new model A owner, modification questions

[CarlG]

Originally Posted by bdave_mcc

Ok so I found a couple issues with the rear main. The oil tube was missing causing most of the oil leaking problems. Also there is about .017 end play on the crank and the babbit on the front part of the main cap was broken. Will that in itself cause problems? Is it worth the trouble to remove the engine to install one of those brass type rear main seals to correct the end play? I know I have to remove the back part of the babbit, is that something that an engine machine shop needs to do or can it be done at home? Thanks

I did mine at home, seems to work just fine. Stopped all the massive leaks I previously had. Did it with the engine out. Much easier to work on the bottom side when it's upside down.

[bdave_mcc]

Originally Posted by CarlG

I did mine at home, seems to work just fine. Stopped all the massive leaks I previously had. Did it with the engine out. Much easier to work on the bottom side when it's upside down.

What did you use/How did you remove the unneeded part of the old thrust area on the babbit?

[darrylkmc]

bdave_mcc,

To me, it looks as if your photo your Rear Main Babbitt is cracked.

Look at the right side, front side of cap, at the radius where it is flush with the block, both sides appear separated. It looks as if it runs from one side to the other, not parallel but at a arc, looks like pitting at the bottom.

Darryl in Fairbanks

[bdave_mcc]

Originally Posted by darrylkmc

bdave_mcc,

To me, it looks as if your photo your Rear Main Babbitt is cracked.

Look at the right side, front side of cap, at the radius where it is flush with the block, both sides appear separated. It looks as if it runs from one side to the other, not parallel but at a arc, looks like pitting at the bottom.

Darryl in Fairbanks

Yes it is cracked. I was wondering what problems , if any that will cause. I found the return tube missing, too much crank end play, and the broken bearing. The engine looks pretty fresh from what I can tell. All the babbit looks OK except for the rear cap and it appears to have all new sleeves and pistons.

[darrylkmc]

bdave_mcc,

I would pull the engine, remove the crankshaft and examine all of the bearings.

If your problem is isolated to only the rear main cap, there are people on this forum who have had success with having just the rear main poured and line-bored. I have no personal experience with this procedure.

A rear main crack at the babbitt like yours shows has likely separated from the cap itself. This will cause oil to flow under the babbitt and and out the rear, bypassing the slinger and/or seal.

Darryl in Fairbanks