Well, I figured since I’m starting to make some headway, maybe I should begin a write up. I’ve seen several that deal with ongoing builds, so I wont feel so out of place here.
The idea of putting a Cummins into my vehicle has been kinda-sorta kicked around for a while. I finally got to a place where I have the time and know-how available to me. I also wanted to try to do something that, in retrospect wound up being a LOT larger than I’d planned, but could also be done by just about anyone. So the idea is to try to keep “custom,” at bay, frame hacking and special know how stuff to an absolute minimum.
I got ‘hold of a 91 6BT out of a wrecked bus. Several of the engine doodads were broken on it, including what used to be an engine mount (This bus used the front engine mounts, which I will be NOT using) and an alternator mount. One thing that was a surprise, was it has an air to water aftercooler on it. From the pictures, before I bought it, it looked like it had no charge air cooler. Score one for me! The plan was to add a cooler from a Dodge after the vehicle was running to reduce the initial headache.
After receiving the engine, all I could really do ‘till the old engine came out (A healthy 400 with some mild warming) was try to make it look half way decent and deal with any issues I could see right now. Having a friend who was a heavy equipment mechanic for many years was helpful in giving it the once over.
The obvious problems I found were that the front timing case locating dowel pin was starting to back out (AKA: Killer Dowel Pin or KDP, if youre into that sort of stuff) and it looked as if the oil sump had sat for years in the dirt; It had some pin holes.
To fix the dowel pin, I hammered it back into its proper spot and made a crappy little retainer out of some thin sheet that I found somewhere. It’s home for good, now.
As for the sump, I’m having to get a friend to weld up the pin holes before I get it painted and attached.
When I got the engine, it had this crazy contraption of steam pipes and electrical tape involved with the heater hoses. Part of it was some sort of cobbled together throttle linkage that looked like it’d been backed over by a Buick and the rest must have been how they figured out they could shut heat off to the passenger compartment in the summer.
Here’re some pictures of the engine paint job. I was inspired by a few pictures of marine engines I’d seen floating around through some magazines. I wanted to go a step further and have everything really looking ship-shape; bolts, mounts and the whole shebang, but not only is it a pain in the ass, but bolts don’t hold paint well as far as I can tell, and I tend to get a little carried away with one project and leave the little things behind.
My engine came sans motor mounts, so that left me a lot of room to build my own or figure out what, exactly, would work best for this particular application. After a quick test fit with an engine hoist (And DAMN, will it be close to that radiator! SO close, I don’t think I’ll be able to use any of my V-belt pulleys…) and some online detective work, I settled on the vanilla Dodge 24V engine mounts. They are stout as hell, and seem to lend themselves to the stock engine towers in the Bronco pretty well. Plus, it fits in with the theme of fabricating as little as possible.
I DID have the minor issue of having the turbo drainline (My turbo came set up BACKWARDS of all the ones I've ever seen! May make routing exhaust easier, however...) attempt to get friendly with the right hand motor mount. Nothing a little cutting of that drain tube and running of flexible line cant fix.
As far as getting the engine to work with the transmission, I wanted to stick with the C-6. I knew it would be a challenge; I still haven’t gotten EVERYTHING worked out with it, but it would do a few things for me. One, since it was a fresh rebuild, with a few extra goodies tossed in, it should hold up well to the mild amount of power I intend to get from the Cummins. Two, being a C-6, they are everywhere and are pretty easy to re-build, when the time comes. And three, it doesn’t have any of the PITA that hooking an E4OD (Probably a much more ideal choice, honestly) would have brought into the equation…like getting another transfer case or desperately hoping I could get the front drive shaft to clear if I kept my NP205.
I did a ton of reading on which engine to transmission adapter to use. I wound up going with the one from Diesel Conversion Specialists. Their customer support has been great so far, and the price was better for the package I thought I’d wind up needing than the other two companies I found out there. When the parts got here, they seemed to be of pretty good quality. The flex plate adapter wasn’t QUITE what I would have let leave my shop if I were turning this stuff out, but it’ll be functional.
Speaking of “Flex plate,” the one I had let me down. I hadn’t even considered that since it was out of a heavy vehicle there may be some difference between what I have and what I need. The one I had wound up being too large. I ordered one online, with the proper diameter and now I’m good to go.
Since I decided that this engine swap was going to give me a chance to do some of the other things I’ve always wanted to do, but never had the motivation, one of the other things I’m adding is air conditioning. I haven’t fully worked out the system yet, but the PLAN is to use the stock Bronco under dash stuff and go with whatever else fits under the hood. I’ll get the biggest condenser I can and run the compressor that fits on the engine. There was NO compressor bracket on the engine when I got it. So, back to the Internet for some forum searching. I found that I can use a Cummins bracket that went in Freightliners and Ford medium trucks to mount the compressor higher than the stock (yet cheap) Dodge mount. With Dodge’s idea, I’d have to cut out more of the front cross member than I want (which is none…we’ll see how that goes) AND a section of the frame. So, I went on a 4 week long trek trying to find a salvage yard, dealer or supplier near me who would deal with a single guy and not just a fleet shop. “Diesel Power,” not too far from me fit the bill. RL there helped me out a great deal with his willingness to check part numbers and actually order the damn thing for me.
So, now I have this:
The same day I picked up my compressor mount, I went to get a nice new compressor for a Dodge with a Cummins. When I bolted it on, I noticed (you cant really tell in the pic) that the AC pulley sits a little off from the water pump; Maybe about two grooves.
More reading and I found out that only a compressor from a medium truck will properly line up. So that’s on order now.
While the engine is out of the vehicle, I have a few things to get working on to make things a little nicer once it gets into its new home. First, I plan to paint the firewall and underhood white. I think it looks clean and it helps ID leaks. I’ve been too lazy to really mask the thing off, yet, though. Maybe tonight…
I also now have a transmission bellhousing to figure out. It was broken when the old engine was removed. I wish I could claim responsibility, cause I’d be a lot less mad but…It was the other guy.
Next few hurdles I see being a huge problem are getting the vacuum signal modulated from the vacuum pump (I picked up a vacuum pump/power steering pump from a Dodge) to the transmission. There’s a workaround mentioned in a pretty damn good write up on this very site, but our throttles are going to be set up differently, so I think I’m going to have to modify the idea some.
And that's about where I am right now. Transmission should be physically out tomorrow and I'll figure out if it can be welded or if it needs to be replaced. Hopefully that will be the last backwards step...
Feel free to send any ideas on things my way. Comments are welcome.
More to follow.