MEP-802A Busted Connecting Rod End

[fosgittr]

So I bought a 1035 hour MEP-802A from GovPlanet, and knew there was something wrong with it, as it was stated to be seized. Got it home, and found that it turned manually, but kept hitting something at the same point in the stroke. Turns out the removable end of the connecting rod was in a little baggy inside the enclosure. Uh-oh, that's not a good sign. So I took the crankcase cover off and sure enough no connecting rod present on one cylinder. Long story short, after the full tear down here are pictures of what I found. The cylinder looks perfectly fine, the crankshaft shows a little wear at the connecting rod location. I think all the military did was open the crankcase, see the problem, and sent it to the auction house. When I tore it apart you could tell it had never been done, the original engine paint was still intact. So what to do, looking for your opinions:

1. Replace the connecting rod (and piston) and give 'er ****
2. Replace the camshaft and main bearings too....?
3. Screw it, and replace the whole engine (PS there is a place in Canton, OH that allegedly has rebuilt DN2Ms for $395)
4. Screw it all, and go into the MEP-802a parts business on Ebay.......

Oh, and this genny does not have the fuse modification on the voltage regulator either. So the thing that sucks is the stator might be blown too, but I won't know that until I can start it up I suppose.

Input appreciated. Thanks in advance!!!!

 

[rcamacho]

Rebuild the engine or sell for parts.


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[DieselAddict]

If you are talking about Adelmans, I urge caution.

They did a bait-n-switch on me on a DM4. I'll not buy from them again and will recommend anyone else not buy from them as to not fall for their false advertising BS either.

Strictly my opinion.

As far as what you have now do a full rebuild and know you have a machine that will outlive you.

 

[NDT]

It was probably generating it’s little azz off when the rod let go. Other rod bearing will be pitiful as well. Be sure to plastigauge the crank before assuming it’s ok to use as is. I would fix what you got.

 

[smokem joe]

Wasn't someone selling new or rebuild engines for these? Maybe Daybreak?

 

[jamawieb]

Replace the mains and rod, then run it. It will be fine. Did you notice if the push rods were bent because the piston looks like the valves hit the top of the piston.

 

[Coug]

If it were mine I'd strip apart the engine, then take the block, crank, and head to a competent machine shop for them to check out.

That bearing looks pretty toasty, I'd be very surprised if the crank bearing surface isn't at least a little messed up as well. The imprint of the valves on the piston top is also a pretty bad sign.

A competent machine shop will be able to clean everything, and magnaflux it to check for any damage, as well as pressure testing the cylinder head to make sure it didn't get damaged either when the piston impacted the valves.

 

[Guyfang]

Not having the Quad MWO is not reason to think the stator is bad. Please remember, before the quad MWO came out, thousands of these gen sets chugged along producing power. If you want to know if the stator is bad, simply test it. It's not hard, procedure is in the book.

 

[Bmxenbrett]

Time to pull the engine appart to further for investigation. You cant make a decision yet because you dont know how bad the other piston and crank is.

I would expect the crank to need some machining at the very minimum.

 

[Guyfang]

Wasn't someone selling new or rebuild engines for these? Maybe Daybreak?

correct.

 

[fosgittr]

I'm thinking machine shop too. The push rods all look fine. But the crank shaft does have some wear marks to coincide with the marks on the bearings in the photos. I have not pulled the other rod and piston yet, or certainly have not pulled the crankshaft.

I have not seen anything in the manuals about removing the engine and/or separating the engine from the generator. Does anyone know what this entails? Or best practices on this? Do I have to pull the combined engine/generator out, or is there a way to leave the generator head installed? Any advice appreciated!!!

 

[Guyfang]

Yes, the entire package must be removed.

Yes the procedure is in the TM. Go to TM 9-6115-641-24, PDF reader page # 188. I would read it once or twice before attempting it. Its not hard. But its better to know before you start, then looking at a mess in front of you and thinking, "Maybe I should have read up on this first".

 

[fosgittr]

Well, with the whole COVID-19 thing forcing me to be at home, I finally found some time to give this project some attention. After looking at the crankshaft, it is grooved at the rod connection so I decided I would replace the crankshaft and rebuild the engine. I took the back end of the machine off per the TM and Guy's suggestion. It became apparent to me that the military must have done this as well. Upon removing the generator assemblies, I determine that the rotor wasn't even attached to the engine. From the evidence, I am going to say that the connecting rod broke, seized the engine, and then the generator sheared off the studs connecting the rotor to the engine. I have OHM'd everything on the generator and it looks fine as best I can tell. So I think I am still going to proceed with my plan to replace the crankshaft and then put it all back together. Am I missing anything? Does anyone else have any thoughts or suggestions? Thanks in advance!

 

[Ray70]

Do you have the parts you need already? If not I have cranks, rods, pistons, rod bearings but no new main bearings.
I also have a rebuilt motor and parts motors, If you need anything.

 

[Light in the Dark]

Ray is a good guy to deal with, if he has the parts you need. I would also recommend Gary Jones over at Diesel Electric Services (https://diesel-electric.us). If its a Lister part, he can get it for you!

 

[fosgittr]

Do you have the parts you need already? If not I have cranks, rods, pistons, rod bearings but no new main bearings.
I also have a rebuilt motor and parts motors, If you need anything.

Ray, I think I am all set for engine parts right now, but the full tear-down is still in progress. But.... I had a stud shear off on my F1+ rectifier, so I might need one of those.

 

[Guyfang]

Well, with the whole COVID-19 thing forcing me to be at home, I finally found some time to give this project some attention. After looking at the crankshaft, it is grooved at the rod connection so I decided I would replace the crankshaft and rebuild the engine. I took the back end of the machine off per the TM and Guy's suggestion. It became apparent to me that the military must have done this as well. Upon removing the generator assemblies, I determine that the rotor wasn't even attached to the engine. From the evidence, I am going to say that the connecting rod broke, seized the engine, and then the generator sheared off the studs connecting the rotor to the engine. I have OHM'd everything on the generator and it looks fine as best I can tell. So I think I am still going to proceed with my plan to replace the crankshaft and then put it all back together. Am I missing anything? Does anyone else have any thoughts or suggestions? Thanks in advance!

I would say you are right as to what happened. I have see this only twice, during the time I worked this gen set, and both times that was the answer.

 

[fosgittr]

Well, further investigation leads to further problems. I put the motor on the bench and began a full disassembly. I went to pull the camshaft, and noticed that one of the tappets under a fuel injector was stuck. As in would not move. At all. I got the camshaft out, tipped the engine on its side, and was able to hammer the tappet out with a socket head through the crankcase opening. Whew. But the bad news is there is damage to the tappet cylinder, and it appears to have been caused by the busted connecting rod. If you look at the pictures, you can see an ever so small defect in the cylinder. The pictures make it look huge, but you can barely feel it with your fingers. Looks like the busted rod slammed against the casting (see depression) and put a slight dent into the tappet sleeve. Unfortunately, I think this block is DOA and it is time to find a new engine. Ugh. Agree? Disagree?

 

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