So here's the plan: 1. 27' Class C RV that's just too thirsty: 2. Remove 7.5 liter gas engine & 3 speed auto transmission and replace them with these: A 5.9 liter first generation Cummins turbo diesel & an Allison 542 (with the 545 extra capacity oil pan) 4 speed auto transmission. Lots of the diesel conversion forums say it can't be done but I've seen a few photos and videos of those who have! What could go wrong?
So here are a few photos of getting to where I am now: Donor truck: A 1992 Dodge, so it's a first generation 5.9L Cummins which means no electronics. Only needs two wires to run: one for the starter and one for the fuel solenoid; and even then the fuel solenoid can be held open manually. That makes the electrical part of this conversion much easier. Engine still in the donor truck: The truck had 187,000 on the clock. The stock 5 speed manual transmission went to a buddy for his own conversion project. Here I am pulling the engine. Slight problem: The lift is at full extension and I still need a few inches to clear the front clip: No problem. Pull the front wheels & drop the chassis to the ground so I can get the engine out: Engine out and getting cleaned up:
A little into the engine: The heads on these things are freakin HEAVY! Oh no! Found the problem: Looks like the injector on #4 was leaky and washed oil off the cylinder till the piston went. What's the cylinder look like? The awesome thing is that the cylinder measures well within specs. Got a ball hone - she'll clean right up. Just shy of 200K and you can still see the cross hatching! Well. That's where I am now. I just ordered the engine rebuild parts yesterday! Now comes the fun!
I'm sure you can get it done. But you can buy a lot of gas for what it is going to cost you esp. if you're time is worth anything if the 460 is still strong. Not sure what you had in the old dodge But I've sold burned up complete cores for $1000.00 just for the engine. Good luck. I'll be watching this one.
Ya gotta love a 12 valve B-Series Cummins. Tried and true non-electronic goodness. I've got over 300,000 on my '94 and it still runs like like the day I brought it home. The only thing I've ever had to do to the motor it is replace a $2 piece of injection return hose.
Ummm. How's the RV's rest of the powertrain gonna take a diesel? Does the diff's, axle's, driveshafts, etc.. gonna put up with the power? Best of luck!
@NDEBT: You're right: I could go a long ways on gas for the money this will cost but what fun is that? My conversion budget it $3000. So far I've paid $1000 for the donor truck. That means: engine, transmission, fuel tank & lines, radiator, intercooler, etc. I just ordered the full gasket kit, cylinder head bolts & piston/rings for $890. I'm still ahead. There's a few more expensive things on the list: 1. Hydroboost system to replace the stock vacuum brake booster system (about $300) 2. VSS to mechanical conversion box - also about $300. Unless I can find a mechanical speedometer pickup for the 500 series Allison transmission. 3. Gas to propane conversion kit for the generator - hmmmm.... also about $300. Till then I'll just haul a small spare gas can. 4. Drive shaft modification Of course there will be lots of fabrication and creativity along the way. The math says I should be able to double the mileage and be able to push the RV, fully loaded, including my 6x10 trailer loaded with bikes across the Colorado mountains at ~adequate~ highway speed. We'll see.
Well, my *expert* analysis says that since lots of guys are putting the same setup in 1/2 ton pickups and putting 10's (or more) thousands of miles on them I figure my E350 chassis should handle it. Yup - that's the extent of my assessment!
Per the VSS thing, i dont know how yours is put together, but if you're trying to trigger a pulse style speedometer without a pulse generator, you can use an inductive proximity sensor, and figure out how many 'vanes' on the output shaft you'd need to drive it. Probably not as easy as a bolt on, but certainly less expensive than a $300 part :)
Oh I agree This is cool don't get me wrong I love this stuff and the mini winnie looks great. I would not be a prisoner to that budget though. Whats the 460 get I'm guessing about 9 MPG? I'm sure you can recoupe some from selling it. I'm still not sure why other than just because wich is cool too. Is there another problem with the big Ford other than MPG?
Budget some money for sound deadening & insulation, and budget some time for the Killer Dowel Pin Remedy: it has to do with a dowel pin in the timing gear case that can fall out & if you're lucky, end up harmlessly in the oil pan. If you're not so lucky, it gets caught in the gear train & trashes it. :eek1
IDK about the dowel pin thing but that is a good point about the noise. These are great engines but as an old friend of mine said as one was running. That thing sounds like two turtles fucking in a bathtub. And it will be right under you. Most was at Idle or hard pulls though.
I know better than to really think I can pull this off for three grand but it's good to have a goal. I think I can get it all together and running for $3K but a project like this may never really end! Homemade KDP (killer dowel pin) retaining plate already in place. Real world mileage averages 6.45. I'm not guessing - I use a mileage tracking app on my phone and I'm religious about using it for all my vehicles. The usable power with the current 460 SUCKS! It's not uncommon on some of the long grades around here for me to have to peg out the old 460 in second gear at 45mph just to climb a hill. And hills aren't the only enemy. Wind really does a number on performance. This is the 3rd RV that I've owned. I've worked on many more and class C's all seem to be under powered and very thirsty. I wouldn't mind the lack of power if the engines were a bit more thrifty with fuel. Yes, yes I could shell out ~$80,000 and get a sprinter based RV but I'd have to drive that thing for 54 years before I came close to breaking even on the fuel I'd save. I seem to own them for about 8 years each. I average about 12,000 to 15,000 miles per year which doesn't sound like much but for casual RVing that's respectable. Even with fuel prices the way they are I figure I'll break even in a little over 2 years. And, really, if nothing else it's just a cool and fun project. I have been thinking about what I can do about the noise, but the existing setup is pretty loud anyway. Honestly, I was pretty surprised at how quiet this engine is (for an American diesel).
My only real RV experience was about 18 years ago. I got a divorce and gave everything away and bought a 34' Pace Arrow class A. I loved it and done it for about 4 years although I've got to say even now they are still built like shit as far as finish. The best I had was a 59 air stream solid oak cabinets and everything. Sorry Hijack off lets se this thing.
About 15 years ago, I repowered an M43 ambulance with a Hercules turbodiesel and was simply stunned by the increase in noise: earplugs were mandatory to avoid tinnitus, and even while wearing them I used to wonder if this was what a Warbird sounded like on takeoff. Now, I realize these two vehicles are hardly comparable in many pertinent ways, but the point I'm trying to make is be prepared to have to deal with a surprising amount of racket-- especially with the back half of the engine in the cab with you. I'm also not trying to piss in your Wheaties, I'm just trying to pass on the warning I wish I would have gotten. I think your project is a great idea (that M43 got 25 mpg at 60 mph).
