1100 parts and advice please

[cjmurph]

Hello. First post.

My Dads 1100 started spewing oil from rear main. We have disassembled and the rear main had spun in the housing.
I realize we will need to turn the crank and oversize the bearing but I'm concerned that the wear on the rear bearing housing is so significant it may simply spin again.
I'm having difficulty tracking down the parts especially the rear main housing and I'm not sure of the proper repair required to make it work or if it is even possible.

Any previous experience or suggestions would be appreciated.
Curt (first post)

 

[Gary Sweat]

I would take the block to a machine shop that specializes in engine repair and see what they say. The block will need to be pressure flushed to remove any possible metal in the oil passages. Did the bearing look like it lost metal off the back side? The bearing is soft metal compared to the block and may not have caused any wear. I would also consider replacing the oil pump and check the oil pickup tube closely for cracks near the oil pump. Usually there is a tab on the bearing to prevent it from spinning. It is possible that the engine could have had the wrong bearing put in at some time in the past during a rebuild or not put in correctly. The important issue is to determine what caused the bearing to fail. Do any of the other bearings show signs of wear?

 

[cjmurph]

Thanks for the help Gary.

Yes the front main also shows minor wear. I believe it to be a likely result of the massive failure at the rear. Rod bearings appear fine, maybe some bushing wear at the piston pin.
Major damage is at the rear. I expected some "tab" or something on the mains as well but it looks like they are simply press fitted. The 2 thrust bearings show some wear and they have the tabs but nothing really keeping the mains in place other than a snug press.
The rear must have been spinning for quite some time. The damage on the bearing housing is not minor. It really removed some "meat". I'll try to get some pics.

Curt

 

[cjmurph]

Grabbed some pics. Yes the backside of the bearing is pretty torn up.
I'm debating on whether to have the machinist build up the main journal and machine to standard to keep the relationship to the rear main housing as tight as possible.
If he machines the crank and I undersize the bearing, the outside diameter of the bearing is the same as a standard right?
Maybe better said, bearing just gets thicker to maintain relationship to undersized crank correct?

There is definitely wear in the housing and I cannot see where there is any tab that would maintain a relationship between the bearing and the bearing housing. I think it's just press fit and if that fit/relationship is marred then I would think I would be susceptable to again spinning the same bearing no matter how well I clean the journal.

 

[Gary Sweat]

Grabbed some pics. Yes the backside of the bearing is pretty torn up.
I'm debating on whether to have the machinist build up the main journal and machine to standard to keep the relationship to the rear main housing as tight as possible.
If he machines the crank and I undersize the bearing, the outside diameter of the bearing is the same as a standard right?
Maybe better said, bearing just gets thicker to maintain relationship to undersized crank correct?

There is definitely wear in the housing and I cannot see where there is any tab that would maintain a relationship between the bearing and the bearing housing. I think it's just press fit and if that fit/relationship is marred then I would think I would be susceptable to again spinning the same bearing no matter how well I clean the journal.

If you don't have a service manual you can get one from Hoye along with the undersized bearings. It will give the tolerances on the bearing plate which the machine shop will need if you decide to go the route of repairing the plate and turning the crank.

You are correct in how the undersized bearings work. The outside diameter will be the same as a standard bearing.

You might want to consider comparing the cost of repair vs locating another bearing plate and replace the bearing in it or even the cost of repair against getting another used engine and taking the parts you need from it. There are a few dealers that keep used machines for parts. Either way the engine can be repaired, just depends on what method you want to go with. At this point of repair, I would go with rebuilding the engine as much as money will allow. The important thing to do if you keep the block is to get it flushed out thoroughly. Most of the metal from the bearing will have gotten caught by the oil filter but that means it also went through the oil pump to get there. The oil pump needs to be checked for wear tolerances.

 

[Kernopelli]

I think you'll be able to make an acceptable repair with the help of a local shop but if you have doubts either about the long term integrity of the rebuild or the cost/benefit over replacing with a good used engine I'd suggest giving Bruce Laten ( TBN member Bruce1966us) a call (931)492-0316. He sells a lot of quality used Yanmar engines and from what I've seen, they are always surprisingly reasonable (in my book) prices/shipping). Often for much less than some rebuilds you can get a low hour engine shipped to your house that's ready to drop in....just a thought.

 

[cjmurph]

Thanks fellows. You can probably deduce I'm a bit over my head but willing.

Found a local machine shop that is sending the crank out for repair. Just turning the two mains likely .030. When we receive it back we will order the bearings and check the fitment. Machinist believes the best option will be to sleeve the rear housing and we will be back in business. It's a slippery slope so I plan to do a thorough cleaning and reinstall staying out of the upper end even though I'm having to completely ignore the small amount of play that I've relegated to worn pin bushings.

Thanks again
Curt

 

[rmully]

Looks like the race just spun in the housing. The bearing might of froze up and caused the race to spin. The shop might be able to put a very thin metal sleeve in the housing and press the new bearing in tight. You could also buy a very good bearing (temkin sp?) and have it spot welded to the housing if push comes to shove. Good luck and a good machine shop will have a good solution.