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2006 Hummer H3 Build Thread

261245 Views 388 Replies 61 Participants Last post by  andtra31
Been lurking on here for 2 years now and finally pulled the trigger about 2 months ago. I had been searching for about 6 months for a decent engine option and finally found one.

Donor vehicle is a 2006 Hummer H3 with the 3.5L. The truck has logged over 260,000 miles on the original engine and at the end of its lifespan was burning a quart of oil every 100 miles. As of today, the factory engine is out and the motor mounts are being fabbed to test fit the 4BT for the first time in a week or so. Project goals as follows :

- The engine will be bone stock except for 1) 3200 RPM governor spring 2) 12cm turbine exhaust housing. Goal will be to get a runner on the road, drive and log some baseline power and economy numbers and upgrade from there.

- Factory drivetrain will be utilized and be retained in the factory location. Unless there is something that just wont fit, the new engine will align with the existing driveline. Although the 4L60E transmission is not the heavy duty ideal, a few upgrades when it is out for service, a mild engine and no heavy towing planned should give a reasonable service life.

- Factory front IFS will be retained unmodified. This may mean some clearancing of the oil pan.

- Factory 4.56 gear ratio will be retained initially. This will put highway RPMs above the most efficient point of the engine, but baseline testing needs to be done before swapping any gearing.

- Intercooling will be done as an option during the install only if simple and feasible.

- Transmission controller will be converted to a standalone controller. The engine will require no electronics to run.

- A/C and power steering to be retained.

- Goal is 22-25 MPG highway with the swap

I'll post some pictures once my post count allows it.
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JimmyD is spot on once again :D

Looking forward to this build!
I much prefer my current setup on my '90 W350 of locking hubs, NP205, 4-Lo, 4-Hi, 2WD and Neutral. If I want I can leave the front hubs locked in even when running in 2WD. Then if things get bad just pull a lever for 4WD. Of course doing it like that makes for more wear and tear on the front axle but locking hubs aren't all that expensive to replace anyway. Just running like that for a month of snow season with moderate use of the truck anyways works real well for me.

This is my preference as well. I see full-time 4wd, in 99% of scenarios, as unnecessary. Even worse, I see full-time 4wd as an excuse for poor driver skill. "I've got 4wd, don't worry about it" type of thing.

However, if you're doing it to retain functionality and make sure that all the dash lights are off, I can understand and appreciate that. However, I see no advantage to retrofitting full-time 4wd to an originally-equipped part-time 4wd vehicle.
Pretty sure what Johnny meant is that people use it as an excuse for their poor driving skills, not that it's a valid excuse. Rhymes with lame brain.
Exactly. I put up a poorly worded post, I apologize. I have no fundamental problem with full-time 4wd, I just wouldn't retrofit it into a truck that didn't already come with it.

Dougal, interesting comments on how it affects handling with a truck. I'll have to research that a bit more.

Hijak over :D
Wow man, just wow.
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Intermittently not receiving fuel at the injectors? Something is wrong with that IP.

I haven't been following this thread well enough to remember if any work had been done to the IP, but the fact that you have fuel leaking from it is a bad sign. I had similar symptoms when I put the governor spring in my IP, but didn't hook it up correctly. Still kicking myself for that mistake :emb:
Sounds great. Looks like you got a bit of a crack in your windshield.
:lol: I was going to say the same thing.

Looks great Casey!
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