Re: Expedition Diesel Conversion??
Conversions can be done, depending how much cash you want to put into it. Obviously if you want to start, you should have the money to finish it before you decide this is what you want to do. There's a lot more besides getting the engine to fit. I'd try a 7.3L myself as it's much more reliable than a 6.0L unit. If anything, I'd try to squeeze in the 5.9L Cummins I6 for best reliability, but it is a couple inches longer than the Ford diesel V8's.
My guess is you'll have to remove some of the front frame, or extend it outwards which would mean custom body work (ie front fenders) in order for the engine to fit with enough clearance to support a properly sized radiator. Once you find a doner engine you'll need the transmission, wiring harness and PCM along with any other electronic hardware you can get your hands on.
The other thing is emissions. You will want to check with your state laws to make sure this is in fact feasible. I can't see why not as the diesel won't pollute as much as the larger gas engine under the same driving conditions. Engine mounts will be different an will require modification. Besides the transmission, you'll have to make sure the axles can handle the torque. You'll notice in the F250 and Expedition vehicles that they have larger axles just for that reason - to handle the extra torque. The front suspension will also have to be upgraded to handle the greater weight that comes with a diesel engine (Cummins will be lighter here).
Still, once its all said and done I can forecast an easy $15-20K depending on the engine combo you decide to go with and if you do the majority of the work yourself. Frankly I'd just get a 5.4L long block from Jasper Engines.
Also, don't be limited entirely by domestic diesel engines. There are several smaller (3.0L) units found in some SUVs (check salvage yards) that are just as reliable as HD diesel engines and will more than likely be easier to fit than a 7.3/6.0 or 5.9L diesel. Obviously it will probably cost a bit more, but the smaller engine shouldn't require the need to upgrade the front suspension. Lots of ideas out there!
'00 Durango R/T 360ci 290hp (modded); 138,500m
'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!