Crate Motor Questions

[acme66]

Forgive me if there is a thread on this, I couldn't find it. Just trying to be informed as I decide to rebuild, repower or put a crate motor in our tour truck a 1984 925a1. I have ruled out a 'take out' motor simply because I am dealing with a 2 out of 3 failure rate on mystery motors so far and spring isn't here yet. (side note, lost liner seals in both motors at the start of spring after running the engines normaly the previous season)

I have questions on the rebuilding process and sealed military crate motors in general.

1. When they are rebuilt, is there a minimum amount of work done? For instance are the heads always pulled, the liners, bearings replaced, injectors inspected? What is the minimum amount of rebuilding I could expect to find in a sealed mystery crate motor?
2. Is there a way to tell of the crate is still sealed?
3. Are the motors run tested at the shop or boxed away virgin? Has it been properly timed or just the close enough to start, time in truck scenario?
4. How long is too long? If the crate still looks sealed up, how long before you just don't dare dropping it in and running it? If I have to pull down the crate motor then might just stay with mine.
5. How complete are they? Should I expect to find water pump, injector pump and compressor bolted on? Power steering pump, intake/exhaust manifolds, starter? My impression from asking around is a direct drop in with everything except power steering pump and starter.
6. What don't I know about crate motors but should before I make a choice and start dropping coin?
7. Personal experiences with them, better luck than the mystery 'ran when parked' motors?

Just for your own entertainment:

Rebuilding - I have pulled one of the NHC250s down (have video) and inspected. Looks like 6 liners, bearings and gaskets and we will be back in business. Trying to decide if piston failure is due to over fueling by an injector or liner failure getting water on the piston skirt. If it is the first then add 6 tested or rebuilt injectors to the bill.

Repower - Motor currently up for consideration is a Detroit 8.2L turbocharged V8 mounted to the GMC top-kick automatic transmission. Not the most loved motor ever in the truck world. We would have some gearing issues but it would be closer when running the 1400 or 1600 tires than thought.

Thoughts always welcome, appreciated and read... but not always followed.

Ken

 

[dmetalmiki]

Those Detroit motors sound the b......s!, and are reputed to be as tough as old boots.

 

[74M35A2]

The one he is talking about is not a 2 stroke Detroit. It is a 4 stroker, nick-named a ""fuel-sipper".

 

[doghead]

Any motor in a crate is a total crapshoot.

 

[red]

Considering that you have the skill to rebuild a motor, you will most likely be money ahead to pick up a spare engine and test/overhaul it yourself. That will also let you verify that it is indeed running and ready to be swapped in.

 

[snowtrac nome]

I worked at a csms shop the motors are completely tore down mic'ed out any components out of tolerance are replaced. The engines are re assembled and dyno tested and broke in. one problem you may have with a canned engine is you wont know if it is serviceable or an un rebuilt core. At gs level there is a standard all engines are rebuilt to they aren't considered local stock. once the motor is rebuilt and back in inventory you could be directed to send it any where in the world.

 

[NDT]

An engine in a can could be: Factory new, factory new but removed due to a knock, rebuilt/good, rebuilt but removed due to a knock, take out/good, take out good but removed due to failed oil analysis. Think this covers all I have seen.


8.2??? Really? Anything else.

 

[Lukes_deuce]

I have no experience with military crate motors, so I cant offer any help with those. It does sound like you are mechanically inclined. If your willing to tackle a rebuild, I read that you have two other 250 motors laying around. I personally like knowing where and how a motor failed, so you know what needs to be fixed. Sometimes buying a used motor is only another mystery. Or if you want to go the repower route, please dont put in an 8.2 Detroit. Those are awful motors. You can find a good used 350 Cummins and most of the parts will interchange with the 250 to make the install easier. It all depends on what you want to accomplish. I would love to see either a 12.7 Detroit or a N14 Cummins. But those are another ball game to fit in. Good luck with your decision.

 

[ca1517]

The engines I have in cans are depot rebuilds, they are test run, and have the dyno sheets with them. If you were looking for one, you can contact me via pm.

 

[snowtrac nome]

I herd the Canadians had some duce's with the fuel pincher. those little engines kind of got a bad rap the reality is I have worked around several and they seem like the energizer bunny they just keep going. I however agree I would stick with a bolt in option say a bc 350 or even another 250. Assaid you seem to have a bit of talent in the field I would suggest rebuilding it your self things are heavy so you are going to need some lifting equipment timing the engine will be your only technical issur and a cummins manual will cover that you may even want to change out to the non emission friendly non topstop injectors. Rebuilding it your self would allow for som customization

 

[check58]

We had several 8.2's in 2000 gal tankers. All of them leaked oil, and seemed to like blowing head gaskets. The fuel system is also a nightmare to get running correctly, (you have to have a special tool). It might be a cheap option up front, but I can promise, it will drain your wallet in the long run.

 

[snowtrac nome]

I thought oil leaks were a trade mark of Harley and Detroit. The last one I worked around did leak a bit around the crank. never had to mess with the injectors I have to believe they are like a 3116 cat as it does require dial indicators to do the overhead. It really wouldn't be my first choice for a 5 ton , now if one wanted to change up look at a 3306 or 3406 cat those would make a wonderful power plant for a 5 ton. the fuel pincher is like a 3208 cat its a good engine but there is better.

 

[acme66]

Non emissions friendly injectors? Can you explain a little bit about those and why I should switch them?

To add a new layer to the crate motor saga, fully understanding that life is full of crazy things that happen... What if the motors in question were Forest Service replacement motors sitting in the warehouse to be dropped into fire equipment and tagged as such. Professional opinion about chance of motor being a good one if they have been stored inside crated up in case the USFS needed a new motor in fire season?


Ken

 

[Chief_919]

Non emissions friendly injectors? Can you explain a little bit about those and why I should switch them?

To add a new layer to the crate motor saga, fully understanding that life is full of crazy things that happen... What if the motors in question were Forest Service replacement motors sitting in the warehouse to be dropped into fire equipment and tagged as such. Professional opinion about chance of motor being a good one if they have been stored inside crated up in case the USFS needed a new motor in fire season?


Ken

Short answer- who knows. since they didn't have anything invested in them if a part was needed fast they could have swapped bad parts for good.

If it was me I would do an in-frame rebuild and then know for sure what I had, especially if it is a truck that is needed to work and make money.

 

[Bandit02]

The Canadian deuce or MLVW they were called had the Detroit 8.2 V8 NA engines with the Allison MT643 tranny. I can remember a few running away when they were started up cold.

If they were factory turbo'd it would have been nice in those lil 2.5 tons.

 

[pjwest03]

For 5 ton, the 8.2 would be under powered and under torque compared to an NHC250.

 

[NEIOWA]

Non emissions friendly injectors? Can you explain a little bit about those and why I should switch them?

To add a new layer to the crate motor saga, fully understanding that life is full of crazy things that happen... What if the motors in question were Forest Service replacement motors sitting in the warehouse to be dropped into fire equipment and tagged as such. Professional opinion about chance of motor being a good one if they have been stored inside crated up in case the USFS needed a new motor in fire season?


Ken

While any Forester using DOD surplus can get any engine listed there is no way to know if getting a fresh rebuild or a shot core. When mil shop changes out an engine the dead unit goes back in the can and gets turned in. The DRMS/DLA yards will NOT give diddly for info on what they have listed. Or typically will not. They may or may not have paperwork that accurately show condition. Been down that road looking for a good 8V92 in can to fix a ladder truck with a blown engine. They dang sure aren't opening a can to check it out. They don't care.

Now you can get good CAT take outs that will be a good but as they are coming out of MRAP being dismantle. Everything in DOD surplus is a pot shot. Request then see if a Steelsoldiers member in the area of the DLA yard will go take a look for you.