Tomorrow's Technician, 11.2012

November 2012

■ 5 GENERATIONS OF DURAMAX ■ LESSONS IN OFF-ROAD SUSPENSION ■ TECH TIPS: ROMEO 4.6L 2V

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CONTENTS

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UNDER THE HOOD 10Five Generations of Duramax DiagnosticsThe Duramax diesel brought GM back as a major play-er to the mid-size truck market by offering dependabil-ity, fuel mileage and quiet operation with plenty ofpower, says contributor Bob McDonald. While theseengines have a great reputation, some problems arebound to arise.

SCHOOL OF THE YEAR 18CPTC Scales to New HeightsClover Park Technical College in Lakewood, WA, wasnamed the 2012 Tomorrow’s Technician School of theYear during a surprise award ceremony in October forstudents and instructors of the automotive program.Read what makes them a Top School in this annual competition recognizing auto programs from across thecountry.

UNDERCOVER 20Lessons in Off-Road Suspension SystemsThere’s a lot more to building a rugged off-road vehiclethan just raising the suspension height and installing bigtires and wheels. Gary Goms highlights some of themore common problems and their solutions in thismonth’s Undercover feature.

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TT Toolbox 27

Tech Tips: Romeo is Leaking 28

TT Crossword 32

Tomorrow’s Technician (ISSN 1539-9532)(November 2012, Volume 11, Issue 8): Published eight times a year by Babcox Media, 3550 Embassy Parkway, Akron, OH 44333 U.S.A. Complimentary subscrip-tions 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.

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Tesla Model S is named 2013 Motor Trend Car of the Year — the first time an electric car wins the title in the award's64-year history. The Tesla's ultra-quiet electric powertrain delivers the driving characteristics and packaging solutionsthat make the Model S stand out against many of its internal combustion engine peers. The carmaker says the TeslaModel S is the fastest American-built sedan on the market, posting 0-60 times as low as 3.9 seconds. Read more at: http://bit.ly/UGuv8h

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Each month, Tomorrow’s Technician takes a look at some of the automotive-related student competitions taking place in this country, as well asthe world. Throughout the year in “Finish Line,” we will highlight not only the programs and information on how schools can enter, but we’ll alsoprofile 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.

Las Vegas, NV — Loara HighSchool, Anaheim, CA, won itsthird straight NationalChampionship Title in the HotRodders of Tomorrow EngineChallenge. Listed as TeamMOTIVE GEAR, the Loara HighSchool student team beat out 12other teams in the 4th Annual"Showdown at SEMA" with anaverage time of 21:24 minutes.

It was a tight competition forthe four-day event. In fact, thetop three teams were so compet-itive that they all ended up lessthan a minute apart. Accordingto event organizers, all 13 teamscompeting this year did fantasti-cally well, with the 13th-placedteam average time being only33:46.

Rodder RebuildThe event itself resembles thetear down between rounds at adrag race. The engines are identically prepared small blockChevys complete with all the performance components:Edelbrock air cleaners, carbs, aluminum manifolds, heads,water pumps and valve covers;MSD distributors and wires; K&Noil filters; Hedman ceramic head-ers; TD timing chain covers;Moroso oil pans; ARP head bolts;Fel-Pro/SpeedPro gaskets andcomponents; Melling oil pumps;

and Royal Purple lubricants.

Race against TimeThe event pits high-school teamsagainst each other in a contest toproperly tear down a race engineto just the crank, cam and blockusing hand tools only with proper de-torque and disassembly procedures.

Once the engine is disassem-bled, the team returns behind its

workbench, and when allowed bythe judges, the team beginsworking to reassemble theengine with correct assemblyprocedure and torque specs, allwhile being viewed by judgesand spectators. Penalty minutesare assessed to the engineassembly recorded time fordropped components, improperdisassembly/assembly, poorsportsmanship, etc. All

edited by Tomorrow’s Technician staff


TEAM MOTIVE GEAR TAKES RACES TO WIN AT HOT RODDERSOF TOMORROW ENGINE CHALLENGE NATIONAL CHAMPIONSHIP

"Showdown at SEMA" is the title of the Hot Rodders ofTomorrow Engine Challenge National Championship at theSpecialty Equipment Market Association (SEMA) Show in LasVegas. This year, 13 High School Auto Tech teams competedOct. 29 through Nov. 1 in the engine teardown and rebuildcontest in front of thousands of spectators at the entranceof the SEMA show.


procedural penalties are in the Hot Rodders ofTomorrow rulebook that was provided to the compet-ing high schools at the start of the school year. Theteam with the fastest time, including penalty minutes, ischosen as the winner.

Event Winners and Wildcard TeamsCompete This year, 13 teams earned their way to the "Showdownat SEMA" national championship. Eight teams wererepresented by winning regional events throughout thecountry, and five additional teams were added to thecontest for having the next best qualifying times during

regional competitions.During the normal regional event competitions

through the year, all participating teams compete once.The team with the best time wins the regional eventand is given the opportunity to compete in the nationalchampionship at SEMA.

However, during the national championship"Showdown at SEMA," all the teams compete a total offour times. On the last day of the four-day event, eachteam's highest time was thrown out and the remainingthree times were averaged to determine the top enginebuilder.

Final Team RankingsFirst Place: Team MOTIVE GEAR (seen to the right) - Loara HighSchool, Anaheim CA - average time - 21:24. Second Place: Team ENERGY SUSPENSION - Eastern OklahomaCounty Tech Center, Choctaw, OK - average time - 21:54Third Place - Team MR. GASKET - East Ridge High School,Chattanooga, TN - average time - 22:19Fourth Place - Team AEROMOTIVE – Burton Center for Arts &Technology, Salem, VA - average time - 24:46Fifth Place - Team MAGNAFLOW - North Orange County ROP, Anaheim, CA -average time - 25:35Sixth Place - Team ROYAL PURPLE - Elkhart Area Career Center #1, Elkhart,IN - average time - 25:50Seventh Place - Team ARP- Elkhart Area Career Center #2, Elkhart, IN - average time - 25:53Eighth Place - Team PROFORM - Peach County High School, Fort Valley, GA - average time - 26:14Ninth Place - Team THERMO-TEC - Thomas County Central High School, Thomasville, GA - average time - 27:40Tenth Place - Team EDELBROCK - Fremd High School, Palatine, IL - average time - 28:50Eleventh Place - Team HEDMAN HEDDERS - Belvidere North High School, Belvidere, IL - average time - 31:04Twelfth Place - Team MSD - Joliet Central High School, Joliet, IL - average time - 32:31Thirteenth Place - Team PAINLESS PERFORMANCE - Sequoyah High School, Soddy Daisy, TN - average time - 33:46

PrizesMore than $1.2 million in scholarship money was awarded to the participants by three auto technologicalcolleges: Ohio Technical College (OTC), University ofNorthwestern Ohio (UNOH) and School ofAutomotive Machinists (SAM).

Each college awarded the following scholarshipmoney:$10,000 to each first-place team member;$9,000 to each second-place team member;$8,000 to each third-place team member;$7,000 to each fourth-place team member;$6,000 to each fifth-place team member; and$5,000 to each sixth- through 13th-place team member.

The competition began at the inaugural Race &Performance Expo in 2008. The Hot Rodders ofTomorrow Engine Challenge has quickly grown into anationwide engine challenge with more schools andsponsors supporting this exciting event each year.

For more information, visit www.hotroddersoftomorrow.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 [email protected].


Back in the 1990s, GM wasn’t makingtoo many waves in the diesel truck market. The 6.2L and 6.5L engines hadbeen around for sometime, but theywere no match for the release of the

Cummins 6BT in the Dodge truck in 1989 andthe Ford Powerstroke in 1994.

GM never really had a strong reputation fordiesel design anyway. What many, includingyour instructor, remember is the GM dieselengines were a clacking bucket of bolts thatwere plagued by many issues from the start ofthe late 1970s. GM’s goal at that time of thefuel crunch was to introduce an engine withgreat reliability and good fuel mileage. Theyweren’t interested in making power, justdependability. By the mid-1990s, GM was defi-nitely behind in both areas and had to find away to compete in a growing diesel market.But, by 1999, GM didn’t even offer a diesel

option in any of its mid-size trucks.Since 1976, GM and Isuzu have worked

together as a joint venture on several projects.In 1996, the two automakers started working ona new mid-size diesel engine, and after twoyears of design, the Duramax was formed; production began in 2000. The engine designwas a 90° V8, iron block, with aluminum heads,32 valves, common rail injection. It was turbocharged and intercooled and produced300 hp and 520 ft.-lbs. of torque. The enginewas offered in GM mid-size diesel trucks at thestart of 2001, and it brought GM back as amajor player to the mid-size truck market byoffering dependability, fuel mileage and quietoperation with plenty of power.

The question that I often hear about theDuramax is “What kind of problems do you seewith these engines?” I have to admit that theseengines have a great reputation. While some

Under the Hood

FIVE GENERATIONS OF

Adapted from Bob McDonald’s article in

problems have plagued a few ofthe Duramax engines, there has-n’t been anything as detrimentalas what other manufacturershave had to deal with. There arealways going to be issues withanything that has to do withinternal combustion. The bestway to examine the Duramaxwould be to break down theengines by their generation andevaluate issues of each.

Injector IssuesA very common problem withearly Duramax engines was injectorfailure. The engine incorporatedthe Bosch common rail fuel system,which was composed of the high-pressure fuel pump, high-pressure

TomorrowsTechnician.com 11

There are five generations of the Duramax engine. The best wayto identify the generation is by the year, model and the RPO(regular production option) code.

The first generation is known as the LB7. This was manufacturedfrom 2001 to 2004, with the eighth digit of the VIN designatedwith the number 1. With the LB7 being the first design, theintegrity of the engine was great; the biggest problem was thefuel system.

1st Generation Duramax LB7

DURAMAX DIAGNOSTICS


fuel rail, hard lines, injectors and electronic controlmodule. For some reason, the Bosch injectors couldnot sustain life in the Duramax. The injectors wouldfail in three different ways — all related to the injec-tor’s body becoming cracked.

One symptom of a cracked injector is excessivewhite smoke coming from the tailpipe, which is gen-erally most noticeable at idle, especially while sittingin traffic. Fuel is leaking into the combustion cham-ber, which cannot be controlled by the engine’s ECU.Fuel is entering the combustion chamber at thewrong time, causing the white smoke, which is anunburned fuel condition.

This can be seen with a scan tool and is known asan injector’s balance rate. The balance rates of aninjector are adjustments of fuel to the injector madeby the ECU. Theadjustments aremade by the ECUfrom fluctuationsof the crankshaftdetected by thecrankshaft posi-tion sensor. Thebalance rates aregiven by thevalue being aplus or a minus tothe volume offuel per cylinder.If there is toomuch fuel for aparticular cylin-der, the balancerates for thatcylinder would be a minus. The ECU would be tryingto take fuel away to correct the imbalance condition.If there were leaking injectors in this fashion wherethere is white smoke, the balance rate for that cylin-der would be a minus.

Another symptom of cracked injector failure wouldbe fuel dilution in the engine oil. This would comefrom the injector’s body being cracked externally,causing fuel to leak into the crankcase. You have toremember that the injectors of the LB7 were underthe valve cover. The hard lines come from the high-pressure fuel rail and went through the valve cover.So if the injectors were leaking externally, fuel dilu-tion could happen fairly quickly and go unnoticedbecause the engine would operate fine. There havebeen some injectors leaking externally so badly thatthe crankcase had filled with so much diesel that itwas coming from the rear main seal. One particulartruck I was working on with this condition was drip-

ping diesel fuel from the rear main seal without theengine even running in the parking lot.

The last form of injector failure was a hard startcondition when the engine was hot. When the enginewas cold, the vehicle would start fine and drive nor-mally without any noticeable problems until theowner decided to stop somewhere like the store toget some fuel. When the owner would try to start thevehicle, the engine would spin over but never fire.The injector’s body was cracked on the return side,causing the fuel pressure that was entering the injec-tor to be returned to the fuel tank. The vehicle wouldliterally have to sit for several hours and cool downbefore the engine would restart. The heat from theengine would cause the crack in the injector body toexpand open. That’s why the engine will start fine

when cold andstruggle to crankwhen warm.

With so manyinjector failuresbetween 2001 and2004, GM extend-ed the injectors’warranty from fiveyears/100,000miles to sevenyears/200,000miles. This did not,however, remedythe problem. Boschwent through sev-eral designs beforethere seemed tobe a cure.

The biggest problem came when customers hadtheir injectors replaced under the seven-year/200,000-mile warranty. Then several years later,after the truck was out of warranty, the injectorsfailed again. This of course angered many customersbecause there was still a problem and now they weregoing to have to pay for it. But, if the other injectorsdidn’t last very long, this would be an ongoing prob-lem for the owner.

The injector replacement in the LB7 Duramax islabor intensive. With the injectors being under thevalve cover, a lot of the components of the top of theengine have to be removed in order to access them.It’s always advised that if there are several injectorscausing problems that it’s better to replace them allbecause of the amount of labor that it takes to get tothe injector. The average cost of an injector replace-ment on the LB7 is generally around $4,000 to$5,000. The replacement process takes between 10


to 12 hours of labor and theinjectors cost around $350each.

Generation IIEnhancementsIn the middle of 2004,GM released the secondgeneration of the Duramax,with the RPO code of LLY,with the eighth digit of theVIN designated as number 2.The LLY was in productionfrom 2004.5 to 2006, and wasmade with 310 hp and 605 ft.-lbs.of torque. There were several rea-sons for the change: the injectorschanged design and were now onthe outside of the valve covers, pro-viding easier access, and the EPAwas tightening down on emissionsstandards for dieselengines in order toreduce NOx gas.

The LLY incorpo-rated the use of anEGR (exhaust gasrecirculation) valve.When engine con-ditions wouldreach a certain cri-teria determinedby the ECU, theEGR valve wouldopen to letexhaust gas to bereintroduced intothe intake mani-fold. Oftentimesthis would cause abuildup of soot in the intake sys-tem due to the exhaust gas dis-placing the oxygen, which wouldcause cooler combustion; the cool-er combustion inside the cylinderformed soot.

In order to reintroduce exhaustgas into the intake of a dieselengine, the exhaust gas has topass through what is known as anEGR cooler. A diesel engineexhaust temperatures can be muchhigher than gasoline, reaching ashigh as 1,200° F.

Before the exhaust gas reentersthe intake at this temperature, ithas to be cooled. The EGR cooleris more or less a small radiator thatis a part of the engine’s coolingsystem, which as the hot exhaustgas passes through the cooler willcool the exhaust gas before reach-ing the intake manifold. Over aperiod of time, the EGR coolerswill fail, causing the engine coolantto enter the intake manifold. Thiswill often result in loss of coolantwith steam emitting from the

tailpipe. The LLY suffered from overheat-ing. When Duramax incorporat-

ed the use of the EGR cooler,the cooling system of theengine was not upgraded.

When towing with the LLY upsteep grades on a hot sum-mer day, owners oftennoticed that the cooling sys-tem could not sustain theengine’s temperature andwould overheat.

One of the other fea-tures of the LLY wasthe use of VNT (vari-

able nozzle turbo). TheVNT was where the turbochargercould change the speed of theturbo by altering exhaust pulses tothe turbine wheel. This created

better spooltime and moreboost for theengine off idleand would alsochange spool atthe turbo whenthe engine wasat cruising speedfor the use ofless boost. Thisis more or lessletting the turbomake boostwhen there is ademand. TheVNT was some-times responsi-ble for the over-

heating issues of the LLY becauseof the more restricted exhaust sys-tem. Some overheating issues didresult, however, in head gasketfailures, which could damage theentire engine.

Generation III In 2006.5 through 2007, theDuramax changed generation(third) again to the RPO code LBZ.Under the LBZ, the Bosch fuelengine management system alsochanged. This time, the fuel

2nd Generation Duramax LLY

system used a new 32-bit controller along withseven hole injectors. The fuel pressures increasedfrom 23,000 psi to 26,000 psi. Fuel sprayeddirectly onto the glow plugs for faster starts. Theglow plugs were also independently controlledfrom the use of a controller for more efficiencyduring cold starts. The block was redesigned withmore integrity along with the pistons and rods forthe increase in horsepower to 360 and 650 ft.-lbs.of torque. The cooling system was upgraded withthe use of a bigger radiator and fan along with abigger EGR cooler. Owners

of an LLY can upgrade the cooling system of theirvehicles by installing the radiator and fan along withthe fan shroud from an LBZ. The Allison transmissionalso changed from 5 speed to a 6 speed. The addi-tional gear in the transmission reduced cruising speedby 200 rpm.

Generation IVFrom 2007 to 2010, the (fourth) generation ofDuramax changed again to RPO code LMM. Theeighth digit of the VIN is designated with the number6. The LMM makes 365 hp and 660 ft.-lbs. of torque.

Because the emissions standards for diesel engineswere changing for lower NOx gas, the LMM incorpo-rated the use of a DPF (diesel particulate filter) in theexhaust system. The DPF is a device that is locatedbehind the catalytic converter that traps soot comingfrom the engine. The DPF is monitored by theengine’s ECU by the use of pressure sensors locatedin the exhaust system. When the DPF becomesclogged with soot, the ECU will actuate the injectorson the exhaust stroke, which will dump raw fuel intothe DPF. The fuel ignites in the exhaust system, whichburns away the soot from the filter in the DPF. Thiswas an effective way to rid soot from the tailpipe, butcauses more fuel consumption. 4th Generation Duramax LMM

5th Generation Duramax LML

3rd Generation Duramax LBZ


Generation VFor 2011 to the present, the(fifth) generation of theDuramax is currently RPO codeLML. Horsepower has beenincreased to 397 along withtorque to 765 ft.-lbs. The LMLincorporates the use of ureainjection. Urea injection is anexhaust after treatment, whichfurther reduces emissions. Ureais injected downstream of theturbo, which becomes a catalystfor NOx gas. Also, the fuel injec-tion has changed to accommo-date the use of piezo injectorsand injection pressures reaching29,000 psi. Piezo injectors incor-porate piezo crystals that areused to create movement of theinjector’s pintle, which is fasterthan the traditional electromag-net. This, along with the higherinjection pressure, furtherincreases engine efficiency.

With more than 10 years ofengine operation, the Duramax isa proven player in the mid-sizediesel world. The engine designhas always been on the sameplatform with only improvementsto the integrity of the design aspower increased and fuel injection changed as emissionsreductions became greater. Therehave been some unusual failuressuch as broken rods or pistons,but very few accounts. Thebiggest problem was the injectorflaws from the LB7. This was themost major failure that put a badtaste of Duramax into owners’mouths. Other than this, thereare occasional mechanical failuresthat can often be associated withany engine design. Parts overtime become tired, it’s just relat-ed to what the vehicle is used forand how much maintenance isperformed. ■

INTENSIVE CAREKeep in mind that the repair costs of the Duramax aren’t

cheap. The parts will be competitive to other brands ofdiesels, but the labor is not. The labor associated with the Duramax, depending on what the repair is, can beintensive.

Take for instance a blown headgasket repair, the laborfor both headgaskets on a Duramax will be around 35hours compared to a Ford 6.0L that takes around 22 hours.



Clover Park Technical College (CPTC) inLakewood, WA, was named the 2012Tomorrow’s Technician School of the Year(ttschooloftheyear.com) during a surpriseaward ceremony in October for students

and instructors of the automotive program. WIX Filters and O’Reilly Auto Parts partnered with

Tomorrow’s Technician as title sponsors for the nationalcontest to find and name the best technician trainingschool in the country.

Wayne Bridges, automotive technician instructor, saidhe was excited that the school had received nationalrecognition for its accomplishments, saying CPTC hasbeen in the forefront of automotive technical educationfor 70 years.

“We have a long tradition of automotive training atClover Park Technical College – our state-of-the-art facilitypaired with excellent instructors bring a wealth of experi-ence and technical resources into the classroom for thestudents,” said Bridges. “We have an incredible adminis-tration that supports our automotive program and under-stands it is essential to stay on top of changing technolo-gies to succeed in this industry.”

The NATEF-certified school, with Mt. Rainier loomingin its background, has placed in the Top 20 of theTomorrow’s Technician School of the year contest twicebefore taking the title this year. The automotive

programs provide students with collision, customizationand restoration, as well as technical/mechanical training.

Bridges said he and his staff try to keep the learninglevel interesting through plenty of performance hands-onlearning, as well as science-based projects that involvethe students.

“We have a 465hp Chevy powered Mazda Miata thatwe use in the curriculum, and we are building a 1989Chevy S 10 “Gasser” pick-up,” Bridges said. “And duringthe Hybrid/Alternate fuels class last spring, students produced bio-diesel and hydrogen which they then usedto power some of our vehicles.”

School of the year

CPTC instructors pose with the trophy presented tothem at an awards ceremony in October.


Another reason for the wide automotive curriculumis due to the program’s diverse student skill levels, assome of the students already hold automotive-relatedjobs. Ages of the students range from 16 to 65, withthe average age being 30. About 90 students from theauto programs graduate from the school each year.

Bridges said besides its long history, the auto pro-gram feels more like a family, rather than just a groupof colleagues teaching repair skills to the next genera-tion of automotive technicians. Of the seven instructorsin the auto department, five of them graduated fromCPTC.

“We have a great team of instructors here totalingmore than 200 years of automotive experience,” hesaid.

Hallowed Grounds and HistoryInterestingly, the CPTC campus was at one time the siteof Tacoma Speedway prior to World War II. TacomaSpeedway (sometimes called Pacific Speedway orTacoma-Pacific Speedway) was a 2-mile wooden boardtrack for auto racing that operated from 1914 to 1922.In its time, the track was renowned nation-wide andwas considered by some to be secondonly to the Indianapolis MotorSpeedway.

After an arson fire destroyedthe wooden grandstands in 1920,the facility was rebuilt, but failedfinancially and racing ended twoyears later.

In December 1941, school dis-tricts located near large militarybases were asked to providetechnical training for the citizensof the area to qualify them torepair and maintain ordnance andmilitary equipment needed for thewar effort.

With shop buildings available at CloverPark High School, a program called WarProduction Training was started. Under the instruc-tion and guidance of instructors such as Jim Hammond(Airframe Mechanic Instructor), Arnold Cassidy (EngineMechanic Instructor), and Dick White (AirframeMechanic Instructor), 500 people were trained as automechanics and aircraft service mechanics.

Thus began the history of what would later becomeClover Park Technical College, and its 70 years of staffand faculty excellence.

Post-war economic growth, baby-boomers, and rock-n-roll ushered in the 1950s. CPTC was a fledgling vocational technical institute, but growing rapidly. In1951, the federal government was phasing out theNavy Supply Depot (the current site of CPTC), and the

Clover Park School District was granted approximately130 acres there, part of which was the former speed-way grounds. Although the local school district occu-pied most of the seven concrete block buildings on theproperty, the school district soon moved to other locations in Lakewood.

In 1954, the Clover Park Vocational-TechnicalInstitute began operating in one of the buildings, han-dling mostly aviation trades. In 1957, the auto shop,machine shop and electronics programs moved into

other vacant warehouses. In 1977, a build-ing renovation/addition project was

completed that included a newAutomotive Service and SalesCenter. In the 1990s, the schoolchanged its name to Clover Park

Technical College and contin-ued its tradition of excellencein automotive training.

Industry SupportClover Park Technical College

(www.cptc.edu) is the fifth-annual recipient of the national

School of the Year award. “It is encouraging to see the students

and faculty of Clover Park Technical Collegeembrace how automotive technicians’ jobs are

evolving as vehicles become more high-tech,” saidMike Harvey, brand manager for WIX Filters. “With

today’s vehicles becoming more complex – fromhybrids, electrics and advanced clean-diesel engines –auto technicians are being trained in new technologies.

“We are proud to support this program recognizingClover Park as the best technical school in the countryand look forward to the success of the school’s futuretechnicians as they begin their careers as the next generation of technicians.”

CPTC received a $2,500 donation from WIX Filters;O’Reilly and WIX Filters gear (hats, backpacks, shopbanners, stools, product samples); 200-piece profes-sional automotive tool set from O’Reilly Auto Parts;

Continues on page 32


Adapted from Gary Goms article in

undercover

Lessons in Off-Road

Chassis CheckNot all chassis can be modified for off-road use.Although this Honda CR-V chassis sports all-wheel drive, it would be a prohibitively expensiveproject to change the suspension and drivetraingeometry on this vehicle to achieve an increase insuspension height. See Photo 1.Vehicles with automatic suspension leveling

and other electronic chassis devices are also diffi-cult to re-engineer. In addition, it’s important todistinguish between AWD and 4WD vehicles.AWD vehicles don’t include a transfer case withan optional low-gear range for off-road service.On the other hand, most 4WD vehicles have alow-gear range that allows the driver to creep upand down steep inclines and ease the vehicleover protruding rocks.

Do The Math: Gear RatiosInstalling larger-diameter tires and wheels is thequickest way to gain a few extra inches of ground

clearance. But larger diameter wheels have alonger rolling circumference, which provides thesame effect as reducing the numerical axle gearratio. Because a radial tire changes radius as itpresses against the road surface, one can meas-ure rolling circumference most accurately by mak-ing a chalk mark on the tire sidewall and measur-ing the distance required for the tire to completeone full revolution.Mathematically speaking, a 32-in. diameter tire

would equal a 100.53-in. circumference (pi xdiameter = circumference or, 3.14159 x 32 =100.53 in.). A 28-in. diameter tire would equal

Photo 1

Suspension Systems

LEGAL SAFETY REQUIREMENTS

The first step in modifying any vehicle foroff-road use is to determine if the vehicle willalso be used on the highway. Any dual-use vehicle must meet its state’s safety require-ments regarding lighting, body sheet metal and suspension height modifications.Some states might require fenders, for

example, and might not allow tires to extendoutside the fenders. In other cases, a statemight not allow excessive suspen-sion alterations thatincrease the roll centerof the vehicle. On theother hand, if thevehicle isn’t licensedand is transported bytrailer to a given location, state safetyrules might notapply.



87.96 in. in circumference.To understand the difference in

requirements for the axle gear ratio,dividing 100.48 in. by 87.96 in. indi-cates that the rolling circumferenceof the tire is increased by about114%. If the vehicle has a 3.73:1 axleratio, the numerical axle ratio mustalso be increased by 114% (or 1.14)from 3.73:1 to approximately 4.25:1,to compensate for the increasedrolling circumference.If tire diameter is changed without

changing axle gear ratio or the pin-ion factor, the vehicle speed sensor(VSS) input will be incorrect, which

will affect speedometer accuracy,transmission shift quality and possiblyeven engine performance. Althoughusing a scan tool on many applica-tions can reset the pinion factor, thevehicle will lack torque in the lower-speed ranges and will generallyprove unsuitable for off-road use ifthe axle gear ratios aren’t changed.In addition, larger tires must have

adequate clearance in the fenderwells and against suspension compo-nents at full suspension compressionand full suspension decompression or“droop” (See Photo 2).To steer correctly, most vehicles

must also allow at least 40 degreeslock-to-lock of steering radius. Of course, some fender-well clear-

ance can be gained by increasingwheel rim offset. The downside ofincreased offset is that it moves thetire outboard of its engineered pivotpoint (See Photo 3). This means that,instead of pivoting at the approxi-mate center of the tread, the tirenow begins to swing through a radiusas it is moved outboard. Increasedwheel offset increases steering effortand increases loading on the wheelbearings, axle and suspension com-ponents. Power steering is generallya “must-have” on vehicles with offsetwheel rims. In addition, larger diameter tires

will decrease the stopping ability ofthe brakes. The only remedy is to

Photo 2

Photo 3

Photo 4

install custom brakes with larger-diameter brake assemblies or moreswept area. Larger tires with morewheel offset is a trade-off and theadvantages must be weighedagainst the disadvantages.

Applying Geometry: Steeringand Suspension IssuesThe simplest method of determininghow an increase in suspension heightwill affect wheel alignment andsteering geometry is to place thevehicle on a wheel alignmentmachine and measure the caster,camber and toe angles as the sus-pension height is being increased. At normal suspension heights, the

tie rod is angled slightly downward(See Photo 4). If a normal weightload is added to the vehicle, the tierod moves to a more level position.In conjunction with the control arms,the steering linkage is normallydesigned to maintain toe angle asthe springs are compressed. Whenthe vehicle suspension height israised, the tie rod angles downward,which causes the toe angle tochange from positive to negative asthe suspension is compressed.The same problem affects 4WD

vehicles with a solid axle and a draglink connecting the tie rods with the

steering gear. Because the drag linkoperates through a sharper angle,the wheels tend to steer to one sideright when the suspension is com-pressed. This phenomenon is called“bump steer,” which can cause thevehicle to wander on paved high-ways. See Photo 5.In most cases, OE suspensions

can be raised only an inch or twowithout encountering serious steer-ing geometry problems. If greaterheight increases are desired, severalaftermarket companies may providemodified spindle assembliesdesigned to increase suspensionheight without seriously affectingsuspension and steering geometry.See Photo 6.


Photo 5

Don’t forget to look atincreasing the stiffnessof the springs and thediameter of the anti-sway bar or “roll bar”assemblies to helpcounteract the vehicle’sincreased center ofgravity on steep slopes.See Photo 7.

Photo 6


Photo 7

Photo 8

Photo 9

Driveshaft GeometryDriveshaft geometry is an often-neg-lected issue on many off-road conver-sions. If the vehicle has an independ-ent front suspension, the front drive-

shaft isn’t affected by an increase insuspension height. If the vehicle hasa solid or “live” front axle, the short-er front driveshaft will be most affect-ed because the operating angles on

the universal joints will drasticallyincrease. See Photo 8.The slip joints are fully extended

and the universal joint yokes aremost likely to contact each other. Theslip joint travel should, for maximumsafety and durability, allow at least2/3 contact between the yoke anddriveshaft slip joints. The slip jointshould have at least a 1/2-in. of freetravel to prevent mechanical interfer-ence at full suspension compression.In some cases, a custom driveshaftmust be made to restore slip jointintegrity. See Photo 9.When installing a rear axle assem-

bly, remember that the pinion anglechanges as the axle rolls upward withthe application of torque. Whilemany stock 4WD vehicles incorporatezero pinion angle, tipping the axleslightly downward would relievestress on the universal joint. Atapered caster shim inserted between the spring and axle wouldequalize the pinion gear angle withthe transfer case shaft angle.

Absorbing ShockShock absorbers should be selectedand installed after the vehicle hasbeen modified. In general, most off-road enthusiasts prefer a heavy-dutyshock absorber with more oil capaci-ty to handle increased heat andmore rebound control to handlerough terrain. To prevent breaking the shock

absorber, the shock absorber musthave enough travel to accommodatethe increased suspension height (SeePhoto 10). Travel should be checkedat full compression and full droop. Ifthe shock absorber is bottoming outat either extreme, a shock absorberwith more travel must be installed orthe shock absorber mounts must bemodified to comply with the increasein suspension height.

Go to www.underhoodservice.comand use the search function to obtainmore suspension-related technicalarticles. �


Photo 10

GearWrench has launched the 120XP Ratchet that features 120 positions for every full rotation, allow-ing it to turn fasteners with a swing arc of as little as 3°. The Double-Stacked Pawl technology provides

an ultra-narrow swing arc allowing users to reach fasteners in severely limited access applications.The 120XP ratchet has a 60-tooth gear that alternately engages the double-stacked pawls. Its

long handle is ergonomically designed to provide comfort and a good grip for users. The120XP ratchets are sold separately and come in select SAE/metric standard/deep

socket sets. Available at major automotive retailers and hardware locations.GearWrench: http://gearwrench.com


Tt Toolbox

General Technologies’exclusive ThermoSounder fea-ture on the LTX12 InfraredThermometer provides users withaudio feedback allowing for quick andeasy detection of both cold and hotspots, without the distraction of having tofollow and interpret the digital readouts.The LTX12 includes: patented ergonomicdesign and styling for enhanced handling anduse; wide temperature range: -20° to 1,200° F(-30° to 650° C) and more. GeneralTechnologies Corp.: www.gtc.ca/

The Hook is the latest circuit tester from Power Probe. This powerful toolcan connect to systems from 12 to 48 volts. Power Probe’s new “Smart TipAdvantage” senses the probe-tip condition and selects the correct meter foryou. When the probe-tip senses resistance to ground, the display reads from 0Ohms to 15 Meg Ohms with a resolution of 0.001 Ohms. When the probe-tipcontacts voltage, the display becomes an instant voltmeter and measures from0 to 99.9 volts. When you press the power switch to activate electrical components, the Hook displays its current draw in amps. Power Probe, Inc.:www.powerprobe.com/

S & G Tool Aid Corp. has introduced two toolsto crimp the Deutsch closed barrel terminals foundon trucks, motorcycles, construction equipment,race cars, agricultural equipment, heavy-duty vehi-cles and other vehicles, and equipment subject toexcessive vibration. These tools are easy to use —just insert the terminal and wire, then squeeze thehandles tightly together to complete the crimp. Aratcheting action quickly provides a perfect crimp.Catalog No. 18880 is for use with 14-, 16- and 18-gage closed barrel terminals and Catalog No.18890 is for use with 20- and 22-gage closed barrelterminals. S & G Tool Aid Corp.: www.toolaid.com

The Gunk engine cleaning system provides technicians with serious solutionsfor engine cleaning and degreasing needs. • Gunk Foamy Engine Cleaner – For built-up road grime, salt and dirt from

tough daily driving, long road trips and seasonal weather build up.• Gunk Original Engine Degreaser – For hard-working engines that have

tough oil and grease build up, work in harsh environments or may be leaking.• Gunk Heavy Duty Gel Degreaser – Formulated to stick in place, penetrate

deep and loosen the toughest caked on grease, baked on oil and engine deposits.After cleaning and degreasing an engine, apply an even coat of Gunk Engine

Protector to create a barrier against heavy deposits of dirt and grease. Available at major automotive retailers.Gunk: www.gunk.com/GunkIndex.aspx

For the latest tool information, products and articles on tools andequipment, check out www.techshopmag.com.


FORD:1998 MUSTANG1998-2000 CROWN VICTORIA

1998-’99 F-250 LD1998-2000 EXPEDITION, F-150

1999-2000 E SERIES

LINCOLN:1998-2000 TOWN CAR

MERCURY:1998-2000 GRAND MARQUISSome vehicles equipped withthe Romeo-built 4.6L 2V enginemay exhibit an engine oil leakor oil weepage from the cylin-der head gasket at the right-hand rear or the left-hand frontof the engine. Oil weepage isnot considered detrimental toengine performance or durabili-ty. An oil leak may be caused bymetal chip debris lodgedbetween the head gasket andthe block, chip debris betweenthe cylinder head and the headgasket, or by damage to thecylinder head sealing surfacethat occurred during the manufacturing process.

If an oil leak is verified at thehead gasket area, replacementof head gasket and cylinderhead can be performed. Referto the following Service Tips.Particular attention must bepaid to inspecting the cylinderblock for metal chip debrisdamage on the cylinder head toblock mating surface, which mayrequire block replacement.

SERVICE INFORMATIONA service remanufactured cylin-der head assembly is available –P/N XL3Z-6049-AARM (left-hand), XL3Z-6049-BARM (right-hand) containing: cylinder headassembly, cylinder head gasket,cylinder head bolts, rocker armcover gasket, intake manifoldgasket, exhaust manifold gas-ket, exhaust manifold studs andexhaust manifold nuts.

Tech Tips

Figure 1

This month’s Tech Tipsare sponsored by:


Always verify the origin of an oil leak by using fluo-rescent dye. At times, a cam cover gasket or engine oilgalley plug (particularly at the rear of the right-handhead) may be the source of the engine oil leak. SeeFigure 1.

1998-2000 HEAD GASKET/ CYLINDER HEADREPLACEMENT SERVICE TIPS

Note: Take extra care not to damage the headgasket sealing surface when performing cylinder headreplacement. The success of the repair is dependentupon following the inspection procedure paying par-ticular attention to the areas depicted in the accom-panying figures.• When cleaning the block deck of residual gasket

coating, use Citrus Metal Surface Cleaner (P/N F4AZ-19A536-RA) and a plastic scraper. Wipe with a lint-freeshop rag. A shop vac can be used to pick up loosedebris/dirt prior to the citrus cleaner application.

Note: Do not use a metal tool of any kind on thegasket sealing surface. Resulting scratches will providea leak path.• During normal inspection, pay particular attention

to the right bank block deck area behind cylinder #4or the left bank block deck area in front of cylinder#5 around the oil hole breakout for dimples andimpressions left by metal chips.

See Figure 2 and Figure 3.• The block surface around the cylinder head

alignment dowels (two per bank) is another commonlocation for scratches or dimples.• A known-quality straight edge should be used to

ensure the block surface is flat. If a dimple or impressionmeasures over 0.001” (0.025 mm) deep, it is recommend-ed to replace the block. This type of damage is rare.

• If the block does not pass checks, a new orremanufactured long block engine assembly must beordered. For truck applications, which require use ofthe Modular Engine Lift Bracket 303-F047 (014-00073) for engine removal, use nine links of 5/16”chain in place of the rear bracket. See Figure 4.

• As part of the inspection of the block for dam-age, remove any machining chips that may be inthe bottom of the cylinder block bolt bosses. Thiscan be done using a pencil-style magnet.• After removal of the chip from the block bolt

bosses, and if no permanent damage to the block isfound, verify that both the block and head sealing sur-faces are clean prior to installing the new gasket.• During installation of the new head gasket(s) and

the new cylinder head(s) to the block, lubricate thenew head bolts with an oil-soaked rag and allow oilto drip from the bolts, prior to assembly.

Note: Inspect the new cylinder head for damageprior to installation.

Note: The gasket should be placed directly intoposition and not dragged or moved along the sealingsurface to avoid damage. The gasket coating is

Figure 2

Figure 3

Figure 4


essential to the function of the gasket. Chips, scrapes or cuts in the surface of the gasket coating may cause the gasket to leak.

Note: Do not apply RTV, copper coat, aviation cement, etc. to thegasket or block/head surfaces. The gasket is to be installed dry. Any for-eign material in between the gasket and the head/block may cause thegasket to leak.

Courtesy of Ford Motor Company

In the Clutch: Active Radius When automotive technicians order parts for a repair job they know theyneed the right part, and a quality part as well. So it’s just a common proce-dure of any repair job that technicians will inspect the new part to makesure it is a correct part as well as a quality part, without any visual or func-tional flaws that would lead to a poor repair job and a customer comeback. Many newer-design clutch friction discs are designed with a thinner

band of friction material than the original disc that came in the vehicle.The thinner band of material on the newer design may seem like a badthing to some technicians as they compare the new and original partsthat came out of the vehicle. Conventional thinking would be that “moreis better;” more friction material will mean a stronger clutch. The active radius of a friction disc is defined as the distance from the

center of the disc’s splined hub to the center of the friction material. So,by using a thinner band of friction material on the disc, the active radiuswill be increased. The active radius can be thought of as a lever. Thelonger the lever, the easier it is to move a given load. The above images illustrate how a thinner band of friction material

will increase active radius and, therefore, the torque capacity of a clutch.The disc on the top has a thinner band of friction material than the discon the right. This will increase the active radius and torque capacity of aclutch. �

Courtesy of Schaeffler Automotive Aftermarket

4.704” 4.367”

$250 gift card from O’Reilly AutoParts; and an appearance by Sarah Burgess, BMITeam owner and driver in theXtreme Drift Circuit, with her 2013Ford Mustang running the 5.0LEngine with a 2.9L WhippleSupercharger.

“Support from manufacturersand the aftermarket industry helpfund quality programs for the nextgeneration of automotive mastermechanics,” Bridges said. “TheSchool of the Year award furthersour great reputation for outstand-ing automotive training and we arehonored to be the 2012 recipient.”

Clover Park Technical Collegejoins the honors of past School ofthe Year winners: ArapahoeCommunity College in Littleton,CO (2011); Caddo Career & Technology Center inShreveport, LA (2010); Ohio Technical College inCleveland, OH (2009); and Waubonsee CommunityCollege in Sugar Grove, IL (2008).

“We are very pleased to recognize CloverPark Technical College as the 2012 School ofthe Year,” said Jeff Stankard, publisher ofTomorrow’s Technician. “We believe CloverPark’s instructors, staff and administrators aretruly working hard to prepare their studentsto become the top-notch professionals thisindustry so deeply requires.”

2012 Runner’s UpThis year’s three runners-up are PennsylvaniaCollege of Technology in Williamsport, PA;Chipola College in Marianna, FL; and SanDiego Continuing Education in San Diego.Each school will receive a 200-piece profes-sional automotive tool set from O’Reilly AutoParts and $250 gift card from O’Reilly AutoParts.

View a video from CPTC, as well as other School of theYear finalists at: www.youtube.com/tomorrowstechnician. ■

© Murray J acksonSolution at www.tomorrowstechnician.com

ACROSS1. Minimum-tread-depth indicator (4,3)5. Cylinder-covering castings8. Space ____, a.k.a. mini spare9. Torque-converter component10. Right on road map11. Engine lubricant (5,3)13. MacPherson's suspension inventions14. Build-it-yourself vehicle (3,3)18. Car painter's weapon (5,3)20. Component, briefly22. Engine-incontinence inhibitor (3,4)23. Body-shop tool, ____ grinder24. Body ____, e.g. sedan or hardtop25. Obeyed triangular sign

DOWN1. Nuts and bolts partners, perhaps2. Service _____, dealership job title3. Cylinder diameter4. Relationships between gears5. Crankshaft adjunct, ____ balancer6. Defunct Isuzu for Spanish pal7. Tire-belt material, maybe12. Coolant anti-freeze type, ____ glycol15. Rejuvenated flat battery16. Tire with new lease on life17. Serpentine belt's guide18. Parts absent in disc-brake system19. Electromagnetic switch for lights, etc.21. Primer, ____-coat, clear-coat finish


Tomorrow’s Technician November Crossword

Auto racer Sarah Burgess,right, was on hand to andprovide students with aninspiring message on opportunities in the automotive industry.

Continued from page 19

Tomorrow's Technician, 11.2012

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Transcript of Tomorrow's Technician, 11.2012