H1 Hummer - A Slow Build

[up-n-over]

I traded my 4Runner for a Porsche GT3, and the GT3 for a H1 Hummer...

There were a total of 11,888 H1 Hummers ever produced. A total of 1,374 were produced in 1996. Of these 1996 rigs, only 214 had gasoline engines. 142 of these 5.7 liter TBI powered rigs were assembled as HMCS wagons. 47 HMCS wagons were produced in Bright White. I haven't been able to determine how many Bright White - HMCS- Gas engine hummers were produced, but I guess that it would be very few.

This is going to be a slow build-up of an EXPEDITION type rig; NOT a rock crawler. It will be used for trail riding, beach trips to the Outer Banks, and will also tow the boat. Here are the specs and plans:

Now:
1996 H1 Hummer Wagon
Weight of vehicle with 42 gallons of fuel and HMMWV wheels and runflats installed - 7070lbs.
57,000 miles
5.7 Liter TBI gasoline engine
4L80E transmission
NP 242 transfer case
Full skid plates and underbody protection
Central Tire Inflation System (CTIS). Front leaks.
Plain steel wheels with CTIS
Towing package
Torsen limited slip differentials front and rear
37-12.50X16.5 Nankang M&S tires

Projects:
Selectable locker for front axle
Detroit locker for rear axle
12000 - 15000 LB. winch
Roof rack
Off road driving lights
Underbody rock lights
HMMWV 24 bolt beadlocks with low profile runflats DONE
Rear tire carrier
Repair CTIS system
3000 watt power inverter

I have already mounted the new HMMWV beadlocks and they look pretty good.

 

[02dmax]

Nice wagon. Ive been wanting a H1 hard top 4 door truck for ever. Maybe one day.

 

[Corigirlloves]

My boyfriend has an H1 and has been doing a rebuild from the ground up...I'm gonna share your thread with him, maybe he'll have some helpful tips

 

[mk1spyder]

Why a gas truck? How much was the GT3 worth? Also junk the weak 242 T-Case.

 

[up-n-over]

Why a gas truck? How much was the GT3 worth? Also junk the weak 242 T-Case.

The reason for the gas truck is that the non-turboccharged diesels are real dogs. The turbo diesels from '96 to about '01 had problems with the #8 cylinder leaning out and burning pistons. I can't afford to buy a late model H1. The gas engine is very reliable and easily upgradable, and it fit my budget.

The Porsche had about $10K worth of problems. I am happy with the trade, that is all that matters.

The weak 242 will be fine for what I plan to do with this rig. It is not a rock crawler, and it will not see the shock loads that seem to destroy chain driven cases.

 

[mk1spyder]

To each their own, welcome to the small family! We ride the short bus hah.

The gas trucks have their benefits and draw backs, one being that the body sits an inch lower from the factory, the turbo diesel trucks got a factory 1" body lift. But you're right they are much more reliable than the 6.5 TD if you have the earlier Z code block. It isn't so much that they run lean as it was a casting flaw in the later runs, and an overall shitty design with a weak block and components period. Mine is a middle run engine and one of the last H1's rolling on the original 6.5 TD (there are not many left).

The T-Cases don't generally fail due to shock load, that will take out a 10.3k CV axle (which you have) or a 1310 10.3k U-Joint (you have) way faster. It's generally because the drivetrain has to turn twice as fast as a normal vehicle to do 60mph, so it burns up the fluid way faster plus it has a sharty cooling loop that if your recall wasn't performed will pump ATF into the hubs/intake and doesn't do a great job cooling, its more of a cold start function.

The upgraded case has a water cooling loop as do the diff covers, to keep up with hot days traveling at any sort of speed.

If its not a rock crawler why bother with the lockers? You have the good 4:1 Torsen 1 diffs like my truck had, with some mild BTM they are basically lockers. Although I can't say I blame you, our absolute lack of suspension flex leads to ton of lifting wheels.

 

[Blaze]

Wait, those things had TPI in them? Does it look the same as the 80s stuff?

 

[up-n-over]

Wait, those things had TPI in them? Does it look the same as the 80s stuff?

TBI. I screwed it up in the first post. Fixed it now...

 

[Blaze]

You should convert it, or go with an HSR or something. I bet you would feel a ton of improvement, is that thing a slug with the TBI?

 

[mk1spyder]

A lot of guys end up putting big blocks in them. They have vortec heads and a pretty decent cam stock, much better than a normal 5.7 Chevy truck. They sound good with an exhaust.

 

[up-n-over]

It is not a rocket, but it is ok. It is much better than the non-turbo diesels that I have driven, but is not as good as the turbo-diedels. It only has 57K miles on it and runs great. As a result, the engine mods are way down on my list of things to do.

I am watching the forums and ebay for a good set of heads and performance parts, but there is no rush.

 

[mk1spyder]

Are you staying with the 37's? Either way I would recommend going to 3.08's if you put lockers in.

 

[Benji]

With it having the 5.7, it could be a easy swap for the LQ4 or LQ6 chevy 6.0....

 

[up-n-over]

I plan on staying with the 37s, but will most likely go to 3.08 gears when I do the lockers. This will help a lot on getting this beast moving and should not hurt the fuel economy too much. It will also give me a little flexibility if I decide to go to larger tires in the future.

I really am not very interested in getting into a project of swapping in a different kind of engine at this time. If I do swap in a different type of engine it will either be a Duramax or a Cummins. Again, this is very low on the list of things to do.

 

[yoder519]

Does it feel like it has as much power or more power as a regular 5.7L pick up? Im just curious. I didn tknow you traded the runner for that porsche!!

 

[up-n-over]

Does it feel like it has as much power or more power as a regular 5.7L pick up? Im just curious. I didn tknow you traded the runner for that porsche!!

Yes, it is like any other 7000 pound gasoline powered truck. It gets up to 40MPH pretty quickly, but it takes a little longer to get on up to 55...

The Porsche was fun to have for a little while, but it never really felt like MY vehicle. It costs so much to do anything to a Porsche that I couldn't afford to do any projects on it. I can mark it off of the Bucket List...

 

[yoder519]

haha yea Ive heard they are expensive to maintain. Guess ill never know!

 

[up-n-over]

Dropped the Hummer off at the transmission shop this afternoon to figure out a shift issue. Last week it started shifting funny. I found that it did not have a dip-stick installed in it, and water had ran directly off the firewall into the dip tube. I drained and flushed the Pepto Bismol out of the transmission and also changed the filter. It shifted pretty good for a little bit, and then started acting funny again. Tim ran a diagnostic check on it and found that it has a code for a bad solenoid valve. He said that this was probably caused by the water in the tranny. I told him to make certain that nothing else was damaged, and asked him to go ahead and install a shift improver kit while he is in there. He is also going to pressure test the cooling system to make certain that none of the water came from the radiator (there are no signs of oil in the radiator, and the tranny fluid does not smell like anti-freeze).

He said that unless he finds something bad in the pan, I should be back in the saddle by Wednesday...

 

[up-n-over]

Murphy is my ever-present companion....

Transmission is completely toast. Clutches came apart after the oil was changed. Oh well, it gives me the chance to build the tranny the way that I like them (nice firm shifts).

He is installing an RV billet torque converter, a shift improver kit, and beefier internals. He also said something about changing to a different kind of bearing on something because the 4L80E has a problem with a specific bearing or bushing....

Anyways, I'll get it back next week.

 

[87GMCJimmy]

Sweet rig! The 24 bolts make it look 10x better!!! Looking forward to watching your build! Sorry your tranny was toast, sounds like you've got a good improvement plan though!

 

[up-n-over]

Yes, the tranny kind of threw a wrench into the budget... Now it will take a little longer to get started with the modifications....

 

[up-n-over]

Got it back from the tranny shop

 

[gmentavlos]

Looks good Robert

 

[up-n-over]

Picked up a spare HMMWV 24 Bolt rim with runflat, Goodyear tire, and a Rhino tire carrier this past week.

 

[up-n-over]

When I bought the truck it did not have a key fob. This past week I found that it is equipped with a Viper alarm system. Did a little research, and bought a new remote. Boy, it is nice to be able to remotely unlock the doors. but I still haven't figured out how to program the system to get the remote start feature enabled...