(ADMIN: I hope I put this in the right category?)

I'm toying around with the possibility of pulling out the GM 6.5 diesel & dropping a Cummins 4bt into an ex-military, (m998) Humvee (a.k.a. Hummer H-1).

I have heard of people putting a 6bt in one, I know while a 6bt swap brings the Humvee immense power and reliability improvements, but a 6bt's rocker arm covers almost touch the top of the engine compartment, requires upgrading the transmission, axle shafts, brakes, & geared hubs, and the mpg really doesn't improve much if at all.

With that in mind, has anyone swapped a 4bt into a Humvee?

1) Does it fit better?

2) Does performance improve over the original GM 6.2 / 6.5?

3) Does MPG improve? (I refer to the mpg & performance using straight diesel, not WVO or alternative fuels)

4) Do you have to upgrade the rest of the drivetrain? like for a 6bt?

5) Are there 4bt conversion kits for Hummer H1's/Humvees?
(Transmission adapters, Crossmembers, Engine Mounts, Pump/Compressor/Alternator Brackets, etc)

Most of my knowledge is on paper or from putting together specs & stuff I find on the internet, and (on paper) a 4bt swap looks like it can be a very good idea for a Humvee (or Hummer H-1), but I have yet to hear (or find an illustrated build thread) from anybody who has actually DONE such a swap.

 

6bt all the way!
You are best off with the engine, transmission and transfer case out of a Dodge. The rest of the drive train is fine. There is no need for axle and brake upgrades. Just put a 2.5 in body lift on it

If you still want to go the 4bt rout, there are a few people who have done it already; just Google it.

 

With a truck this big I would go 6bt over a 4bt. You will thank yourself in the long run.

 

I found a quality shop in Whichita, Ks on the internet that does this. It looks first class to me. Not cheap but very doable. Hope this helps.

Diesel Conversions Eco Power Increase MPG More Horsepower - Clean Futures