Anyone ever lengthened the engine bay on one of these trucks? One of my long term projects is building a trailer puller using a medium duty I6 engine (6CTA/DT466/7.8) and probably MD3060 trans, but rather than shoehorning it in like the most of the other conversions I've seen, I'd like to just extend the engine bay about 6" so it's not a pain to work on. I also want to use the medium duty radiator/intercooler/fan rather than using stock idi stuff which adds more space and also means I'll be reegnineering the front frame (maybe) and radiator support. Obviously this will require a lot of custom fab/engineering which doesn't bother me much. What I am concerned about is the body work - originally I had thought of just welding 2 sets of fenders/hood together to make longer bits, but the lines woln't line up if I do that. Maybe some sort of custom fiberglass setup? I want it to look clean and not like redneck cobbled up junk.

 

Given enough time & money they say anything can be done!

That is a lot of work just to fit a motor in.
Have you thought about cutting firewall to get the room then deal with that?
Also how tall are those motors as some look pretty tall?

Keep us posted
Dave - - - -

 

Oh, I agree anything can be done....

I'd like to avoid cutting the firewall since then you have to reanage all the stuff under the dash, the engine is impossible to get to any things are just generally tight. I'll likely wind up cutting it a bit, but was thinking moving the cab aft might work better.

I'll need more vertical room too, yes. The 6C cummins is about 4" bigger in length and height than a 6B which is in turn longer than the idi. Number I saw was 44" long/42" high vs 30" long & 36-ish" high for the idi. Using the MDT radiator/fan probably would add a couple inches too. I'm figuring about a 6" longer engine bay, probably a couple inches of body lift maybe with hood/trans tunnel modifications. May also shorten the oil pan some for clearance. Obviously lots of work but would be a cool project.

Right now this is a sort of wish list project - no idea if I'll ever actually do it, or if it'll go the way I think, just asking questions and contimplating at the moment.

The big picture is a f450/550 frame/axles, MDT drivetrain, 80's f350 cab/front clip, probably a flatbed, possibly a later 90's 4 wheel ABS system if I can get it to work. Big project, but not that difficult.

Sticking point so far is the body work, esepcially since it wouldn't be as simple as just putting sections together, but I'll need to basically make a new custom hood & fenders. Thinking fiberglass will probably be the best approach.

 

Now you may compromise structural integrity and the cab could fold like an accordion.

 

Not if the added part is in front of the front wheels.
The only thing it is holding up is the nose, radiator of the truck so I don't see an issue there.


Also if done right the word "right", he could also add between the front & rear wheels and not have any issues.


I just think there are other power plants that could be used with a LOT LESS work to make fit like a 4BT.
If you want to go crazy look into a Detroit 2 stroke as I believe they were a smaller package might be too tall also?


Just thinking if I was going to try and add to the front I would look into adding it between door & front wheels.
Say add a 2nd cowl with out the slots pushing the hood forward. Then add to the fenders between the doors & wheels what is needed to line it all up.
Doing it this way I would need to look into where to make the frame longer and how to get the hood hinges solid.


Then again use a 2nd cowl to push the hood forward, work out the hinges but add to the fenders at the front between wheels & bumper.
This way you are only dealing with the front part of the frame.
Dave ----

 

Seems like a lot of work for questionable gains. I'd sooner modify the crossmember and firewall for clearance. Keep up posted on the project if you proceed. Oddball swaps are always cool to see how they're done.

BTW Thanks for that turbo, I rebuilt it and it's been serving me well.

 

Years ago I remember seeing pictures of an old body style Ford with a C Cummins swap and a Roadranger 10 speed. The guy who built it had cut out the firewall and put a doghouse inside.

Seems to me it would be a lot easier to build a B Cummins or DT360 to make serious power. Either one would fit without modifying the engine bay. The DT360 is a pretty stout engine. Tractor pullers have been making insane amounts of power with the DT466 for years and the 360 is just a smaller version of it.

 

I'm all for the idea of a Fummins, but my two cents would be to avoid the C8.3 engine. For almost any application you would be using a light duty F series for the B5.9 would be more than sufficient. Almost every application that C series engines came in the B was in as well. Transit buses, school buses, straight trucks, etc.

If you do decide to go with a C, make sure to avoid any engine that has the CAPS type injection pump.

With that being said, can't wait to see pics of what you end up with.

 

Can't think of any reason cab strenght would be comromised but perhaps I'm missing something? I wouldn't touch the cab itself, just move it aft a bit. Fenders/hood aren't structural unless I'm missing something. Inner fenders are a bit, but can't imagine it would matter that much. Redoing the cab mounts and making it all fit on a different frame could matter, but that's relatively easy to properly engineer.

As far as safety goes I think the only major item is the steering column since there would need to be some sort of extension. Definitely something to be careful with, but also relatively easy to make work safely.

Woudn't be extending the frame either - frame would be a stock F-450 frame. I'm thinking either a crew cab or reglaur w/ 12ft flat bed as a doner and then with the extended engine bay a regular or x cab and an 8-9 ft bed would fit well. The flatbed would be lengthened/shortened to make everything fit so I don't have to cut/weld the frame.

Planning to add between door and wheel well, yes. I want to extend the hood rather than add a cowl - cleaner look and keeps easy engine access. Fiberglass hood might be light enough to use stock hinges, otherwise would probably have to add some gas shocks or something to hold it up.

Sure, I could use a 6B, but what's the fun in that? I already have a 6.9 with a HX35 that makes decent power.... It's a good truck for some things, but smaller than I'd like for some. I also have a 500 hp Detroit in a freightliner 3 axle... but that's a bit overkill.

The intent here is a solid reliable truck that can safely and easily pull a 20-25k gooseneck trailer without having to jump through all the hoops of a medium/heavy duty. Sure, and F350 could do it, but I'd rather have a big simple mechanical engine than an electronic wonder or a tweaked small motor. Undoubtedly harder/more expensive than the more conventional option, but what can I say, I'm stuborn.

I also think don't think it would as difficult as it's made out to be. Much of the difficulty seems to be physically fitting the engine in, which is why I want to make room for it why lengthening the engine bay rather than cutting the firewall and the shoehorn.

 

Honestly completely forgot about that, took me a couple times reading it to figure out what the heck you were talking about. Glad it was useful!

 

Being you are thinking? of moving the cab back I think I would setup the front radiator support/grille, radiator inter cooler? assy. so you know where to mount the motor & trany at.
Then mount the cab to clear the back of the motor/bell housing.
At this point you will know how much of a gap you need to fill by extending hood & fenders.


As for the steering shaft I don't see that as a big deal that a few ujoints and some shaft cant fix.


Cutting the firewall and adding a dog house is not a bad way to go - think COE!
If you don't use the stock AC/Heat box there really is not much there.
Dave ----