MEP 802A Fix-up Thread 3.0

[loosegravel]

Just wondering what the indications were that told you the bearing was bad. Noisy I suppose? Hoping the new bearing goes on easily for you. Normally on an interference fit the outer part gets heated and the inner part gets cooled to make them go together without too much fuss. In this case the outer part is the bearing, so cooling it in the freezer I believe is going to have the opposite affect that you’re looking for.

I should have elaborated a little more. Heating causes expansion, while supercooling causes contraction. That’s what we do when assembling interference parts. The outer part is heated to expand it some while the inner part is supercooled to contract it some. When the temperature of both parts is equalized, that’s what gives it an interference fit. The difference is very small, but it makes a big difference when assembling them.

 

[loosegravel]

So the other part of this is I’ve never had to replace this bearing. Is the inner race of the bearing the interference fit on the rotor shaft? Or is the outer race of the bearing the interference fit on the bearing support? Or are both the inner and outer races an interference fit on their prospective parts?

 

[CallMeColt]

Just wondering what the indications were that told you the bearing was bad. Noisy I suppose? Hoping the new bearing goes on easily for you. Normally on an interference fit the outer part gets heated and the inner part gets cooled to make them go together without too much fuss. In this case the outer part is the bearing, so cooling it in the freezer I believe is going to have the opposite affect that you’re looking for.

It would sequel from time to time.

I plan to put the bearing in the end of the housing first, then push it on the shaft all as one unit, that is why I put it in the freezer. So in that case, it is the inner part.

 

[CallMeColt]

So, got the bearing on. But, it's not on quite as far as the other one was. I'm not sure if this is an issue though. To me, it seems like it can be the way it is, as long as it is making contact fully on both surfaces of the bearing to make support.

NOTE: In the picture, it's sticking slightly out and I did get it seated flush.



Wanted to add a link to the bearing;
https://amzn.to/3pYvyMx

 

[loosegravel]

So, got the bearing on. But, it's not on quite as far as the other one was. I'm not sure if this is an issue though. To me, it seems like it can be the way it is, as long as it is making contact fully on both surfaces of the bearing to make support.

NOTE: In the picture, it's sticking slightly out and I did get it seated flush.

View attachment 897026

I see what you mean when comparing this photo with the one before you removed the bearing. The inner race of the bearing appears to be sticking out off of the rotor shaft ever so slightly. I’m just wondering if you have a brass drift thats the same size as the inner race. You may be able to dive it on farther with that and a big hammer. Or, a large 3/4 dive socket that’s the same size as the inner race. I wouldn’t want to hit the outer race in an effort to drive that bearing on farther. There may also be some stress on that bearing support spider right now. It may pull itself onto the rotor shaft when it’s up and running. But it would then require you to remove the rear cover to recheck.

 

[loosegravel]

I see what you mean when comparing this photo with the one before you removed the bearing. The inner race of the bearing appears to be sticking out off of the rotor shaft ever so slightly. I’m just wondering if you have a brass drift thats the same size as the inner race. You may be able to dive it on farther with that and a big hammer. Or, a large 3/4 dive socket that’s the same size as the inner race. I wouldn’t want to hit the outer race in an effort to drive that bearing on farther. There may also be some stress on that bearing support spider right now. It may pull itself onto the rotor shaft when it’s up and running. But it would then require you to remove the rear cover to recheck.

Actually, it looks like the outer race isn’t in as far as it was either. So in that case I’m with you. It’s probably ok as is. But again, hoping that someone with some experience with this bearing will chime in. It’s pretty awesome though. With these gen heads this is the only wear part to replace!

 

[loosegravel]

I had to remove the gen head on one 803A unit to replace the rear crankshaft seal. As I recall, the bearing on that unit was perfectly reusable and it came off of with the bearing support spider.

 

[CallMeColt]

I had to remove the gen head on one 803A unit to replace the rear crankshaft seal. As I recall, the bearing on that unit was perfectly reusable and it came off of with the bearing support spider.

This one went the other way around.

 

[CallMeColt]

So, Got it all back together. I managed to drive the bearing on a bit more.

Put everything back the way it should be. Used a take off, much nicer cover for the generator head that was from a part out unit. I think I mentioned that I saved it earlier in the thread.

Used new hardware along the way & cleaned things up as I went along. Used some body hammers to straighten things out a bit.



Did an oil & filter change while I was at it since it was rainy & didn't want to drag it out in the rain for a load test.

Started the load test the next day, and ~20min in, started to get some bogging w/black smoke. I have not done the fuel filters, so I just stopped the load test & was going to change them... turns out I don't have any left! Got some on the way. My guess is it is them. Who knows when they were done last & usually bogging under load ends up being a fuel restriction of some sort. Plus, I was going to do it anyway.



Started to paint it as well. Going to try & get a proper stencil set. All the units I have could use a fresh coat to look snazzy.

 

[uniquify]

Is that a speader / lifting bar on top? Looks slick.

 

[CallMeColt]

Is that a speader / lifting bar on top? Looks slick.

Yes, I fabricated it for the LMHC on my LMTV since I need to get the generators as close to the boom as possible to get in the bed as it's a small crane.

Honestly, I have only used it to tug, but will be testing it soon. No doubt it will work great. Made from all scrap stuff.

Will share a picture when I use it as I'll be using it a bunch.

 

[loosegravel]

That’s awesome! It could then also be used to lift these units up onto a sufficiently supported working platform to get you up off of the ground when working on them

 

[CallMeColt]

That’s awesome! It could then also be used to lift these units up onto a sufficiently supported working platform to get you up off of the ground when working on them

If I only had something in my shop to do that. One day!

 

[loosegravel]

Hard to believe, but we’re almost 1/2 way there to Christmas. Santa is coming!

 

[CallMeColt]

Well, I was hoping that this project would be done, but it taking a not so fun turn. Hoping it's something simple.

Replaced filters. As I was letting it prime up, the electric pump made some bad noises. It was the original, and the square ones are not the best, so I figured I would change it out since it could have also been part of the problem. Doing both certainly would not hurt. Rather it be right.

Did all that, let it prime again for a bit, & it fired up & ran for a few seconds. Basically, burned off what was in the injection lines.

I cranked quite a bit for 10 seconds at a time to purge more air... no luck. So, for the first time since ever servicing these types of generators, I used the air bleed off screws on top of the fuel filter. They both did bubble. Also, opened the water drain & it came out hard at first as I guess there was some air pressure in there.

After doing that, cranking it a bit more, and it stumbling a bit, it did start. Had to keep at it to purge out the rest of the air but it got there.

So, here is where it has me a bit puzzled.

Engine still doesn't seem to be running that well. I can tell it's struggling. It would run at 63htz with no load and the adjustment pulled all the way out, now it will do 61htz. It's not as smooth. If you apply load, it wants to bog out & die.

I confirmed the new pump is moving fuel. I'm wondering if there is just more air trapped somewhere that is hindering fuel delivery? Usually, the electric pump purges it within a few minuets.

My only other thought is bad fuel. Maybe some moisture got in the jug I had it in & the pickup is taking it in. If this was the case, could have been why it started running poorly after about 20min or so to begin with as that's about how long it took the "new" fuel to make it's way to the injectors.

irritating! Was hoping it would be doing it's 4hr load lest today & be done! But, maybe it is just terd fuel & it will be still, just into the evening.

 

[loosegravel]

Well, I was hoping that this project would be done, but it taking a not so fun turn. Hoping it's something simple.

Replaced filters. As I was letting it prime up, the electric pump made some bad noises. It was the original, and the square ones are not the best, so I figured I would change it out since it could have also been part of the problem. Doing both certainly would not hurt. Rather it be right.

Did all that, let it prime again for a bit, & it fired up & ran for a few seconds. Basically, burned off what was in the injection lines.

I cranked quite a bit for 10 seconds at a time to purge more air... no luck. So, for the first time since ever servicing these types of generators, I used the air bleed off screws on top of the fuel filter. They both did bubble. Also, opened the water drain & it came out hard at first as I guess there was some air pressure in there.

After doing that, cranking it a bit more, and it stumbling a bit, it did start. Had to keep at it to purge out the rest of the air but it got there.

So, here is where it has me a bit puzzled.

Engine still doesn't seem to be running that well. I can tell it's struggling. It would run at 63htz with no load and the adjustment pulled all the way out, now it will do 61htz. It's not as smooth. If you apply load, it wants to bog out & die.

I confirmed the new pump is moving fuel. I'm wondering if there is just more air trapped somewhere that is hindering fuel delivery? Usually, the electric pump purges it within a few minuets.

My only other thought is bad fuel. Maybe some moisture got in the jug I had it in & the pickup is taking it in. If this was the case, could have been why it started running poorly after about 20min or so to begin with as that's about how long it took the "new" fuel to make it's way to the injectors.

irritating! Was hoping it would be doing it's 4hr load lest today & be done! But, maybe it is just terd fuel & it will be still, just into the evening.

That’s frustrating, I know. My experience with these 8XX series is just like yours. The electric lift pumps are great because they normally self-bleed. Could you tell if it was firing on all cylinders?

 

[loosegravel]

That’s frustrating, I know. My experience with these 8XX series is just like yours. The electric lift pumps are great because they normally self-bleed. Could you tell if it was firing on all cylinders?

I just realized that it’s only two cylinders! So it probably won’t even run on only one cylinder. I suppose that one cylinder could be weak but still providing some power.

 

[loosegravel]

That’s frustrating, I know. My experience with these 8XX series is just like yours. The electric lift pumps are great because they normally self-bleed. Could you tell if it was firing on all cylinders?

You could also siphon off some of the fuel into a clear jar to check the clarity. If you have some bad fuel, you would usually see it that way. Also, is it possible that you have a leak on the suction side of that lift pump? Have you pulled the dipstick when the engine was running? Blow-by? Just some thoughts.

 

[CallMeColt]

I just realized that it’s only two cylinders! So it probably won’t even run on only one cylinder. I suppose that one cylinder could be weak but still providing some power.

It would run on one, but would be very obvious.

 

[CallMeColt]

You could also siphon off some of the fuel into a clear jar to check the clarity. If you have some bad fuel, you would usually see it that way. Also, is it possible that you have a leak on the suction side of that lift pump? Have you pulled the dipstick when the engine was running? Blow-by? Just some thoughts.

I used the fuel drain. Fuel was good. No blow by. I did find a suction leak.