I am thinking of building my next truck. This will be my general use truck, hualing, towing, DD, and trails. I want to use a Jeep M-715 as the base. My 79 K5 has a 94 7.4l with a 4L80E, but this time I want no electronics if possible. 40"+ tires are no problem with these trucks so I can keep the RPMs down. My first choice is of course the Cummins 6BT 12v. They have Great power, good mileage and aftermarket support. On the down side, They are very heavy and pricey. Second option is an Isuzu 6BD1T (or 6BG1T). The power is good (175 hp, 400 Tq), mileage is great (22-30 mpg) and cheap to buy. The down side on these is the lack of info and aftermarket support. I thought about the Chevy 6.2 and 6.5 but I can not find a strong reason other than price. Are there others I should look at? I am grateful for any input. normally I am over at CK5 but this seemed a better place to ask.
CUMMINS waytogo . Isuzu parts are way too expensive and I don't know if there are any power enhancements for those engines.
The 6bt is a good choise, its widely available, has a huge aftermarket, and you can buy parts for it at your local parts store. Probobally the most comon diesel swap these days. GM 6.2/6.5 is an option, but not a very exciting one. I have a 6.2, and while it has been a decent motor, if this is going to be a tow rig i may avoid it. They do tow alright, but i know i am hurting for power alot. If you were looking at a V-8 diesel, i personally am a huge fan of the IDI Navistar motors used in fords. The old 7.3's in particular. They are strong motors, again parts are easily atainable, and can make good power. Nothing like the 6bt, but good nubmers nonetheless. You do have to find one that was well maintained, though, as they are suceptable to cavitation if no additives were used in the coolant. I know nothing of the Isuzu motors other than they are reliable.
Are you going to have a D60 under the front of this truck? Do you know what that Izuzu motor weighs? I would agree on the weight of the 6BT, it's a heavy unit and would think it would make those expensive 40" tires wear fast. I would consider the 6.5TD engine. It makes quite a bit more power than the 6.2 and is a reliable engine from what I have heard. There is a small amount of aftermarket support for it too if you want to hop it up. I agree with Joez on the Ford engines, they are good engines but I don't think anything from Ford that isn't computer controlled could compete in power to the GM 6.5, turbo'd Izuzu, and obviously the 6BT. Maybe the early 7.3 IDI that was turbo'd (IIRC) but I see no reason unless you come up with the right engine with low mileage, yada yada....and you would have to potentially go with the Ford tranny also. At least with the 6BT you could get an adapter to bolt it to your 4L80E.
This is for a M-715, they are stock with old style Dana 60 /Dana 70. I am debating on newer D60/D70 or go nuts and use rockwells. Gears are the main concern with rockwells. I plan on keeping the K5 intact. I will be looking for either a non-computer controlled auto trans or a strong manual (NV4500, NV5600, SM465).
I have no idea what an M715 jeep is nor do I know what would be under one. Never liked jeeps. On the tranny issue, I see. I would forget an SM465, using a non OD tranny would seem a little silly to me, unless thats all you have. You could use an older Dodge 518 auto tranny. THey can be built up well and be plenty strong, and has OD.
Either Diesel you install isn't gonna do well with the Rockwell 6:71 ratio unless you double O/D it for street use. Do the Cummins. It's been done before. I think the guy is on TDR.
Bobby, while 7.3 IDI's are no powerhouses from the factory, they pull a lot better than the GM 6.2/6.5TD motors, have a stouter bottom end, and can be built to handle more power. Plus they can run on WVO with very little work waytogo
I would think the 6.9 N/A motor has no chance against the 6.5TD correct? I know that the 7.3 was an N/A motor for a while but was it turbo charged before the PS? IIRC it was. I would think that would be a good engine and I agree. The 6.2 is out of the question. I would think the 6.5TD wouldn't be a bad choice?...But yes I would agree the 7.3 is a stouter engine, but the 6.5 is probably stout enough. Never owned either engine though.
