As of this update (Dec 2021), I did this build 10 years ago. Figured I'd post some Bottom Line Up Front info in this first post for folks who find this thread and don't want to scroll through 7 pages of posts, challenges, updates and ultimate victory.
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Pre conversion (7.5L gas engine w/ 3 speed Ford C6 automatic transmission): average cost per mile: $0.56
As for this conversion project - I sold it quite a few years ago. I really enjoyed it while I had it. I put about 50,000 miles on it before selling it. Once I got everything worked out it ran great. It has changed hands twice now since I sold it and last I heard it's still putting miles on the odometer and smiles on the owner's face. I've long since lost track of it. I expect the body of the RV would have given out by now so maybe the engine and transmission have been removed and are powering something else.
Some good engine bay and cabin photos of the build in progress in post #55
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Now, let's get to the original beginning of this thread. This was documented as I did the work - not once the project was completed. Had I known what I was up against..... Well, this project might have had a different outcome.
I hope this helps inspire others. At a minimum, it documents how I stuffed a 1st gen Cummins into an Econoline engine bay. Enjoy - Mark (edited Dec 2021)
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I've owned a few motor homes over the years and just have never been all that impressed with the power delivery. After spending a bit of time in Europe and seeing lots of great little campers with 2.5L turbo diesels and many with manual transmissions I just couldn't get the thought of building one out of my head. Nearly a year's worth of research and long nights with my friend Google, I finally convinced myself that I could do it. Through a strange set of events I stumbled across a suitable donor engine. A very good deal was made and the truck was mine (minus the original Getrag 5 speed manual).
Here's the recipient:
A 27' Class C on a Ford E350 chassis. In it's original form it had the fuel injected 460 with a 3 speed C6 automatic, 3.54 gears and 30" tires. The price was right and the RV was in good condition. Of course a 450 chassis would have been much better. Or maybe I could have even found a diesel powered one but what fun would that be? The 1991 RV would allow me to do the conversion without needing to configure an OBD II interface to get it recertified so I could change the fuel designation on the title. The 1st Gen Cummins would be a straightforward swap without needing to mess with any computer integration.
Here's the Cummins out and ready to get torn down:
It's a 1st Gen so all mechanical - easier for my brain to digest.
Although it was running when I got it I still didn't know what the 'noise' was until I got this far into it:
Looks like the head gasket failed and leaked down for months finally wearing the piston skirts on #4. No problem.
Shiny and new:
Everything else looked and measured fine so I put a fresh set of gaskets in and put it all back together:
Engine ready - now I need something other than the Allison 542 that I got with the truck (wrong high gear ratio)
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Pre conversion (7.5L gas engine w/ 3 speed Ford C6 automatic transmission): average cost per mile: $0.56
- embarrasingly slow on long mountain passes, hills, against wind, etc
- 6.5 MPG average
- Wolf Creek Pass (Colorado) at ~10 MPH
- more than enough power for EVERYTHING!
- Average high 13 mpg with a few tanks above 15. (just depends on driving conditions and my ability to keep my foot out of it)
- Wolf Creek Pass at 55+MPH , passing quite a few cars on the way up
As for this conversion project - I sold it quite a few years ago. I really enjoyed it while I had it. I put about 50,000 miles on it before selling it. Once I got everything worked out it ran great. It has changed hands twice now since I sold it and last I heard it's still putting miles on the odometer and smiles on the owner's face. I've long since lost track of it. I expect the body of the RV would have given out by now so maybe the engine and transmission have been removed and are powering something else.
Some good engine bay and cabin photos of the build in progress in post #55
=====================================================================
Now, let's get to the original beginning of this thread. This was documented as I did the work - not once the project was completed. Had I known what I was up against..... Well, this project might have had a different outcome.
I hope this helps inspire others. At a minimum, it documents how I stuffed a 1st gen Cummins into an Econoline engine bay. Enjoy - Mark (edited Dec 2021)
=====================================================================
I've owned a few motor homes over the years and just have never been all that impressed with the power delivery. After spending a bit of time in Europe and seeing lots of great little campers with 2.5L turbo diesels and many with manual transmissions I just couldn't get the thought of building one out of my head. Nearly a year's worth of research and long nights with my friend Google, I finally convinced myself that I could do it. Through a strange set of events I stumbled across a suitable donor engine. A very good deal was made and the truck was mine (minus the original Getrag 5 speed manual).
Here's the recipient:
A 27' Class C on a Ford E350 chassis. In it's original form it had the fuel injected 460 with a 3 speed C6 automatic, 3.54 gears and 30" tires. The price was right and the RV was in good condition. Of course a 450 chassis would have been much better. Or maybe I could have even found a diesel powered one but what fun would that be? The 1991 RV would allow me to do the conversion without needing to configure an OBD II interface to get it recertified so I could change the fuel designation on the title. The 1st Gen Cummins would be a straightforward swap without needing to mess with any computer integration.
Here's the Cummins out and ready to get torn down:
It's a 1st Gen so all mechanical - easier for my brain to digest.
Although it was running when I got it I still didn't know what the 'noise' was until I got this far into it:
Looks like the head gasket failed and leaked down for months finally wearing the piston skirts on #4. No problem.
Shiny and new:
Everything else looked and measured fine so I put a fresh set of gaskets in and put it all back together:
Engine ready - now I need something other than the Allison 542 that I got with the truck (wrong high gear ratio)