1991 GMC Suburban: Doomsday Diesel Part 6

37-Inch Tires, Brutally Simple Suspension, and a Dozen Other Parts Built To Last Forever

David Kennedy
Oct 1, 2012
Photographers: David Kennedy
When building a diesel truck you want to last, less is always more. Less plastic means more steel, fewer electronics means more reliability, reduced options means more capacity, and zero spark plugs means more power and fuel economy.
Photo 2/22   |   Doomsday Diesel is a ’91 GMC Suburban 2500 that began life with a gas engine. Now it has a ’95 12-valve Cummins built by Industrial Injection between the framerails.
When we began our 5.9L Cummins-powered Doomsday Diesel project back in the January ’12 issue, we knew we wanted a low-tech truck that would be too simple to fail, yet easy to fix if it ever stopped running. We didn’t anticipate we’d be replacing or rebuilding everything that spins or holds fluid on this ’91 GMC Suburban —but that’s what we’ve done. As you can imagine, it’s taken us longer than we expected.
Photo 3/22   |   Mercenary Offroad’s Todd Farrand pulled the engine and TCI 6X (based on a GM 4L80E) so he could modify the pan.
Why have we gone this far? Well, building a vehicle that will function through the apocalypse required an assembly of parts that we could be certain wouldn’t fail. The best way to gain that certainty was to inspect each critical component. The systems deemed worn out were rebuilt, those pieces seen as weak were upgraded, and the creature comforts discovered to be unnecessary were removed.
When Doomsday Diesel is complete, we expect to have an all-terrain vehicle with a 1,000-mile fuel range, seating for four, and virtual (if not actual) bulletproof durability. The true test of this machine will be an escape from Los Angeles scenario, in which we see what it really takes to escape this booby-trapped metropolis after society crumbles. Or we’ll just try to drive out of town on the Friday afternoon before Labor Day weekend.
Photo 4/22   |   We planned to keep the Suburban’s original vacuum brake booster and master cylinder, but in order to get the most out of our new four-wheel EBC disc brakes, and to make sure the injection pump won’t hit the master cylinder (arrow), we’re ditching it in favor of a Hydroboost system.

Sources

Energy Suspension
San Clemente, 92673
888-913-6374
http://www.energysuspension.com
Rancho Suspension
Monroe, MI 48161
734-384-7804
www.gorancho.com
Rockland Standard Gear
Sloatsburg, NY
877-774-4327
www.rsgear.com
LMC Truck
Lenexa, KS 66219
800-562-8782
www.lmctruck.com
Dynatrac
Huntington Beach, CA 92647
714-596-4461
www.dynatrac.com
Borgeson Universal
Torrington, CT 06790
860-482-8283
www.borgeson.com
Industrial Injection
Salt Lake City, UT 84104
800-955-0476
www.industrialinjection.com
BFGoodrich
877-788-8899
www.bfgoodrichtires.com
Reid Racing
Pleasant Hill, CA 94523
925-935-3025
http://www.reidracing.biz/
Mercenary Off Road
Sun Valley, CA 91352
www.mercenaryoffroad.com
TCI Auto
888-776-9824
www.TCIAuto.com
Hutchinson
Trenton, NJ 08609
609-394-1010
http://www.rockmonsterwheels.com
Lee Power Steering
818-768-0371
www.lee-powersteering.com

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