Greetings,
I recently added a 77 Born Free motorhome to my fleet of vehicles and since it is a gasser, I am looking at an engine swap. This RV is based on a Ford E350 chassis, and has a 460 gas engine with 3 speed auto transmission. I am considering swapping in a diesel engine, preferably a Cummins with 5 speed, but I know that would be a fair amount of messing around to make that work, so I am looking at easier swaps. I know that the E350 chassis was available with the Ford (IH) 6.9 as early as 1983 or 84. So, given that the E350 chassis did not have significant changes for about 15 years, what are the possibilities of bolting the 6.9 right into place of the 460? Is that too much to hope for? The 6.9s and 7.3s are cheap and plentiful as compared to the Cummins. Preliminary comparisons of the RV 460 gas to a friends mid 80s pickup with 6.9 were encouraging.
So, if you have done this, know someone who has, or can point me to a resource to determine the complexity of this swap, I would appreciate it. I have already contacted Destroked and FordCummins, both of which were supportive but they deal mostly with swaps into pickups, not vans.

Lastly, I already know that this does not make economic sense, that I can't save enough fuel cost to pay for the cost of the swap, etc. We all know that any of these diesels will get significantly better fuel mileage than the gas engine. And, the simpler IDI diesel engines could be run on WVO or biodiesel. That is the ultimate goal.

Thanks in advance for your suggestions,
Chris

My advice would be to get an E350 diesel with the 7.3 and the E4OD overdrive auto trans. There are small differences in the 7.3 between the trucks and vans. This would be the easiest to swap into your van I think. For reference I get about 14-15 mpg which is 95% city driving and my van weighs 6000lbs with 3:54 gears. I've heard of guys getting 18+ mpg when tuned up right.

BTW,


It makes perfect financial sense if 1) you do the labor yourself, and 2) you either run WVO, homebrew bio, or blends. With my blending I estimate I saved at least $1500 just this year alone over 15,000 miles. My blending cost runs between 20-60% the cost of diesel, figure an average for the year of say $3.25 per gallon, split the difference on the blend cost at 40% and I'm at $1.30/gal. I used about 1000 gallons this year so $1300 vs. $3250, comes out to $1950 this year in gross savings. Throw in $300-400 for my setup and supplies and it's about $1500. To put it in perspective I also own a loaded '03 Expedition in very nice shape while the van is in rough shape and has no options. I always drive the van unless we are taking the kids somewhere. My fiancee who usually drives the Expedition (12mpg city) drives my van whenever she has errands to run alone or with just one kid. She uses 1000-1200 gallons per year of gasoline in the Expedition. Our plan it to pay off and sell the Ex, get an IDI passenger van from the south and convert both vans to 4x4 since we have a steep driveway (I hate having to clear the drive before work in the morning and if we park on the street the plows bury us in) Some might say I'm crazy for spending that kind of time and money on old vans but we have 5 kids between us, every dollar counts and WVO blends sure make a big difference.

I have been considering this same kind of engine swap for my 73 Winnebago motor home. It sounds like you have not used yours much yet, I suspect you will get about the same gas milage as I do with my 413 V8 dodge gasoline engine, I get 5 to 6 MPG. A diesel engine should reduce the fuel use by at least half, more likely closer to 2/3, 12 - 15 MPG is much better than 5-6, especially if it is burning a much less expensive fuel. Switching to a transmission with an overdrive gear should make up for the lower rear end gearing that is usually found in a vehicle with a gasoline engine.

This current discussion Has a bit more info on the differences between the 6.9L and a 7.3L IDI Ford engines, past posts have indicated that there is really no noticeable power difference between the two engines, I am watching for a 6.9L IDI engine and a newer overdrive auto trans. The factory did not put a turbo on these IDI engines except during the last year of use (1993) of the 7.3L, but there are after market kits available, I would suggest a mild turbo, 10-12 pounds max, if you will be doing much mountain driving.