How not to install a Duramax in a M998

[Mogman]

I have a duramax/allison 5 speed in my Civillain Hummer, it has 2.56 gear and max speed is 87 mph then its governed by the ECM, We had one in a race Hummer also and it would only do 91 in baja. You conversion looks great.

If I remove the speed limiter but leave the stock rev limiter in place it will do a little over 120MPH.
Almost 17K on the conversion and have not had to rework anything I can think of, I have blown out a bunch of aftermarket half shaft boots but what can you expect from cheap Chicom stuff.

 

[thoner7]

If I remove the speed limiter but leave the stock rev limiter in place it will do a little over 120MPH.
Almost 17K on the conversion and have not had to rework anything I can think of, I have blown out a bunch of aftermarket half shaft boots but what can you expect from cheap Chicom stuff.

Can I ask how much you paid for the wrecked donor truck?

 

[Mogman]

Can I ask how much you paid for the wrecked donor truck?

Around $3200 with fees, I paid less than $2500 for the 07 LBZ for my next conversion, if I can ever walk again
The LBZ is a better fit IMHO

 

[thoner7]

Wow those are good prices. Where are you finding these trucks again?

 

[Mogman]

Copart

 

[Mogman]

Turned 25K on the conversion this week with no significant re-work of the original installation, still loving every minute

 

[Rescuediver1982]

Awesome build thread!

Throwing a quick question into the mix, I understand you rewired a bunch of the truck to run on 12v and still some aspects run on 24v. My M998 is all 24v except a few audio/comfort things that run off of a 24/12 stepdown. Could you you standalone swap harness for the D-max, keeping it fully separate from the rest of the m998's body system?

Also, what intercooler/radiator did you end up running? Factory Dmax? Any chance we could get a picture?

 

[Mogman]

Awesome build thread!

Throwing a quick question into the mix, I understand you rewired a bunch of the truck to run on 12v and still some aspects run on 24v. My M998 is all 24v except a few audio/comfort things that run off of a 24/12 stepdown. Could you you standalone swap harness for the D-max, keeping it fully separate from the rest of the m998's body system?

Also, what intercooler/radiator did you end up running? Factory Dmax? Any chance we could get a picture?

Well it would be tough to find a converter to run the 12V starter on the Dmax.
You would not have to re-wire the truck to run on 12V just replace the bulbs, horn and a few other things, you would still need 24V for the inst and heater fan.
I build 12V WW motors.
The inst. would be a hassle as the sending units do not lend them well to adaption to the Dmax engine, on that note you will have to have two of evey sending unit for the oil, and temp, one for the truck and one for the ECM'

The conversion I am starting hopefully this spring is using a LBZ Dmax, this will allow me to easily use the factory LBZ inst. cluster, much less wiring and complication other than adapting the cluster to the dash.
Another consideration is what Dmax you are going to try to use, anything newer than the LMM and the engine gets too tall to reasonably fit into a HMMWV, LBZ seems to be the sweet spot, I had to use some of the induction parts along with the oil fill pipe from a LBZ
But still it would be a awful mess, it was much easier for me anyway to just rewire the entire truck.
Here is a pic of the intercooler, I believe a pic is already on this thread, it is simply a unit I picked up on fleabay.
The radiator is just the three core Chicom aluminum ones found on fleabay, I have no heating issues other than uncomfortable EGTs if I push it too hard, I have never reached over 1200 deg. 1300 being getting into concern

 

[DeMilitarized]

I wonder if a 6.7 power stroke would fit..

 

[WillWagner]

I wonder if a 6.7 power stroke would fit..

Oh, I am sure one could fit one in there, but I bet working on it in the HMMWV would suck!

 

[thoner7]

Well it would be tough to find a converter to run the 12V starter on the Dmax.
You would not have to re-wire the truck to run on 12V just replace the bulbs, horn and a few other things, you would still need 24V for the inst and heater fan.
I build 12V WW motors.
The inst. would be a hassle as the sending units do not lend them well to adaption to the Dmax engine, on that note you will have to have two of evey sending unit for the oil, and temp, one for the truck and one for the ECM'

The conversion I am starting hopefully this spring is using a LBZ Dmax, this will allow me to easily use the factory LBZ inst. cluster, much less wiring and complication other than adapting the cluster to the dash.
Another consideration is what Dmax you are going to try to use, anything newer than the LMM and the engine gets too tall to reasonably fit into a HMMWV, LBZ seems to be the sweet spot, I had to use some of the induction parts along with the oil fill pipe from a LBZ
But still it would be a awful mess, it was much easier for me anyway to just rewire the entire truck.
Here is a pic of the intercooler, I believe a pic is already on this thread, it is simply a unit I picked up on fleabay.
The radiator is just the three core Chicom aluminum ones found on fleabay, I have no heating issues other than uncomfortable EGTs if I push it too hard, I have never reached over 1200 deg. 1300 being getting into concern
View attachment 957538

Let me know when you start taking orders mogman! Haha

 

[thoner7]

I wonder if a 6.7 power stroke would fit..

There is one on YouTube