Main Bearings

[Aeroking]

Looking for some info.

First off, i'm checking my bottom end before assembly. Cant get to a parts store to get some plasti-gage. I use it only as a double check, cause i prefer a more precise tool.

Anyways.

I know main bearing clearance should be in the .0020 to .0025 range.

What is the thickness of stock main bearings?

How large should the main bore be?

All my parts were machined together, and i bought the Clevite bearings x909x.

Numbers ended up being.

Main bore with no bearings & torqed main caps : 2.640

Crankshaft journals: 2.449

and Bearing thickness : .090

Now adding up the should give me .011 clearance. when i should be at .0020

any ideas? are the Clevite bearings too thin? did my machine shop over bore the main bore?

i couldnt find any specs for what diameter the main bore is.

 

[4C FED]

Re: Main Bearings

You need to load the bearings into the mains, torque them down properly then take a measurement with a bore gauge to get an accurate measurement.

 

[Don W.]

Re: Main Bearings

Bearings may be to thin. Only way to check is as above. Torque 'em in, without the shaft, and measure the hole VERY CAREFULLY bearing material is soft. Then measure the shaft. Difference is clearance. Ya gotta be fairly good at this to be accurate. A snap gauge may make it easier.

 

[Aeroking]

Re: Main Bearings

yea, i was using a snap gage, i'll check it with the bearings in tomorrow.

thanks guys