Tomorrow's Tech, May 2014

■ COMPETITIVE ENGINE BUILDING ■ HONDA BRAKE SYSTEMS ■ A/C COMPRESSOR CONCERNS

May 2014 TomorrowsTechnician.com

CONTENTS

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ENGINE SERIES..................................12 Being Competitive in Super Comp To be competitive in the Super Comp class, you don’t need the fastest car in the field. In fact, that’s why most of the people who race in this class like Super Comp. Find out what it takes to build a winning engine for Super Comp drag racing.

12 UNDERCOVER...................................20 7th Generation Honda Brake Service The 2003-’08 Honda Accord and Acura TL are some of the top-selling vehicles in the U.S. They also have a very simple brake system to work on. However, these systems can be prone to brake-noise issues if they’re not properly serviced.

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UNDER THE HOOD..........................30 Lessons in BMW Variable Capacity A/C Systems Despite the many advances in A/C systems during the past 10 years, it’s important for technicians to understand basic theories of operation. In this issue, we take a look at BMW A/C service.

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Career Corner: What Employers Want

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Finish Line: Student Achievements

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Service Advisor: Crossing Wires

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TT Crossword

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TT Classifieds

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Report Card:

Kia Stinger Concept

Editor:

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EDITORIAL STAFF:

Managing Editor:

Edward Sunkin, ext. 258 esunkin@babcox.com Tim Fritz, ext. 218 tfritz@babcox.com

Coordinating Designer:

Dan Brennan, ext. 283 dbrennan@babcox.com

Advertising Services:

Valli Pantuso, ext. 223 vpantuso@babcox.com

Publisher:

Subscriber Services:

Jeff Stankard, ext. 282 jstankard@babcox.com

Maryellen Smith, ext. 288 msmith@babcox.com

Tomorrow’s Technician (ISSN 1539-9532) (May 2014, Volume 13, Issue 4): 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.

2 May 2014 | TomorrowsTechnician.com

HOME OFFICE 3550 Embassy Parkway Akron, Ohio 44333-8318 330-670-1234 FAX 330-670-0874 www.babcox.com PRESIDENT Bill Babcox bbabcox@babcox.com 330-670-1234, ext. 217 SALES REPRESENTATIVES: Roberto Almenar ralmenar@babcox.com 330-670-1234, ext. 233 Bobbie Adams badams@babcox.com 330-670-1234, ext. 238 Doug Basford dbasford@babcox.com 330-670-1234, ext. 255 Don Hemming dhemming@babcox.com 330-670-1234, ext. 286 Sean Donohue sdonohue@babcox.com 330-670-1234, ext. 206 Jim Merle jmerle@babcox.com 330-670-1234, ext. 280 Glenn Warner gwarner@babcox.com 330-670-1234, ext. 212 John Zick jzick@babcox.com 805-845-1400 Fax-805 324-6015

Career Corner

Adapted from content at AutoProJobs.com

WHAT SHOP OWNERS LOOK

FOR IN EMPLOYEES

N

ow more than ever in the automotive service industry, employers are looking to hire automotive technicians with more that just the traditional set of automotive technician skills required to do the job.

Automotive service shops prefer job applicants with general business and communication skills, on top of their automotive service skills, that give them an edge in the automotive service industry. These skills extend to areas such as business, marketing, communications, sales and customer service. In addition to these skills, other skills like computer proficiency and phone skills make job seekers more competitive.

Here are some very specific skill sets taken from Monster.com, CareerBuilder.com and AutoProJobs.com postings: • Candidates with ASE automotive certifications and current Mercedes experience will be viewed favorably.

• Job requirements include commercial tire service experience, good work history, clean driving record, customer service skills, and a strong track record of trust and integrity.

• Seeking an automotive technician/mechanic applicant that can work under the guidelines of the Arizona Motorist Assurance Program.

• Hiring an automotive service technician position capable of troubleshooting and testing cars.

• Looking for an auto technician with a clean driving record and a familiarity with import vehicles from Asia.

• Must have strong computer skills.

As you can see, being a simple handy man no longer cuts it when you’re searching for a job in the automotive service industry. Don’t fret!

AutoProJobs.com has tons of great advice on how to stand out. Check out the rest of the blog and our job openings today.

10 Tools Every Auto Tech Grad Needs to Land a Job Submitted by Ford R. Myers You've spent hours crafting the perfect resume. The format is eye-catching, the paper feels substantial and the wording is practically Pulitzer Prize winning. But, you'll need much more than a wellcrafted resume if you want to land that all-important first job!

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Ford R. Myers, career coach, speaker and author of "Get The Job You Want, Even When No One's Hiring," says, "The resume is just one of many 'tools' a job seeker should have in his or her “Job Seekers' Tool Kit." "Unfortunately, most people don't know what these other tools are or how to use them. By integrating other elements into the job search – and not relying solely on the resume – candidates can add power, professionalism, and flexibility to their efforts," states Myers.

To stand out from the crowd, Myers suggests the following 10 items every new auto/truck, collision, powersports or racing/ performance graduate should have in their "Job Seekers' Tool Kit”: 1. Accomplishment Stories: Write five or six compelling stories about school or work-related tasks that made you feel proud. Include tangible, measurable results.

2. Positioning Statement: Prepare and practice a "15-second commercial" about who you are, what you've done in the past (academically and professionally, if applicable), and the particular strengths you can contribute to an employer.

3. Professional Biography: Write a one-page narrative of your career in the "third person"– as though someone else wrote it about you.

Use this document as your primary networking tool.

4. Target Company List: Make a "wish list" of adjectives that would describe your ideal employer, such as size, location, industry, culture and environment. Then research specific organizations that meet those criteria and put them on a list of 35 to 50 "Target Companies."

5. Contact List: Compile a list of all the people you know personally and professionally, including their contact information. Remember that approximately 80% of new opportunities are secured through networking.

6. Professional/Academic

References: List instructors or professors who would "sing your praises" if asked about you.

Contact each of them, and get approval to use their names on your list of references.

7. Letters of Recommendation: Request letters from four or five respected business colleagues or academic associates, which will be printed on their professional letterhead. Make copies, but always keep the original.

8. Networking Script: Write out a full networking discussion or script so you will know exactly what to say in the networking discussion – how it flows, what to expect, how to react to the other person's comments, etc. Use this for the initial outreach call, when you ask someone to network with you.

9. Tracking System: Keep a detailed record of your job search activities, including phone calls, networking meetings, interviews, cover letters, offers, etc. This is essential to keeping your process organized and productive.

10. Resume: It's last on the list, but still indispensable. And, it has to be GREAT. Be sure your final resume is carefully edited and succinct (no more than two pages), with a layout that is easy for the eye to follow.

Myers adds, "It may take some time to produce these documents and to learn how to use them effectively, but it will be worth it.

Building a satisfying career is much easier when you have the right tools!"

For more information and other useful tips to help those in career transition achieve career success, visit www.GetTheJobBook.com.

Reprinted by permission of Ford R. Myers, career coach and author of "Get The Job You Want, Even When No One's Hiring." Download your Free Special Report, "10 Vital Strategies to Maximize Your Career Success" at: www.careerspecialreport.com. ■

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.

Top Students from 50 States Prepare for National Auto Competition Automotive high school students from around the country are gearing up for the 2014 Ford/AAA Student Auto Skills Competition.

The Ford/AAA Student Auto Skills competition fosters young people's interest in the automotive industry through a spirited nationwide competition with opportunities to win prizes, scholarships, tools and awards, along with an experience that could help shape the future of their careers. The national competition will take place June 8-10, 2014 in Dearborn, MI. The competition is co-sponsored by AAA and Ford Motor Company, and is designed to encourage talented young people to pursue careers as automotive service technicians.

During the state and local competitions held earlier this year, everyone who registered had the opportunity to demonstrate their automotive knowledge and qualify for prizes by taking a written exam. Those students scoring the highest (typically the top 10 teams) participated in a "hands-on" competition within their respective state, challenging students to diagnose and fix uniformly "bugged" new Ford vehicles as quickly as possible while ensuring quality workmanship. The winning two-person team from each state and their instructor is provided an expense-paid trip to the national finals.

The national finals include a written test and a "handson" competition, similar to the "hands-on" competition at the state level, but with a different, new Ford vehicle.

The team with the fewest quality-of-workmanship

Colorado State winners Jared Freihoefer, Shane Cleavenger and instructor Brian Manley, will be one of the 50 teams competing in the National contest in June. demerits and the best combined total score of repair time and written exam scores will be the winner.

Staff from Tomorrow’s Tech magazine will be on-hand at the national competition next month.

Mike Mullen is U.S. Rep for SkillsUSA in WorldSkills Competitions SkillsUSA, the organization that represents the United States in the WorldSkills Competition, sent an automotive technical education student and members of the SkillsUSA WorldTeam to Bogotá, Columbia, in April to compete in the WorldSkills Americas competition.

Mike Mullen from San Luis Obispo, CA, a student

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at Cuesta College, competed in the automobile technology challenges. Mullen received a silver medal in the competition and, in addition, received “Best in Nation” honors. Mullen also will compete in the WorldSkills Competition to be held in São Paulo, Brazil in August 2015.

Also attending the competition was Mike Elder,

automobile technical expert from Pittsburg State University, Pittsburg, KS, and Scott Norman, technical delegate from Pittsburg State University, Pittsburg, KS. WorldSkills Americas (WSA) is a not for profit, nongovernmental organization. Its primary objective is to improve the quality of vocational education by the means of exchanging information and best practices

among North American, Central American and Caribbean and South Americna countries, and by involving governments, industries, commerce and vocational education and training organizations/ institutions.

To learn more about the WorldSkills Competition, go to www.worldskills.org.

SCHOOLS COMPETE IN LATEST ECOCAR3 CHALLENGE REDESIGN The U.S. Department of Energy (DOE) and General Motors Co. recently announced the official launch of the EcoCAR 3 competition, revealing the Chevrolet Camaro as the vehicle selected as the platform for the competition.

EcoCAR 3 is the latest DOE Advanced Vehicle Technology Competition (AVTC) series, and is North America’s premier collegiate automotive engineering competition.

The DOE and GM are challenging 16 North American universities to redesign a Chevrolet Camaro into a hybrid-electric car that will reduce environmental impact, while maintaining the muscle and performance expected from this iconic American car.

While the model is the most technologically advanced Camaro in the vehicle’s history, EcoCAR 3 teams will be tasked to incorporate innovative ideas, solve complex engineering challenges, and apply the latest cutting-edge technologies.

Teams have four years (2014-2018), to harness those ideas into energy to meet engineering, environmental and economic goals. The Camaro PARTICIPATING SCHOOLS ARE: Arizona State University California State University – Los Angeles Colorado State University Embry-Riddle Aeronautical University Georgia Institute of Technology McMaster University Mississippi State University Ohio State University Pennsylvania State University University of Tennessee, Knoxville

10 May 2014 | TomorrowsTechnician.com

will keep its iconic body design, while student teams develop and implement eco-power and performance under the hood, retain safety and meet high consumer standards. The teams also will focus on developing technology that will lower emissions by incorporating alternative fuels.

University of Alabama University of Washington University of Waterloo Virginia Tech Wayne State University West Virginia University For more information, visit www.ecocar3.com. ■

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.

Engine Series

Adapted from Larry Carley’s article in

COMPETING IN THE SUPER COMP

BUILDING MARKET

W

hat does it take to build a winning engine for Super Comp drag racing? The Super Comp drag racing class runs on a 8.90 time limit, with essentially no rules regarding engine displacement, carburetion or type of vehicle.

Engines can burn either gasoline or alcoho, but no nitro or nitrous. Engines can be naturally aspirated or boosted with a blower. Most racers are running a single four-barrel Dominator-style carburetor, although a few are using injectors on their engines.

To be competitive in the Super Comp class, you don’t need the fastest car in the field. In fact, that’s why most of the people who race in this class like Super Comp. The cars that race in this class typically hit 165 to 175 mph in the traps, but speeds can range anywhere from 150 to 190 mph. It’s not the speed that matters most – it’s the elapsed time. In Super Comp, you just have to beat the other guy to the finish line without breaking out of the 8.90 limit.

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A typical Super Comp event at some local tracks will usually attract 26 to 27 competitors. At an NHRA divisional event, there may be 80 or more cars, and at an NHRA national event there could be 140.

Super Comp doesn’t require much engine maintenance compared to some of the higher classes such as Comp Eliminator. Racers in Comp seem to be constantly tearing engines down and replacing parts.

staying within the 8.90 time limit.

The majority of vehicles racing in Super Comp are rear engine rail dragsters because they are lightweight, relatively simple and affordable. Most of the dragsters are powered by big block Chevys, ranging from 509 to 632 cid, although some racers are running Chrysler engines or even small block Chevy V8s. A popular setup is a 565 cid big block Chevy built to redline at 7,500 rpm while making 900 to 1,000 horsepower.

Charles Linne, president of the Pacific Northwest Super Comp Association says his group races at four different strips and usually averages 15 to 20 competitors per event.

“You probably need at least 800 horsepower to be competitive in our series, but you don’t need any special tricks to be a winner. It depends more on driver skill than the engine or chassis.”

Linne races a Super Comp dragster himself and has his car dialed in to run consistent 8.90 ETs. “Once you’ve established a baseline, you can fine-tune your car to run 8.88 to 8.92 consistently.”

Linne says that racing in Super Comp doesn’t require much engine maintenance compared to racers in some of the higher classes such as If you run a lower ET, and both racers break out, then whoever is closest to the 8.90 time is the winner.

Super Comp is a more affordable alternative to some of the other drag racing classes where it can take lots of power and lots of bucks to be a winner. In Super Comp, you can be competitive with a 600 to 800 hp engine in a rear engine dragster. Some racers are running upwards of 1,200 hp, but they don’t really need that much power. In fact, some racers say if a car makes too much power and is too fast, it makes it harder for the driver to judge his distance to the finish line and the car in the other lane.

Ideally, you just want to nose out the other car at the finish line while

Most of the dragsters are powered by big block Chevys, ranging from 509 to 632 cid, although some racers are running Chrysler engines or even small block Chevys.

TomorrowsTechnician.com 13

Comp Eliminator who are constantly tearing their engines down and replacing parts. “I’ll run my engine two seasons before I’ll refresh it,” he says.

Linne believes one thing every Super Comp racer needs is an accurate weather station to monitor temperature, humidity and barometric pressure. These are the The majority of vehicles racing in Super variables that affect engine tuning so you have to know what kind of jetting and tim- Comp are rear engine rail dragsters ing changes to make as the weather because they are lightweight, relatively changes. simple and affordable.

Rich Kwasiborski of the Midwest Super Comp Series says a typical Super Comp event at a local of these engines have radical cams that require a lot of track in Illinois will usually attract 26 to 27 competitors. At valve spring pressure and strong pushrods, so you have to an NHRA divisional event, there may be 80 or more cars, keep an eye on the valve springs and the roller lifters,” and at an NHRA national Super Comp event, the field is Kwasiborski says. “But other than that, the engines hold usually limited to 140 cars. up well.”

“Many racers are now using some type of data acquisiGeneral Engine Building Tips tion system that records engine rpm, torque converter If you are building an engine for a customer who wants to and driveshaft rpm to see if they are getting too much race a Super Comp dragster, consistency and reliability tire slippage,” says Kwasiborski. “This kind of information are essential. You want a strong block (cast iron or aluis necessary to help them dial in their cars so they will be minum), a strong crankshaft (forged 4340 steel), and rods more consistent.”

(H-beam) and pistons (forged) that can take the punishKwasiborski says most of the dragsters in the Midwest ment. The top compression rings should be steel or ducSuper Comp Series are in the 900 to 1,000 horsepower tile iron with a moly facing to withstand the heat. The range, turning 7,500 rpm and running 160 to 180 mph compression ratio will depend on the fuel, so if your cuswith 4.10 gears. The engines are equipped with one of tomer wants to run alcohol or a high octane racing fuel two kinds of throttle stops: under the carburetor or inyou can run more compression. line. The throttle is usually CO2 operated, which controls A leaded racing fuel rated at 107 pump octane can how quickly the throttle comes on and off. “You don’t want all the power to hit the wheels all at once; otherwise typically handle compression ratios in the 12:1 range. Run the engine on 110 pump octane leaded racing fuel and you’ll lose traction,” Kwasiborski explains. the compression ratio can be bumped up to 13:1. Use He says most of the engines are lasting up to three 112 pump octane racing fuel and the engine can be built seasons, thanks to the fact that most of them are being cooled by radiators to keep the heat under control. “A lot with up to a 15:1 compression ratio.

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Super Comp cars typically hit 165 to 175 mph in the traps, but speeds can range anywhere from 150 to 190 mph. It’s not the speed that matters most – it’s the elapsed time. You have to beat the other driver without breaking out of the 8.90 limit.

Oxygenated racing fuels can typically make up to 3 to 7% more power than leaded racing fuels. The higher the oxygen content of the fuel, the greater the potential power gains it can deliver. An oxygenated fuel such as E85 ethanol (85% ethanol and 15% gasoline) typically carries an octane rating of 110 (or 116 for some E90 blends). A compression ratio of 14.2:1 works well with E85.

The compression ratio will also depend on the size of the combustion chamber (small versus large) and valve overlap and timing. The higher the compression ratio, the greater the thermal efficiency of the engine and the more power it will produce.

Camshaft selection will depend on the heads and how much power you want to make. You’ll need a cam with a lot of lift and duration if you want to make 800 to 1,000 hp, but you don’t have to go crazy with lift, duration and valve spring pressure. A cam that delivers a flatter, broader torque curve will be easier to race and tune than a cam with a narrower and peakier torque curve.

A typical cam profile that is capable of producing up to 1,000 hp in a BB Chevy 565 engine would be

283/296 degrees duration at .050” lift, and .824˝/.785˝ of lift with 1.7 ratio rocker arms.

The roller lifters and pushrods should be stout enough to handle the required valve spring pressure for up to two racing seasons. The cam drive system should also be strong and reliable, and allow easy cam timing adjustments.

Engine oiling is also critical, so you want an oil pump that will provide plenty of oil pressure and flow, and a baffled oil pan to prevent the oil from climbing up the back of the pan when the dragster is accelerating down the strip.

Since the engine is going to be turning a lot of rpm, a good balance job is critical for reliability.

Engine assembly, break in and tuning is like any other performance engine you might build.

Make sure everything is thoroughly lubricated when it goes together, and that the oil system has been primed before the engine is fired up for the first time.

For more information about drag racing engine builds, visit enginebuildermag.com. ■

Undercover

Adapted from Andrew Markel’s article in

BRAKE LINE OF SUCCESSION:

7TH GENERATION HONDAS

T

he seventh-generation Honda Accord (2003-’08) and Acura TL are some of the top-selling vehicles in the U.S. They have a very simple brake system to service, but it can be prone to brake-noise issues if it’s not properly serviced.

The system uses single-piston floating calipers in the front.

In the rear, some models use single-piston floating caliper disc brakes with a ratcheting-style parking brake. Low-end versions of the Accord use drums in the rear. Late-model Acura TLs use a disc brake system with a drum-in-hat style parking brake.

ABS Era Almost every seventh-generation Accord comes with ABS. All have standard Electronic Brake Distribution (EBD), so don’t look for a proportioning valve. Most 2006-’08 models have Brake Assist Systems that help recognize emergency braking situations and momentarily apply extra brake force in a “panic stop” or until the driver releases the brakes. The system uses inputs from steering position, yaw and pitch to determine if brake assist will be used.

If the steering position sensor is not calibrated, it

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has been reported that the misinformation from the sensor causes the ABS and stability control system to activate during some maneuvers and during cornering when it’s not needed. Customers may report loss of speed and changes in the brake pedal level during braking and turning. The condition commonly happens on freeway exits. If a customer reports these symptoms, it may save you some time if you look at the output for the steering position sensor.

Sourcing Parts The seventh-generation Accord brake system comes in two versions and with two different rear brake systems.

Systems are made by either Akebono or Nissin.

When ordering pads, make sure you have a VIN and production date. Also, find out if the vehicle is equipped with ABS and/or TCS. Some brake part electronic catalogs might ask for the trim level. The smaller brake system came with 15-inch wheels and the larger system came with 16-inch or larger wheels. But, some special editions and later models violate these rules.

The DX model is the low-end of the range and is equipped with the smaller front brakes and rear

The seventh-generation Honda Accord front brakes come in two versions. The V6 models have a thicker rotor and a larger caliper compared to the 4-cylinder models.

drums. The LX version is the midrange model and can have either brake system, depending on whether it’s equipped with 4-cylinder or V6.

Also, the level of ABS and stability control will determine if it’s equipped with rear disc brakes. The next trim level is the EX. These models typically have the larger front and rear disc brakes.

Don’t skimp on the brake pads. All the Accords of this generation are designed to work with ceramic friction formulations. It’s critical that a similar friction material goes back on the vehicle. If an aggressive semimetallic friction material is used, more heat could be transferred to the caliper piston, making it possible to boil the brake fluid. The problem becomes even worse if you use a cheap brake pad set that does not include a set of shims.

Honda engineers use this design to stop the vibrations so Honda can use a lighter caliper and knuckle to increase gas mileage and improve ride quality. If you think you can outengineer a bunch of Honda engineers with a cheap shim and tube of brake lube, you may have a comeback in the near future.

Service Tips • The best piece of advice provided by one Honda technician is to remove the bolt that holds the front brake hose bracket on the knuckle before you start a brake job. It makes it easy to hang the caliper out of the way and to service the pads and caliper bracket.

• Inspect the bushings and ball joint on the upper control arm. If these components are worn, they will produce a clunking noise during initial braking.

• Make sure the notch in the rear

Soft Touch Affected Vehicles: Accord (2003-’08) Symptom: When the brakes are applied, the brake pedal travels lower and feels softer than normal.

Cause: The ABS/TCS or VSA modulator-control unit has leaked air into the brake system.

Diagnosis: If the brake pedal travel is not lower than normal and the feel is not softer than normal, do not proceed with the diagnosis or the repair.

1. Inspect the brake system.

Replace any leaking, worn or damaged parts.

2. Manually bleed the brakes. Do not use a pressure or vacuum power bleeder.

3. Apply the brakes to check the height and feel of the pedal. If the brake pedal height and feel is now normal, the vehicle can be returned to the customer. If the brake pedal height and feel is still low and soft, continue with normal troubleshooting procedures. The recommended repair is to replace the ABS/TCS or VSA modulator control unit.

caliper piston is lined up with the tab on the in-board rear brake pad.

Failure to do this could make it difficult to reassemble the rear brake assembly and cost you time and money.

steering wheel due to uneven rotor wear (thickness variation).

Honda’s corrective action was to replace the brake pads and refinish the rotors. Also, Honda tightened up the specs for runout and thickness variation during this time.

Bleeding the System 1. Make sure the brake fluid level in the reservoir is at the MAX (upper) level line.

2. Attach a length of clear drain tube to the bleed screw.

3. Have someone slowly pump the brake pedal several times, and then apply steady pressure.

4. Starting at the left front, loosen the brake bleed screw to allow air to escape from the system. Then securely tighten the bleed screw.

Move to the right front next, followed by the right rear and the left rear.

5. Repeat the procedure for each wheel in the sequence until air bubbles no longer appear in the fluid.

6. Test-drive the vehicle.

7. If the brake pedal is now spongy, there may be air trapped in the modulator and then induced into the normal brake system during modulation. Exercise the ABS and bleed the brake system again, starting with the front wheels.

Reputable Rotors The rotors on the seventh-generation Accord have a good reputation with technicians. Most technicians report front rotors can be turned at least once before they are below service limits.

Honda issued a TSB in 2007 advising technicians that 2003-’07 4-cylinder Accords could develop a brake judder that could be felt by drivers in the

Corrosion between the abutment clips and bracket can cause premature wear and noise.

Runout: For the front or rear rotors, set up the dial gauge against the rotor and measure the runout at 10 mm from the outer edge of the disc. The overall brake disc runout (front or rear) cannot exceed 0.10 mm. If the front rotors are beyond the service limit, refinish the brake disc.

Spec Setup Front Brake Disc Specs: 15-inch brake type: 22.9-23.1 mm Max. Refinishing Limit: 21.0 mm 16-inch brake type: 27.9-28.1 mm Max. Refinishing Limit: 26.0 mm Rear Brake Disc Specs: 8.9-9.1 mm (0.35 - 0.36 in.)

Max. Refinishing Limit: 8.0 mm

Front Brakes 1. Remove the brake hosemounting bolt.

2. Remove the lower flange bolt while holding the flats behind the flange with a wrench. Do not spin the caliper pin in the bore. Damage can occur to the bore and pin boot.

3. You can rotate the caliper upward and secure it if you’re replacing just the pads. If not, remove the upper flange bolts.

Thickness/Parallelism: Using a micrometer, measure disc thickness at eight points, approximately 45째 apart and 10 mm in from the outer edge of the disc.

Replace the brake disc if the smallest measurement is less than the max. refinish limit. 0.015 mm is the maximum allowable difference between the thickness measurements.

4. Remove the brake pads and pad shims. New pads should have a thickness of 10.5-11.5 mm and the pads should be replaced once the friction material is worn below 1.6 mm.

5. Check the hose and pin boots for damage and deterioration. Remove the pins and coat with a siliconebased caliper grease.

6. Remove the pad retainers/abutment clips and check the caliper pins for free movement.

7. Clean the caliper and slides thoroughly. Remove any rust, and check for grooves and cracks.

8. Clean and install the brake pad retainers.

9. Apply a light coat of molybdenum-based lubricant to the pad retainers, pad sides of the shims and the back of the brake pads. Wipe excess paste off the pad shim and brake pads.

10. Install the new brake pads and shims. Install the brake pads with the wear indicator on the inside. The wear indicator should be on the top of the pad.

11. Gently push in the piston so the caliper will fit over the new rotor and/or pads.

12. Install the flange bolt and tighten it to 26 ft.-lbs. for the smaller system and 37 ft.-lbs. for the larger system.

13. Install the hose-mounting bolt.

14. Test-drive the vehicle.

Rear Brakes 1. Remove the lower flange bolt while holding the flats

behind the flange with a wrench. Do not spin the caliper pin in the bore. Damage can occur to the bore and pin boot.

2. Remove and inspect the pads. New pads should have a thickness of 8.9-9.1 mm and the pads should be replaced when the friction material is worn below 1.6 mm.

3. Remove the pad shims.

4. Remove the pad retainers.

5. Clean the caliper thoroughly. Remove any rust and

check for grooves and cracks.

6. Check the brake disc for damage and cracks.

7. Install the pad retainers.

8. Apply a thin coat of molybdenum-based lubricant to both sides of the shim and to the back of the brake pads.

Wipe excess lubricant off the pad shims and brake pads.

9. Install the brake pads and pad shims. Install the brake pad with the wear indicator on the inside bottom. If you’re reusing the brake pads, always reinstall the brake pads in their original positions to prevent a momentary loss of braking efficiency.

10. Rotate the caliper piston clockwise into the cylinder, then align the cutout in the piston with the tab on the inner pad by turning the piston back. Lubricate the boot with rubber grease to avoid twisting the piston boot. If the piston boot is twisted, back it out so it’s positioned properly.

11. Install the caliper. Install the flange bolts, and tighten it to the specified torque 17 ft.-lbs.

12. Press the brake pedal several times to make sure the brakes work.

Parking Brake 1. Pull the parking brake lever with 44 lbs. of force to fully apply the parking brake (use a fish scale). The parking brake lever should be locked within three to five clicks.

2. Adjust the parking brake. For vehicles with drum brakes, loosen the parking brake adjusting nut, start the engine and press the brake pedal several times to set the self-adjusting brake before adjusting the parking brake.

3. Remove the center console.

4. Pull the parking brake lever up one click.

5. Tighten the adjusting nut until the parking brake drags slightly when the rear wheels are turned.

6. Release the parking brake lever fully, and check that the parking brakes do not drag when the rear wheels are turned. Re-adjust if necessary.

7. Pull the parking brake all the way up, and make sure the parking brakes are fully applied.

8. Reinstall the center console. â–

28 May 2014 | TomorrowsTechnician.com

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Under the Hood

Adapted from Sergio Fernandez’s article in

LESSONS IN BMW

VARIABLE CAPACITY A/C SYSTEMS

D

espite the many advances in A/C systems during the past 10 years, it’s important for technicians to understand basic theories of operation.

Understanding how a system moves heat from the confined space of the passenger compartment and dissipates it into the atmosphere will assist the technician in analyzing system failures and performing the required maintenance and service.

The refrigerant circuit is divided into a highpressure side and a low-pressure side. The highpressure side is composed of the compressor, condenser, condenser fan, pressure sensor, receiver dryer and expansion valve. The lowpressure side also includes the compressor and expansion valve, along with the evaporator and blower fan.

The expansion valve separates the highpressure side of the system from the low-pressure side. Pressurized liquid refrigerant exits the receiver dryer and, as it passes through the metered orifice of the expansion valve, it decompresses and boils.

The compressor is responsible for the pressure in the A/C system, and there are basically two types of compressors in use today: a reciprocating compressor or a rotary compressor.

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May 2014 | TomorrowsTechnician.com

The clutch on the front of the compressor is a good clue as to the type of compressor the BMW you’re working on uses.

The activation of the compressor clutch is controlled by the IHKA (Intergriertes Heizung und Klima Automatic or Integrated Automatic Heating and Cooling) module. If the evaporator temperature is above 37° F, and the refrigerant pressure sensor indicates acceptable pressure, the control module then enables the ECM to activate the compressor.

System Deactivation The system will deactivate the compressor if it detects any of the following conditions: 1. The ECM detects full engine load or aggressive throttle position.

2. The evaporator temperature is less than 35° F. 3. The coolant temperature is more than 245° F. 4. The refrigerant pressure sensor (located in the high side) indicates pressure is too low or too high.

Photo 1

Current Check If you do not have a scan tool that can monitor the clutch Parameter IDs (PIDs), you can measure the current pulled by the compressor clutch coil by clamping an amp probe on the positive wire going to the clutch. If you have an enhanced scan tool, the A/C clutch can be operated independently to observe operation.

On modern BMWs, the most common type of compressor used is the swash-plate compressor (also known as a wobbler compressor); this fits into the reciprocating-compressor category. The swash plate converts the rotary motion of the driveshaft into an axial motion.

It changes the pivot point of the pistons to change the stroke. This varying piston stroke delivers a variable cylinder displacement.

The compressor and control module can change the stroke for the most efficient HVAC operation and fuel economy.

Depending on the design, this may involve five to seven pistons that are arranged in a circle around the driveshaft. An intake/pressure valve is assigned to each piston, and these valves open/close automatically in time with the operating cycle.

In the Clutch Depending on the application, the compressor may have a magnetic clutch. Clutchless compressors found on some BMWs are constantly engaged when the engine is running.

As mentioned earlier, the compressor output is always variable displacement and is controlled internally by either a “mechanical” control valve that operates solely on an A/C pressure differential and does not need electronic signals, or by an “electronic” control valve that is operated directly by

32 May 2014 | TomorrowsTechnician.com

signals from the IHKA control module, depending on the system.

On systems with a mechanical control valve, the displacement is controlled by changes in internal pressure, which is modified by a mechanical control valve mounted in the rear of the compressor. The mechanical control valve contains a pressure-sensitive bellows exposed to suction-side pressure. The bellows acts on a ball and pin valve that is exposed to high-side pressure. The bellows also controls a bleed port that is exposed to suction-side pressure.

Pressure in the crankcase is increased for reduced stroke and displacement. This increases the pressure behind the pistons and reduces the angle of the wobble plate. See Photo 1.

At higher engine rpm, and when the load on the system is low, the swash plate moves so that the piston travel is shortened. This reduces the constant high-load output of the compressor any time the A/C system is on.

Photo 2 It also reduces the cycling of the compressor due to the low temperature of the evaporator (the evaporator temperature sensor causes the system to cycle at 37° F), resulting in improved fuel economy.

Pressure inside the crankcase is reduced for increased stroke and displacement. The opposing internal forces cause the wobble plate to tilt at a greater angle. See Photo 2.

The inclination of the swash plate changes, determining the displacement volume and, therefore, the refrigeratin.

The compressor output capacity (and therefore the delivery volume) can be set from 0-2% minimum to 100% maximum.

At low engine rpm and/or hightemperature loads, the travel (displacement) of the compressor pistons are at the maximum point.

This allows the compressor to provide maximum cooling efficiency at idle speeds and when high output is required.

On systems with an electronic control valve, the IHKA control unit can infinitely change the displacement of the compressor, depending on the ventilation temperature, exterior and interior temperatures, as well as the target and actual evaporator’s temperature.

The voltage signal to the valve is a pulse-width-modulated voltage signal.

For example, the IHKA control unit activates the control valve accordingly when a higher refrigerating capacity is required. A pulse width-modulated voltage signal moves a tappet (plunger) in the control valve. The adjustment range is determined by the amount of time the voltage is applied. The adjustment varies the opening cross-section in the control valve between the high-pressure and lowpressure sides of the crankcase.

The evaporator temperature is controlled to a value between 35° F and 46° F, depending on the cooling power request. The temperature sensor signal in the evaporator is used as a feedback signal to the IHKA control unit.

The refrigerant request is limited by the potential evaporating power of the evaporator. The evaporator is prevented from icing up by controlling the compressor output.

34 May 2014 | TomorrowsTechnician.com

Highs and Lows When servicing the system, techs need to keep in mind that refrigerant pressure is directly proportional to its temperature, so as the temperature goes up, so does the pressure, and vice versa.

Refrigerant in the A/C system is prompted to change its state from a liquid to a gas and back again.

During every change of state, heat is either absorbed or dispersed in the process. This thermodynamic property is put to use in the low and high sides of all A/C systems.

The low-side pressure is a direct reading of the evaporator temperature and its heat exchanging capabilities. Low-side pressures should average +/- 2 bar (28 to 32 psi), meaning that actual pressure of a variable displacement compressor/TEV system can be between 1 to 3 bar or (15 to 45 psi) at any given time.

The high-side pressure is a direct reading of the condenser cooling efficiency. Although high-side pressures may vary between 150 to 300 psi, normally they should be about 2 to 2.5 times the ambient temperature. Depending on humidity, an outside temperature of 80째 F should produce pressure of 160 to 200 psi on the high side.

36 May 2014 | TomorrowsTechnician.com

When the high-side pressure is way above normal, it may indicate that the condenser auxiliary cooling fan is not sufficiently cooling the refrigerant. Proper airflow across the condenser ensures the efficiency of the entire system. The cooler the refrigerant leaving the condenser, the lower its pressure; and, the lower the temperature of the refrigerant entering the evaporator, the more heat can be absorbed from the passenger compartment.

Pressure gauges are indispensable when diagnosing an A/C system, but they are incapable of measuring the quantity or, for that matter, the type of refrigerant in the system. The refrigerant capacity of an A/C system can be found on the A/C label under the hood and in the technical information relating to the specific system.

For a quick check before and after working on an A/C system, note the ambient humidity and ambient temperature, close all the windows and doors, raise the engine speed between 1,500-2,000 rpm, set the blower at medium speed, set the temp desired at Max Cold, turn the A/C button on and leave the system working for three minutes. The temperature at the center vent should be 20째 F less than the ambient temperature.

Oil Balance Issues The purpose of oil balancing is to make sure the amount of oil in the A/C system remains at the correct level. The first thing to consider when performing the process is the amount of oil contained in the replacement compressor. This can vary from a full charge of oil (8 oz./236 mL), to a half charge of oil or no oil at all.

If oil is contained in the replacement compressor, it will have to be removed and reinstalled in the correct amount to propTwo styles of compressor clutches where a traditional spanner erly balance the system.

When performing a compressor oil balwrench cannot be used. ance, always follow the instructions provided with the compressor or in the vehicle service Rotating the compressor clutch is usually done by manual to know how much oil to add to the compressor hand or with a spanner wrench. Another option is a prior to vehicle installation. Most times, oil balancing compressor turning tool. On direct-drive compressors, involves draining and measuring the oil from the failed the pulley and clutch are one and the same. compressor, followed by adding a specific volume of The turning tool performs the same function as the new oil to the replacement compressor. spanner wrench, but itâ&#x20AC;&#x2122;s installed on the threaded hub Itâ&#x20AC;&#x2122;s also important to use the viscosity of oil of the clutch. After the turning tool is installed, use a recommended by the compressor manufacturer. If the wrench to turn the tool and clutch. The turning tool can compressor requires heavier-weight oil, such as PAG be used on some clutches that cannot accept a spanner 150, but PAG 46, which is lighter-weight, is used, the wrench because of clutch design, or where a solid grip result could be noisy compressor operation and by the spanner wrench cannot be achieved. The turning premature wear. tool can also be used in place of the spanner wrench, After adding the oil to the compressor, a good providing an easier method of clutch rotation, and it service tip is to rotate the compressor clutch at least can be done off or on the vehicle. four turns prior to compressor installation. Rotating the Never use a socket on the shaft nut or bolt to rotate clutch circulates oil through the compressor, which the clutch. Doing so may affect the air gap between reduces the potential of compressor damage due to the clutch driver and compressor pulley, resulting in dry bearings, and it also reduces initial torque when compressor issues. the clutch is first engaged.

Courtesy of Delphi Product & Service Solutions â&#x2013;

38 May 2014 | TomorrowsTechnician.com

Service Advisor

Adapted from Scott “Gonzo” Weaver’s article in

GETTING YOUR WIRES CROSSED WIRE SPLICING FOR SENSITIVE CONNECTIONS

A

long time ago, I learned a method of splicing wire that has stuck with me since those early days. I actually picked this method up while I was in the military (USMC), so I can’t take credit for inventing it or perfecting it.

But, since it has helped me all these years, I thought it best to share this method with the next generation of auto and heavyduty technicians.

Making a Connection The resistance from a weak connection or poor connection can produce a tremendous amount of centralized heat. This heat can build the longer the current is flowing, which increases the resistance even more.

Electricity does not flow “in” the wire, but actually travels “on” the surface of the wire.

This is one of the many reasons why there are so many small strands in a given wire.

A butt connector has a very small, connecting surface in which the surface area of the strands in a wire are not entirely used. The strands in the middle of the wire are trapped between the other strands and have no chance to pass their electrical effort. This forces the current to travel only through those strands that are actually

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May 2014 | TomorrowsTechnician.com

touching the surface of the butt connector. More heat buildup will be the result of fewer wire strands being used.

Using the following handsplice method will allow a great deal more strands from each wire section to be touching the spliced area as possible.

Strip and Shrink Tube First, strip back about 3/4 of an inch of insulation from both of the wires that you’re going to be splicing. Add a section of shrink tubing onto the wire.

(Don’t forget this step… or you’ll regret it after you’ve finished the splice.)

Divide the bare strands into two equal sections and form them into a “Y.” Hold a wire in each hand, and then take the “Y” and interlock the two wires together.

But, (very important) leave room between the two “Y”s that’s large enough for the outer insulation from the “none” strip section of wire to easily pass through. Lay the “Y” sections down along the wire without bending them backward, straight and even with the wire.

Find the edge of the gap you left in the “Y”s (That thickness measurement of the outside insulation, just about halfway between the two wires).

Y Rotation Using one hand, pinch down on that spot while taking

the legs of the “Y” from the same side and stand them straight up 90 degrees from the splice. Now, using your other hand, with firm finger pressure, rotate the two legs of the “Y” around the splice toward the opposite wire.

If done correctly, the spacing you left between the two “Y”s will actually lie down and end up right where the insulation begins. Also, as you pinch and roll the bare wire, keep it as snug as possible.

You want to end up with it no larger than the outside diameter of the insulated sections.

Now switch procedures from the right hand to the left hand and stand the other set of “Y” legs 90-degrees, do the same crimp and turn all the way to the other insulated section of wire.

Once you’ve got the hang of it, you’ll find that the splice is extremely strong, even without solder or shrink tubing.

Solder and Shrink When soldering, be sure not to soak the splice with solder. The solder should only aide in holding the splice in place so it won’t unravel. Obviously, the shrink tubing is for overall weather protection, and to shield the bare wire.

Done right, the splice should have plenty of mechanical hold without soldering. I don’t recommend this for battery cable (4gauge and larger).

Crimped or soldered connectors are still the best method for them.

But for the average gauge wire, this method works extremely well.

Give it a try, and when you've mastered the technique, try it on your friends and see how much effort it takes them to pull it apart, even without soldering it. ■

42 May 2014 | TomorrowsTechnician.com

CrossWord PuZZle Tomorrowâ&#x20AC;&#x2122;s Technician May Crossword

ACROSS 1. Service-bay wipes (4,4) 5. Disc-brake wear items 9. Tachometer feature 10. Engine-power booster 11. Fastener type, e.g. T-15, T-40 12. Repair-cost prediction 14. Persuader in tool box 16. Dealership documents 19. Maximum steering angle (4,4) 20. Tread's traction slit 23. Intake/exhaust valves' resting places 24. Windshield-post term (1,6) 25. Intake- or exhaust-valve section 26. Resurrected a rusted wreck

DOWN 1. Paint damage, often 2. Firing ____, a.k.a. ignition sequence 3. Fuel ____, EFI component 4. Wheel-bearing lube 6. Body parts below front bumpers (3,4) 7. Oil-burner output 8. Racy paint-job features 13. Entry-system type 15. Odometer info 17. Took the wheel 18. Gasoline rating 19. Auto-electric safety valves 21. Steering-system ____ arm 22. Auto-glass feature, frequently

Solution at www.tomorrowstechnician.com

TPMS Q & A Q: Can the Tire Type and/or Placard Value be changed if aftermarket tires or wheels are installed?

A: The Tire Type (P Metric, LT Load Range C/D/E) and the Placard Value (Front Placard and Rear Placard, individually) are stored in the receiver as calibrations and can be revised on some vehicles through flash reprograming. Since the under-inflation threshold is calculated as a percentage of the placard; correcting the placard values when different tires are installed will bring the vehicle back into compliance.

Q: Can Tire Pressure Monitoring be turned off?

A: No.Tire Pressure Monitoring is now a mandated safety system in the United States and cannot knowingly be disabled by an OEM nor an aftermarket service provider (49 USC 30101).

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May 2014 | TomorrowsTechnician.com

Q: Will a tire pressure sensor fit in every wheel?

A: Stock wheels are designed to accommodate tire pressure sensors. Many aftermarket wheels also accommodate tire pressure sensors, but not all do. In some, the valve stem hole is placed in such a way (pointing straight into the middle of the wheel on some off-road wheels) that the motion detection components inside the sensor will not work correctly.

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May 2014 | TomorrowsTechnician.com

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Report Card

Hearkening back to the glory days of purebred, affordable sports cars, Kia Motors America (KMA) unveiled an aggressive concept car earlier this year at the North American International Auto Show in Detroit.

The GT4 Stinger is Kia's eyecatching concept that pushes the boundaries of performance with a rear-drive 2+2 sports car that places human and machine in harmony on the road or track. For those in the know, it comes as no surprise that the GT4 Stinger is the wild-style child of Kia's California design team, home to its 2012 predecessor, the Track'ster concept (see May 2012 issue). And, like the Track'ster, the GT4 Stinger's racy appeal is more than skin deep.

Beneath the low wedge of the GT4 Stinger's hood resides a tuned version of Kia's proven 2.0L turbocharged gasoline direct injected (T-GDI) four-cylinder engine putting out an impressive 315 horsepower.

"Driving enjoyment was the number one priority in designing the GT4 Stinger," said Tom Kearns, chief designer, Kia Design Center America (KDCA). "It's an authentic 2+2 sports car that can turn heads as a daily driver while also being right at home on the track. It's about purity, simplicity and timelessness. The GT4 Stinger is a throwback to days when driving a car was a visceral experience that wasn't muted by electronic gimmickry."

48

By Ed Sunkin, Editor

The engine power is put to the ground via a close-ratio six-speed manual transmission driving the rear wheels, which are wrapped in 275/35R-20 Pirelli P-Zero performance tires.

Underpinning the GT4 Stinger's sculpted "Ignition Yellow" body is a custom chassis with independent double wishbone suspension. With a shorter wheelbase (103.1 inches) and overall length (169.7 inches) than a Forte sedan, a width (74.4 inches) greater than a Cadenza, and a swooping roofline nearly nine inches lower (49.2 inches) than a Rio subcompact, the GT4 Stinger cuts a menacing figure. It tips the scales at a scant 2,874 lbs, and weight distribution

April 2014 | TomorrowsTechnician.com

is spread nearly perfectly at 52% up front and 48% at the rear. The GT4 Stinger also features a quick-ratio steering rack for direct feedback and uncompromised control.

Source: Kia Motors America â&#x2013;