671 Detroit in my M818?

[JeremyB]

Hello,

I was wondering what the obsticles would be to run a Detroit Diesel in my newly acquired M818 would be? It needs an engine and the 671 and tranny are under a grand and running strong. Has anybody done something like this or what would the problems you could list be?

Thank you

 

[wreckerman893]

That particular Driptroit is a two cycle engine...like an old Yamaha dirt bike...it has a power band and does it's best work at high RPM...it burns oil just like a chain saw.
I used to run to Cal in a KW with a 8V92 and it used about 6 gallons on a round trip.
They can suck fuel if ran hard for a long time.....and you are gearbound in a 5 ton already.
And they are LOUD and put a lot of vibration thru the driveline.
If I were going to run a Dripper in a 5 ton I would go with a V-8 OO 92 with a 13 speed Road Ranger.

 

[jimbo*]

Sure it can be done--I have an M51 that some doofus swapped a 6-71 into.
The question, is why?
Look around, and be patient, a Cummins will turn up, affordably.

 

[lacoda56]

The old detroits have absolutely no lugging abillity and like wm said your 5 ton doesn't have enough gears to keep the rpm's in an acceptible range. Your main problem, other than owning an oil well to keep the leaky pig well oiled, would be no power at the low end where you want it. My opinion would be find another engine. By the way, other than the name, the newer four stroke detroits have nothing in common with the two strokers.

 

[m16ty]

Well it sounds like he's getting a trans with the engine (maybe a 13 speed or something). That would help.

I kind of have a love/hate relationship with Detroits. I've ran some that had plenty of power if you kept it reved up and didn't leak too much oil. Then I've ran others that had no power and would just put out a bunch of smoke and leaked oil about as fast as you poured it in. Also seems like one will run forever without even turning a bolt on it but once you start having problems it seems they never end. A Detroit has alot of moving parts and manual adjustments that have to be just right for the thing to run right. Most of the time when they leak oil it's comming from the blower seals or oil gets past the piston rings and into the blower housing. GM must have known they were going to leak from the factory as they have a drain tube on the blower housing.

 

[papabear]

Seek out a 250 Cummins...you will always be glad you did..IMO

 

[OPCOM]

I'd vote for finding a Cummins. Maybe you can find a big cam one, would be a direct swap..

But if the other stuff is cheap enough and you just got to do it.. well there is also alot of work to do to mount it all up and make it fit right. Your truck and $. Think about the 3-4 shift. That is a reach down to low RPM in these trucks especially if you put bigger tires on. The only alternative is to go 1-2-3-4-5 low then 4-5 hgh which is not much better.

For my part, I do not like 2-strokes. You have to add oil, mix oil, whatever, they use alot of it. Maybe diesel 2-strokes are OK but gassers like a dirt bike suck. Foul the plugs unless run wide open. I will never own another one if I can help it. I can't even stand a chainsaw.

 

[m16ty]

For my part, I do not like 2-strokes. You have to add oil, mix oil, whatever, they use alot of it. Maybe diesel 2-strokes are OK but gassers like a dirt bike suck. Foul the plugs unless run wide open. I will never own another one if I can help it. I can't even stand a chainsaw.

I Detroit doesn't use oil when new. It's because of the design that they will use/leak quite a bit of oil when they get some wear on them. They are a two stroke (and I know Wrecker compaired them to a chainsaw ) but there is hardly any design similarities in it and a two stroke dirt bike.

One of the selling points of the 2-stroke Detroits was that you can get almost twice the power per CID than you can with a 4-stroke because it fires every time the piston comes to the top. This is also why they are called "screaming Jimmies" because they sound like they are turning twice as many RPMs than they really are.

If I could get a good running 671 with matching trans I'd go for it for that price. Just to have something different and is 318HP if I remember correctly.

 

[southdave]

I always loved running 671 fast, fast until you get a load on it 671t with 10 speed swear I could almost beat vett off the remember being 19 in autocar triaxle doing 80mph before I knew it had gvw around about 45,000 thought if MF gose that what I replace it with as for oil, it just part of it

 

[lacoda56]

I think a 6-71 detroit had around 230 hp., the 8V-71 had 318.

 

[m16ty]

I think a 6-71 detroit had around 230 hp., the 8V-71 had 318.

The more I think about it I think you're right . I have driven several 6-71s that will out pull a 250 Cummins though. Don't know what's up with that.

 

[lacoda56]

No offense, but might they have been 92s instead of 71s? Just wondering because I haven't seen a 71 series in a truck in over 30 years. Seems to me the 92s came out around 1980 maybe?

 

[yeager1]

Check out this info- He's running a 6-71 in a 5 ton.
http://www.steelsoldiers.com/5-ton-up/31609-bridge-truck-53s.html

 

[m16ty]

No offense, but might they have been 92s instead of 71s? Just wondering because I haven't seen a 71 series in a truck in over 30 years. Seems to me the 92s came out around 1980 maybe?

No, they were 6-71s. My brother had a '71 (I think) GMC with a 6-71 that would run off and leave a '69 IH truck I had with a NHC-250 with the same load. That old Jimmy spilled more oil on the ground than the Exxon Valdez though.

 

[SuperJoe]

the cummins is referred to a lot as popular? how about a 365 with a fuller 10 speed? thoughts on this combo

 

[dumptruck]

may have a 5 ton engine for sale with 1800 hrs that looks new soon.vg

 

[SuperJoe]

how much is list on something like that. if i can find a cheap 5 ton and the engine will offset the total cost i will have my truck soon.

 

[Farmun]

No offense, but might they have been 92s instead of 71s? Just wondering because I haven't seen a 71 series in a truck in over 30 years. Seems to me the 92s came out around 1980 maybe?

We had a 6-71 in a '68 Ward Lafrance. It was a screamer, and a really nasty leaky smokey truck, that you didn't have to worry about ever rusting. Never had a minute's trouble out of it, as long as you kept feeding it oil. We did have it run backwards one night, and that was very interesting to say the least.

We've got a 6v92 in a truck now, and even as loud and nasty as the 6-71 I think I prefer it to the 6v. We can't get the 6v to run hot enough to keep it from slobbering everywhere. We have the radiator completely covered, and it still won't go over 160 degrees.

 

[JeremyB]

We had a 6-71 in a '68 Ward Lafrance. It was a screamer, and a really nasty leaky smokey truck, that you didn't have to worry about ever rusting. Never had a minute's trouble out of it, as long as you kept feeding it oil. We did have it run backwards one night, and that was very interesting to say the least.

We've got a 6v92 in a truck now, and even as loud and nasty as the 6-71 I think I prefer it to the 6v. We can't get the 6v to run hot enough to keep it from slobbering everywhere. We have the radiator completely covered, and it still won't go over 160 degrees.

My deuce was like that,I couldn't get it over 165. In the summerI would dog it in 105+degree heat. I was melting though,The thermomiter hit 124 in the cab.

 

[OPCOM]

I always loved running 671 fast, fast until you get a load on it 671t with 10 speed swear I could almost beat vett off the remember being 19 in autocar triaxle doing 80mph before I knew it had gvw around about 45,000 thought if MF gose that what I replace it with as for oil, it just part of it

what?