Cummins 4BT & Diesel Conversions Forums banner

2006 Hummer H3 Build Thread

261310 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.
1 - 3 of 389 Posts
4.56's will be great, with 38's.
I think you have excellent wrap on the alternator and compressor at the expense of the crankshaft pulley. Looks to me that the drive pulley could slip. All of the heavily loaded pulleys I've seen on factory stuff have close to 180 deg of wrap.
To add to JimmyDs comments,
Your comparing a V8 to a inline 4. V8s have a power pulse every 90 deg, the I4 its every 180 degrees, which is much harder on a drive train.
1 - 3 of 389 Posts