Main Bearings BAD...But....w/Pics

M

mjr67

Junior Member
So... I'm in the process of working on a Model A block I picked up last fall. I don't have a car yet, and figured working with this block would be a good learning experience before getting one.

My hope was to tear the block down, clean and reassemble it and add the components I need to get it running (distributor, water pump etc...). I don't have any plans to put it in a car, but wanted to mount it on a stand and run it for a few minutes at a time as an accomplishment.

Here's what the rear main bearing and crank ends look like... terrible with cracks and breaks...they really need rebabbiting....Front and center bearings are worn, but no breaks or cracks... There were no shims with any of the bearing caps on the main bearings or the cconnecting rod caps.


My question is:
Would these bearings function if I only wanted to run this engine on a stand for a few minutes at a time...?

Any advice is appreciated. I do also have the Zannis book on pouring and line boring bearings and could try that for a future project...

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Were there any shims left between the bearing cap and the block when you took it apart?

I've seen them worn / burned to the point where there's no oil-groove left in the cap-babbit.

If you just want to run the engine in a test -stand, as long as you're not running wide-open throttle, this should be a no-load situation, and you can probably use the bearings as-is.

If it were my project, I would at least go-over the bearing journals with crocus-cloth (very, very fine abrasive cloth), and polish it till bright.

Both the crank and babbit need to be re-done, judging from your pictures, so as long as there are no chunks of grit or hard metal in the babbit that would score the journals further, I don't think you'll do any harm that can't be corrected at rebuild time.

Just my 2-cents...

Frank
 
I agree with Frank.
It looks like it was a running engine when parked, so if you clean it as Frank mentioned, it should run again. I'd clean up the teeth on the crank gear also. Any rust and pits will chew up a fiber cam gear.
 
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