GM turbo or Cummins? Again!

Hey everyone,

I have a dilemma. I was looking into getting a GM turbo setup from a 98 3500 for my 1008 but the father of my friend is possibly selling his 95 3500 Dodge 2wd with a cummins and a 5 speed manual transmission.

I am not sure which one to do now. I know there are a lot of little things to do for the swap and the GM turbo swap is easier.

What at would you all do? I do not want to spend a ton of money on this, so I am looking for the most bang for the buck. I am looking for answers from expirenced people.

Thanks a bunch!

Cummins all the way. You spend a little extra but it will be worth it. The 95 5.9 has the p7100 injection pump too!

What all extra is there? The cummins should have a Holset HX35 right? The HX35 will bolt directly to a 6.5L TD exhaust manifold, the oil feed and return line is the biggest hassle (at least that is what i have found so far). That is the route i am going.

Cummins without a doubt

You'll spend more to do the 12v cummins swap. But even stock, you'll be better off power wise. Not to mention, the Cummins will outlast the 6.2 by about 3 times.

The NV4500 that truck has can be used as well with a tailhousing and shaft swap.

I mis-read what you were asking. You are trying to decide between a GM turbo install and an engine swap with a cummins? There is a pretty big difference in cost i would imagine between the two...

It is always helpful to ask a question that is easily interpreted by the other readers.

At this point some people are thinking engine swap while others are thinking turbos.

So which is it?

I was asking for input on both. I am just not sure what I want to do. I want to do the Cummins and transmission swap but an not sure I want to take the truck offline for that long.

The turbo swap could be done cheaper and quicker but I am afraid that it may not be what I want for the truck in the long run.

I guess I will see how much the Cummins will cost and go from there.

It not that bad, the expanse comes when you redo things countless times, than pull it out and do it all again lol.. plenty of info on line for such a swap.. and a lot after market parts for 6bt in square bodies ect.. just plan are your moves an execute. should take 3-4 weekends to complete a swap another couple to wrap up..

Have you thought about going with a Banks Sidewinder setup instead? Just another option.

southdave said:

...just plan are your moves an execute. should take 3-4 weekends to complete a swap another couple to wrap up...

Click to expand...

This statement should be qualified, I'm doing a 6BT in a square body crew cab that's being turned into a CUCV, I have about year into the truck and I'm still getting parts collected. Expect to spend around $5-10K putting a 6BT in "correctly". The time it takes depends on what level of technical expertise you or your available friends have, the tools and space you or they have, and the time you have available for working on the project. It's funny how missing one important part in the middle of an assembly can stop it dead in its tracks leaving you waiting for the UPS guy to deliver your part from where ever you can find it. If you are on a time crunch, like if this is your daily driver, I'd recommend having all parts of the assembly mocked up and complete before even starting to tear down the original drive-train. This lowers the risk of the project tremendously.

For my truck, I already have a daily driver pickup which doubles as a parts runner - it would suck to tear down your only running truck only to find you need a part which requires a truck to fetch.

Other than than my opinion having driven trucks with both engines, the Cummins 6BT is the better engine, the transmission that Chrysler/Dodge put behind the Cummins is a weak point - the web is filled with stories of people chewing the NV4500/NV5700 up by driving "spirited". The nice thing about the Cummins is that is is a wide install-base engine - everything from agricultural and construction equipment, generators and water pumps, to on-road trucks school buses and marine applications - so there are pars options out there that even the local Dodge dealer won't think of, even 24Volt parts if you want to keep the original CUCV dual voltage system. There is no cast-in flywheel housing, so you can unbolt the flywheel housing and buy one that fits the transmission you like after the fact. Being an even cylinder count inline engine, it's much easier to balance, since you only have to match the piston and push-rod weights and balance out the crank shaft separately rather than getting complicated with the crank shaft balance as an assembly with flyweights. The only thing it lacks for my definition of "perfection" is replaceable cylinder liners. There are Dodge trucks out there that have put over 1-million miles on the original block, I haven't heard of and definitely haven't seen personally any 6.2L or 6.5L GM diesels with more than 300K, without major engine repairs.

With the P7100, the big risk is fuel starvation, so even if you trust the maintenance of the engine source, replace your lift pump and fuel filter. With a pre-97 block you may also have risk of the Killer-Dowel-Pin failure, so take a look inside the gear-train cover before you spend any time fitting that block in the truck.

Mine took 3 weekends to do.. about 6mo of research to do.. easiest swap there is is 4bt with th475 (th400) it has a gm adpator on it and set the motor at 15 degree tilt, this advoids the pumkin nicely,and will bolt up directly to your existing turbo 400 with the existing torque converter.. the motor mounts you can buy or fab up to suit your taste, I use fuild mounts that came with the motor took about 2 weekends to figure out.. ended up using the front mount. i left the trans in for engine placement.. here is where I got stupid.. decided I need more power and a manual trans and an axle swap.. that slowed up me up alot. pulled motor sent to machine shop to freshen up, ring mains cam ect.. swap in new spring for head to eliminate float and the typical fixs for cummins shortcomming, dowel pin and frezzeout plugs, rebuilt the with fuel pin and gov spring mods 2weeks..
transmission- 93 nv4500 out of chevy, freshen up disks installed the new 5th gear nut found a flywheel for cheep had it drilled to accept a 12in gm clutch.. note the cross member from the 700r4 from squarebody works perfectly in my nv4500 to 241 swap..
the hydrualic clutch/brake pedals setup from 85-91 square body truck master cylinder with external slave.. has and still giving me fits 'air in the line".. i used brake line and compression fitting to make the connections...
with all that I ended up with POS CUCV M1009 that is drive able and maintable.. this weekend I am rebuilding the axles bearing and shafts before i install dana 44 with 14 bolt semi floating 3:73 gear for drive ablity.. I know I need a locker but it beyond my skill set to do it right. besides i need the cash for my new fog lights lol..
there is alot little crap like the electric fan and controller new fuel pump and filer system.. fixing the hole in floor board from shfter tower gauges that should be doing but.. if i finish it what will I do???

That's exactly the type of qualification I was expecting. When I started doing my truck, I was also hearing "Oh yeah I finished it in a month..." from a lot of people - but then in disbelief, I started digging, and found the stories to be much the same. I have seen Cummins swaps done for less than $10K, but they usually reuse or lightly modify existing components. southdave's experience seems to align with this, but note that he took a lot of time to figure out what he was going to do - the actual installation only took him a few weekends, but he had:

• A plan
• A budget
• Knowledge
• Time

Without the above, it will take a lot longer. Note that he spent time doing an engine clean-up - if you get a block that needs work (pretty much anything you get), figure on adding a few weeks. In my area, there are no more engine shops - they've all moved out of the S.F. Bay Area and into the central Valley (California farm country). If you run into this situation, figure on your engine taking more like a month - these little things can add up quickly, especially if you can't do them in parallel (wait a week for parts, wait two weeks for the engine shop to clean and balance the engine and your new parts, another day to a week for a tuning shop to get it tuned - and transit time for all).

Why do you want to freshen up a motor before putting it in a truck?

1. Maintenance claims are no equal to opening up an engine and checking bearings, cylinder rings, cylinder scoring, checking for cracks (magnaflux) - replacing parts that would require you to take the engine out and/or apart (if it's out, save the time an effort).
2. If you're dropping a 2-5K engine in your truck it's either to replace a bad engine or to "improve" your engine situation - ask your self honestly, is the engine you're about to put in really going to accomplish either if you've never turned it over or looked inside?
3. If you are getting an engine like a pre-1998.5 Cummins 6BT with a known catastrophic risk, and don't check if it's been handled AND you like the way it was handled, well I'd be the guy in the back of your shop with a beer laughing... opcorn:

Of course this is my frame of mind when doing a project like this - it's your truck, do it your way - I wouldn't hesitate to stop if I saw a CUCV (or any other military vehicle) on the side of the road to help out, even if I knew the owner did something I disagreed with, that's kind of the point of helping out isn't it .

Wow! This has given me a lot to think about. Thanks for the detailed replies!

A 6.5, with a HX40WII turbo is what I'm doing. Very straight forward. A kit to fit the turbo is available from PT Wiring.

It helps if live in appalachiania, seem to have a inhaustible amount Youngins with facial hair in odd configuration that work, sleep and eat cummins. Several of theem have been wealth of knowledge. Local knowledge of 6.2 and 6.5 is limited to their fathers that long ago gave up on that platform for the powerstroke, and cummins...and now drive the old man half ton and dream of thier death truck