The common-rail injection took injection pressures to 27,500 psi. The transfer pump supplies fuel to the fuel rail at 280 psi. The reduction of sulfur levels in ULSD means less lubricity, so circulating the fuel rapidly at high pressure keeps heat down. The turbocharger was changed to variable nozzle technology, which can offer proper amounts of boost at all engine speeds. What is really impressive is that these engines
Piston height is inspected with a dial indicator and recorded on a Quality Control Card. Circle 119 for more information EngineBuilderMag.com 19
Main bearings are lubricated after installation as they are readied to receive the crankshaft.
can have a service life of 450,000 to 500,000 miles on a blend of B50 biodiesel. The 3126 and the C7 configurations share many similarities. The bore is 4.330˝ and the stroke is 5.000˝. The compression ratio was 16.5:1. The cylinder block has “parent” bore
The Cat C7 Was Available With These Horsepower Ratings: 210, 230, 250, 275, 300, 330, 350 and 360 hp Torque ratings ranged from 520 up to 925 lb-ft. The 201, 230 and 250 hp. ratings were available in either a low torque or high torque option. The choice of torque options allowed different transmissions, which are rated by torque capacity, to be matched with the C7. The 330 through 360 horsepower ratings were only available in RV and firetruck applications.
20 November 2012 | EngineBuilder
cylinders, meaning it does not have replaceable liners, but the cylinders can be sleeved if necessary. Before boring the cylinder block to accept repair sleeves, follow the OE guidelines to ensure that the block is salvageable. One guideline in particular explains that the cylinder block should be measured with a digital disc brake caliper to determine if the cylinder wall thickness is thick enough to accept a cylinder repair sleeve. Insert the thinner leg of the caliper approximately 1.25” into the water passage at the front between of each cylinder. The block must be a minimum of 0.170” (4.3mm) for the block to be salvageable. The use of a stress plate is also recommended for measuring & honing the cylinder diameters. The single cylinder head is similar to the late 3126B heads, with 3 valves per cylinder (one exhaust valve and 2 intake valves). The electronicallyactuated injectors are located between the three valves. A common push rod and rocker arm design operates the valves, driven from a camshaft located in the cylinder block. The head is a cross flow design, with the intake ports located on the left side, and the exhaust ports on the right. There are provisions on the left side of the cylinder head for the high-pressure fuel lines. The exhaust rockers incorporate small spray holes that are used to cool the injectors. The front cover has changed to incorporate the highpressure fuel delivery system. But there are some differences as well. The connecting rods and crankshaft still share the same journal sizes but have some changes also. The counterweights of the crankshaft are smaller to accommodate a lighter piston design. The rods are not forged as previous versions were but are now powdered metal with a “cracked cap” design. There are two different sizes of the small end of the connecting rod, depending on the piston used. The C7 used two different pistons depending on its horsepower. There is a short one-piece aluminum piston
Journals are lubricated after installation and prior to the installation of the main caps.
for 210 hp and below engines that incorporates a smaller 1.5˝ diameter wristpin. There is a taller aluminum piston with a 1.811˝ wrist pin diameter for 230 hp and higher versions. A steel piston is used with the smaller 1.5˝ wristpin design for smaller hp applications. The front gear train of the engine has changed which includes fewer teeth and a more coarse design. This is so that these gear designs cannot be interchanged with older versions. The front gear train drives the camshaft, oil pump, accessory drives,
Crankshaft end play is inspected with a dial indicator and recorded on a Quality Control Card.
ACERT The Basic C7 Engine Features An In-Line Six-Cylinder And Four-Stroke Diesel Engine The C7 model sets up as a turbo-charged engine, and the official compression ratio comes in at an impressive 16.5:1. The cooling system holds 3.5 gallons, while the lube oil system holds 5.5 gallons to ensure everything runs smoothly. These heavy engines weigh over half a ton with the flywheel, coming in at 1,295 pounds according to company specifications. and the high pressure fuel pump for the common rail fuel system.In addition, the oil pump now produces a higher volume. Many C7 engines are now facing the need of a rebuild. Most of these engines see a service life of around 500,000 miles. In researching this article, Bill Wessel and others at Jasper Engines and Transmissions in Jasper, IN, explained that they have taken on production of the Cat C7 to meet the changing needs of the diesel engine aftermarket. Jasper incorporates precision machining and quality parts on the rebuild of each C7 as they do with the other engines that they stand behind, and Wessel offers some tips. Even though the cylinders are not sleeved,
the block can safely be bored. The cylinder block is torque plate honed so there will not be any cylinder distortion. The high pressure fuel lines are also replaced. Cat recommends this if they are ever removed. Cat itself does not offer any gasket sets for this engine, so Jasper is working with leading gasket manufacturers to offer complete gasket sets needed for use during the engine install process. Other replacement parts are available for this engine in the aftermarket as well. Special thanks to Bill Wessel, Brad Boeglin, Chip Helderman, Jimmy Corbin and Mike Pfau from Jasper and Steve Scott from IPD LLC for their assistance with this article. â–
The ACERT technology combines advances in four critical engine systems: air intake, fuel, electronic controls and exhaust aftertreatment. The air intake system uses traditional wastegated turbochargers to boost air intake pressures. The medium-duty engines uses a single turbocharger, and the heavy-duty engines use two turbochargers working in series. Cat uses variable valve actuation controlled by the engine electronics to adjust the amount of air that enters the cylinders for optimum combustion. The variable valve actuation will also allow Cat to offer an optional integral compression brake on two of their heavy-duty engines. The fuel system uses existing hydraulically actuated, electronically controlled unit injectors on medium-duty engines, and mechanically actuated, electronically controlled unit injectors on heavy-duty engines. The two injection systems have been modified with multiple injection technology that pulses multiple bursts of fuel to produce more complete combustion. The electronic controls use the same hardware found on previous Cat engines, but they have reprogrammed software to control the various new components and systems. Finally, the exhaust aftertreatment package consists of a diesel oxidation catalyst to reduce particulates. This device has been used on certain Cat engines for several years with great success. It is incorporated into the muffler and requires no maintenance or cleaning. Cat says the expected life of the aftertreatment unit is equal to the life of the engine itself.
Rocker side play is inspected and adjusted to correct tolerances.
EngineBuilderMag.com 21
EDITOR Doug Kaufman dkaufman@babcox.com
T
ypically the questions with a stroker are, ‘How big can you make it?’; ‘How big do you want it?’; and ‘How are you going to swing all that mass in there?’” explains John Nijssen, aka Stroker John. The Apple Valley, CA-based engine builder operates strokerengine.com and builds domestic V8 engines for the U.S. and international (primarily Australian) enthusiast markets. He says he doesn’t try to push his desire onto the customer. “I don’t sell you what I like, but rather you and I figure out what you really need for power and price,” Nijssen says. “Customers (I prefer to call them ‘clients’) enjoy discussing their engine build. I ask them what they want the new motor to do for them. From there I can make recommendations and ask for their approval,” he says. Nijssen considers himself a custom engine builder, rather than a builder of crate motors. “I try to build the best possible combinations within the limits of the client's budget.” “The main purpose of a stroker engine is to make more power. My company motto is ‘Bigger engines make more power.’ What does that really mean? When I talk about power, I’m typically talking about torque. “In Ford, I do the 302 block as 331 or 347 like everyone else,” he explains. “With a Windsor, the 408 and 418 work very well. If you want more torque this block will go 427 and 434. If we step up and use a Dart block, 467 is about the limit. I made 711 hp at 6400 rpm with a Yates Wedge cut head on a 463 22 November 2012 | EngineBuilder
Clevor. The 460 block works well as a 545, and with the Kaase P51 heads makes an effortless 600 horsepower.” Nijssen says, “I do not ‘sell engines’ – I build engines. Mostly, they’re street/strip combina-
tions, both lower cost ‘budget’ motors and maximum monster power makers.” His shop is a small operation specializing in powerful street V8 engines to meet specific needs, either massive low speed torque or upper rpm horsepower. “If you increase the cubic inch displacement of the engine it should make more power. Obviously a 460 engine will have a lot more pulling power at 2,500 rpm than a 302 will – common sense tells you that and it happens in the real world.” Nijssen says you can typically estimate the torque that an engine will put out based on a very simple formula: stock heads will typically make 1 foot pound of torque per cubic inch, so a 302 is usually capa-
ble of putting out about 300 lb.ft. If you get a set of performance heads and raise the compression ratio, you’ll typically make about 1.25 to 1.3 lb.ft. of torque per cubic inch. So a 302 at the smaller number equals about 377 foot pounds of torque over the stock heads (Editor’s note: see Larry Carley’s article on cylinder heads in the March ’12 issue of Engine Builder magazine for more information.) Another way of increasing torque is to raise the compression ratio, explains Nijssen. “There are limits on what you can do with the compression ratio, however, before you run into detonation. Detonation is connected to fuel and is keyed to the octane rating.” We know from experience that the maximum compression ratio we can run based on the fuel the customer plans to run is a set number – that number is a variance based on the engine build.” Nijssen says each full compression ratio increase is worth power. “That is to say, going from 9:1 to 10:1 or from 10:1 to 11:1 is worth four percent more power each time, pretty much across the rpm range. For example, if we have an engine making 500 hp at 10:1, and we raise the compression ratio to 11, we would gain four percent more power or 20 hp. That’s not a tremendous gain, so if we raise it to 11:1 and it starts detonating, not only would you not make the extra 20, you would lose some of the 500 you had because detonation is not burning the fuel causing expansion and power, but exploding it causing shock and damage. So, we tend to build motors conservatively, keeping them in the safe zone, perhaps 10.7:1, leaving that .3 as a safety
“Stroker John,” John Nijssen.
margin and the power loss is like 1.2%, not enough to worry about.” The choice, explains Nijssen, becomes, how much cubic inch increase do you want and how much can you fit in the block? When you increase cubic inch capacity of the engine you’ll make more torque. It doesn’t matter if you’re doing that by increasing the bore or the stroke. There is a direct relationship between torque and cid (cubic inch displacement) as long as the cid comes up the same; the torque output increase will be the same. If you’re making 1 foot pound of torque per cubic inch and you multiply it by 350 it doesn’t matter if it has a 4-inch bore and a 3.5-inch crank or a 3-inch crank and a 4.3inch bore. However the power curve between the two combinations look different. The shorter stoker larger bore motor will produce less torque at lower rpm and peak at a higher rpm than the long stroke combination. This is why in part diesel motor utilizes very long stroker, more torque or pulling power at low speed. Nijssen acknowledges that if the discussion has been centered on the same cid engine, “You might say ‘I want the bigger bore 24 November 2012 | EngineBuilder
combination,’” he says. “Great…so you go out and buy an aftermarket block. “Now we can take a 351 W from a 4.030˝ optimal bore size to 4.155˝ (a .030˝ over) or some blocks you could push it out to 4.200˝. So in-
stead of a small bore with a plus 1/2˝ stroked 408 ‘stump puller’ you can build a 1/8˝ stroked 402 ‘screamer.’” “But once you have a nice big bore block what happens if you put the big crank in there as well? “Well then you can go from a 434, which is the biggest crank you could put in there to a 471 cid motor,” he says. “For the street, because most of the time you’re driving around in the 2,000-4,000 rpm range, having the big stroke crank will pay off more often. On an oval track, having a shorter stroke will have the advantage because you’re not only dealing so much with torque production and acceleration you’re dealing with miles per hour and the issues involved with that.” For drag racing Nijssen says there’s a balance between the longest possible stroke and something a little less. “Choosing the stroke has a lot to do with the maximum rpm requirement of the engine. For example, in the Ford family on a Windsor block, I might encourage the use of a 4.000˝ stroke crankshaft to turn to
The small block Chevy has a valve angle of 23 degrees; the small block Ford has a valve angle of 21 degrees. When you have less valve angle the turn from the port into the valve pocket isn’t as severe. Aftermarket heads often have valve angles of 14 degrees and 11 degrees. So, the Ford heads have a slight advantage over the Chevy heads due to the valve angle.
Circle 125 on Reader Service Card for more information
Limitations to a stroker include striking the oil pan. Nijssen says sometimes he can cut into the oil pan rail as long as there’s not a bolt there.
7,000 rpm, whereas on the street, I might want to suggest a 4.100˝ stroke crank to turn to, say, 6,500 or I might even suggest a 4.250˝ stroke if we’re only going to 6,000 rpm because of the frictional loss concerns. “However, while a longer stroke crankshaft tends to make more torque early on in the rpm range, and about the same amount of torque at peak horsepower,” Nijssen continues. “But what happens is, the longer stroke crank pulls the piston down the cylinder a longer distance. You’re dragging the rings further, so friction becomes an increasing problem as rpm increases because it’s putting the brakes on and it’s absorbing more energy. As the rpm goes up it’s robbing more and more power – they call it friction horsepower – like anti-horsepower.” Nijssen says that since the piston has to travel a greater distance in the same half a revolution, then accelerate from a dead stop, then stop it and start it again – it requires more energy usage, so it loses power again. “A longer stroke crank won’t make the same amount of torque at the higher rpm so it won’t multiply out into horsepower, he says. “The bigger bore, shorter stroke motor will typically make more horsepower and if max rpm is a concern it will have an advantage. But for sheer acceleration off the line and 60 foot times it’s hard to beat the long stroke small bore because it will just push you back in the seat 26 November 2012 | EngineBuilder
harder as it accelerates from 2,000 rpm up. But once you pull it out of gear at 6,000 and put it in 2nd gear it drops down to 5,000 rpm and it’s now operating at a higher rpm range and will do so through all the gears until you lift your foot. So a bigger bore short stroke motor will have an advantage.” Nijssen says another point to consider on the particularly long stroke motors is the feet per second travel of the piston. “There are limits to how fast a piston should be accelerated and decelerated,” he cautions. “There are structural limitations of all the internal components.” You can typically buy a 2618 forged piston that can handle a lot of abuse. Pistons seldom fail; they’re usually destroyed by something else going wrong. So if you were to rev the engine particularly high you would want to use a better quality crankshaft, typically American made, than say a cheaper crankshaft.”When it comes to comparing a Ford stroker to a Chevrolet stroker for the street, there are other issues involved. For example, the angle of the valves plays an important role. The small block Chevy has a valve angle of 23 degrees; the small block Ford has a valve angle of 21 degrees. When you have less valve angle the turn from the port into the valve pocket isn’t as severe. Nijssen says this is an important point. “Aftermarket modified racing heads often have valve angles of 14 degrees and 11 degrees – when you look at the cylinder head itself the intake port is standing up more toward the vertical making the heads very tall, and the exhaust side becomes very long, in comparison. So, the Ford heads have a slight advantage over the Chevy heads due to the valve angle, he says. “In the case of a Cleveland cylinder head, because the valve is canted on a second angle, there are other benefits as well. The incoming air stream doesn’t just flow straight in, arriving 90 degrees over the top of the piston – you’re tipping it a
little more toward the center of the cylinder, which helps the air swirl around in the cylinder as it comes in. Like water going down the drain, it swirls around going into the cylinder, which is good for keeping the air and the fuel thoroughly mixed up. Homogenization is maintained so you don’t get rich and lean pockets throughout the air-fuel charge,” he says.
Rotating Assemblies Typically, says Nijssen, you can put a pretty big crank in a small block and rev it to 7,000 rpm. “But when we get into the big blocks and we start putting in 4.500˝ or 4.750˝ strokes, that rpm limit starts coming down to 6,500 to 6,000 rpm. If you’re using an iron crankshaft, 6,000 rpm would be the limit. So when choosing a stroke length, you have to pay attention to rpm and that may be a limitation.” Another consideration is rod angle: often referred to as rod to stroke ratio, he explains. When the crankshaft is rotated 45 degrees and
You can put a pretty big crank in a small block and rev it to 7,000 rpm. But when you put in 4.500˝ or 4.750˝ strokes in a big block, that rpm limit starts coming down to 6,500 - 6,000 rpm. If you’re using an iron crankshaft, 6,000 rpm would be the limit, says Nijssen.
Nijssen says he the Ford 302 block as 331 or 347 like everyone else. With a Windsor, the 408 and 418 work very well. If you want more torque this block will go 427 and 434. If want to step up and use a Dart block, 467 is about the limit, he says.
the piston is halfway down the cylinder traveling at maximum speed just before it begins to decelerate as it nears the bottom, the rod tips over on an angle. As you increase the stroke length the rod angle is increased. So it’s desirable to increase the rod length to take some of that angle out of the rod, because it is transferred to side load or thrust against the piston. “It’s pushing the piston harder and harder against the cylinder wall as the stroke is increased. Once again, that’s friction and wear. So we want to increase the rod length when we increase the stroke length,” Nijssen says. “The limitation of that becomes the block deck height. Basically it all has to fit in the block. “Custom pistons provide the solution to many combinations and we want to use the longest rod length we can. We have some discretion with the piston compression height. The question is whether there is enough material on the piston to fit the rings in and allow the valve pockets to be strong enough?” he says. “We’re limited by two factors when it comes to piston compression heights: we have to fit all three rings between the wrist pin and the top of the piston
and have enough thickness between them for the ring lands to be strong enough to support them all. We can raise the wrist pin up into the oil ring groove almost to the top of the oil ring groove. We can compensate for the cut by putting in a steel rail that covers the wrist pin area that was cut out. The steel spacer ring helps support the area that was cut out.” Nijssen suggests that when there are concerns about negative side effects or effectiveness of a working component it simply comes down to a debate over which is more important: making more power or endurance? “The other consideration with pistons is valve pocket depth. This is not usually a concern with a Windsor but if you have a Cleveland, which tips the valve over on an angle, now the valve pocket is extended over into the side of the piston where the top ring is. So you have to have enough material in the top of the piston to put the valve pocket in place without touching the top ring,” he says. “Typically you could perhaps get a Windsor piston with a shorter compression height than a Cleveland piston. Custom pistons allow you to minimize the piston squish height, al-
lowing the piston to reach the top of the cylinder bore.” says Nijssen. “Typically when we’re building street engines we’re going for the big power increases. We’re not chasing three horsepower, that’s for racing applications where everything is on the line,” he says. From a stroking point of view one of the most significant differences in deciding to build a Ford over Chevy comes to block construction. “A Ford 302 can’t be as large as a small block Chevy (SBC) stroker but a Windsor motor can be substantially larger than a SBC stroker. The Windsor is a taller block, so you can put a longer stroke crankshaft in it,” explains Nijssen. “Typically, a factory Chevy can be stroked to a 383. You can take them to 396 and 408 although you’ll be pouring block fill in the bottom of the block so you can grind clearances into the bottom of the block into the water jacket and not have water pouring out. This isn’t as big a problem for Ford because of the way the blocks are cast – you can cut a fairly substantial groove in the bottom of the cylinder and still not be near the water jacket,” he says. In addition, the Windsor block has a higher camshaft height than the comparable Chevrolet. “When you’re building a Chevy you first have to consider adding the extra clearance for the rod when it comes around, otherwise, when the rod comes around, the nut will collide with the bottom of the cylinder; then you have to grind the corner off the other end of the bolt on the other side so it won’t collide with the camshaft. You hear about small base circle camshafts – this provides more clearance for the rod on the cam lobe rather than on the connecting rod.” Nijssen suggests that when using a connecting rod with a cap screw bolt on it, you have more clearance room for the camshaft and you’re not compromising the bolt by grinding part of it away. “On a Ford this is almost no problem at all because the camshaft is so high up that you won’t get interference even with a very long EngineBuilderMag.com 27
Nijssen suggests that stroker engine builders caution customers that replacing an engine with a more powerful stroker engine may require increasing the strength of related components, such as the transmission, U-joints, driveshaft, differential and axles.
stroke you can put in a Ford block.” Limitations to a stroker include striking the oil pan. You can’t go out through the oil pan rail, but Nijssen says sometimes he can cut into the oil pan rail as long as there’s not a bolt there. In addition, aftermarket oil pan makers often form additional clearance into the side of the oil pan. He cautions, however, that you need to be careful about how far you’ll pull the piston down the bottom of the cylinder. If your connecting rod is too short, even if it doesn’t hit the counterweight, you may find you’re pulling the piston out the bottom of the cylinder further than you want to. And the piston may rock and as it comes back into the cylinder and it can scrape the piston skirt and thereby damage it. An example is with Clevelands. A 4.000˝ stroke 6.000˝ rod does not clear the counterweight on all brands of crankshafts. Often the part number reflects the rod length – p/n 4006200 for example, indicates a 6.200˝ long rod. Using a 6.000˝ will not work. When choosing cranks, particularly longer stroke cranks, you run into the balancing issue. Ford typi28 November 2012 | EngineBuilder
cally has external balanced cranks in all of its motors, Nijssen explains. “When you go to an aftermarket crank and increase the stroke, it makes the crankshaft inherently heavier on the connecting rod side of the crank since you have more metal going out in that direction. Therefore as the stroke increases you start to find the weight of the counterweight is inadequate. According to Nijssen, with an aftermarket crankshaft you might want to have it internally balanced even though the factory crankshaft was externally balanced. “You decide whether you’ll want to take advantage of that or just go ahead and use the factory harmonic balancer and flexplate and drill the counterweight like Swiss cheese,” he says. “As you increase the cubic inch displacement,” he says, “not only do you want to increase the rod length, you want to change the camshaft duration. Because the engine is larger it needs a bigger gulp of air to produce power at the same rpm than a standard stroke engine. And a bigger engine wants bigger ports to feed it, so once again, if you use the same head as on the stock engine, you’ll want to
increase the camshaft duration. If you can put a larger cylinder head you might be able to keep the same duration.” “I started out in this field as an apprentice automotive machinist in New Zealand in 1977. I graduated first in my class 1980 and moved to the U.S. in 1982,” Nijssen explains. “I worked in various machine shops for many years until 2001 when I decided to start building custom high performance engines for those who where looking for something more than the typical crate engine combination.” Nijssen suggests that stroker engine builders caution their customers that replacing an engine with a more powerful stroker engine may require increasing the strength of related components, such as the transmission, U-joints, driveshaft, differential and axles. It may also be a good idea to improve the brakes, and if you add enough extra power, you may need to stiffen the chassis frame rails. In addition, traction may become a problem. Slicks increase stress, where as smoking street tires ease this load on the drive train. “Long duration camshafts may require a higher stall torque converter, and high compression ratios will require racing gas or octane boasters. Be sure you plan your engine combination carefully,” he says. “High compression ratios, long duration camshafts high speed torque converters work well when racing, but can just waste gas, and be a pain to drive in stop and go commuting to work traffic,” he says. “Sometimes, the best thing is to explain to a customer that a modestly powerful engine may be all he needs.” Today’s cars and trucks use electronic fuel injection (EFI) which require ECU reprogramming, and States with smog regulations limit engine modification, but these are subjects of another discussion. Finally Nijssen suggests you do your math, consider the application and enjoy building more power eiyh your Ford Strokers. ■
Circle 129 on Reader Service Card for more information
Circle 130 on Reader Service Card for more information