■ SIZING UP THRUST ANGLES
■ ENGINE AIR-FLOW DYNAMICS
■ 'COOL RUNNINGS'
November 2013 TomorrowsTechnician.com
CONTENTS IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII
UNDER THE HOOD/////////////////////12
‘Cool Runnings’ While changes in modern cooling system technology might not be apparent in day-to-day servicing, see how auto manufacturers are continuing to increase fuel economy and power output by changing how the cooling system operates.
12 UNDERCOVER/////////////////////////28
The Pressure of Learning About Brake Boosters Contributor Gene Markel explains how atmospheric pressure and engine manifold vacuum are the two factors that make a brake booster work. Find out what it takes to service Brake Booster Systems in this month’s Undercover.
28 ENGINE SERIES////////////////////////34
Going with the Flow In this installment of ‘Engine Series,’ former automotive instructor Gary Goms stumbled upon a loss of power complaint in a 2002 Toyota 4-Runner with the 3.4L V6 engine and automatic transmission. Discover what he has to say about engine airflow and its impact on engine diagnostics.
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November 2013 | TomorrowsTechnician.com
Career Corner: Asking the Right Questions in an Interview
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Finish Line: Winning Scholarships
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2013 School of the Year:Sinclair Community College
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Service Advisor:Thrust Angles
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TT Crossword
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Report Card: Citroën’s Cactus Concept
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Tomorrow’s Technician (ISSN 1539-9532) (November 2013, Volume 12, Issue 8): Published eight times a year by Babcox Media, 3550 Embassy Parkway, Akron, OH 44333 U.S.A. Complimentary subscriptions are available to qualified students and educators located at NATEF-certified automotive training institutions. Paid subscriptions are available for all others. Contact us at (330) 670-1234 to speak to a subscription services representative or FAX us at (330) 670-5335.
4 November 2013 | TomorrowsTechnician.com
Career Corner sponsored by Autoprojobs.com
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t’s the morning of the interview and you have prepared all night, going over all the questions you may be asked. You can relate your experiences and describe your skills working with heavy- and medium-duty diesel, gasolinepowered engines, light-duty pick-up truck engines and van engines. You have worked with engines, transmissions and brake diagnostic equipment. You can talk about all of the training you’ve had and how to identify problems. You are qualified and ready, right? Surprisingly, the biggest mistake jobseekers can make going into an interview is not that they are unable to answer questions. A future technicians’ biggest mistake is not being prepared to ask questions.
Why should I ask questions during an interview?
When interviewing for a technician or service writer Asking questions during the interview position, be prepared to ask questions to learn more about shows you are engaged and very interested the shop owner’s goals. Source: Oceanside Transmission owner Dean Kuhn.
in the position. It’s a positive way to learn more about the owner’s goals for the shop, expectations he has of his employees, future advancement opportunities, etc. All of these questions may not be brought up in a normal interview format. You may find your goals as a technician and the owner’s goals are not the same. This could be beneficial to know early on. Or, you may find that this shop is the perfect match for you!
What type of questions should I ask? The questions you should ask during the interview need to be open-ended, requiring an answer other than yes or no. Here are some examples of appropriate questions: “What are my options for advancement at this shop?” “How will my performance be evaluated?” “What are the future goals of this shop?” “What are your expectations of your technicians?”
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What type of questions should NOT be asked? Just like any situation, there are off-limit questions. These questions may imply you are not willing to go above and beyond to get your work done. Your employer may question your credibility and willingness to put in the hours required. Here are questions you should NOT ask in your interview: “When can I take time off for vacation?” “How long do I have to work here until I get a raise?” “Will I just have to work 40 hours a week?” “How many warnings do we get before we are fired?” You will be surprised at the information gained from asking questions during an interview. You never know, one simple question may prove that you are the technician for the job! ■
edited by Tomorrow’s Tech staff Each month, Tomorrow’s Tech takes a look at some of the automotive-related student competitions taking place in this country, as well as the world. Throughout the year in “Finish Line,” we will highlight not only the programs and information on how schools can enter, but we’ll also profile some of the top competitors in those programs. Because there are good students and instructors in these events, we feel it’s time to give these competitors the recognition they deserve.
PA STUDENT WINS VIC EDELBROCK SR. SCHOLARSHIP AWARD
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yoTech announced Scott Brown, an automotive student at the Blairsville, PA, campus, was the recipient of the Vic Edelbrock Sr. Scholarship Award. The $5,000 scholarship was presented to Brown at the Specialty Equipment Marketers Association (SEMA) trade show on November 7, in the presence of show attendees and Scott’s family. Vic Edelbrock Jr., Chairman of Edelbrock LLC, presented the scholarship from the Edelbrock trade show booth during a record-breaking event at the Las Vegas Convention Center. “With a 4.0 GPA and a strong work ethic, Scott was our first choice for the scholarship that honors the memory of my father,” said Vic Edelbrock, chairman of Edelbrock LLC. “Scott’s integrity and his passion for performance were evident throughout the interview process. It was great to meet him and his mother, Judy, who were both first time SEMA show attendees and life-long automotive fans.” The Vic Edelbrock Sr. Scholarship Award is presented to students and graduates who have shown excellent attendance and earned top grades during their studies at an automotive trade school. The desire to build high-performance engines and to be employed in the automotive aftermarket are just a few of the qualities required of the scholarship recipient. Brown was one of many candidates who applied for this year’s prestigious award. After serving four years in the Army, Brown made the decision to attend WyoTech in Blairsville to learn the skills he needed to open his own automotive performance shop. Originally from Chesterton, IN, Brown scored 10 out of 10
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points for his work ethic, character and ambition. When asked about his dream job, Brown said, “I want to design high performance systems for everyday cars. In other words, tear apart brand new cars and make them better!” “Scott is an outstanding student and we’re thrilled that he was awarded the Edelbrock scholarship,” said Art Herman, WyoTech Blairsville campus president. “Not only is he a deserving United States veteran, but he also achieved the highest score possible in three of his automotive core program classes, and continues to excel in his studies.” For more information about WyoTech, go to www.wyotech.edu.
WIN A SEMA SCHOLARSHIP FROM PERFORMANCE ENGINE AUCTION The SEMA Scholarship Committee has announced that its 2013/2014 SEMA Engine project will feature a 700+ horsepower package based on a Dart LS Next cast iron block. The engine will be offered on eBay beginning Dec. 12, 2013, and the proceeds will benefit the SEMA Memorial Scholarship Fund, which aids young men and women seeking careers in the automotive industry. Heading the SEMA build team is Dart’s Richard Maskin, who has been the engine builder/crew chief for several NHRA National Points Championship-winning efforts in Pro Stock. Maskin has developed a 434 c.i.d. engine combination that is dyno-proven to generate in excess of 700 horsepower utilizing a single 4-barrel carburetor on pump gasoline. Dart’s unique LS Next block evolved from the popular LS Series engine family introduced by General Motors in 1997. This aftermarket iteration incorporates a number of unique features, the most noticeable being a redesigned bottom end with improved oil control and a reduction in windage. It also utilizes a standard distributor instead of a factory coil pack setup.
A pair of CNC-ported Dart Pro1 aluminum cylinder heads will be employed in the SEMA Scholarship engine. Components from a number of highly respected aftermarket firms are being used in the build. They include Allstar Performance, ARP, ATI, Callies, Champion, Clevite, Comp Cams, Dart, Diamond, Fel-Pro, Hedman Hedders, Holley, Joe Gibbs Driven, Meziere, Moroso, MSD, PowerMaster, Total Seal and Trend. The engine will be finished to the requirements of the buyer, whether it’s to be used for racing or the street. SEMA’s scholarships are awarded to university, 2-year college and trade school students pursuing a career in the automotive industry. 2014 applications for the scholarships are now available at www.sema.org/scholarships. “Students coming through the SEMA Scholarship Program have demonstrated great potential and share the enthusiasm and passion that has fueled our industry,” said Zane Clark, SEMA education director. “Our hope is that we’ll continue to attract highly qualified students who will contribute and make strong, positive impacts in our industry.”
DONNA WAGNER NAMED TO CHAIR NU’S AFTERMARKET MANAGEMENT PROGRAM Northwood University has announced the appointment of Donna Wagner as chair of the Aftermarket Management Program. Wagner is now responsible for the aftermarket program on the Michigan Campus. Dr. Keith Pretty, president and CEO at Northwood University, states, “We are very pleased to have Donna as the chair of the Aftermarket Management Program. Her knowledge of Northwood and her experience in the Automotive Aftermarket Industry will be valuable assets to the program here at Northwood.” Wagner earned a B.S. in computer science from Mount Union College in Alliance, Ohio, and her M.B.A. in marketing from Bowling Green State University in Bowling Green, Ohio. She also earned her Automotive Aftermarket Professional designation (AAP) in 2000 from Northwood University. She was
10 November 2013 | TomorrowsTechnician.com
awarded the Northwood University Automotive Aftermarket Management Education Award in 2000. Wagner brings more than 20 years of experience in the automotive aftermarket industry to Northwood University including serving as the president of the Car Care Council, which then became part of the Automotive Aftermarket Industry Association (AAIA). She is a program committee member and previous speaker for the Global Automotive Aftermarket Symposium (GAAS). Other working experiences include Wells Manufacturing as a category and marketing manager and marketing services manager for Tenneco. ■ Do you have an outstanding student or a group of students that needs to be recognized for an automotive-related academic achievement? E-mail us at esunkin@babcox.com.
Under the Hood
Adapted from Gary Goms’ article in
Cool Runnings HOW FUEL ECONOMY AND POWER DEMANDS IMPACT CHANGES IN COOLING SYSTEM TECHNOLOGY
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hile changes in modern cooling system technology might not be apparent in day-to-day servicing, the fact is that auto manufacturers are continuing to increase fuel economy and power output by changing how the cooling system operates. But technical change has developed very gradually. In the beginning, a few turn-of-the-century auto manufacturers relied on a thermal-expansion cooling system that was based upon the tendency of hot water to rise out of the engine cylinder head into the top of a vertical-core radiator, where it would condense and re-enter the bottom of the engine block. Although thermal expansion systems worked well on low-output engines, they were insufficient to cool the high-speed engines introduced in the 1920s that have evolved into the efficient powerplants we have today.
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The first step in diagnosing modern engine cooling system problems is to connect a scan tool.
Cooling System Evolution Engine-driven water pumps came into common usage early in the century. Thermostats operated by wax pellets or thermostatic springs came into common usage during the 1920s to warm the
This engine-driven water pump represents an efficient, modern design, with a cast impellor spinning inside a high-flow housing.
engine faster and maintain even operating temperatures. Further refinements included a cooling system bypass system designed to circulate coolant throughout the engine while it’s warming up. Some engines also use double-seat thermostats to close the bypass when the thermostat opens. Pressurized cooling systems were also introduced to prevent coolant boil-over on hot days. The first cooling fans were conveniently mounted on the enginedriven water pumps and remain so today. During the 1960s, cooling fans were mounted on temperature-sensitive fan clutch devices to reduce power loss at the engine crankshaft. The 1960s and ’70s also saw horizontal-core radiators being introduced to accommodate reduced body height and increased cooling system demand. Many horizontal-core radiators also require remote coolant reservoirs to help evacuate air from the cooling system. Electric cooling fans began to appear on many vehicles because they could be activated only when engine temperatures reached a critical point. This feature not only
eliminated the power loss associated with mechanical fans, it also increased fuel economy and reduced cold-engine exhaust emissions by reducing engine warm-up time. To further reduce emissions, thermostat opening temperatures were increased to about 195° F.
Belt-Driven vs. Electric Pumps The basic belt-driven water pump design in most applications hasn’t changed for many years. Most water pumps are centrifugal designs with cast or stamped metal impellors. But, some designs use molded plastic impellors. The water pump must produce enough volume to cool the engine at idle and also at full speed and power output. In concert with water pump design, thermostats are designed to slightly restrict coolant flow from the engine. This restriction allows the water pump to build additional pressure in the engine water jackets to further reduce surface boiling on the cylinder heads and to reduce pressure on the radiator header tank at high engine speeds. TomorrowsTechnician.com 15
At higher engine speeds, the water pump begins to “cavitate,� which means that the water pump speed has reached the point at which most of the coolant is no longer contacting the water pump impellor. At this point, a negative pressure develops along the surfaces of the water pump impellor that increases the tendency of the coolant to boil and the engine to overheat. In extreme cases, cavitation can erode water pump impellors and housings. Many performance engine builders address this problem by installing special pulleys to reduce water pump speed. Modern auto manufacturers are similarly addressing the cavitation problem with electric water pumps. In contrast to a belt-driven pump, the electric water pump avoids cavitation by running at a constant or at a selected, pre-programmed speed. By eliminating another belt-driven accessory to
reduce rotating friction, engineers can also increase the engine’s power and fuel economy. For now, electric water pumps are being used mostly in racing applications, where the gains in horsepower can be anywhere from 3-10%. But, there is talk of more highend vehicles moving toward electric water pump systems that allow the manufacturer to precisely set how much coolant flows through the engine at given temperature ranges. So, it's actually more efficient and more in tune with your engine's specific cooling needs than beltdriven pumps. And, on hot days, when the engine needs more cooling, an electric-controlled water pump can continue to operate after the vehicle is shut off, thereby saving on engine component wear.
Cooling the Head Performance enthusiasts and engineers have known for years
Conventional thermostats like this badly corroded example might become a thing of the past.
that increasing the engine’s compression ratio can increase power and fuel economy. But detonation, which is the sudden and spontaneous combustion of fuel contained inside the combustion chamber, is the downside of increasing compression ratio. The force of detonating fuel is such that it breaks spark plug insulators, piston rings and pistons. Since the early 1970s, the elimination of ethyl lead has basically limited compression ratios to about 9:1 at sea level conditions to eliminate detonation. Since an aluminum cylinder head reduces combustion chamber surface temperatures, compression ratios can be slightly increased without introducing detonation. Electronic engine controls further reduce detonation by adjusting spark timing and exhaust gas recirculation rates. Knock sensors built into most engine management systems are designed to reduce spark advance if detonation is detected. In contrast, the recent popular introduction of direct fuel injection systems, in which fuel is injected directly into the combustion chamber, also allows compression ratio increases ranging up to 13:1 on some applications. This increase is possible because the combustion process is precisely controlled and the fuel is injected into the cylinders in a manner that helps reduce combustion chamber temperatures. Performance enthusiasts and engineers also discovered many years ago that reducing cylinder head temperatures reduced the tendency of an engine to detonate. Some high-end manufacturers have, therefore, introduced reverse-flow cooling systems in which the return coolant from the radiator flows into the cylinder heads rather than the water pump. But, reducing cylinder head temperatures also reduces fuel economy and increases the tendency of an engine to develop crankcase sludge. At the other temperature extreme, fuel atomizes better when it’s exposed to higher coolant temperatures. So, it’s obvious that having full control of the engine coolant temperature can increase performance and fuel economy.
Thermostat Technology While originally introduced on high-end imports, one of two types of electronic thermostats will undoubtedly be found on our future commuter vehicles. The first type is basically a conventional thermostat that is opened by electrically heating the surrounding coolant. The second type is a new design in which the thermostat opening is directly electronically controlled. In either case, the powertrain control module (PCM) will use these types of thermostats to regulate engine temperature to match the demands of part-throttle and wide-open throttle operation.
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The contamination on the flat side of this timing belt came from a leaking water pump.
Cooling System Maintenance Automotive engineers are currently faced with increasing the efficiency of the cooling system while reducing cooling system weight. Because many original equipment radiators have marginal cooling capacity, internally or externally clogged radiator core tubes will reduce cooling system performance to the point that an overheat condition will result. Internal rust corrosion is the worst problem on the older cast-iron engines equipped with brass radiators, whereas electrolysis is, perhaps, the worst problem associated with modern bi-metal engines using aluminum radiators. Consequently, the additive packages in most coolants contain inhibitors that reduce corrosion caused by rust and electrolysis. When the coolant’s additive package wears out, rust flakes from the engine’s cast-iron water jackets begin to clog the radiator core tubes. In some rare cases, the water pump impellor and other sheet-steel cooling system components, like core plugs, will also corrode due to poor metallurgy. In any case, rusty
coolant indicates that the cooling system is headed for trouble. Electrolysis occurs because a very mild electrical current develops between two dissimilar metals exposed to water-based solutions. Unfortunately, electrolysis tends to transfer from one metal to another. This results in the “solder bloom” found on the cores of the old soldered brass radiators. In more modern engines, electrolysis can cause cylinder head
gasket failure by severely pitting cylinder head gasket surfaces and eroding the metallic portions of the gaskets themselves. In the current market, most auto manufacturers supply long-life coolants designed to function with the specific metallurgy and designs of their cooling systems. Most manufacturers address deterioration in their additive packages by recommending scheduled coolant changes.
Service Tips Modern scan tools are essential for diagnosing late-model cooling systems because a vehicle’s temperature gauge indicates only that the vehicle operating temperature is generally within normal ranges. Normal ranges include thermostat opening temperatures now exceeding 200° F and cooling fans that might not activate until operating temperatures exceed 230° F. At the very least, the coolant and intake air temperatures displayed on the data stream should closely match those taken with a non-contact pyrometer. Also check for DTCs indicating a pending or history code problem with thermostatic temperature control or coolant levels. Check cooling fan operation by turning on the air conditioner with the engine running. If your scan tool has bi-directional capability, cycle the cooling fans through their various speed ranges. Always check high-speed fan operation to ensure that the engine will cool in high-demand situations. Visually check for debris accumulating between the air conditioner condenser and radiator. Also check for external leaks, drive belt condition, and cracked or hardened coolant hoses. Visually inspect the coolant level and color. Low coolant levels indicate internal or external leakage. Rusty or off-colored coolants might indicate that the coolant needs to be flushed. Keep in mind that mixing various types of coolants will reduce their freezing and boiling points. If in doubt, always replace suspect coolant with original equipment or manufacturer-approved coolants. ■
20 November 2013 | TomorrowsTechnician.com
T t School of the Year
By Ed Sunkin, editor
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ince 1906, the school now known as Sinclair Community College in Dayton, OH, has been training tomorrow’s technicians. And a little more than a century after its beginnings as a YMCA-sponsored school, the institution has been recognized as the top automotive program in the nation. In October, Sinclair Community College was named the 2013 Technical School of the Year by Tomorrow’s Tech magazine and WIX Filters during a surprise ceremony at the school for 150 students and instructors of the college’s Automotive Technology program. Sinclair Community College is the sixth recipient of the annual program created to find and name the best technician training school in the country. WIX and O’Reilly Auto Parts are title sponsors of the national award in conjunction with Tomorrow’s Tech.
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Sinclair Community College, located in the city known for its aviation history and aeronautical industry, is named for David A. Sinclair, a Scottish immigrant and secretary of the Dayton YMCA (1874–1902), who founded the adult training school that eventually became Sinclair College in 1948. The name was later changed to Sinclair Community College in 1966. “As a longtime supporter of technician edu-
cation, it is encouraging to see schools like Sinclair Community College focused on student outcomes that benefit an entire industry,” said Mike Harvey, brand manager for WIX Filters. “The School of the Year program is a great opportunity for technical schools nationwide to gain exposure for their programs and recognition for their efforts in training the next generation of highly skilled technicians.” As the recipient of the 2013 School of the Year award, Sinclair Community College’s automotive program received $2,500 from WIX Filters; professional automotive tool set and $250 from O’Reilly Auto Parts; and O’Reilly and WIX Filters merchandise.
2013 Runners Up This year’s three runners-up are: • Eastern Oklahoma County Technology Center, Choctaw, OK.; • Northwest Iowa Community College, Sheldon, IA; and • Salt Lake Community College, Salt Lake City, UT. Each runner-up will receive a professional automotive tool set and $250 gift card from O’Reilly Auto Parts. In addition, staff from the school attended a Babcox Media recognition dinner at the Automotive Aftermarket Products Expo (AAPEX) in November. Upon the announcement of the award, Justin Morgan, chairman of the Automotive Technology program at Sinclair Community College said he felt humbled that his school had been honored as having the best auto program in the nation.
“It’s great for the students, the faculty, the staff, the administration, the community — I’m very excited about it,’ Morgan said. Although this is the program’s first time winning the award, in 2011, Sinclair’s automotive program made it as a regional finalist and in 2012, they were considered a top 20 school. Morgan said Sinclair’s Automotive Technology Program works diligently at providing NATEF-certified training for students aspiring to become automotive service technicians. The school offers specific corporate training in the following programs, all designed to develop technicians for their respective dealerships: General Motors ASEP (Automotive Service Education Program), Chrysler CAP (College Apprenticeship Program), Ford MLR (Maintenance and Light Repair), and American Honda PACT (Professional Automotive Career Training). “I receive phone calls every week from dealers, manufacturers and the aftermarket industry in search of technicians trained in the advanced technologies required to service today’s high-tech, complex vehicle systems,” said Justin Morgan, chairman of the Automotive Technology program at Sinclair Community College. “Hybrid and alternative fuel systems require a different way of thinking and that’s where the automotive training program at Sinclair Community College excels,” he said. “We provide hands-on, certified automotive training designed to ensure skilled entry-level positions with a high-paying career path. There is a very bright future ahead for the next generation of automotive technicians and we are very humbled that our efforts in this area have been recognized by the national School of the Year program.” The school also is known for its automotive high performance program, and offers a certificate for stu-
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Service Advisor
Adapted from Andrew Markel’s article in
A STRAIGHTFORWARD LOOK AT THRUST ANGLES
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he thrust angle is an imaginary line drawn perpendicular to the rear axle’s centerline. It compares the direction that the rear axle is aimed with the centerline of the vehicle. It also confirms if the rear axle is parallel to its front axle and that the wheelbase on both sides of the vehicle is the same. It is one of the most important diagnostic angles during an alignment. To measure the thrust angle on a vehicle, you have to perform a four-wheel alignment. Even if the rear axle is non-adjustable, you need to take rear axle readings to properly align the front suspension. A thrust condition exists when the rear individual toe is not equal. The thrust angle of a vehicle can be generated by two conditions or angles. This makes it difficult for some technicians to properly diagnosis the problem. First, the thrust angle could be generated by the angle of the axle or a misaligned rear suspension cradle that can change the toe angles.
Normal Thrust Angle
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Also, a thrust angle can be generated by rear toe settings that are independent of the axle angle or implied axle angle. The thrust angle can determine the straightahead position of the front wheels. So, ignoring this angle can undermine even the most accurately aligned front suspension. It can result in a crooked steering wheel as the front wheels steer to align themselves with the desired direction of the vehicle. Also, a misaligned thrust angle can cause the vehicle to handle differently when turning one direction versus the other.
RWD Readings Most rear-wheel drive cars and trucks with rear leaf spring suspensions don’t have adjustments built into the suspension. But, the thrust line is a very important angle that can help you diagnose other problems. If the rear live axle vehicle has a greater than normal angle, thrust angle is an indication that
Negative Thrust Angle
This is what “dog-tracking” looks like on a large scale. It can occur on vehicles with solid axles or independent rear suspensions. the axle has shifted or the mounting points on the frame have shifted. To get a better picture of the damage, look at the setback of the front wheels. Setback is a diagnostic angle that measures the difference in distances between the centers of the front wheels. Differences in the setback angle can indicate damage in the frame or within components like control arms and bushings. Take a closer look at caster angles from side to side to see if there is a larger problem. A setback and thrust angle misalignment could be an indication of frame damage. If the vehicle has suf-
fered a recent collision that was offset, the frame may be suffering from a condition known as a “diamond frame.” This occurs when one side rail shifts in relationship to the other side rail. On a vehicle with an independent front suspension and a rear live-axle, the shifted rails will cause the front suspension to have an increased setback and thrust angle. This is caused by the mounting points of the
If a frame has experienced an offset impact, it can cause setback and thrust angle problems.
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suspension moving. Another piece of diagnostic information to look at is the ride height. On rear suspensions with leaf springs, the leaves of the springs can become damaged and can change the ride height and the position of the axle. One remedy for this problem is a plate that can go between the axle and springs, and allows some fore and aft repositioning of the
axle to equalize rear toe readings on both sides. Install the plate on the side of the vehicle which will help to equalize ride height. Installation of this kit may change ride height 1/2 inch. If ride height is negligible, then installation should be done on the right side for leaf springs above the axle (left side for leaf springs below the axle) to account for road crown.
Positive Thrust Angle Axle housings can become bent from impacts. If you see an axle with a difference in toe greater than .50º, look at the axle for possible damage.
Rocking the Cradle More and more automakers are offering all-wheel-drive on an increasing number of vehicles from small SUVs to compact sedans. On these vehicles, they are mounting the differential and suspension components of a cradle that may only connect to the uni-body in four to six locations. While this may make for easy assembly, it makes the alignment technician’s job more difficult. When aligning these types of vehicles, pay attention to rear wheel setback and the thrust angle. These diagnostic angles can help you determine if the cradle or suspension components are damaged. Most thrust angle problems on these suspensions can be resolved with toe adjustments. But, if the cradle has shifted, you may quickly run out of adjustment on the toe links. ■
26 November 2013 | TomorrowsTechnician.com
UnderCover
Adapted from Gene Markel’s article in
The Pressures of Learning Brake BoosTer sysTems
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n school, I took physics and wondered if I would ever use all the scientific stuff. All of that stuff is kind of important if you want to know how altitude can affect the performance of a vacuum brake booster, engine, your body and a whole lot of other stuff. Atmospheric pressure is measured as a differential between a vacuum and the atmosphere. In 1643, Evangelista Torricelli invented the barometer. It was made of a glass tube sealed at one end filled with Mercury (Hg) and the open end placed in a dish of Mercury. The weight of the created a vacuum at the top of the tube and atmospheric pressure on the dish of mercury forced the Mercury to rise 29.53 inches in the tube. To this day meteorologists use this measurement in forecasting weather. There is a need to convert barometric pressure into a dimension that can be used to measure the force of atmospheric pressure. Atmospheric pressure can be converted to 14.7 pounds per square inch of pressure at sea level.
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In 1929, atmospheric pressure was given a scientific unit of “bar.” One bar is equal to 14.504 pounds per square inch. Table 1 shows how atmospheric pressure changes with altitude and temperature. Today, the Pascal (Pa) is the scientific unit to measure barometric pressure. One bar is equal to 100,000 Pascals or 100 Kilo Pascals (100 Kpa). This is the unit of barometric pressure used in the scan tool. Since the 1980s, a barometric pressure or Baro sensor, or Manifold Absolute Pressure (MAP) sensor is used to measure barometric pressure for engine emissions control. This information can be shared with other controllers on the buss. The MAP sensor is actually a Baro sensor attached to the intake manifold. When the ignition is turned on, the controller measures barometric pressure and stores it in memory. The controller then measures the differential from atmospheric pressure to manifold pressure. The MAP and Baro sensors are constructed of a vacuum chamber and
Figure 1: MAP sensor
diaphragm that is connected to the intake manifold. The differential in pressure between the vacuum chamber and manifold vacuum changes the resistance of the diaphragm and voltage signal to the controller (Figure 1).
Applying the ‘Scientific Stuff’ Atmospheric pressure and engine manifold vacuum are the two factors that make a brake booster work. The pressure differential created on either side of the diaphragm(s) in the booster produces a force on the piston of the master cylinder. If engine manifold vacuum is 20 inches Hg or 68 Kpa at sea level, the booster is capable of exerting 9.8-PSI ± 0.5 PSI on the diaphragm of the booster. There is 53.6 square inches of surface on an 8.5-inch booster diaphragm. Multiplying the surface of the diaphragm X, the pressure available would equal total output of 525 pounds of force on the master cylinder pistons at a 100% apply of the booster. As altitude increases, barometric
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pressure is reduced. Zero atmospheric pressure occurs at approximately 30 miles or 158,400 feet above sea level. In Denver, CO, atmospheric pressure is 17% less than at sea level. Table 1 shows how atmospheric pressure changes with altitude and temperature. If a vacuumassisted brake booster is rated at 100% efficient at sea level, its efficiency is reduced by 17% at the State Capitol building in the mile high city of Denver, CO. In Denver, it would be 436 pounds of force at atmospheric apply. Most stops use approximately 20 to 40% of the atmospheric pressure differential to stop the vehicle. A stop from 30 mph requires 20% of an atmospheric apply in Denver that would equate to 87 pounds of force on the master cylinder pistons. The 87 pounds of force transferred a 0.75 (19mm) master cylinder piston would equal 38 psi of hydraulic pressure. The area of a circle is calculated as A=r2. The hydraulic pressure is applied to calipers with 2” (50.8mm) diameter. This would generate 119 pounds of force on the brake pads.
Booster Operation There are two types of booster units. The most common is the single diaphragm used for compact vehicle applications. It has a single vacuum and pressure chamber. The tandem is the second type unit is used for full size vehicles, light trucks and SUVs (Figure 2). It uses three diaphragms to form two vacuum and pressure chambers. There are four modes of operation for a vacuum brake booster during a brake application. They are rest, apply, hold or balance, and release. In apply mode, the pressure from the brake pedal causes the push rod to move the treadle valve forward and close the vacuum port to the vacuum diaphragm chambers and isolate the vent valve. As the push rod continues to move forward, it opens the vent valve to atmospheric pressure and pressurizes the boost chamber(s) to create a force on the diaphragm(s), power piston, and push rod connected to the master cylinder pistons. In hold or balance mode, the pressure generated by the brake pedal push rod and pressure from the master cylinder piston push rod equalize. This causes the treadle valve to close the vent valve to maintain the power piston a pressure
Figure 3
Figure 2: Teves Master Cylinder differential assist to the master cylinder. Release and rest mode are the same. When the pressure generated by the pedal is released, the vacuum valve opens, the pressure from the boost chamber(s) is evacuated, and the power piston is returned to its rest position by the spring in the main vacuum chamber (Figure 3). The vacuum check valve is a key component to the operation of the booster. A leak in the valve can cause a reduction in the performance of the booster and increase pedal travel. A manifold vacuum of 20� Hg or greater can be achieved during engine deceleration. The booster chambers can be evacuated and retained at this pressure by a properly operating check valve. Anti-lock brake systems (ABS) and Electronic Stability Programs (ESP) will function at their best when full vacuum boost is applied.
A Brake Assist System (BAS) utilizes a mechanical or electromechanical function to apply a 100% vacuum/pressure assist. In an emergency stop where the brake pedal is rapidly depressed, the vacuum booster may not be able to react fast enough to apply adequate force to the master cylinder to provide the shortest stopping distance. The BAS is an enhancement to ABS, ESP and Adaptive Cruise Control (ACC). The BAS brake booster unit will contain additional components. The Continental Teves unit is used on full-size vehicles. It uses a brake apply/release switch, diaphragm travel sensor and a solenoid winding. The brake apply/release switch closes when the brakes are applied. The diaphragm travel sensor measures the speed at which the brakes are being applied. If a rapid/emergency brake apply is sensed, the BAS controller will energize the solenoid winding to increase the apply pressure on the master cylinder push rod. This BAS is active at speeds above 5 mph and there are no fault codes present in the controller. The TRW Mechanical Brake Assist (MBA) uses a permanent magnet to engage maximum assist for emergency stops in a single diaphragm unit (Figure 4). The Adaptive Cruise Control (ACC) is a system that uses a radar sensor to calculate the distance between the ACC vehicle and vehicle traffic within range of the radar signal that can be one tenth of a mile. The system will match the speed of the vehicle by reducing the throttle and/or applying the brakes without requiring the driver to brake or adjust the cruise control settings. The BAS can implement ACC braking. Other methods can use a pump to supply a hydraulic brake apply. In the case of the BAS, the ACC will send a message to the BAS controller and it will activate the solenoid and apply and release the brakes. A change in throttle position from the driver will also disengage the auto braking function. When the driver throttle input is released and cruise speed is Figure 4: TRW Mechanical Brake Assist. Notice the resumed, the auto braking function is reactivated. â–
magnet that can control boost levels.
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Engine Series
Adapted from Gary Gom’s article in
Solving an Air-Flow Dilemma on a Toyota 3.4L V6 Engine In this installment of ‘Engine Series,’ former automotive instructor Gary Goms has stumbled upon a loss of power complaint in a 2002 Toyota 4-Runner equipped with the 3.4L V6 engine and automatic transmission (see Photo 1).
T
he 4-Runner had a relatively smooth idle, but wouldn’t shift gears at wideopen throttle (WOT). Because I live high in the Colorado mountains, loss of power complaints are relatively common and, in most cases, can be confirmed by test-driving the vehicle up one of the mountainous inclines in my area. While the complaint was readily verifiable, the actual cause wasn’t as obvious. But the symptom of a no up-shift condition with the transmission indicated that the engine wasn’t
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pumping air as efficiently as it should. The mass air flow (MAF) sensor was indicating slightly above 57 grams per second (gps) air flow at about 4,300 rpm. Air flow should have been well above 100 gps. The fact is, air flow is an intricate process that shouldn’t be taken for granted. A slight restriction caused by a mechanical malfunction in an engine’s induction or exhaust system can make subtle, but well-defined differences in how the powertrain operates. In this case, the vehicle ran well until it down-shifted. The only way the driver could get it to up-shift was to reduce throttle.
Conventional Air Flow Before we diagnose air flow problems, let’s look at how air actually flows through a naturally aspirated engine. Crankpin angle is critical
because the air entering the cylinder doesn’t achieve maximum velocity until the crankpin approaches 45° after top dead center (ATDC). Most of the air flow into the cylinder should therefore occur somewhere between 45° and 135° ATDC. To calculate the duration of any intake valve timing event, add 180° to the intake opening and closing time. For example, if an intake valve opens at 10° before top dead center (BTDC) and closes at 20° after bottom dead center (ABDC), the duration of the valve timing event is 210°. Exhaust timing follows a similar calculation.
Volumetric Efficiency Although some automotive enthusiast publications like to express volumetric efficiency as “horsepower per cubic inch,” that definition is irrelevant for diagnostics. For diagnostics, we need to evaluate how completely the cylinder fills with air at a sea-level air pressure of 14.5 pounds per square inch. While cranking at WOT, an engine comes very close to filling its cylinder with air. This would be very close to 100% volumetric efficiency. As the engine starts, the throttle plate closes to idle speed, thereby restricting air flow into the engine. At closed-throttle, an engine has a very low volumetric efficiency and a very high pressure differential between manifold and atmos-
Photo 2: For maximum volumetric efficiency on racing engines, correct TDC must be verified and the intake valve opening adjusted to the camshaft manufacturer’s specifications. pheric pressure. At a WOT governed speed of 2,000 rpm, the pressure differential between intake and atmospheric values drops to nearly zero because the only restriction to air flow would be the throttle plate diameter. At 2,000 rpm WOT, volumetric efficiency can drop to about 80% on conventional engines simply because the physical size of the intake and exhaust valves and the timing of the valve events tend to restrict air flow at higher engine speeds. Volumetric efficiency obviously varies among engine designs. At one extreme, we have the lawn mower engine and at the other, we have the supercharged racing engine.
Photo 1: Like most other modern vehicles, the diagnostic individual procedure is often determined by component accessibility.
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The inertia of this column of air allows the cylinder to continue filling even as the piston begins traveling upward on the compression stroke. Most important, the higher the air velocity in the intake port, the sooner we can open the intake valve and the later we can close it.
The Exhaust Valve Going back to crankpin angle, much of the combustion gas pressure contained within the cylinder is spent by the time the crankpin passes between 45° and 90° ATDC on power stroke. When the crankpin passes 90° ATDC, the piston is generating very little downward pressure on the crankpin. To enhance volumetric efficiency, engine designers begin opening the exhaust valve well before BDC to relieve gas pressure built up in the cylinder during combustion. As the piston passes BDC and begins ascending on the exhaust stroke, the flow of the The Intake Valve exhaust gasses is restricted by the exhaust valve size The column of air contained within the intake port and exhaust port configuration. See Photo 3. and manifold runner has inertia, which means that it So the exit velocity of the exhaust gasses through tends to remain at rest the exhaust port and or remain in motion. manifold runner can The column of air conbecome extremely high. tained within an intake Performance port must also concamshafts take advanstantly accelerate and tage of extremely high decelerate in relation exhaust gas velocities to the opening and by keeping the exhaust closing of the intake valve open ATDC. Due valve. to the high velocity of Opening the intake the exhaust gas passing valve slightly before through the exhaust the piston reaches port at high engine TDC can increase highspeeds, a slight vacuum speed volumetric effior pressure differential ciency. See Photo 2 is created in the engine cylinder. Since the on page 35. By the intake valve opens time that the piston slightly BTDC, this presreaches TDC, the Photo 3: Because exhaust gasses exit under pressure, sure differential or “vacintake valve is beginthe exhaust valve and port can be made smaller than uum” helps accelerate ning to achieve an the intake. the flow of intake air “effective lift,” which into the engine’s cylinallows the air in the ders. The degrees of engine rotation in which the intake port to begin accelerating into the cylinder exhaust and intake valves simultaneously remain open even as the piston approaches TDC. This cylinder fillare called valve timing overlap. In contrast to naturally ing effect is further increased by leaving the exhaust aspirated engines, valve timing duration and valve valve open, which is described under the exhaust timing overlap are reduced on supercharged or valve section of this text. turbocharged engines. To further increase high-speed volumetric efficiency, the intake valve can stay open well after bottom Variable Camshaft Timing dead center because, once accelerated, the column Modern engines incorporate variable camshaft timing of air passing through the intake valve into the cylinto further improve the volumetric efficiency of an der tends to remain in motion.
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Photo 4: This converter was taken off at about 160,000 miles. As you can see, the degree of exhaust restriction can vary considerably among vehicles. engine. Manufacturers advance the valve timing to improve lowspeed power and retard the camshaft timing to increase highspeed power. Dual overhead camshaft engines coupled with computer controls expand the opportunities to change valve overlap to further increase lowspeed torque or increase highspeed power. While I won’t dwell on the complexities of variable valve timing, keep in mind that most of these systems use a camshaft position sensor and a valve timing sensor to monitor valve timing and to store a diagnostic trouble code in the PCM’s diagnostic memory if the variable timing system fails.
increased air velocity by reducing sharp bends in the intake ports and manifold runners. Another method of increasing air flow and volumetric efficiency is to utilize the pressure wave that develops in an intake port when the intake valve closes. At low engine speeds and port velocities, this pressure wave is more readily contained in a long intake port. At higher engine speeds, a short port more efficiently utilizes this pressure wave. Most auto manufacturers have therefore introduced “tuned” intake manifolds that optimize low- and high-speed engine torque by changing the effective length of the intake ports as the engine accelerates.
Tuned Intake Manifolds I previously mentioned that the velocity of the air flow through the intake port is a critical aspect of valve timing. Engineers have actually reduced the cross-sectional size of intake ports to increase air flow velocity on modern designs. Engineers have also
Horsepower and Torque In brief, an engine produces maximum foot-pounds of torque at maximum volumetric efficiency. But, remember that torque is a static value measured in footpounds. In contrast, horsepower is a calculated value combining
foot-pounds of torque and time. One horsepower is therefore equal to 550 ft.-lbs. of work done per second of time. Given the same torque output, a crankshaft spinning at 6,000 rpm will perform twice as much work as a crankshaft spinning at 3,000 rpm. Torque output is reduced once the intake system begins to restrict air flow into the engine and thus reduce volumetric efficiency. So, while the torque value begins to decline with volumetric efficiency, the engine’s capacity to do work continues to increase with speed.
Understanding Air Flow While many advanced diagnostic technicians have devised their own methods of measuring air flow through an engine, let’s first master some basic methods of evaluating air flow and volumetric efficiency. Remember that valve timing and air flow velocity are a delicate balance. Any mechanical malfunction that interferes with air flow velocity through the intake or exhaust ports reduces volumetric efficiency and power output. Air flow through an engine is generally affected by intake air restrictions, valve timing restrictions and exhaust system restrictions. Intake air restriction is generally caused by clogged air intake screens, clogged air filters and collapsed air inlet ducting. Because MAF sensors simply report air flow, the PCM uses MAF input to calculate air/fuel ratios. The air/fuel ratio will therefore not change due to an intake air restriction.
Diagnosing incorrect valve timing can be complicated because an engine can be a dual as well as a single overhead camshaft design and because just one bank of a V-block engine can be affected. But the diagnostics can be simplified on single camshaft designs by remembering that advanced valve timing generally increases intake manifold vacuum and lowspeed engine torque. Exhaust restriction is more difficult to assess because exhaust restriction gradually increases as the catalytic converter becomes contaminated and, in some cases, begins to disintegrate. See Photo 4 on page 38. At some point in its service life, exhaust restriction through the catalytic converter begins to affect volumetric efficiency. Due to differences in camshaft and intake port design, some engines are less affected by exhaust restriction than others, so it’s hard to establish definitive standards for measuring exhaust restriction.
Setting Your Scanner
Because most modern engines use the MAF sensor to sense engine load, one symptom of restricted air flow is that the calculated load displayed on the scan tool is reduced well below its normal values. The engine load calculation is basically the PCM mathematically comparing the air flow measured by the MAF with the throttle opening and engine speed. During this road test, our calculated load was only 55% at WOT, 4,540 engine rpm, which is indicative of an air flow restriction. See Photo 5. A low calculated load at WOT is indicative of restricted air flow because, in most cases, calculated load should be at least 85% at WOT. Since the owner had already replaced the MAF sensor and upstream oxygen sensor, we regarded the calculated load percentages to be correct for the moment. Fuel trims can be used to diagnose exhaust restriction on V-block engines equipped with a Photo 5: Notice that the fuel trims are 0.0% SFT and 3.1% catalytic converter on each bank. In many LFT at partial throttle. cases, one fuel trim number will be positive, the other negative. See Photo 6. But remember that the PCM goes into open-loop mode at wide-open throttle, so fuel trim numbers are no longer being calculated. At this point, it became obvious that the Toyota 4-Runner performed well in ordinary driving, but lost power under high rpm, fullthrottle operating conditions. Back at the shop, a vacuum gauge test indicated a slightly higher than expected intake manifold vacuum. See Photo 7. At 2,500 rpm, steady throttle, Photo 6: Because fuel control goes into open loop at WOT, the intake manifold vacuum plummeted to fuel trims are no longer being calculated. nearly zero.
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Toyota that had skipped timing on the passenger-side camshaft due to a seeping water pump that had formed a coolant “icicle” just above the timing belt’s crankshaft sprocket. The icicle fell onto the timing belt, causing the right-hand camshaft to skip timing. That condition was easily diagnosed by recording a 10-psi difference in cranking compression between the right and left cylinder banks. Removing the upper timing cover on this 3.4L revealed that both camshafts were advanced two teeth on the crank sprocket. In this case, the same coolant icicle had formed and dropped onto the timing belt. Advanced camshaft timing would explain the relatively smooth idle, good low-speed performance, and the sudden loss of intake manifold Photo 7: Backpressures in excess of 6 psi at snap-throttle or WOT vacuum at 2,500 rpm. Keep in should be considered as restricting air flow. mind that engines are much more sensitive to retarded Suspecting a severe exhaust restriction, we tested camshaft timing. In practically all cases, retarded exhaust back pressure at idle, 2,500 rpm and snapcamshaft timing results in very low intake vacuum and throttle, with the highest value being about 4-5 psi. a pronounced loss of engine performance. Obviously, While that number was high, it did not explain the air flow was being impeded by the intake valves clossudden loss of intake manifold vacuum at 2,500 rpm. ing too early. As basic as these test procedures might So, at this point, I had to consider incorrect valve be, they served to quickly diagnose what had been a timing. Several years ago, we had experienced a 3.4L very troubling engine performance complaint. ■
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CrossWord PuZZle Tomorrow’s Technician November Crossword
ACROSS 1. Ratchet's heavy-duty attachments (6,7) 8. Shifter knob's N 9. Ran for pinks 10. Word following crash or road 11. "Shut Up ____," Rihanna song (3,5) 13. Slang, defunct-brand car 15. Trailer-towing concern, ____ weight 17. One of the Big Three automakers 18. CV-joint protector 21. Serpentine-belt pulley 22. GM-owned auto-parts company (1,1,5) 23. Steering-wheel lever, perhaps (7,6)
DOWN 1. Spark-creating components (8,5) 2. Threaded cylinder-head inserts 3. Briefly, pre-EFI fuel/air mixer 4. Vane in sliding driveshaft section 5. Truckers' talk tools (1,1,6) 6. Auto-glass security-marking process 7. 2-Down item feature (4,9) 12. Hood support, sometimes (3,5) 14. Milan-based tire maker 16. Technician's assignment 19. Applied liquid lube 20. "Ford has a better ____," '60s slogan
Solution at www.tomorrowstechnician.com
BOOK REPORT: Classic Japanese Performance Cars: The History & Legacy One of the hottest new trends on the street is to own and drive a vintage Japanese performance car. Whether it’s a Datsun 510 or 240Z, an early ’70s Mazda RX2, or an early Toyota Celica, these cars are gaining attention from enthusiasts and collectors alike! Some of the first cars to be imported from Japan were sports cars, and they have been popular with collectors for years. Many of these cars were raced when they were new, and have a dedicated fan base among those who drove them 30-40 years ago. Additionally, these same cars were popular platforms for enthusiasts in Japan and other export markets as well, so many aftermarket high-performance parts were made for them. Building a retro-flavored vintage Japanese performance car can be rewarding on many levels, and as these cars continue to gain popularity, they’ll gain value as well. This book shines on many fronts. Certainly, it is the first of its kind on this particular subject, but it also gives credence to both restoration and tasteful customization. Performance upgrades are shared, as are the various racing histories of the most popular and successful models. Information on Japan-exclusive models is also included where they influenced the cars that came to America, or where their success in racing impacted the engineering of American models. Publisher: CarTech Paperback: 144 pages Price: $24.95 plus S & H Product Code: CT504 To Order: http://www.cartechbooks.com
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Ranger Products Introduces Portable Jack Ranger Products, a division of BendPak, recently unveiled their new QuickJack portable jack system that makes vehicle maintenance on the track and off convenient and lightning fast. The 3,500-lb capacity lightweight QuickJack can go anywhere and can be easily stowed in the trunk or back seat of most cars when not in use. Bring it to the track or drop it on your garage floor to perform routine maintenance in the comfort of your home, all in seconds. The QuickJack collapses to a low threeinch profile so it fits where other jacks don’t. Features open-center design, rugged safety lock bars, remote pendant control on a 20-foot cord, quickconnect hoses and a built-in flow divider for precisely equalized lifting. For information contact Ranger Products at 805-933-9970 or visit the website www.quickjack.com.
Report Card
For its latest concept car, Citroën has gone back to basics and asked themselves, which elements of a modern car are essential, and which might be entirely superfluous? As technologies and possibilities move ever onward, the company’s designers said it's a good idea to pause once in a while and take a good look around. The result was unveiled at the Frankfurt Motor Show in October — the Citroën Cactus. Just like its desert plant namesake, Citroën Cactus thrives despite modest resources. And if the name and the mission seem familiar, that's because they are. In 2007, Citroen exhibited its CCactus concept, which gathered into one vehicle many of our ideas about efficiency, sustainability and versatility at the time. The 2013 Cactus concept addresses broadly the same questions. But with six years of progress behind them, the answers are noticeably different. One obvious change is that the connection between car and driver is now 100% digital. In the new Cactus, the conventional instrument panel is replaced with a 7-inch screen, while an 8-inch touch-sensitive panel provides control over many of the car's functions – including connected services and driver aids. Similarly, push buttons and paddles replace the old-fashioned gearstick. Inside, Cactus provides a spacious and inviting interior, bathed in light courtesy of a panoramic
sunroof that reflects heat as well as harmful UV rays. Upholstery, such as blue-heathered cotton and vegetable-dyed 'camel' leather, is modeled on contemporary furniture, while fittings, such as door handles, take their cues from designer luggage. Designers opened out the interior by questioning other assumptions. For example, the passenger airbag inflates downwards from the ceiling rather than upwards from the dashboard, liberating the area in front of the sofa-style seating. Today's Cactus concept
also incorporates the latest thinking in efficient propulsion. It employs our Hybrid Air drivetrain, which uses simple, clean compressed air to capture the energy normally wasted when a car brakes, before storing it and releasing it to help bring the car back up to speed. The result is more than 94 mpg, and up to 45% reduction in fuel economy in urban driving. The company also brought air to play in another important way. Vulnerable areas of the Cactus’ bodywork feature 'Airbumps' – flexible, soft-skinned pads that resist scratches and gently absorb the kind of light knocks all too easily inflicted in a bustling urban environment. The innovative 'Airbumps' contribute to the appealing aesthetics of a body that, by virtue of light weight, clean aerodynamics and standout style, also point the way for future Citroëns. ■ TomorrowsTechnician.com
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Continued From page 23
dents seeking specialization in various areas of high-performance engines and fuel induction. The program is also designed to prepare students for the ASE (Automotive Service Excellence) engine machinist series. Besides its efforts to link students with local dealerships and auto repair shops, Morgan said other top reasons students enroll in Sinclair’s automotive department is that it utilizes small class sizes to promote a positive learning environment and that its tuition is one of the lowest in the state. “We don’t believe in burdening the students with a lot of debt when they graduate,” he said. The School of the Year program is open to all high schools and post-secondary schools that have a subscription to Tomorrow’s Tech magazine. Of the 158 entries for the 2013 contest, 60 were from different high schools, technical schools and colleges in four geographic regions of the United States. Twenty schools were asked to submit a video highlighting their technical programs. Judges selected the four finalists from the video entries, including Sinclair Community College as School of the Year.
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“We are very pleased to acknowledge the instructors, staff and administrators of Sinclair Community College on their efforts to deliver top-notch automotive-related training and instruction to its students,” said Jeff Stankard, publisher of Tomorrow’s Tech. “Winning the national honor of School of the Year is quite an achievement,” Stankard said. “Each year, we continue to see that the level of automotive education programs in this country continues to improve. It is our goal that we, along with the contest’s generous sponsors, highlight the skills and knowledge that the next generation of automotive service technicians are taking with them into the field.” Learn more about the school by viewing a video on the Tomorrow’s Technician YouTube: http://www.youtube.com/watch?v=fzaccy8KjWY ■