1990 f250 cummins swap help

[newman3928]

ok guys, new here, thanks for having me! what I currently have is a 1990 f250 4x4 with a 351w gas engine, Im looking for any and all help on this conversion as i swap in a 12v cummins from a 95 ram, if anyone has done this before and could provide me with a list of parts iam going to need to gather up that would be great! I have the motor and I plan on doing it some time this summer/fall so i have some time to get everything i need, but defently need some guidence as to what parts to gather up, front to back and any pointers or tips you may have, thanks again

 

[HHhuntitall]

Welll, first off, welcome... secondly, get ready for a lot of opinions.... Thirdly, do your research and take a look at what information is available so you get an idea of what you are getting into.....

A few places to start reading:

www.fordcummins.com
www.destroked.com
www.dieselconversion.com (the new fordcummins.com website)

Now you want to decide what transmission you're going to use, as that isn't overly complicated, but plays into what all you'll need in parts.....

You'll start with motor mounts, of course, then go to a rear transmission mount to keep it all straight. Then a new radiator and intercooler (optional, but I suggest it if you want to pull a trailer much and for just general intake temp reduction). Driveshafts, transfer cases, wiring.... Since you're going to use a 12v, that makes it pretty easy, wiring wise...

I've done several of the late 80's and early '90's Fords.... two of which I still have and drive occasionally.... (I really have wayyyy too many trucks, if there is such a thing.....) For my own preference, I use the NV trannies and NP transfer cases. I can pick up a ZF transmission with one hand and load it. Not so much with an NV4500. The New Process T-case that came with the truck may fit it, depending on what it is.... Being a gas engine, it most likely has the smaller input shaft, but there are several they use....

 

[newman3928]

Thanks so much for the humble welcome and great info/advice....ok as far as transmission goes I was definitely leaning towards the doge nv4500 trans, that said what would be the parts to get to make that work? Do I fab up a crossmember or is there one to work and what would I do as far as driveshafts? And also with it being a gas truck right now would I be best to get tanks and lines from a 7.3 truck and swap over? And as far as the radiator situation should I get one for a 7.3 aswell? Thanks again for helpband I do apologize for all the what may seem like stupid questions haha

 

[HHhuntitall]

Parts to make the transmission work? I'll presume you have the Dodge bellhousing, flywheel, clutch..... The factory crossmember isn't going to work without some serious mods.... The NV is quite a bit taller, so you'll have to lower the rear crankshaft angle some to get the transmission to clear the cab floor.... That's going to lower you're factory crossmember about 4" or so... I don't remember the exact measurements.... you'll definitely have to weld on that one or make your own. The hydraulic lines from a Dodge can be used in conjunction with a Dodge slave cylinder and the Ford master cylinder.

The gasoline tanks have the electric pumps in them, but should be the same as the diesel. You'll just want the diesel sending units, or modify those to remove the electric pumps and keep the fuel pickup tubes.

Driveshafts have to be made once the transmission and T-case are installed.... I'd suggest having them measured by the actual shop making them, unless you have experience in that area. The ZF transmission has a much smaller output shaft, and the gas engine trucks have a much smaller driveshaft, overall. There are a lot of options there, so again, I'd suggest a good shop, there.

The Diesel radiator has a different front radiator support. You'll need that if you go with a factory Ford diesel radiator. If going that route, you might find a front crossmember out of a PowerJoke, along with the intercooler.... but your headlights won't bolt up, IIRC, as they're different styles in the '90, so that may not be a good option for you.... A plasma torch and sawzall might be a good friend to have on that project....

Your questions aren't stupid. But, you can answer a lot of them by researching a little, both on here and on the websites I offered.... I'm sure some others will chime in soon....

 

[newman3928]

Sounds good, youve definitely given me a great start, I will certainly research those sites aswell, truly appreciate it man, and as for the trans....I dont have anything just yet so as u stated my options are wide open, if I get a zf from a 7.3 truck or 460 truck and go with an adapter for the cummins would that allow me to stick with a ford cross member and drive shafts etc?

 

[HHhuntitall]

The ZF transmission will allow you to keep your crossmember, but it will have to still be modified some. The Cummins is a bit longer than anything else put in the Fords, so it helps to lower it to clear the firewall a little, and move it back to give more room for the fan.

 

[newman3928]

Ok that make sence, now if I use an adapter and go with a zf will I still need to alter my drive shafts?

 

[rscurtis]

Before going any further, I would verify that you can re-title your truck as a diesel and that your insurance Co. will insure an altered vehicle. Shouldn't be too much trouble there, as Ford offered diesels for that model year. You may also have to swap out the gasoline fuel tank for a diesel tank. www.4btswaps.com is another helpful site. I can't help but ask the question, instead of doing all this work, why not just buy a Dodge?

 

[newman3928]

No legality issues on the swap, and why not buy a dodge? Well id love to but I cant afford that....

 

[HHhuntitall]

Using the ZF might allow you to keep your stock shafts if you're careful about where you mount the engine, but it's going to put the Cummins too far forward to use your stock radiator. I meant to take some picks of one of mine today, but in all the work I have to do, I forget about it until nightfall....

Insurance shouldn't be able to say anything about it either way, as long as it passes a state inspection. The state may require a retitle/title modification due to the change from gas to diesel fuel, so as to be able to pass emissions for an inspection, depending on where you live. Certain high population counties in Texas require emission testing... a gas engine test is not going to pass a diesel engine. Due to it's age, it shouldn't be an issue, but you might check.

 

[JCrockett]

I have done this exact swap with my 90 Ford. If you are having any issues still send me a PM. I don't get on here much but I would be glad to help if you are hung up on any little things. Did my conversion with a 97 12V back on winter of 05/06 and its still running great.