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Cummins/Bronco buildup

34140 Views 134 Replies 50 Participants Last post by  fatboyf150
Cummins/Bronco buildup (video added, page 3!)

One of my good friends here owns a junkyard, so he's got plenty of potential for oddball projects. He's always been really into Broncos, with his most current DD being a '91 Eddie Bauer, with a Mustang GT 5.0, 5-speed and manual transfer case, HP44 SFA swap, and a semi-float 10.25" rear.

Well, in June the clutch went on it. About that same time we got this beauty in at the junkyard:



'94 Ram 3500, cummins diesel.

Since he had been more than unhappy with the Mustang 5.0, and since the trans had to come down anyway to do the clutch...why not swap in a cummins?



Of course it isn't quite that simple. The donor Dodge was only 2WD, so we had no transmission sitting around that would bolt up and be 4WD. However, we did have a ZF 5-speed from a 7.3L Powerstroke motor. Through a little digging, we found an obscure conversion company (www.fordcummins.com) that specializes in these things, and they manufactured us a bellhousing adapter to mate the Ford ZF to the Cummins motor.



This conversion uses the Dodge flywheel, clutch, and pressure plate, which were upgraded to Centerforce II pieces. The pilot bushing is a custom piece that came with the adapter plate. The stock Ford slave cylinder and clutch arm are used with the Dodge throwout bearing. The Dodge starter is reused as well, but is relocated to spot where the Ford starter used to be. This fits the chassis nice, but required a little bit of grinding on the inside of the bellhousing in order to fit the nosecone properly.

Next, we decided the stock Borg-Warner t-case wasn't badass enough. So we did a little more digging and found a Ford NP205 case from a '79 Bronco. With a little trimming of the mounting flange on the trans to clear the shift rails, it bolts right up.



At this point, the project took a big halt. My friend went back to school for a few days a week, the EPA did an inspection at the yard and found a bunch of stuff that needed to be taken care of, so that left no time for the buildup.

Sometime during that lull, we decided that after test-fitting everything, it was gonna be a bit tight. So we found a 3" body lift kit sitting in a dusty box in the basement, and figured it would probably solve all the clearance issues. Around that same time, a near-mint '96 Bronco rolled into the yard, being scrapped due to flood damage. Since my friend's '91 had all kinds of body rust, and we pretty much had to pull the body anyway to do the body lift...why not swap over the nicer, newer one?

So the body came off, which made test-fitting and mounting the motor much easier.



Note the onboard air bottle, and the missing front crossmember - we cut it out and are almost finished with the engine cradle that will hold the Cummins motor. We also raised the gas tank up a few inches because we were bored.

Here's the powertrain as it sits:


12-valve Cummins, with Banks turbo kit (why not?), Ford ZF 5-speed, Ford NP205, with a PTO hydraulic pump on it. This was added as an afterthought, just because we had it sitting around.

And, installed in the chassis:


The last few weeks have been spent making the crossmember for the motor mounts, and also running fuel supply/return lines. Tonight, after securely bolting everything down, we finally got to try firing up the motor. And man, does this thing run!

http://www.phatserver.net/users/chris/cumminshi.wmv (23 mb)
http://www.phatserver.net/users/chris/cumminslo.wmv (10 mb)

Frame seems to be flexing a little bit, but we'll be adding a bit more reinforcing down the length of it. Plus with the body installed plus shocks and stuff it shouldn't be too bad.

As far as axles go...the bastard got a HP60 from a '78 F250 for free (some guy just junked the truck without knowing what he had), so that'll be going in, and we've got a D70u for the rear. He ALSO got a set of 5 Goodyear MT military tires, 37x12.5R16.5 for free, with 4 being brand new. Guess there are some perks to owning a place like that.

As it continues I'll update this, but it's lookin pretty good. The body fits wonderfully with the 3" lift. The only clearance issues we may run into are fitting the radiator, intercooler, and condensor inside the front clip...but that'll get figured out in due time.

If anyone wants more detail on any aspect of the build just let me know.
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wow mines like a minime of that!
mooktank said:
wow mines like a minime of that!
:laughing:

Nice.

Does yours have the intake grid heater? We got the standalone electronic module that controls that, so we'll have the wait-to-start lamp, fuel-in-water, fuel heater, all that good stuff. If you need info on that let me know.
Lol all I have is one 12V wire to the fuel solenoid and a block heater. That's it!
mooktank said:
Lol all I have is one 12V wire to the fuel solenoid and a block heater. That's it!
Yep...sounds about right. Funny thing is we ditched the fuel solenoid and hooked up a manual cable shutdown for the fuel valve. Only thing it actually *needs* 12V is for the starter, but theoretically the entire truck would run just fine with no battery at all and a push-start. Pretty cool. Gotta love the mechanical diesels.
lucky bastards.....just have a cummins layin around, just a body lift layin around, just a Np205 layin around
thats pretty sweet.... bet yall cooked that starter pretty good...
wow, that's sick. Post this over a www.fullsizebronco.com if you haven't already. I'm sure the folks over there would love to see this build-up.
I need to buy me a junkyard.
vetteboy79 said:
Through a little digging, we found an obscure conversion company (www.fordcummins.com) that specializes in these things, and they manufactured us a bellhousing adapter to mate the Ford ZF to the Cummins motor.
$699? OUCH!

Awesome conversion, btw. What is the OD ratio on the ZF?
0.76 Od
I dream of owning a junkyard, but I have a feeling I would be my own best customer.
zainyD said:
I dream of owning a junkyard, but I have a feeling I would be my own best customer.
hahah yeah i hear that, if i had access to only 5 trucks at my local junk yard for free id be in heaven. i think its something all us builders wish
That sounds badass, and I had thought slightly about this as a future project but I know I probably couldn't afford to do it.

Am I the only one seeing red x's though?

Brian
Sorry, my server was down for a while...must be a bad week for servers, given how this place has been lately too...

Anyway, I did some work on the t-case shifter setup today.



You can see the cutting/grinding needed to clear the shift rods:



Here are the cables we're using: push/pull, load rated to 100 lbs, from McMaster-Carr...about $40 each.





At this point, I'll let the pictures do the talking...









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The mounted product:







There will most likely just be some sort of plate that bolts through the hole in the shift rods, that'll get push/pulled via the cables.

After the body goes on, shift lever fabbin' will be next...and I think we're gonna do something pretty nifty for that.

Also, we got the radiator and intercooler mocked up:





Those are two Taurus electric fans, with a big relay that'll be triggered by a temperature switch/controller on a coolant hose. We went with the twin electrics instead of the mechanical due to space constraints...as it is, the whole front clip will likely have to be custom, with a big possibility of having a one-piece front that tips forward.

There's plenty of room for the intercooler and radiator hoses though, which is a good thing. The factory Dodge radiator hoses will work fine.
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I think I'd be boxing the hell outta that frame if it it was me....

Other than that, looks awesome!

Oh - I'm drunk
yeah i 2nd the box frame. Please do it. Oh while your getting the free stuff throw a dana 60 up front and a dana 70 out back, why dont you take the 70 out of the dodge and put under it.
Havent been at the ford cummins site for a while, but as I recall, the 80 and newer trucks didnt need any cutting of the crossmember, let alone removing it.
wyldstallyn73 said:
Havent been at the ford cummins site for a while, but as I recall, the 80 and newer trucks didnt need any cutting of the crossmember, let alone removing it.
Well, that may be true for swapping a Cummins into something that had a Powerstroke before...but for a Bronco, that thing didn't stand a chance of fitting. We had all the motor mounts and whatnot off the Powerstroke truck, and when we looked at what it would take to mount them to the Bronco chassis, it was gonna be easier to just make a whole new crossmember/engine cradle. That, and since it was a TTB truck converted to SFA already, there were additional clearance issues with the panhard and the diff itself.

Tide612 said:
Oh while your getting the free stuff throw a dana 60 up front and a dana 70 out back, why dont you take the 70 out of the dodge and put under it.
Did you read?

As far as axles go...the bastard got a HP60 from a '78 F250 for free (some guy just junked the truck without knowing what he had), so that'll be going in, and we've got a D70u for the rear. He ALSO got a set of 5 Goodyear MT military tires, 37x12.5R16.5 for free, with 4 being brand new. Guess there are some perks to owning a place like that.
And the D70 out of the Dodge is a DRW and it wouldn't fit worth crap. I guess we could do a dually Bronco but that'd just be sort of weird I think...
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