Cummins 4BT & Diesel Conversions Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
1 Posts
Discussion Starter #1
Hello,

Im looking to swap a 6.9 IDI into my 86 F250. I have no concerns about fitment or frame strength, I can fabricate that much. But coming from a six cylinder gasoline motor, to a diesel system, Aside from the motor and attatched components, what will have to be swapped/notswapped? I.E, will the radiator work? Will the entire wiring need to be changed? Will my single, INTERSTATE MegatronII deep cycle battery work with 770 CCA?

The fuel system I can handle, with a new tank and lines, but its the running systems and such that I don't know much about.

Also, I have the 4 speed manual, granny low 4x4 trans no overdrive (I believe a variant of the SM465), will this transmission handle the IDI motors power output?

Thanks- Ratt
 

·
Registered
Joined
·
43 Posts
All F250 frames are the same I6 to IDI. You will need the engine mounts for the IDI. You will need the core support and radiator for the IDI. The wiring harness could be made to work with a little cutting and splicing. :D

As for batteries, more amps. Two 850CCA batteries would be minimum for a cold weather starting an IDI.
 

·
Premium Member
Joined
·
182 Posts
If your set on doing this swap it would be much easier to buy the complete truck with the engine and use all the factory parts to convert your truck. Their are a lot of little parts that you will need aside from what was stated by trackspeeder, to make your swap much easier.
 

·
Registered
Joined
·
10,675 Posts
To answer some of your questions, frame strength is no issue, I6 radiator is way too small (these engines produce a lot of heat), single deep cycle battery no way (need at least 2 800cca batteries and 2/0 cables), and lastly you need to look at a wiring diagram for the IDI. It's not like replacing with a bigger gas engine. Your HD 4 speed may be ok but you'll be hard pressed to find a bell housing that will mount to the IDI. Best transmission is one of the ZF 5 speeds.
 

·
Registered
Joined
·
1,394 Posts
Be aware the proper IDI radiator is not cheap, I just replaced one and the budget line was $300. I tried finding a good used one first but they all seemed leaky.

If your 4spd is a T19 (which is very possible) you're in luck, the 4spd used behind early IDIs was the T19. You'll need the right bellhousing of course.

Unless your truck is something special, you're probably money ahead selling it and buying a factory IDI truck. Or if you can get a complete donor with a rotted/wrecked body for dirt cheap.
 

·
Registered
Joined
·
10,675 Posts
Damarble, those radiators aren't cheap. Don't be afraid of a leaky used one if it's cheap enough. Those things are brass and copper so they can be repaired. Most replacements are aluminum which is much lighter. Those OEM units are pretty heavy.
 

·
Registered
Joined
·
1,394 Posts
No kidding on the weight. I got about $80 at the scrapper for the old one, vs $7 for an aluminum 302 radiator.
 

·
Registered
Joined
·
314 Posts
I agree with: (1) best to sell your truck and buy one with the Diesel, and second best (2) is buy whole donor truck with motor, tranny, axles, radiator, and every little other thing.

What differential gearing do you have now? Probably too low for a IDI and non-OD tranny.
 

·
Registered
Joined
·
2,862 Posts
Congrats on a great engine choice-if keeping near stock. I personally love the idi IHs. IMHO they are every bit or more reliable as anything else except perhaps the non turbo 4 cyl mercedes car engine. The pre powerstroke rotary inj pump engines seemed to run forever if the fuel was kept clean and the engine wasn't overheated. They seemed to take forever to get to speed when heavily loaded-but they'd get to speed with loads you'd never expect they could handle. And like the tortoise and the hare, when the 6.2-6.5 has popped a head gasket and the 360-440 dodge is sitting at the gas pumps here comes the 6.9/7.3 puttering on like the Energizer bunny. The introduction of the detuned 5.9 Cummins med. duty truck engine and its ability to be cranked back up to designed power levels caused this wonderful engine to be largely forgotten and dismissed as a great low-power, low cost, simple, but longevity "goaled" (made up word) swap.
Doing a swap will likely be viewed as not worth the effort by many, given the other engines that you could choose from for that labor outlay. Unless you have a beautiful or personal connection truck I agree, you may want to look for a nice truck tucked into a barn somewhere that was a farmer's Sunday driver. I like the '86 ext cab, sealed beam style personally! Chop the frame, drop on a stepside bed, and a se of short cab-high stacks and I'm in love! I love the sound of these and the 6.2/6.5 GMs with dual exhaust with glasspacks.
Unfortunately these trucks tended to be bought for their intended purpose-not social/status symbols, and were driven till they dropped or rusted away. By that time the Cummins had been introduced and perfectly running 6.9/7.3s went to the crusher without being stripped for swaps! I think these make killer streetrod engines. Add some chrome or powder coated parts and stainless injector lines feeding out of that rotary pump and some SS braided hoses and it will look amazing and unique with a sweet exhaust note!:idea:
 
1 - 10 of 10 Posts
Top