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2002 Chevy 2500 Pickup - LB7 Engine Rebirth: Part 1

The venerable LB7 Duramax engine can’t hold up to everything - sometimes it needs a good rebuild

Kanan Gubins
Feb 10, 2014
Photographers: Kanan Gubins
With all the fanfare attached to the introduction of General Motors’ Duramax engine back in 2001, there were big expectations. But it has proven to be a superb powerplant. These trucks have been on the road for 12 years now, and they have turned out to be great workhorses. But when an engine is modified to almost double the stock power, it speeds the engine aging process up quickly. With the loss of oil pressure that can happen with a highly modified Duramax, the main seals can go out, and seeing chunks of copper in your oil is never a good sign. That’s what happened to this engine, thus a visit to Guy Tripp’s SoCal Diesel was in order. We think highly of the engine-building skills of Guy.
For the most part, this ’02 Chevy 2500 pickup spent its life towing studio trailers in Hollywood. The LB7 went through the wear and tear of being an LB7 engine, which included injectors being re-done two times before 200,000 miles. The cause of failure was loss of oil pressure due to the injectors dumping excess fuel, which caused the oil’s viscosity to thin out. It also did not help that the truck usually had to pull up a steep grade. The loss of oil pressure caused the main bearings to wear, and that required a complete rebuild of the engine.
Top-notch Engine
If you’re even thinking about (or in the process of) rebuilding your tired Duramax engine, this is the go-to guide for you. When we teamed up with SoCal Diesel, we were looking to have a top-notch engine. And SoCal Diesel is the kind of place you can go for towing or racing applications -- it’s a one-stop shop. With this this article, you should be able to get a feel for the process of building a Duramax diesel engine with the proper tools and methods. As SoCal Diesel engine builder Chris Hicks explains, tolerances will make or break an engine. Coming from a man who built race-winning NASCAR engines for more than 20 years, it would be foolhardy to question him. An engine build such as ours is not for everyone, so if you have any doubts about your mechanical knowledge or skills, you should leave it to the professionals.
Operation One Bad Duramax
The 2500HD Crew Cab longbed 4x4 had 225,000 miles on the odometer when the unfortunate damage happened. Modifications to this truck included: EFILive, a built Sun Coast transmission, an 8-inch lift, and 37-inch tires.
Checking the Destruction
Every engine that comes to SoCal Diesel is completely disassembled, ensuring every part is within spec for reassembly. SoCal Diesel’s engine builder, Chris Hicks, inspected the block and discovered the main bearings were rubbed so bad that the crank could not be reused. Even more bad news came from Magnufluxing the block, as that showed us deposits in the cylinder walls. For cases like this, purchasing a low-mileage engine to start the rebuild is a good idea. All other components, such as the connecting rods and the heads checked out OK. As it turned out, we were upgrading everything that was OK -- go figure! The newer LLY block we procured was within the same spec as the LB7, it did not require a larger bore, and it allowed us to start the rebuild of the engine quickly and less expensively.
The Work Begins
Check out the photos to see just what the SoCal Diesel crew does when they rebuild a Duramax.

Sources

Merchant Automotive
Zeeland, MI 49464
866-399-7169
http://www.merchant-automotive.com
Manley Performance Products
Lakewood, NJ 08701
732-905-3366
http://www.manleyperformance.com
SoCal Diesel
Valencia, CA 91355
661-775-5620
www.socaldiesel.com
Nic industries Inc.
866-774-7628
www.nicindustries.com
Mahle/Clevite
888-255-1942
www.MahleClevite.com

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