I've been thinking about putting in a diesel when the ol' 390 goes belly up. Question is, which one? I'm thinking non-electronic 6.9,7.3, or a 5.9 Cummins.Any of these are going to weigh at least 500 lbs more than the 390, but since it's a F-350 it should handle the weight. Then again I could get the front coils from a later diesel PU.
Should I keep it auto, or go to a manual. I think with the 4.10s I'm going to be using a V-8, since I think the Cummins will run out of rpms at too low of a road speed.
This is just a mental exercise right now, as the 390 is still in good shape.
Comments? Problems?

Thanks,
John

 

With the 4.10s and any diesel, your going to run out of revs at about 60, and the mileage is going to suck. I would go to a 3.55 rear gear, and a five speed overdrive.
Have you looked into Deutz diesels? I am working on dropping one into a 77 4x4, so I will have instructions for most early Ford trucks before too long. Nice, efficient, torquey, and air cooled, so no need for a cooling system.

 

Deutz diesels are too hard to find around here so I too am thinking of a 7.3/5 speed for my 71 F350. Didn`t know about the 4.11 rear end, looks like I will have to change that as well. Hope the weight factor is not too much of a problem. I have manual steering as well to consider.

 

Actually, Deutz six cylinders are surprisingly easy to find- Almost any Allis-Chalmers combine has them, as well as larger wood chippers used by utility companies, log loaders, larger I-R trailer air compressors, bobcats, even John Deere used them in a few models.
I wouldn't even bother with manual steering, just do the 73-79 power steering and disk brake upgrade, and box the frame while everything is out of there.

 

let us know how it goes it sounds neat. i think it would be a first. so it would be very neat to say the least. the 5.9 and the 6.9 have both been done to many times so a deutz would be off the beaten path and plus the name sounds cool. "That Thing Got a Hemi" hell no this "thing" got a "DEUTZ Diesel".

 

John, There have been a few hurdles that have been hard to overcome with the converstion. It has only been in the last few years that using the diesel here as we know it is starting to come around.

The gas engines rev fast, and run at higher rpms than the diesel. I looked at a Ford retrofit back in the mid 80s from a commercial Ford engine dealer. They had put one in a E250 van, like one that I had. Mine was a cargo and theirs was a passenger. I refered to it as being like having a 35 horse Johnson, on a 21 ft boat. It took forever to pick up speed and topped out at 62 mpg.

Turbos can help with the faster reving. The overdrive trannys can help with rpm limits. Another problem has been, the torque that the diesel delivers, will kill the weaker built trannies.

Going in the direction of diesel engines that can be fueled with renewal fuel sources like soy beans, and used french fry oil, certianly have a role in the future.

An air cooled engine sounds great, but you had better hope it doesn't get cold or you need to run a defroster for the windshield where you live.

There are a truck load of issues to be addressed, and with guys like the readers here getting involved, I believe it will happen.

My couple coppers worth

John

 

My 86 with 6.9 has 4.10 axles factory issue, has plenty of get up and go, and will go over 70. With the overdrive, you will get better fuel mileage than I do, but the point my truck likes to run best is 60-70 mph. I can get 15 mpg on average, drops 10-12 with a heavy load on the trailer. My truck is 4x4 as well, so that can cut into the efficiency. My father's newest acquisition is an 84 extended cab 2wd 6.9 4 speed with 4.10 axles, and they are getting close or over to 20 mpg out of it. it maxes out just under 70, so there is a difference in governor setting. The IH diesels will run a little higher rpms than a Cummins will though. Cummins need to run closer to the 2000 mark, where the IH diesels will run around 3000 ok. Oh, and my dad's newest truck will pass mine... With an automatic though, the 6.9/7.3 are quite doggy...

 

A lot of good ideas to digest here, fellro86. I had a 89 F350 2 wheel drive with the 7.3/5 speed. Lots of power and it would go more then fast enough for my needs. The milage wasn`t too great around 11 to 12 mpg but the power was very good for towing a heavy trailer (15 to 20,00,000 lbs). The IH diesels run higher rpms than a Cummins so that is much better, 3,000 sounds better then 2,000 unless I want to change my rear end gears. For now I don`t want to mess with it.