M936A2 Engine swap ideas

[Ssmax]

So I have an m936a2, which i know for a fact has a blown head gasket and most likely a cracked liner or many. Burns coolant, blow by, overheats, exhaust in the coolant and coolant in the oil... Could go on lol...Having said that I've been on here look at different engine rebuilds and 6CTA tare downs, I'm not really that confident in this engine. Seeing some people on here pull a head and see a crack in the block...This engine also has just above 9000miles on it and 300 and change hours. Just looking for some opinions on what you guys would think a good swap would be if I were to go that route.. Which I probably am. Thanks in advance for any input!

 

[BKubu]

If it was me, I'd find the same engine out of a low mileage/hour truck and go with that. My $.02.

 

[M35A2-AZ]

Here is a take out for sale here on S/S. https://www.steelsoldiers.com/showthread.php?184423-Cummins-6CTA8-3-Engine-8-3L

 

[simp5782]

You are limited on the A2 trucks due to the engine placement and how crazy you want to go. You can shove everything back and install a1 mounts and add an A1 cab/dog house so your engine choices are more abundant like a big cam or small cam Cummins . For your stock mounts You can go with a cheap 3116 or a DT466. Some Mods would have to be done. Dt466 would have more power of the two. Or if you have cash a 3126 or c7 but those would be equal to an 8.3 replacement

 

[Two Stroke Madness]

Well first take the head off your engine and see just what you've got going on there... it may be easier to fix than you think. If your engine is junk and you want to switch to something with some proven reliability then I would look into the later model 3306 Cat engines. Some of the truck engines were rated up to 310 hp, and had the #2 flywheel housing. There are both IDI, and DI models of that engine... you'll want the DI model truck engine. I think they are a 10.4 liter displacement. Don't quote me on much of this... it's been a while since I've looked into it.

 

[Ssmax]

Awesome guys thanks a lot... All really good things to consider, I did find a few big cam cummins but great to know its going to be a bit more involved swapping that into an A2 truck. I'll just cross that off the list lol... I'll check out some places online tonight where i can find either 3116 or the 3306. to be honest for the price i'm also interested in that 8.3 take out thats on this site. i'll post updates on what I decide to go with and detailed pics of the swap AND when i rip into my engine to see what did end up failing inside the engine. Thanks again!!

 

[74M35A2]

The flywheel housing on the a2 8.3's are SAE #2 bolt circle, but are unique to the Allison trans that is behind them, as they are not "standard" depth. They are approximately 1" deeper to make room for the large Allison torque converter. So, with that, on any other engine you'd slam in there, you'd have to also find their unique flywheel housing which would have been used with such Allison trans if you were keeping that as well, which I assume you are. Not all Allison's use this unique engine side flywheel housing. Not sure, but this could be a pain in the *** to find. I think the Allison MT654CR is kind of old/rare in non-military applications?

I have a super clean DT466E for $2,000, Cummins 8.3L out of my M925a2 for $4,500 (not yet removed), or an ISX Signature 600 15L (600hp) non-EGR engine for $9,000. All complete and great runners, can demo any to start and run properly. The ISX and DT are on run stands, the 8.3L is currently in my truck as it originally came, 20,000 miles on it now, 11,000 when I bought it 6 years ago. Oil changed every 2,000 miles since I've had it, injection pump never touched. Complete with modern gear reduction starter, 130 amp genuine Delco alternator, and genuine Sanden high capacity A/C compressor, driven off the serpentine belt, passenger side. 120V block and oil pan heaters added. Mechanical lift pump recently replaced. Truck reaches and holds 67mph any day of the week, even with a load.

I agree with 2-stroker, pull your head and see what you have first. I'd guess you have a cylinder liner that got ate through from coolant cavitation. You can pull the injectors and use a compression tester adapter to blow compressed air into each cylinder. Back the valves off, and see where the air is coming out of. 8.3L head gaskets usually don't just let go unless the pump/boost/timing are turned way up, or it was overheated pretty badly. You can also pull the injectors and go into each cylinder with a scope, they are pretty cheap now. Even my local lawn mower shop has and uses one with great results.

 

[Ssmax]

Really good to know! yes lol I'm looking to just keep the transmission. So right now we have some bad weather coming for CT. As soon as that blows over i'll get going on the removal of the head ( going to be doing this outside). I'm planning on starting early next week. I'll start another thread with my findings. 74m35a2 thanks a lot, and depending on what I see when I get in there I may be buying one of those engines off of ya! Again thank you guys!

 

[74M35A2]

No problem. Take your time. Everybody here knows I’m not in a hurry, at all.

 

[M35A2-AZ]

If you remove the motor.
FYI, I have changed out a NHC250 and it is faster and easier to remove and install the motor and transmission at the same time.
Be sure to have some help.

 

[Jbulach]

...74m35a2 thanks a lot, and depending on what I see when I get in there I may be buying one of those engines off of ya! Again thank you guys!

Buy the big one, that way you can eat his lunch with his own (former) motor.

 

[snowtrac nome]

put in a 6v-71 t Detroit your neighbors will love you when you start it in the morning.

 

[74M35A2]

put in a 6v-71 t Detroit your neighbors will love you when you start it in the morning.

^^^This^^^

I do also have a 6-71T, but not for sale. :/

 

[simp5782]

https://youtu.be/JxLb3Yqqds4

 

[Ssmax]

A Detroit in one of these would be awesome, I can only imagine my neighbors reaction to that lol. That ISX swap sounds pretty interesting, 600hp would be amazing to have in this heavy pig, i'd imagine there would have to be some modification to the Allison or a whole other trans altogether no? Would be fun none the less... I may even be able to pass a civic in my wrecker! lol..... BTW the oil pouring out of that 16v71 before its about to seize is nuts..

 

[simp5782]

you would have to shove everything back and add a doghouse like i said. Probably even raise the cab and the hood.. make new engine mounts, cab mounts, etc. It isn't as easy as it seems. With an A1 truck you have everything already set back cause of the bigger 14L engine. The A2s aren't setup like that.

The ISX would be a nightmare. A big cam would be the cheapest heavier mod more than likely even with the set back work but getting the small cam mounts and what not would be cheap.

 

[steelsoldiers]

https://youtu.be/JxLb3Yqqds4

Did anyone else cry a little bit when they killed it or was it just me?

 

[porkysplace]

you would have to shove everything back and add a doghouse like i said. Probably even raise the cab and the hood.. make new engine mounts, cab mounts, etc. It isn't as easy as it seems. With an A1 truck you have everything already set back cause of the bigger 14L engine. The A2s aren't setup like that.

The ISX would be a nightmare. A big cam would be the cheapest heavier mod more than likely even with the set back work but getting the small cam mounts and what not would be cheap.

Just go with a V-671 length won't be a problem. The canadian deuces had Detroits.

 

[snowtrac nome]

Need to add the air starter to just to add to their frustrations.

 

[Scar59]

Did anyone else cry a little bit when they killed it or was it just me?

Yeah, that wasn't right. Could have been a cool stationary exhibit.