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6.2L And 6.5L GM Diesel Power Recipes

For $1,500, $4,000, $9,000, And $20,000 Budgets

Text By Jason Thompson

We began our Power Recipes series back in August of 2009 with the 7.3L Power Stroke. We showed you how to make reliable power while still staying inside a budget. Then we moved on to the Ford 6.0L and 6.4L.

In the last few months we did the same thing for four generations of Cummins' engines. In this issue we are going to cover the GM 6.2L and 6.5L. Many diesel enthusiasts stick their nose up at this engine and wonder: Why would anyone want to mess with high-compression indirect injection? These people might have had a bad experience or know someone with an IDI horror story and only focus on the engine's many shortfalls instead of its good points. A few benefits include:

1. These engines are literally cheaper than scrap iron.
2. They are readily available in your own backyard nearly anywhere in the world.
3. They have cheap and easy to get replacement and performance parts.
4. They can be swapped in the place of a gasoline small-block Chevy.
5. The early (non-electronic versions) are self-contained and need no electricity to run.

Just think of how many GM 6.2L and 6.5L diesel engines there are in existence. Applications include a nearly two-decade run in GM pickups, SUVs, vans, military Hummers and boats around the world. The fact is, many people are able to get a ton of work done with these engines-either by carefully reworking them or just experiencing good luck. The 6.2L and 6.5L Power Recipes use a modified format, since these engines require more initial groundwork to make reliable. Therefore, the $4,000 recipe includes the cost of the modifications recommended in the $1,500 recipe, and the $20,000 buildup includes the cost of the parts added to the $1,500, $4,000, and $9,000 recipes.

BUDGET: $1,500 (GM 6.2L AND 6.5L WITHOUT GETTING INTO THE ENGINE)
MODIFICATION: COMPANY: REASON: PRICE: VENDOR:
Gauges Auto Meter To keep an eye on 15 psi $220-600 Heath Diesel Power, Huckstorf Diesel
Isspro, SPA Technique of boost and EGT Kennedy Diesel, Predator Motorsports
Electric lift pump Heath Diesel Power Supplies fuel to $95-220 Heath Diesel Power
(and control Kennedy Diesel injection pump Kennedy Diesel
harness for 6.5L) Predator Motorsports Predator Motorsports
Mechanical Airtex Supplies fuel to engine $20 Heath Diesel Power, Kennedy Diesel
lift pump (6.2L) Predator Motorsports
Fuel pressure Isspro Tests 2 to 7 psi Loaned (free) Heath Diesel Power
test gauge while driving $60 (buy)
Air filter AFE, S&B Filters cold air $60-249 Heath Diesel Power, Huckstorf Diesel
K&N Kennedy Diesel, Predator Motorsports
Glow plugs ACDelco Preheats the $96-149 Heath Diesel Power, Huckstorf Diesel
Bosch combustion chamber Kennedy Diesel, Predator Motorsports
Thermostat(s) Robertshaw Regulates coolant $12-40 Heath Diesel Power
(single '82 to '96) ACDelco Kennedy Diesel
(dual '97-up) Huckstorf Diesel
Remote PMD and cooler Kennedy Diesel Cools and relocates $160-630 Heath Diesel Power
(pump-mounted Heath Diesel Power problematic PMD originally Kennedy Diesel
driver or FSD fuel RapCool, Stanadyne on injection pump Huckstorf Diesel
solenoid driver) DTech, Heat-Sync Predator Motorsports

CDR Standard Motor Replaces faulty CDR if cleaning $62 or free Heath Diesel Power
(crank case depression Products is ineffective (regulates Predator Motorsports
regulator) valve, hoses, crankcase vapors at 1 psi of RockAuto
and grommets vacuum to prevent oil leaks) Kennedy Diesel
4-inch exhaust Heath Diesel Power Free flow exhaust for $450-519 Heath Diesel Power, Huckstorf Diesel
is all a 6.2L Kennedy Diesel better cooling and Kennedy Diesel, Predator Motorsports
to 6.5L needs Predator Motorsports performance
Turbo-Master Turbo-Master Factory vacuum- $90-119 Heath Diesel Power
Boost Control operated wastegate Kennedy Diesel
TM-GM96 prone to fail
Heavy-duty fan clutch BorgWarner Factory fan clutch problematic- $97-250 Heath Diesel Power
Hayden Automotive specially calibrated sourced Kennedy Diesel
unit is available from
Kennedy Diesel
Harmonic dampener Fluidampr Factory dampener $415 Heath Diesel Power
prone to fail

130 to 190 hp
Weak Links Fixed: Stock PMD located on injection pump overheats and fails on electronically controlled Stanadyne DS-4 injection pump. Vacuum actuated wastegate is prone to fail and takes out belt system. Starting with a good engine is key. One way to check is to take a 3/8-inch id (inside diameter) by 5-feet piece of clear tubing and attach it to the dipstick tube. Put the other end in a glass of water and no bubbles should come out. If bubbles appear, that means there is either a defective CDR valve, piston, or cylinder ring blow-by. Water should go 1/2 inch up the tube at idle and 1 inch up at 2,000 rpm. This small amount of vacuum helps prevent oil leaks. Also make sure the cooling system is clean inside and out.
Total: $663 to $1,500

BUDGET: $4,000 (PRICE INCLUDES MODIFICATIONS MADE IN $1,500 BUDGET)
MODIFICATION: COMPANY: REASON: PRICE: VENDOR:
Cylinder head studs ARP Studs stronger than bolts $225-269 Heath Diesel Power Kennedy Diesel
Main Bearing Kit Heath Diesel Power Factory block is weak $185-500 Heath Diesel Power
'82 to '92 6.2L Kennedy Diesel Kennedy Diesel
'92 to '96 6.5L without oil-cooled pistons
'96-up with oil-cooled pistons
Performance crankshaft Scat Factory crank $459 Heath Diesel Power
prone to fail
Fuel injectors and Bosch Injectors wear out $419-724 Heath Diesel Power
return line kit with Delphi (standard flow) Kennedy Diesel
copper washers Predator Motorsports
Remanufactured fuel injection pump Stanadyne Injection pumps $475-998 Heath Diesel Power
6.2L/6.5L DB-2 (mechanical) wear out Kennedy Diesel
6.5L DS-4 (electronic) (standard flow) Predator Motosports

130 to 250 hp
Weak Links Fixed: The stock main bearings in the engine block that hold the crankshaft are flimsy. The crankshaft and harmonic balancer are also prone to failure.
Total: $3,263 to $4,145

BUDGET: $9,000 (PRICE INCLUDES $1,500 AND $4,000 BUDGETS)
MODIFICATION: COMPANY: REASON: PRICE: VENDOR:
New Fuel Injection Pump Stanadyne Fuel Injection $1,195-1,849 Heath Diesel Power
6.2L/6.5L DB-2 Marine (mechanical) Pumps wear out Kennedy Diesel
6.5L DS-4 (electronic)
Fuel Injectors (high-output) Bosch, Delphi Fuel injectors wear out $600-724 Heath Diesel Power, Kennedy Diesel
Performance-calibrated GLE Provides more control $495-575 Heath Diesel Power
ECM 6.5L Kennedy Diesel control over injection Predator Motorsports
RapTorq and drivetrain Kennedy Diesel
Torque converter (auto), GM4L80E Sun Coast Converters Stock converter may slip $1,100-$1,300 Sun Coast Converters
GM4L80E complete GM Replacement rated $4,499 Predator Motorsports
transmission 400 hp and 800 lb-ft
Clutch upgrade (manual) South Bend Clutch Stock clutch will $1,100 South Bend Clutch
'92 to '02 five-speed NV4500 slip due to wear
'82 to '92 four-speed SM465
Remanufactured turbocharger GM Replace worn-out $829 Heath Diesel Power, Kennedy Diesel
turbo Predator Motorsports
Pistons Mahle Replacement or $395-995 Kennedy Diesel
lowered compression
Gear drive timing set Phazer Gears stronger than chain $400 Heath Diesel Power
Remanufactured GM Replaces worn $990 Predator Motosports
cylinder head and gasket cylinder head

200 to 300 hp
Weak Links Fixed: New and highest-performing injection parts along with a few transmission improvements, replace worn parts
Total: $7,504 to $11,500

BUDGET: $20,000 (RRICE INCLUDES MODIFICATIONS MADE IN PREVIOUS BUDGETS)
MODIFICATION: COMPANY: REASON: PRICE: VENDOR:
Complete remanufactured General Engine Products Fresh start $5,399 Heath Diesel Power, Kennedy Diesel
long-block (tin to tin) Predator Motorsports
Intercooler Spearco Cools intake air $1,999 Heath Diesel Power, Kennedy Diesel
Predator Motorsports
Water-methanol injection Snow Performance Cools combustion $496-999 Heath Diesel Power
Heath Diesel Power Snow Performance
Propane injection Kennedy Diesel Extra-clean fuel $625 Kennedy Diesel
Predator Motorsports Predator Motorsports
CNG injection PDI Extra-clean fuel $4,548 PDI
DeLuca Fuel Products DeLuca Fuel Products
Supercharged 6.5L Lysholm No turbo lag and $2,713 MarineDiesel
300 hp

300 to 550 hp
Weak Links: If your GM 6.5L or 6.2L is making more than 500 hp you are almost in uncharted waters. Diesel Power covered Bill Heath's 153-mph 6.5L land speed racer in "This 6.5L Chevy Runs 153 mph," January '09. To see exactly how he did it, look for a more in-depth and up-to-date article soon. Heath is gunning for his old record.
Total: $17,213 to $21,543

SOURCES
Snow Performance
1017-A East Highway 24
Woodland Park
CO  80863
866-365-2762
www.snowperformance.net
Heath Diesel Power
161 Mission View Drive
Ellenburg
WA  98926
877-894-6266
www.heathdiesel.com
Sun Coast Converters
819 Navy St
Fort Walton Beach
FL  32547
800-868-0053
www.suncoastconverters.com
Huckstorf Diesel
9745 South 58th Street
Franklin
WI  53132
800-776-7102
www.hdiesel.com
ARP
1863 Eastman Avenue
Ventura
CA  93003
800-826-3045
www.arp-bolts.com
Kennedy Diesel
W3351 26 RD
Loyal
WI  54446
715-255-9433
www.kennedydiesel.com
South Bend Clutch
709 W Jefferson Blvd
Mishawaka
IN  46545
800-988-4345
www.southbendclutch.com
Lysholm
NA
CA
www.opcon.se
Spearco Performance Products
2255 Agate Ct.
Simi Valley
CA  93065
805-581-0338
www.turboneticsinc.com
MarineDiesel
S-26272
Engelholm
CA
www.marinediesel.nu
DeLuca Fuel Products
Columbus
OH
774-062-2794
www.delucafuelproducts.com
PDI
687 N. Industrial Rd
Saint George
UT  84770
800-511-1231
www.pdidiesel.com
Fluidampr
180 Zoar Valley Road
Springville
NY  14141
716-592-1000
www.fluidampr.com
Predator Motorsports
1250 Distribution Way
Vista
CA  92081
877-733-2867
www.predatorinc.com
General Engine Products
2000 Watkins Glenn Drive
P.O. Box 488
Franklin
OH  45005
734-523-8889
www.amgeneral.com
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By Jason Thompson
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