[Fot] checking bearing clearances

[Henry Frye]

My machine shop uses the mic method only.

I assemble all my own motors, and once asked if I should check with
plasticgauge. His answer was a resounding NO.

I have had these guys call me to tell me the bearings I supplied were no
good, too much clearance. They were new old stock Vandervells. I had to
either find new bearings or pay to have all big ends resized, line bore
the block, etc. We were talking about less than 1/2 a thou!

Nine years of racing, more motor rebuilds than I care to think about,
never a bottom end/oil related issue. Every main bearing looked like it
could be reused, some rod bearings have shown signs of wear, but never
even close to failure. You should get the bearings back marked where
they get reinstalled, and you will see little superficial scratches
where the inside mic was used. I always smile when I see those scratches
on teardown!

Yes, I am knocking on wood...


> -----Original Message-----
> From: Scott Janzen
> Subject: [Fot] checking bearing clearances
>
> One builder I know installs the bearings in the rod ends or
> mains, torques the caps and uses an inside micrometer to
> check bearing clearances before installing the rods or crank.
> Another one swears that method is not sufficient and you have
> to use plastigauge.
> What says the group?