MEP002A Oil Pump

[Ray70]

Yes they definitely are Priceless!
I purchased a 003A parts motor last year ( I wanted the IP out of it ) and the failure point was smashed up gears, with the crank gear being split open at one of the threaded puller holes.
The timing cover was also cracked as a result of the exploding gears.
I'm going to see if I still have the cover around here somewhere and see if the roll pin is intact or not.
Unfortunately the IP plunger was slightly rust pitted at the end, rendering it useless.
I think a little water / moisture had gotten into the IP through the disconnected line fittings and pitted the plunger.

 

[Boonies]

Excellent video and very good explanation and details. I was the one who started this thread when my 002A oil pump failed in June. It was not the roll pin in my case. I was never able to determine what caused my failure. The shaft on my oil pump gear sheared off but there was no damage to either the cam or crank gears. No evidence of anything getting caught in the gear teeth to shear the pump gear. There was some minor damage to the oil pump gear but it appears as though it was caused by the spinning gear colliding with the gear cover, which also had a hole in it. Fortunately for me, the oil pump gear didn't bounce around or get thrown into the other gears causing more damage. All I had to do was replace the oil pump, which was a major job in itself, and I used 2 part metallized epoxy putty to repair the hole in the gear cover. I wish I new what you learned about the roll pin when I was working on mine. Mine still has that roll pin in there just waiting to cause problems. My unit now has 6953.3 hours and is running strong. The new pump has 539.5 hours on it. The putty worked on the gear cover. There are no leaks.

 

[Guyfang]

I would not worry toooooooooo much about the roll pin. Its not a failure seen all that often. I worked on Army gen sets almost 30 years, and never saw that failure.

 

[Chainbreaker]

Never-the-less, I agree with Blade that using a steel roll pin in an aluminum boss is not an optimum design given its critical location, the vibration and temperature swings these engines are subjected to.

I also appreciated the excellent video as well as the fix Blade came up with. According to Guyfang's experience, and with no apparent "past history repairs" of these types of failures reported on Steel Soldiers, the statistics seem to be on our side that it won't become a common failure.

Regardless, fingers crossed I never face this type of failure!

 

[Jim Layton]

I just found my rollpin sitting in the bottom of the cover...people here directed me to your video. Yeah, I think I'm drilling and tapping mine, no more pin.

 

[Boonies]

I just had the same failure. It was the roll pin in the aluminum cover that fell into the gear set and caused catastrophic failure.

Hi Blade, When I first came across your post with the video of the MEP-003A gear failure behind the blower fan I downloaded it. I just re-watched it because I had a very mysterious failure. In June 2021 the gear on the oil pump on my MEP-002A sheared off. The only thing that got damaged was the gear cover plate and the oil pump. I got some really good help here on the Steel Soldiers. I got a new oil pump and installed it and everything was fine. Then I saw your posting and wished I had done the same kind of upgrade to that governor pin that you had trouble with. Anyway, the generator ran fine for a while. Then the governor started acting up. It would run great for a while and then it would start "hunting" where the frequency/RPM would be erratic. I spent many hours on many different occasions trying to adjust the governor. It didn't seem right to me that it was so difficult to adjust. I would get it running pretty good then all of sudden it would get erratic again. It never occurred to me to ask for help. I just thought it was a difficult adjustment. The generator ran OK and the frequency variations didn't seem cause any real problems so I sort of got used to it. Every so often I would go in and attempt to adjust the governor again but I was never able to eliminate the "hunting". I actually used it like that for about 2 years or so. A while back I got another MEP-002A. The governor was really good and did just what anybody would expect. I fiddled around with it some and found that it was not difficult or finicky to adjust at all. It was robust and there was good range of adjustment that would work. I decided to go into the older generator and find out what was wrong. I pulled the fan and the gear/governor cover and what I found is the pin that you had difficulty with had sheared off. It did not come loose like yours, it was sheared off right at the edge of the aluminum casting. The mystery and astounding part about this is that the pin is gone. It did not go into any of the gears and it was not laying at the bottom of the cover. It is completely gone. The only thing I can imagine is that somehow is got into the oil pan. I cannot believe that really happened, but where else could it be? There is very little clearance under that cover plate and the only openings into the oil pan are below the gears. How could that pin shear off and get through all those tight places and end up in the oil pan? Maybe some day I will have need to remove the oil pan and find it there? The other generator I got has some problems that I won't go into now so what I decided to do is take the cover plate that still has the governor pin off of the newer generator and put on the old one. It worked!! It took about 3 to 5 minutes to get the governor adjust and the generator runs great with no "hunting" at all even with large load changes. I have only run the generator about 100 hours since the fix, but it would never go for more than an hour or so without getting erratic.