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It is time... Enter the age of the Cummins

burbn10

burbn10

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The 6.2 is dying in my M1008 and I finally got my hands on a 12-valve 6BT Cummins. As soon as I find a NV4500 for a reasonable price, I am going to start on this project. I'll update this post as much as possible with pics and tips from the install.

For a starting point, I got a 1998 P-pumped 12 valve 6BT Cummins Turbo-Diesel from a Dodge 1-ton. It's already been modded. Has oversized delivery valves, 70+ injectors, 4000rpm governor springs, ATS exhaust and intake manifolds, and the killer dowel pin fix. It currently has a Banks Quick-Turbo upgrade, but I'm in the process of obtaining an ATS Aurora 3000 turbo to make it spin up faster and keep the EGTs down.

The plan is to back this engine up with a 5-speed (or 6-speed if the price is right) manual transmission (NV4500 or NV5600) into a NP205 transfer case. Like I said, as soon as I find a used one for a reasonable price, I'll get this ball rolling and start the build and documentation. Wish me luck!
 
niferous

niferous

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Houston, TX
burbn10 said:
Just the motor. Truck got totaled last winter and my buddy parted it out. Nothing I wanted off it anyways besides the motor, intercooler, and turbo plumbing.
Click to expand...

I'm not as hot as I should be on Cummins motor swaps. With the older 12 valve motors do they have any kind of computer or stuff like that or are they pretty much mechanical just like the 6.2? I know that they were using vacuum to control the cruise control as my brothers busted a hose and we had to repair it. I'd like to do this one day to my Suburban!
 
burbn10

burbn10

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niferous said:
I'm not as hot as I should be on Cummins motor swaps. With the older 12 valve motors do they have any kind of computer or stuff like that or are they pretty much mechanical just like the 6.2? I know that they were using vacuum to control the cruise control as my brothers busted a hose and we had to repair it. I'd like to do this one day to my Suburban!
Click to expand...
The 12v Cummins is all mechanical like the 6.2. It weighs 1200lbs roughly and the stock engine can take a ton of power without failure. Mine had a computer hooked to it, but that was to control the electronically controlled 47RE transmission. I've fired the engine up sitting on the cradle before by just giving it a fuel source and hooking the battery to the starter and fuel shutoff solenoid. This is the only medium-duty application diesel put into a light-duty chassis.
 
jimmy-90

jimmy-90

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I've thought alot about doing the exact same swap on my m1028. One thing that I am worried about is the fact that the 12v cummins is such a low rpm motor. How fast do you think it will go with the 4.56 gears plus the NV4500s overdrive? I noticed that most cummins equiped trucks are geared really high. Also are you gonna use a body lift to be able to close the hood? I saw someone on another site a while back selling motor mounts to do a cummins to chevy swap without a bodylift or cowl induction hood. If I remember right he wanted some outrageous price for them though. Like $500 or something.
 
burbn10

burbn10

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jimmy-90 said:
I've thought alot about doing the exact same swap on my m1028. One thing that I am worried about is the fact that the 12v cummins is such a low rpm motor. How fast do you think it will go with the 4.56 gears plus the NV4500s overdrive? I noticed that most cummins equiped trucks are geared really high. Also are you gonna use a body lift to be able to close the hood? I saw someone on another site a while back selling motor mounts to do a cummins to chevy swap without a bodylift or cowl induction hood. If I remember right he wanted some outrageous price for them though. Like $500 or something.
Click to expand...
Several companies make governor spring kits for the 12v to increase it's RPMs. Mine has a 4000rpm spring kit in it. Plus the NV4500 is an overdrive transmission, so I can drive at reasonable RPMs on the highway. As far as hood clearance goes, I'm not worried about it. The mount I have from Avalanche keeps it low enough to clear the hood just fine without a body lift.
 
ODdave

ODdave

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just a heads up, with only a 4 in lift and no body lift that avalanche enginering mount only gives you about 2in of clearance between it and the front axle. i had to switch to a 6 in because of this. and your cummins is gonna hate those 4.56's you are gonna wanna keep that engine around 2k rpm for max econ and life. Oh yea, if your wanting that crossmember in the next month or 2 you better order it now, there slow...........
 
burbn10

burbn10

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ODdave said:
just a heads up, with only a 4 in lift and no body lift that avalanche enginering mount only gives you about 2in of clearance between it and the front axle. i had to switch to a 6 in because of this. and your cummins is gonna hate those 4.56's you are gonna wanna keep that engine around 2k rpm for max econ and life. Oh yea, if your wanting that crossmember in the next month or 2 you better order it now, there slow...........
Click to expand...
I was planning on doing a 1" Zero-Rate kit all around on the suspension. Do you know of any other crossmembers that are available with more clearance? I'm not worried about the 4.56's, with the 37's and the overdrive trans, I should be able to do 65mph at around 2000rpm. Plus my friend is claiming he can get me a Gear Vendors overdrive unit for cheap from somebody he knows. If that goes through, the gearing won't be an issue.
 
Croatan_Kid

Croatan_Kid

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New Bern, NC
First off, I hate you for getting a P-Pump motor for a grand!!! :drool: :driver:

A 12V will fit in a GM frame with no suspension lift, in case anyone was wondering. You don't need any body lift to make it fit either.

Scott Oswalt, owner of TN Diesel Conversions makes a crossmember and motor mount kit, which is what I'm using. While they are somewhat pricey, you can have them the same week. He keeps them in stock and is also a Cummins dealer; I deal with him frequently. Also, any time I have ever called him for "tech support" he has always answered and walked me through my problem, even on a Sunday.

A good reason not to use a Duece trans is ease and availability of parts, plus it's really heavy and adapting it to a transfer case would be a pain. Then you have to get the clutch hydraulics to function, etc. Too much work...plus, SAE bellhousings are huge and there's not a whole lot of room to work with in a GM transmission tunnel when doing this swap.

I have a 3200 rpm governor spring in my VE pump. Works a lot better than the stock 2400. Way easier to cover the gearing gap between 3rd and 4th on an NV4500 and I can make some nice boost (a hair over 30 lbs). With 4.56s and 39s, I can easily run down the highway with traffic (faster too) and net some pretty good fuel milage.

What else? Umm...


Oh, if you use the 34" core radiator from the 6.2, you will severely over-cool a Cummins. In addition, the intercooler will not fit around it and getting the radiator hoses to fit is a pain in and of itself. 2nd gen intercoolers (IE: P-pump motor 94-98.5) fit better and you really don't have to trim much out of the core support.

Lastly, there are no computers. All 12V Cummins motors are mechanical, however, in certain applications such as a Dodge truck, they used a computer to control the alternator's output and the transmission. This is not needed to make it function as you can use a Dodge style external voltage regulator, but you will need to add a capacitor in the keyed wire to keep the lights from pulsing OR you can do what I did after you get tired of that crap and get up with PA Performance for one of their 1-wire conversion alternators. You can get a 136 amp or a 200 amp hi-output alternator. I also got a 4 ga power wire kit with a 200 amp mini-fuse holder. No more charging problems what-so-ever, plus more amperage than the stock 120. Again, expensive parts, but they're worth it and they last a while.

I suggest using everything from under the hood of the Dodge. Radiator, intercooler, etc, etc. Makes everything fit better and work likes it's supposed to. Also, first gen (89-93) exhaust fits much better because of the downpipe. I was running a 2nd gen exhaust, but the downpipe was on the firewall, so I copied the design of the first gen downpipe and made my own.


If you have any more questions or concerns, feel free to ask. If I can't answer them, I'll put you in contact with some people than can!
 
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