I have a friend who is looking at putting a 3126 CAT into a 5 ton. I'm sure this has been covered several times but I was wondering if anyone has any tips or pictures. Or is there a better engine to swap in? Thanks for any help.
If it is a 5 ton with the 250 Cummins in it I would try to stick with a Cummins, maybe moving up to a 350 or 400 with turbo.
A Cat will eat your lunch as far as replacement parts and getting it worked on. Cummins are fairly cheap to keep if you can do your own labor.
There also may be an issue with motor mounts, engine position and mating it to the bell housing.
Just my rambling thoughts.
You're right with the Cat being expensive, but you won't find a better engine. I seem to remember the Cummins 350/400 are longer than a 250 and will bring on more mounting problems. Don't get me wrong here, Cummins builds a good engine and it looks like I might be driving a 400 in a binder this summer, but Cats are hard to beat. Remember, this is my opinion, and being an old fart, I'm sticking to it.
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Lord, please don't let me screw this up!
The last time I asked a question you told me the brakes are crap. The reason he is thinking about changing is because the multifuel has blown a head gasket at the front of the block twice and he is afraid it might happen again. I guess I should ask what needs to be done to put a 250 cummins in it since that would be the easiest. If anyone has any insight I would greatly appreciate it. I'll be sure to warn him about the brakes.
Brakes on a 5 ton are crap? It must be that particular truck because the brakes on my M813 are smooth, easily modulated and brutally strong when needed.
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1977 USMC M813-A1
M796A1 Trailer
MKT-95 Field kitchen
The cummins won't fit (or any other long 6 cylinder) in an M39 series truck without serious modification. The 800 series truck had a longer nose to accomodate the longer engine. I guess we were thinking you were talking about an 800. As for brakes being crap, how come? I've never had a problem with any 5 ton I've driven. If they're adjusted properly they work just as good a straight air.
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Lord, please don't let me screw this up!
There are a couple of guys who put Cat V-8's in deuces. the 5 ton should have more room, as they originally had the R6602 gasser in them. You might have enough room to move the engine ahead and put in an 8 or 13 speed tranny as well.
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Currently out on the road programming robots.......
Thanks for the replys. Does anyone know if a multifuel is prone to blowing the head gasket at the front of the engine or is there a chance the block has a bad spot? We had the heads planed when we fixed it the last time so I was hoping that would be the end of it. We also used the new style gasket from Memphis Equipment. Thanks for the help.
It is very suspicious that the headgasket would blow twice in that one spot. Perhaps the deck is not straight? Twice could be a coincidence, but three times would be just about proof. Have you kept the old gaskets from before to examine? pictures would be good, and also images the new gaskets and how they went. Then some of the experts around here might be able to make some comments. It is way cheaper to replace gaskets than the engine.. If it comes to the engine deck being 'wrong' somehow, then it would be a big money issue to have the block out and decked. I looked at a stock 5-ton with the cummins, and there was very little room in there between it and the radiator.
5 Ton Engine Swap Question
