Picked up 6 MEP-802A gensets and will be documenting making them all runners here

I really admire your work you have 40 time the amount of energy that I have. Plus I appreciate the pictures these will be extremely help full to all other members.

But I still think your nuts!! these sets prob would of started right up and ran perfect way to much work for a generator.

CDR said:

I really admire your work you have 40 time the amount of energy that I have. Plus I appreciate the pictures these will be extremely help full to all other members.

But I still think your nuts!! these sets prob would of started right up and ran perfect way to much work for a generator.

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With all the rust and crap in these units if you could've started them you would have destroyed them in short order. The way "pclausen" is rebuilding them is the right way to go. Plus he will know that everything is OK in the units.

Yeah, these particular gensets were in pretty bad shape despite being less than 10 years old.

I'm focusing on the 2009 unit now and got the generator head separated from the engine. Check out the bearing on the genhead, I don't think I have ever seen a bearing quite that bad off before!


http://www.cstone.net/~dk/MEP802-2009-8-23-01.jpg

I'll need to figure out where to get a replacement bearing from. It's hard to make out the markings on it, but I'll try to decipher them somehow.

Here's a shot after removing the stator:


http://www.cstone.net/~dk/MEP802-2009-8-23-02.jpg

Inside stator. I plan to soak some sheets of paper towel in Evaporust and lay in there to hopefully get rid of most of that rust after blowing it out real good with compressed air.


http://www.cstone.net/~dk/MEP802-2009-8-23-03.JPG

And here's the rotor. I have not yet been able to pull the inner race from that destroyed bearing. Hopefully letting it soak overnight in PB will do the trick. If not, I guess I'll have to resort to heating it up, but have to be very careful not to melt the wires and such. Also, there was tons of caked on dust/dirt all inside the rotor.


http://www.cstone.net/~dk/MEP802-2009-8-23-04.JPG

So I'm finally down to just the engine block now


http://www.cstone.net/~dk/MEP802-2009-8-23-05.JPG


http://www.cstone.net/~dk/MEP802-2009-8-23-06.JPG

Next I blew out the rear housing assembly and noticed 3 trouble areas where the wires had been rubbing against the housing.


http://www.cstone.net/~dk/MEP802-2009-8-23-07.JPG

This area is the worst and those are the L1-L3 lines!


http://www.cstone.net/~dk/MEP802-2009-8-23-08.JPG

This area is not as bad, but I'll wrap electrical tape around the individual wires that are affected and then add wireloom on top of that.


http://www.cstone.net/~dk/MEP802-2009-8-23-09.JPG

You can cut an inner race off the shaft without damaging the shaft - it requires a delicate touch with a dremel tool and cutoff wheel, but it can be done. Once you get a good cut about halfway through the race you can usually pop it off with a smack at the cut with a cold chisel.

Thanks for the tip! That sounds like a much safer way to go than resorting to a torch. I have a 4" air cut-off wheel, but that might be too much. Will try a few things this evening to see what works.

You can do it with your 4" wheel. Cut diagonally on like a 45 degree angle to help avoid cutting into the stop. Even if you cut the shaft a tiny bit, it won't matter, the race doesn't spin on the shaft, so a small nick won't affect anything. Cut as far as you can and split it open by pounding in a chisel like steelypip said. I do it all the time on automotive wheel bearings. You can also heat the race with a torch and expand it a little and it will probably slide right off, or heat it while you have your puller on it.

Got it off!

I sized things up with the 3" wheel (sorry, I thought it was a 4"), but it would have had to be more of a 60 degree angle or something, so I ended up using a 1" on a dremel.

I only nicked the rotor shaft ever so slightly at the base where the bearing rests against. (that tiny shiny spot down low in the pic below)


http://www.cstone.net/~dk/MEP802-2009-8-4-01.jpg

Here's the inner race. Once I got close I would try the air chisel a little, then cut some more until I finally saw the fracture line and the puller fell off. Then it was just a matter of putting the puller back on and it pulled off rather easy.


http://www.cstone.net/~dk/MEP802-2009-8-4-02.jpg

The tools I used to get it off:


http://www.cstone.net/~dk/MEP802-2009-8-4-03.jpg

Next up will be to tear the engine all the way down!

steelypip said:

You can cut an inner race off the shaft without damaging the shaft - it requires a delicate touch with a dremel tool and cutoff wheel, but it can be done. Once you get a good cut about halfway through the race you can usually pop it off with a smack at the cut with a cold chisel.

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That's the way we do it at work. Don't use the torch on a heat treated item like the shaft.

Your doing an excellent job restoring these units !

Thanks Rusty!

Looking in TM9-6115-641-24P, I see that the part number for the rotor bearing is 510-0112.

A Google search on "generator bearing 510-0112" gives me the following promising links:

https://yakimagenerator.com/generators/index.php?main_page=product_info&products_id=13284

http://usauctions.com/ItemDetails.aspx?ID=9345

Looks like the right bearing from what I can tell? Shipping is $9.50 from "yakimagenerator". I guess I'll pop the rear cover on the 2 other generator heads to see if those needs to be replaced before placing an order so I can save on shipping.

Any other recommended sources for getting this bearing?

Thanks!

It amazing that so parts of these generators are not really built well I have electrical issues with my from wires rubbing and terminal ends breaking

Those bearings should have a number on the side of them. With a little polishing, can you locate it?

Our electric motor shop has a dip tank of varnish and a baking oven. If the field and armature check out electrically, no shorts, I would have them dipped.

Ask a motor shop to do a megger test. It verifies the insulation by generating very high voltage and seeing how much "leak" there is (if there is no direct short). Usually this is used to see if there is water present. No short but a failing megger test may be fixed with the varnish. First bake, then dip, then bake again. It makes it nearly waterproof.

its a good cummins # https://quickserve.cummins.com/genuineparts/MECH_00005100112.html

I believe there was a paper on the wires rubbing. I ran across several safety MWO type papers a few months ago on my phone, while in a waiting room, but haven't been able to find them since.
I know the battery cable routed underneath the generator is likely to rub. Mine had rubbed through and been repaired with electrical tape. I replaced it, and routed it away from anything it could rub through and short against. I'll have to check the L1/L3 leads, though, forgot about them.

tobyS said:

Those bearings should have a number on the side of them. With a little polishing, can you locate it?

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I do see the letter/numbers, but they are very hard to make out, even after quite a bit of polishing. I can make out some of the markings, which appear to be:

EXPLORER 6305-2RS1/JT64

Our electric motor shop has a dip tank of varnish and a baking oven. If the field and armature check out electrically, no shorts, I would have them dipped.

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I believe these were already dipped originally. Here are some closeup pics showing the varnish.


http://www.cstone.net/~dk/MEP802-8-6-01.JPG


http://www.cstone.net/~dk/MEP802-8-6-02.JPG


http://www.cstone.net/~dk/MEP802-8-6-03.JPG


http://www.cstone.net/~dk/MEP802-8-6-04.JPG

As I mentioned earlier, I'm going to see what I can do with the Evaporust and then go from there. On the stator housing, not sure how to best fix it. I guess get rid of the rust and then just rattle can those areas?

Good point about check the resistance of each coil to make sure nothing is shorted out. I'll look into the "megger" test as well.

I pulled the engine off the skid. Wasn't all that heavy with the head off, so I just lifted it by hand and sat it on my table.

Power washed the skid to get the oil and grime off it.


http://www.cstone.net/~dk/MEP802-8-6-05.JPG

Engine on table


http://www.cstone.net/~dk/MEP802-8-6-06.JPG

Front cover removed. Things look pretty good here I think


http://www.cstone.net/~dk/MEP802-8-6-07.JPG

Engine flipped on its side showing crank and a decent looking cam lobe is also visible at the top


http://www.cstone.net/~dk/MEP802-8-6-08.JPG

Remove the cap from rod #2. Journal looks good. I wasn't able to push the piston out by hand and there is very little room to get at it without removing the crank, so I guess that's next.


http://www.cstone.net/~dk/MEP802-8-6-09.JPG

Finally, here's a shot of 2 of the lifters. I pulled all 4 and they all look ok.


http://www.cstone.net/~dk/MEP802-8-6-10.JPG

Need to read up on what I need to mark before pulling the gears off the front as well as dealing with all the fuel rack components.

Got the pistons out. The trick was to put a cap bolt back on and leverage against it to pop out the pistons.

#1 piston. Rings were all moving about freely and appear to be in good shape.


http://www.cstone.net/~dk/MEP802-8-7-01.JPG

#2 piston. The lower ring was free and came off easily. The 2 upper rings are stuck on there pretty good though


http://www.cstone.net/~dk/MEP802-8-7-02.JPG

I'm letting that piston soak overnight in diesel in the hope that will free up the rings.


http://www.cstone.net/~dk/MEP802-8-7-03.JPG

Assuming things go well and I can get the 2 stuck rings off without damaging them, I'm thinking I that if I reuse all the rings, I should not bother honing this particular engine. This one was not all that rusted and there was no pitting in the bores. Since the rings already seated in these bores, less is more, right?

Your this far along you have to hone and and least put new rings so it's almost like a Freash motor

If you put it back together with old rings all your work is a complete waste of time

CDR said:

If you put it back together with old rings all your work is a complete waste of time

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I agree with "CDR" . After all the hard work you've done why stop short of the finish line ? New rings and a light hone and you should be Golden !