1978 Bronco + 1991 Cummins 6BT
#1
1978 Bronco + 1991 Cummins 6BT
OK, I posted some pics of my Bronco in my introduction thread, but I just read a few comments on the forum about there not being enough Cummins conversion threads. So I figured I would go back, dig up some pics and post them along with a detailed write up in my own brand new conversion thread. So here it is.
First of all, the '78 Bronco is by far my favorite truck of all time. The first time I saw one of these, I was 10 years old and the Bronco was sitting at a local Ford dealer. I remember it was red with a white top. I was instantly hooked on the looks of the new '78 full size body, as I think they're esthetically perfect.
Being only 10 at the time, I settled on buying a red '79 Bronco Stomper 4x4 toy, like this one:
[Fast forward 30 years: 2 marriages, 2 kids, lots of work, no time for hobbies etc etc]
So back in early 2009, I come across a '78 Bronco on craigslist, and I buy it for $700.
This is what it looked like the day I brought it home:
The inspection sticker read 1992, so this puppy had sat in pieces in the guy's garage for the last 17 years. He had already blasted the frame and underside of the body, and sprayed it with black epoxy primer. All new Skyjacker suspension, poly bushings, all new shocks, and most of the steering stuff and all already installed. Talk about a dream come true!! I barely got dirty working on this thing, it was so clean.
It came with two brand new original Ford front fenders, and the tailgate.. wow.. the ORIGINAL 30 year old tailgate was perfect:
And the truck had only 86,000 miles on it, the door hinges and other such wearable points were tight and like new.
All for $700?? I was on this thing like a wolf on bloody meat.
So finally, after 30 years, I got the truck I wanted as a kid. It looks an awful lot like that Stomper 4x4 toy truck doesn't it??
Now comes the interesting part. As you can see, the truck didn't have a motor, but it did come with the original 86k mile NP205 t-case. My brother and I built a 460 for his F250 a few years ago, but he ended up buying a new diesel F350 instead, so the big block was still sitting in the shop. The Bronco was set up for a 400, so the 460 would have literally bolted right in, and it would have been running in one weekend. HOWEVER, I already have a 530 hp Mustang that gets terrible fuel mileage, and I figured one gas hog was enough for one man. And I'd read a lot about the Cummins 12V motors, and I was very interested in them. I'd worked on a few of them over the years, doing minor stuff at my buddy's shop, and I liked the way they were set up. At my job, I drove a 4-car carrier with a Cummins 24v, and it was by far the best motor of all the flatbeds, both in terms of longevity and power. (it had 425,000+ miles on it and still ran) I found a '91 Dodge Cummins work truck for $1300 at a shop a few weeks later, and I snapped it up. It had 159,000 miles on it, and ran like new.
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Much more to come, after the football game..
First of all, the '78 Bronco is by far my favorite truck of all time. The first time I saw one of these, I was 10 years old and the Bronco was sitting at a local Ford dealer. I remember it was red with a white top. I was instantly hooked on the looks of the new '78 full size body, as I think they're esthetically perfect.
Being only 10 at the time, I settled on buying a red '79 Bronco Stomper 4x4 toy, like this one:
[Fast forward 30 years: 2 marriages, 2 kids, lots of work, no time for hobbies etc etc]
So back in early 2009, I come across a '78 Bronco on craigslist, and I buy it for $700.
This is what it looked like the day I brought it home:
The inspection sticker read 1992, so this puppy had sat in pieces in the guy's garage for the last 17 years. He had already blasted the frame and underside of the body, and sprayed it with black epoxy primer. All new Skyjacker suspension, poly bushings, all new shocks, and most of the steering stuff and all already installed. Talk about a dream come true!! I barely got dirty working on this thing, it was so clean.
It came with two brand new original Ford front fenders, and the tailgate.. wow.. the ORIGINAL 30 year old tailgate was perfect:
And the truck had only 86,000 miles on it, the door hinges and other such wearable points were tight and like new.
All for $700?? I was on this thing like a wolf on bloody meat.
So finally, after 30 years, I got the truck I wanted as a kid. It looks an awful lot like that Stomper 4x4 toy truck doesn't it??
Now comes the interesting part. As you can see, the truck didn't have a motor, but it did come with the original 86k mile NP205 t-case. My brother and I built a 460 for his F250 a few years ago, but he ended up buying a new diesel F350 instead, so the big block was still sitting in the shop. The Bronco was set up for a 400, so the 460 would have literally bolted right in, and it would have been running in one weekend. HOWEVER, I already have a 530 hp Mustang that gets terrible fuel mileage, and I figured one gas hog was enough for one man. And I'd read a lot about the Cummins 12V motors, and I was very interested in them. I'd worked on a few of them over the years, doing minor stuff at my buddy's shop, and I liked the way they were set up. At my job, I drove a 4-car carrier with a Cummins 24v, and it was by far the best motor of all the flatbeds, both in terms of longevity and power. (it had 425,000+ miles on it and still ran) I found a '91 Dodge Cummins work truck for $1300 at a shop a few weeks later, and I snapped it up. It had 159,000 miles on it, and ran like new.
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Much more to come, after the football game..
Last edited by American Thunder; 09-26-2010 at 12:02 PM. Reason: Automerged Doublepost
#4
Ok, so I found the Dodge truck for $1300, pulled the Cummins, and sold the rest for $1500. Yes, the Cummins cost me negative 200 bucks. I think that was pretty reasonable..
More pics of the Bronc when I first brought it home:
Cummins 6BT still in the donor truck:
Guess what I found upon cleaning/degreasing the motor?
An old "repair" from a Killer Dowel Pin incident..
So of course, off comes the cover, out comes the camshaft, and I found a nice used timing case/cover from a guy in Arkansas for $75.
You can buy those wooden dowels in the "Cummins KDP repair" aisle at Lowes or Home Depot.
All fixed, pin secured, painted in Ford blue and cast coat on the timing cover.
More pics of the Bronc when I first brought it home:
Cummins 6BT still in the donor truck:
Guess what I found upon cleaning/degreasing the motor?
An old "repair" from a Killer Dowel Pin incident..
So of course, off comes the cover, out comes the camshaft, and I found a nice used timing case/cover from a guy in Arkansas for $75.
You can buy those wooden dowels in the "Cummins KDP repair" aisle at Lowes or Home Depot.
All fixed, pin secured, painted in Ford blue and cast coat on the timing cover.
#5
Motor mounts from fordcummins
Some mount plates I made so I could use the original integral nuts in the frame. The motor and drivetrain now sits 4 inches further back than stock, removing much/most/all of the extra 300 lbs of engine weight from the front axle.
Adapter and billet flexplate from Destroked. Quality is awesome.
Motor sitting where it belongs, and freshly polished/clear coated intake tube.
Brake booster, master and rear wheel cylinders are upgraded to F350 pieces.
Dynamic Racing Transmissions built this C6 for me, complete with a 1200 rpm stall speed billet torque converter.
Freshly cleaned and painted NP205. These things are even heavier when you have to install it yourself in the mud with a crappy jack.
All new hand bent green coated brake lines. I don't know if the green coating actually makes them last longer, but it looks cool.
Super-Lift extended brake hoses. Braided stainless, lined with teflon, covered in urethane.
I used the Dodge brake prop valve, because the Bronco's was screwed up, and the Dodge piece was an identical fit.
#6
Stock fuel tank with return line fitting installed.
6.0 Ford starter installed, and transmission heat exchanger bracket modified to work with the Destroked C6 adapter. The cooling lines are 3/8", and are very short, only about 2 feet long.
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New Bronco power steering hose with one end cut off, and joined to the stock end for the Cummins p/s pump using a steel compression fitting.
My brother and I cut down a pair of 1983 Bronco driveshafts on his lathe to fit my truck. Moving the drivetrain back 4 inches required the change.
You can see how far the fan is from the radiator in this shot. I still need to make a fan shroud for it.
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I installed a 3" body lift, which gave me quite a bit more clearance for the drivetrain, so the total lift is 9", with 35" tires on it.
Last edited by American Thunder; 09-26-2010 at 03:53 PM. Reason: Automerged Doublepost
#8
To make the C6 shift properly, I had them build the trans with the C6 shift governor from a 6.9, and then I used the VRV valve from those early diesel trucks, to regulate vacuum based on throttle position. I just had to weld up this bracket for it.
This is how I hooked up a new '78 external Voltage regulator to the Dodge/Cummins alternator. A new alt at Napa is $90, and they're in stock, the volt reg. is $20, and it's in stock. The more in-stock and inexpensive parts I can use, the better, in case I break down on a trip or something.
The steering u-joint in the truck was seized tight. I've never seen one do that before, but anyway, I had a F800 joint laying around, so I welded it in. It even has a zerk fitting now.
3" into 4" exhaust, no muffler, nice and simple. No fumes get in the truck, even with the rear window down. I also like this set up because with the pipe outside the frame, it's not adding heat to the transmission and lines, and less clutter under there as well.
Taken the other day, most of it's done.
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That's pretty wild, our Broncos are even the same color, with the rare round headlights found only in '78 Customs. I must say, you have good taste in trucks!!
Last edited by American Thunder; 09-26-2010 at 09:12 PM. Reason: Automerged Doublepost
#10
Thanks for the compliments!
A couple more pics:
I had to relocate the battery to the driver side in order to install this big universal K&N air filter.
I made the intake pipe from exhaust pieces, and the bracket from sheet metal. The whole deal cost me $65. I designed the bracket to bolt to the previous battery tray's integral nuts.
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Next on my list of things to do; Find and install an Intercooler, then turn up the injector pump a little more. Eventually, I want a bigger turbo, maybe an S300? Anyone have opinions on the S300 or some other turbo choice? After that's in, I'll go 4" into 5" exhaust, and bigger injectors. My goal is 400-450 hp, eventually. I'm planning a D60 coil spring front swap, while I'll probably keep the 9" in back, with an 8-lug conversion on it.
In case anyone is wondering what a Cummins Bronco weighs, I pulled it on my Brother's truck scale and it weighs in at exactly 5100 lbs, with 2885 lbs on the front, and 2215 lbs on the rear.
A couple more pics:
I had to relocate the battery to the driver side in order to install this big universal K&N air filter.
I made the intake pipe from exhaust pieces, and the bracket from sheet metal. The whole deal cost me $65. I designed the bracket to bolt to the previous battery tray's integral nuts.
---AutoMerged DoublePost---
Next on my list of things to do; Find and install an Intercooler, then turn up the injector pump a little more. Eventually, I want a bigger turbo, maybe an S300? Anyone have opinions on the S300 or some other turbo choice? After that's in, I'll go 4" into 5" exhaust, and bigger injectors. My goal is 400-450 hp, eventually. I'm planning a D60 coil spring front swap, while I'll probably keep the 9" in back, with an 8-lug conversion on it.
In case anyone is wondering what a Cummins Bronco weighs, I pulled it on my Brother's truck scale and it weighs in at exactly 5100 lbs, with 2885 lbs on the front, and 2215 lbs on the rear.
Last edited by American Thunder; 09-27-2010 at 12:16 AM. Reason: Automerged Doublepost