Diesel Swaps
 

It's prety well known that for a given HP, big cylinders are more efficient than small cylinders due to better surface to volume relationships. Less heat leaks out to coolant.

My 6.0 liter Ford Powerstroke is an 8 cylinder, and it has way too much power for my needs. I'd love to swap a 5.2 liter Isuzu or (even better) a 3.9 liter Cummins 4 cylinder. My F 350 could hit the magic 25 mpg with these motors. Anybody know a shop that does engine swaps?

I don't know any specific shops that do engine swaps. I'm sure you could find some diesel shop that would be willing to do the work, but it would cost a ton in labor for the custom fabrication of engine mounts and transmission adapters.

Anyway, I'd say go with the 3.9L Cummins if you want a massive gain in fuel economy. If you want a gain in fuel economy and still have massive pulling power (even more than before) get a 5.9L Cummins inline-6. As you said, it has a lower surface to volume ratio so it is more efficient and inline-6s are naturally balanced do to their design so they vibrate which translates into more power and longer life. Not to mention it has about 20% less parts than your V8. Your engine is rated at 325HP at 3300rpm and 560ft-lbs of torque at 2000rpm. The 2005+ 5.9L Cummins also has 325hp but at 2900rpm, and it has 610ft-lbs. of torque at 1600rpm. So with that engine you're getting more power and its in the lower rpm range as well meaning better fuel economy.

It looks like the 3.9L Cummins made 130HP and 355ft-lbs. of torque, but I'm not sure what rpm range that is in. But that's still just a tad less than torque than a 5.7L gas engine which a lot of trucks have.

Actually...value of your F-350 will drop way down with that swap. If its too much for your needs maybe consider selling it and picking up a lighter truck, and using the money you have left over from the sale towards the swap costs? Then again, I suppose you could sell the 6.0L engine by itself once it was out and remake some money off of that.

It sounds like a vary interesting swap, please keep us updated on how it goes! I'm definitely very interested in how it will turn out (as you can tell from the length of this post, lol). Good luck!

Really? Does that mean that a 100 year old Oldsmobile with a 707 cu. in. T-head six, 60 hp, is more efficient than my Geo with a 61 cu. in engine, @57 hp?

The statement was probably meant in a context of "all other things being equal".

As for the swap idea, I'd love to see it happen and see the results, but the cost could buy a LOT of fuel.

Ever consider SVO/WVO (not biodiesel)? I've dreamed of a system that does ALL of its processing onboard, rather than requiring you to settle/boil the water out first and whatever else. A F350, if you can give up some bed space (or squeeze the equipment into the underbody/engine bay), is a good platform for it...

Obviously, a 100 year, old side valve, low compression engine isn't going to be as efficient as a modern diesel with 18:1 compression. You have to compare similar engines......:)

With WVO, you are still going to need to filter it before putting it in the tank. I guess you could put the required filtering system in the truck, but it's easier and cheaper to just set up a gravity system in the garage.

It's definitely cheaper, and easier to design, to process it in the garage. However, for ease of use, my dream includes onboard filtering. I'd say the filtering is the easiest part to do onboard anyway.

You're supposed to let it settle to separate all the mixed liquid components too. It's relatively easy to boil out the water, but what about any other contaminants?

You could also use a water seperator or even mix in some alcohol or acetone to allow it to mix. Do comercial greaser conversion kits pump the oil through the vehicle water seperator?

It's the other stuff, bits of food, hair, dust, and anything else that falls in to the WVO, that are the hang up for your dream. Depending on the WVO source, you might be replacing the onbroad filters with every tank. There goes the ease of use advantage. Larger filters just cost more. For timely, economical filtering off the vehicle, most use centrifugal systems. I don't think those will run well on a moving vehicle.