5 Ton Engine Swap Question

LC

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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.
 

wreckerman893

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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.
 

lacoda56

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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. 2cents
 

acetomatoco

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Why would anyone want to change? You would certainly not want to go faster, cuz you have crap for brakes.. RAM
 

LC

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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.
 

lacoda56

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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.
 

rdixiemiller

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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.
 

LC

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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.
 

OPCOM

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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.
 

Bidslinger

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LC,

Are you following any type of torque sequence when installing the head. Also look for blockage in coolant passages. Just an idea
 

LC

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Yes, we have the multifuel book from Memphis Equipment with the torque sequence. We also have the two wrenches that you need to torque the heads.
 
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LC, 2 wrenches? Are do you mean the "U" shcped wrench and a standard socket? Very strange to loose the gasket twice in the same spot. Did it blow the fire ring or just spit the fiber out?

Brakes???? With the ability to lock down at 55,000# (yea I know that was with over 30k in the back....) what more do you need in brakes. Besides the 24k tailer has its own brakes and took care of itself (Snicker).
 

LC

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We have two of the U shaped wrenches. One is a longer with a 45 degree bend and the other has a 90 degree bend. It blew the fire ring out last time. I haven't seen it yet this time. I agree the brakes work fine. Everytime I ask a question that guy tells me the brakes were designed in the 1930's and are crap. I'm glad they work better than he thinks they do.
 

Vintage iron

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I would like to change the multifuel in my M64 I just picked up, to a Cummins 350. I will have to put the two trucks side by side to see the differences when I get it home. If you live anywhere near New Bedford Ma. it would be "Side by each":p

I was going was to fast on a unfamiliar back road and a stop sign appeared out of no where. I was driving my M813 with a bunch of extra tires and troop seats in the back. My M813 stopped as smooth as silk and fast too. I am very pleased with the brakes on my truck
 

Vintage iron

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The guy I am buying the truck from is trying to find the title. The truck is like a M109 but it is a 5ton. I can't find a picture anywhere. The M39 models lists a Van body as M64. this one is not expandable. It was outfitted with chemical agent ducting, it has a big ass workbench, a generator, ladder, a VIC system, and a bunch of other stuff too. The multifuel was rebuild in 1987 and has almost no miles on it.
 

EMD567

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Brakes on a 5 ton? Just get off the gas, and the **** thing will just about throw you though the windshield. The brakes on my 814 work very well.
 

73m819

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That is a good question, what are the numbers of the 39 series van bodied trucks, I just looked in my -211 TMs either I missed them or have there own TMs, not like the -260 (809 series) with the 820, ect
 

papercu

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None of the 5t series have a van body like the M109A2 (AFAIK), the 5t had the Expansible body (M39 series are Truck, Van, Expansible M291A1 M291AlD) but even those didn't have a generator in them. Maybe a batwing truck? Wayne
 
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