Diesel conversion

[James72]

I'm looking at donor trucks for my diesel conversion (7.3 turbo), I'm wondering if anyone has done this. It looks like the hardest part is the trany, auto or stick. My truck is currently a 4 speed but the newer clutch mechanism is much different, so I'm looking for tips or ideas, Thanks

[averagef250]

4BT Cummins pretty much bolts into our trucks. The 3.9 liter 4BT easily makes more power than a turbo 7.3 and weighs 500 pounds less. Just thought I'd share that since you haven't bought an engine yet.

Ranchero5.0 has installed a 6.9 in his bumpside with a 5 speed and documented it well in the projects section. It took quite a bit of work to fit.

You can easily run a hydraulic clutch or find a mechanical clutch diesel bellhousing for your 4 speed from an early 80's truck.

[AustinTom]

4BT Cummins pretty much bolts into our trucks. The 3.9 liter 4BT easily makes more power than a turbo 7.3 and weighs 500 pounds less. Just thought I'd share that since you haven't bought an engine yet.

Ranchero5.0 has installed a 6.9 in his bumpside with a 5 speed and documented it well in the projects section. It took quite a bit of work to fit.

You can easily run a hydraulic clutch or find a mechanical clutch diesel bellhousing for your 4 speed from an early 80's truck.

I'm not so sure that the 4bt makes more power than the 7.3 L. Even the 6.9 n/a motor made 170 hp 310 ft/lbs stock upping displacement and adding a turbo are only going to help that. the 4bta only made a max of 130 hp from factory. If its a Powerstroke those things can make some serious power.

However from what I understad the 4bt is a much easier swap into one of our trucks.

[averagef250]

You can buy the 4BTA from Cummins with ratings up to 335 HP and 625 lb/ft.

A couple screw turns and a VE pump 105 HP model is making 170+ (that's more than the 89-95 Dodge 5.9 made)

[AustinTom]

You can buy the 4BTA from Cummins with ratings up to 335 HP and 625 lb/ft.

Where do you see that? Highest ratins I can find are 125hp and 373 lb/ft.

http://www.everytime.cummins.com/every/ ... atings.jsp

[AustinTom]

I'm not saying that you're wrong, or I don't believe you its just that I can't find the engine you're talking about. If they do make one with those ratings I'm takin out a loan for it.

[James72]

ok, ok, I'm looking into a cummins. Regardless, it's going diesel.

[Ranchero50]

Yeah that.

For the turbo 7.3, I think they were piss poorly designed. Ford bought the conversion from ATS and rebadged the air filter housing. The base engine can't handle boost over 10psi and has cavitation problems that causes the antifreeze to eat through the cylinder wall. Basically they're built too thinly and flex causing head gaskets to fail and the diesel explosion isn't absorbed by the walls and the shock loading on the coolant causes it to errode the walls. The Cummins don't have those problems. A bone stock virgin 6bt will drag a 7.3 turbo all over the place. With the 6bt you forget you're pulling a load, the 7.3 never lets you relax enough.

I'm running a 6.9 N/A and don't expect miracles, but my truck is lighter than the '84 4x4 F250 it was sourced from and that truck would mow the rear tires off in second with 4.10's

Jamie

[James72]

So are you saying if you had to do it again you'd go with cummins? The reason I'm looking at 7.3's is that fords came with em, and my buddy has one with 1.1 million km on it (tow truck) and it's original. I've heard of cavitation problems but was also told to run Cat extended life coolant (red stuff) to couneract it. Also, you can't beat the sound of a V8. I have access to a couple cummins engines and will weigh the pros and cons, maybe forget them both and go caterpillar!

[averagef250]

I think what Jamie's getting at is if you have your pick and you want it right go cummins. The IDI isn't a bad engine, but it's a pickup engine, it's bulky and not in a package that fits a bumpside well.

The Cummins B series engines are medium duty truck engines. Put 3.9/5.9 Cummins parts side by side with IDI stuff and there's a world of difference. If you're really stuck on using an international engine over a cummins and since you'll be trimming to fit a 7.3 anyway why not go DT466? The 466 is a REAL International engine, a medium duty engine like the Cummins. It's in a bigger package though and you won't have much firewall left after swapping one in.

Cat's a good name, but you pay for it. There's zero aftermarket support for Cat engines and they're inefficient. Similiar sized Cat and cummins engines have around a 10% difference in fuel rates for the same power.

[James72]

As it stands I have a 6.9 with an ATS turbo on it, but it's been heavily abused. I had this before my bump. I also work with a guy that has 5 cummins engines from dodge pickups and I could probly get one for a song. The reason I brought up Cat is because I work for a Cat equipment dealer and have seen a few warranty engines go into the steel bin for no good reason (most of the guys have Cat engines in all their toys). So I'm keeping an eye out for a good 4cyl for the wifes cherokee anyway. It's a big decision for me because this truck will be with us for life, and I appreciate all your input.

[Ranchero50]

I guess it all depends on what you want out of it and how much trouble you want to go through to make it work. From experience the 6.9 swap is tight. The manifold rides right on top of the power steering box. The oil pan needed trimmed an inch. You need to install a 1.5" body lift and don't expect to remove the drivers side valve cover easily if you have power brakes. An inline motor resolves all of those problems. Like you I had the motor and tranny given to me and a lot of support to keep plugging away at it. Check out some of the pics over on the project updates forum before you decide. I'm still in bodywork mode so it hasn't run yet, plug diesel is 20 cents higher than premium now...

Jamie

[James72]

Wow, here diesel is 15 cents lower then regular. Besides my wifes uncle refines used vegtable oil and runs it in his '04 dodge cummins, so the fuel cost is about 20cents a gallon and he's proven it already. It dose look like a ton of work either way, I'm starting to think cummins may be the way to go for easyer future repairs. Also the turbo on the 7.3 is hard enough to get at in it's natural habitat.

[68Mercury250Ranger]

Nobody mentioned the Navistar DT360 turbo and intercooled . Wet sleeve engine, unlike the cummins no sleeve. Also has an Inline injection pump. Sorry can't tell you what years/models. I did an Inframe rebuild on one about 5yrs ago and it was significantly smaller than the DT466.

I like the cummins idea but here in Ontario, the Cummins 4bt are almost non existent other than offroad applications and the occassional Front wheel drive wheelchair bus. $ 3000-4000 , unless you want a core motor.

As for Cat motors , I am watching for a burnt/rolled 3126 powered medium duty truck to put under my Mercury M700 body.

Thats one nice motor, no performance mods required!!!!!!