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To get a Cummins, or not to...

mountainexplorer

mountainexplorer

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1990 Dodge Cummins 2500 truck... wrecked, bent frame, all running gear there (Dana 60 and Dana 70 rear, 3.54 gears), Cummins Diesel motor with automatic tranny and T-case, 200,000 miles, apart but was all running good before the wreck. Comes with some old '63 Dodge frame with a 1-ton rear end and a closed knuckle Dana 60 front with a 360 and 4spd.

It's for sale $2500 for all or make offer... I wonder if I should get it and take on the project of swapping the motor into my '81 Crew Cab. But I really would want a 5spd manual. What automatics were used behind a Cummins in 1990?
 
Allan, your NV4500 would bolt to a Dodge cummins bellhousing :thumb: They offered the NV4500 from the factory in the Dodge trucks. It definitly sounds like it is worth the money they are asking and you could resell the axles and other parts to help recoupe some of the money. But like all good deals you had better jump on it fast.
 
Allen
Don't listen to any of them, they don't have a clue,(you are getting sleepy.......) you need to buy it then sell the motor to me you need the axels:D
(we need hynotic smiles)
 
Only problem is that I know that I'm incapable of tackling a project of swapping my Crew Cab over to the Cummins... motor mounts, electrical, fuel system, etc... it's all beyond me and my tool selection.
 
Fuel system is the easy part, there is no electrical other than a grid heater, starter and alternator, power steering is built into the motor, TH400 adapters are available unless you would rather go manual, in which case 465/4500 adapters are out there, the hardest part would be motor mounts and making it fit. possibly cooling, but a 6.2 radiator would solve that and bolt in place. You could even run the dodge auto and 205 case and even have the pass. side drop for the t-case.

It wouldnt be the easiest swap, but it is doable.

I say go for it.
 
So, pretty much I can use the existing '81 GM wiring harness? Nothing special needed to change over? I guess I'm getting the whole rest of the Dodge truck and wiring anyway. If I ran it, I'd use my NV4500, get a Dodge Bellhousing and adapter for a 205.

Motor mounts would be the biggie.
 
kennyw said:
Allan, your NV4500 would bolt to a Dodge cummins bellhousing :thumb: They offered the NV4500 from the factory in the Dodge trucks. It definitly sounds like it is worth the money they are asking and you could resell the axles and other parts to help recoupe some of the money. But like all good deals you had better jump on it fast.
Click to expand...

You are right, they did offer the NV4500 behind Cummins in Dodge trucks, but not in that vintage, only the '94 and up models. A NV4500 can be put behind that motor, but the plate on the back of the motor is different than later ones, so a conversion bellhousing is necessary. I had to go through this with my Cummins/NV4500.

As far as being a good deal, I would say it is a pretty fair/good deal if the axles are not damaged and the motor is an intercooled model (some of the early ones were not intercooled). I paid near that for my Cummins motor alone (it did come with a COMPLETE Banks kit though :D ).

As far as the conversion goes, in all actuality, it really isn't THAT difficult. There are some things to deal with, but knowing how to use basic tools and having some basic fabrication skills will get it in there and running. As far as wiring goes, it isn't as difficult as it may seem. You can re-use alot of the Dodge stuff if you want to, or create your own (what I'm doing), or pitch it all as that motor only needs two wires to run--the fuel solenoid/shutoff valve and a starter solenoid wire. That's it. The reason I went with the "build your own" route is because I priced the heater grid/KSB control box and it was around $400.00. I figured as much as I would need the heater grid etc, I would manually control those items myself.

Just my $.02 though.
 
I doubt you could use the harness, im just saying to get the engine running, im really not sure about senders and gauges and whatnot. It doesnt take much to make them run, I did forget about the fuel selenoid though, so the pump does need an ignition signal IIRC. at least thats how my 6.2 is, all i really need is a starter and 12v going to the pump for it to run, and that 12v to the pump can be bypassed in an emergency.

You may want to PM laketex, as he now owns a CC GM with a 6bt in it, and there is another one floating arround. I didnt really think of guages when i made that post.
 
mountainexplorer said:
So, pretty much I can use the existing '81 GM wiring harness? Nothing special needed to change over? I guess I'm getting the whole rest of the Dodge truck and wiring anyway. If I ran it, I'd use my NV4500, get a Dodge Bellhousing and adapter for a 205.

Motor mounts would be the biggie.
Click to expand...

You can adapt what you need out of the '81 harness. Pull the senders out of your exixting motor and the gauges will function.

Motor mounts won't be too hard if you can salvage the engine x-member from the Dodge. It is a fairly simple piece that should be relatively easy to adapt to your frame.

The hardest part shoud be getting the motor low enough as the crank pulley/balancer *should* hit the forward x-member (prop valve is mounted to this). You can tilt the motor down in the back to raise the front up, but I'm not too keen on this method. It WILL work, I HAVE seen it done, I just don't care too much for it, but that is just my opinion!!
 
I was trying to buy that '79 Chevy Crew Cab with a Cummins in it that K30CJ had last fall. But I couldn't come up with the money.


I can buy the motor, tranny and T-case together for $1000. She said $2500 for everything. A friend wants the 60, and she said she'd take $400 for it. I was going to offer $1900 cash for everything, and my friend can pitch in $400 and me $1500. He can take the 60 and I'll take everything else for $1500.

What sort of an automatic tranny is it going to have? Regardless, I want a 5spd manual. So I guess I'll try and adapt my GM NV4500 to bolt to this Cummins.

What's the "heater grid" and KSB control box?

Being a 1990 Cummins, how does this motor differ overall from other variations/years? So far I've heard bellhousing bolt pattern, and intercooler.
 
Bellhousing pattern is the same on them all, you should be able to get a used sm465 adapter from a 4bt that came from a breadvan to use your GM 4500. I dont know the company that is selling them, ill let somebody who has bought one cover where to get that. I think that would be stomper, but im not positive.


It has a VE rotary pump on it, which is a fine pump, but limited to flow, it doesnt flow the stupidly insane ammounts that the P7100(94-98.5 dodges) is capable of. Unless you plan on making this a drag truck or a sled puller, the VE will be more than adequate, even when modifiying the motor. I *think* 1990 would still have the TF727 for an auto, stout tranny, but only a 3 speed.


The heater grid is just what the cummins used instead of glow plugs, its just to aid in cold weather starting.


And i had the same problem, i wanted that crew cab bad, but couldnt come up with the cash. Im still kicking myself for not buying K5Drager's when it was for sale, but thats another story.
 
If it does have a TF727, then it will have a D61 front axle and the oddball D70 rear. I thought that when a truck came that way, it had 3.08 gears, so it may be an O/D tranny. I don't know the #, but its basically a 727 with OD.
 
allan///

please reread my cummins to chvy post in the diesel forum... I just updated it


good luck

cam
 
I'll check out the post. :)


I just committed to buying it. I bought everything except the axles for $1500. Cummins motor, tranny, and T-case, frame and cab, (my friend bought the 60 front for $500, and she wanted another $500 for the 70 rear, so I passed on that), plus I got the old '63 2wd frame with some old Dually rear end. The other Dana 60 front was an ad mistake I guess, cause there is none.
 
Document the project well. I am particularly interested in how you accomodate the extra weight.


:cool1:
 
The truck has used 6" front lift springs under it right now, and a 454 and a Warn M12000. Needless to say, it's heavy now and will get heavier. Might have to add a 1" zero rate.
 
The extra weight isn't that big an issue, especially when a big block was already there. You are only talking about a 250-300 lb gain which can be easily combatted with an add a leaf if in fact there is any sagging after the swap. If he were not running a winch, I beleive it would be a non issue, but with the winch and the Cummins, an add a leaf may be needed.
 
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