How not to install a Duramax in a M998

[TOBASH]

How loud is the motor noise?

 

[Mogman]

How loud is the motor noise?

Not too bad I can barely hear the exhaust at highway speeds, at low speeds it is obvious it has a big ass turbo, this is a totally different animal being it has a variable geometry turbo charger and a performance one at that.
With the stock tuning at idle is sounds like a turbine jet engine because the exhaust vanes are pinching off the exhaust to increase the velocity across the exhaust turbine creating as much boost as possible from idle and up, I have tuned that out so now at idle it sounds like a big block Chevy with a some turbo whine, but as soon as you step on the gas the vanes slam shut again to start to build boost, The stock exhaust is evidently designed to suppress those high frequency sounds and of course the turbo being a Cheetah aftermarket performance part probably make more turbine whine also.

As far as the "diesel" sound from under the hood being a high tech variable direct injection engine it is quieter than even the indirect injected 6.2/6.5L the reason for indirect injection was to reduce the "diesel" noise to make it more acceptable in passenger and light truck applications with the trade off of less efficiency and MUCH harder to start, heck until you get near freezing the Duramax does not even need glow plugs, I don't even have them connected.

 

[Mogman]

I'm almost certain the manual for my duramax block heater said it doesn't activate until -18C which is right around 0 F. ........The injectors don't need help until 0F and that is just nuts. The seat in the truck is frozen solid like a rock but the oil, bearings, fuel, def, ....everything keeps working. I ran in -40 always on a block heater and expected head gaskets to go but the duramax never let me down.

The only problem I had was the 2016 and burning up pulleys right off the lot. I'm sure they went to imported bearings being punched out in a sand factory. I always broke them in by the book so pulleys are something to wiggle and test for heat after a run. I was in break in mode in a brand new truck in the middle of the city with belt smoke just rolling out from under the hood. That's funny!

It's not easy going through a build like this so thanks again for sharing it and taking it to the end. We gotta see some video and stats on 0- 50 or 1/4 mile runs. 0-50 mph is easy with a camera pointing at the speedometer and 'youtube' having a clock set up to do the timing. My record with the deuce is under a minute. Here's an entertaining hummer vid mate.

Yea I have seen these guys before, disappointing they never lifted the hoods on ether of them..

 

[Mogman]

Managed to get plates today, I thought the whole thing was doomed, the first 45 min. was trying to figure out how to issue "radio operator" plates (even though they have done it before). Really funny, Texas allows up to three vehicles with the same amateur call sign on them, the ONLY plates that can be issued to more than one vehicle, so both of my HMMWV's will have the same plate number, the second hour was due to them filing the title work incorrectly when I turned up with the SF97 last year, seems it was classified as a truck when it should have been classified as a pass/truck, so I had to surrender my title and they re-did everything, Geez!! Well at least now I HOPE it's fixed...

 

[Mogman]

I want to go riding but it has been raining here for about a week, I was lucky to get to Beeville and back dry Monday I unfortunately I have to treat this like a garage queen until I get the doors and top installed, they say rain until next Tue.
It is said,
"South Texas is in a perpetual drought only interrupted occasionally by torrential rain"

 

[Russ Knight]

I want to go riding but it has been raining here for about a week, I was lucky to get to Beeville and back dry Monday I unfortunately I have to treat this like a garage queen until I get the doors and top installed, they say rain until next Tue.
It is said,
"South Texas is in a perpetual drought only interrupted occasionally by torrential rain"

Send it to us, we need it.

 

[Mogman]

Took it out for a 100mi jog this morning, this thing it a hoot to drive, it is SO much more relaxing driving at 2000RPM rather than 3000RPM.
All pressures and temps look great!
Spotted my propane guy on the state hwy on the way home and decided to "ambush" him from behind, I was pleasantly surprised at how fast she jumped up to 95.

 

[Action]

Took it out for a 100mi jog this morning, this thing it a hoot to drive, it is SO much more relaxing driving at 2000RPM rather than 3000RPM.
All pressures and temps look great!
Spotted my propane guy on the state hwy on the way home and decided to "ambush" him from behind, I was pleasantly surprised at how fast she jumped up to 95.

It probably wouldn't hurt to hit the diffs, hubs, brakes, etc with an IR temp gun after a 95 mph drive.

 

[Mogman]

It probably wouldn't hurt to hit the diffs, hubs, brakes, etc with an IR temp gun after a 95 mph drive.

LOL, yes probably so, did not last more than a few seconds, I am still running the original tires, I am waiting for by balancers to get here before installing the new Baja tires
I purchased a dozed temp sending units for my transmission temp gauge (that is the number they were offered), I have one on the old engine oil cooler (now a trans cooler) and just ordered a replacement pan for the trans that will get one, as soon as I figure out an acceptable way to switch them I will add them to all the gear boxes.

Here in Texas we don't use no stinking brakes, the state is big enough to coast to a stop.....

 

[Mogman]

I installed the drive by wire cruise control this week, They are made by Rostra but rebranded (and a fair increase in price) by Dakota Digital, I found a used DD cruise control without switches and purchased a Rostra dash mount switch ass, whole package was $225.00 Works like a charm, the lowest I tried it was 20MPH and she did great, seems the sweet spot with the old run-flats is about 70, I still have not been able to get the damn electronic transfer case to work, will not mess with it too much longer, I have a floor shift transfer case but would need to go through it first, in hindsight I probably should have gone through it and switched to begin with.

Great for the old knees
EDIT, I did get the TC working, it was a defective shift motor

 

[Mogman]

So I ran down to the CAT scale this morning, she does not weigh as much as I figured.
Steering axle 3060
Drive axle 2360
Total 5420

I am not sure what the "curb weight" included for 5200lb as it was originally but mine is stripped about as far as you can go, it still has the B pillar but no doors or top.
Up to 360mi on the odometer, going to run down to Port Aransas tomorrow to check out the tourists, going to stay off of the FWD section as I have no FWD at this time, it would be rather embarrassing to stick a HMMWV in beach sand...

EDIT, I did get the electric shift MP1626 working some time ago, the "shift on the fly" is pretty cool

 

[Mogman]

Just an update, turned 3K on the clock on the way to Beeville yesterday for a Chinese lunch and all is well!

 

[Mogman]

Turned 13K the other day, still loving it every time I drive it, installing A/C and a low profile helmet top at this time, then she gets a new paint job!
I have my eye on a few Dmax salvage trucks coming up for auction, after I turn the DuraVee into a soccer mom truck with doors, top and A/C I will need another open little hot rod to drive around.

 

[thoner7]

Mogman- this is an old thread and I was reading it just bc I was bored. But I am curious about the electrics, why did you convert everything to 12v??

Could you have fit a dual voltage regulator under the hood and ran a dual system?

Or do they make 24v starters for the Dmax?

re-wiring for all the lighting and windshield wipers and all that sounds terrible, I was thinking that going to LED you may have been able to keep the OEM wires (but I’m certainly unqualified to know)

Can’t wait to see it painted and with the helmet top, I’ve always liked those for some strange reason

 

[Mogman]

Mogman- this is an old thread and I was reading it just bc I was bored. But I am curious about the electrics, why did you convert everything to 12v??

Could you have fit a dual voltage regulator under the hood and ran a dual system?

Or do they make 24v starters for the Dmax?

re-wiring for all the lighting and windshield wipers and all that sounds terrible, I was thinking that going to LED you may have been able to keep the OEM wires (but I’m certainly unqualified to know)

Can’t wait to see it painted and with the helmet top, I’ve always liked those for some strange reason

Everything but the wipers and fans are 12V, no reason not to, trying to blend the two wiring harnesses would have been a bastardized system to say the least.
Re wiring is much better, trying to run the 24V gauges on the Dmax would have been a pain.
I have two complete systems one 12V and one 24V with two alternators the Dmax is already set up for dual alternators all you have to do is bolt it up and buy the correct belt.
I have no idea if they make a 24V starter for the Dmax but would not want to pay for one if they did
It would not have made any difference going to LED headlights which I dislike, LED headlights are too harsh IMHO, I used the LED tail and turn signals just because they work just as well on 12V
No $250 turn signal relay etc, is also a good incentive.
Re-wiring the truck was actually easy, one of my strong points is electrical.
My next conversion I plan on using a LBZ, all the good stuff is in the ECM like cruise control and the drivers for the inst. panel which I plan on using making for much less wiring as the inst. panel is "fly by wire" requiring only a data connection and the original sensors are already needed for input to the ECM anyway.
AND the donor truck for my next conversion had all the electrical components stripped out and they chopped up all the harnesses in the process so re-wiring that truck is a no brainer.
The helmet top I am using on the Duravee is really cool as it is a low profile very similar to the civy Hummer wagon.

 

[thoner7]

So you already have a new donor truck? Do tell

 

[Mogman]

So you already have a new donor truck? Do tell

It is the one in the picture above, a 1994 M1097A1 the top and rear doors are going on the Duravee.
It is in very nice condition, they stripped all the electrics and steering components, why the front wheels look a little wonky.
IMHO the Basic or A1 is the way to go because of the 2.56 gears.

 

[Mogman]

I was asked about if my truck had full time 4wd and if I towed with the Dmax.
I am using the original transfer case from the 2008 LMM donor truck, it is electronic, has its own computer and is shift on the fly, meaning you can switch from any mode to another and when the TCCM decides things are right it will make the shift, to say if you are sitting there spinning the rear wheels it will not shift into 4WD until the gears can mesh without grinding, pretty dang cool and handy for sure.
But it is only part time 4WD so it is in 2WD on the pavement.
I have not towed with the DuraVee but I did have a big S788 shelter on it which had tons of drag and had no issues with heating, I have never had any coolant overheating but there have been times when running against a cross/head wind that I would back off from my normal 80MPH highway speed to reduce EGTs even though they are not at the danger point for the Duramax, I would like to install a larger intercooler in my next conversion this winter if I can find one.

 

[Gcelevator]

I was asked about if my truck had full time 4wd and if I towed with the Dmax.
I am using the original transfer case from the 2008 LMM donor truck, it is electronic, has its own computer and is shift on the fly, meaning you can switch from any mode to another and when the TCCM decides things are right it will make the shift, to say if you are sitting there spinning the rear wheels it will not shift into 4WD until the gears can mesh without grinding, pretty dang cool and handy for sure.
But it is only part time 4WD so it is in 2WD on the pavement.
I have not towed with the DuraVee but I did have a big S788 shelter on it which had tons of drag and had no issues with heating, I have never had any coolant overheating but there have been times when running against a cross/head wind that I would back off from my normal 80MPH highway speed to reduce EGTs even though they are not at the danger point for the Duramax, I would like to install a larger intercooler in my next conversion this winter if I can find one.

Thank you mogman.

 

[Baja Hummer Man]

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.