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RE: Main bearing problem

To: "'mgs@autox.team.net'" <mgs@Autox.Team.Net>
Subject: RE: Main bearing problem
From: Patti & John Morris <mgj2@globaldialog.com>
Date: Sun, 3 Aug 1997 01:41:23 -0500
Remember that you have standard bearings. Make sure that you have the =
correct bearing set for your car and not for something else. Any work =
done to the crank..turning or polishing will make the crank smaller so =
the fit will be looser. The scenario below could only happen if you have =
the crank turned say 20 thousandths (.020") undersize and you got .030" =
oversize bearings. Or if the shop somehow made a mistake and didn't turn =
the crank down as far as they said.=20

A bent crank would have been noticed right away by the shop when they =
started to polish the journals. They should check for straightness =
first. You could have it checked again..or at least ask about it if the =
following stuff doesn't help...

If you still think it's the center mains and that you have the correct =
bearings for the engine and they are the correct size, look very close =
at the center bearing caps..check that they are in the right location =
and facing the right way. The caps did come from this block..right? =
Can't mix'em from block to block without having the block line bored. If =
you can tighten all the caps but one before the crank won't turn, try =
turning that cap around..approach it systematically..you'll find the one =
that's the problem. Check that you didn't damage your bearing shells.

Course dirt under or on the bearing shells is bad. Use a little =
lubricant on the shells and journals..some sort of assembly lube ment =
for this or STP (only thing it's good for). You want something that will =
stay put for a while and that's not motor oil. I used Lubriplate =
assembly lube once..that was bad. looked like it would stay then seemed =
to separate and run. I always used STP before that and ever since. When =
all is right you will be able to turn the crank easily with your hand at =
the flywheel boss at the rear of the crankshaft...you can't spin it but =
it should turn.

If you can't find the problem, don't hesitate to haul the crank, block =
and bearings to your machine shop and ask them to look it over. They can =
see it ..I can't.

You'll find it hang in there!!

John=20


----------
From:   Spook37211@aol.com[SMTP:Spook37211@aol.com]
Sent:   Saturday, August 02, 1997 4:23 PM
To:     jape@email.unc.edu; mgs@autox.team.net
Subject:        Re: Main bearing problem

John,
Back to basics:

Did you mike your crank after it came back from the machine shop?----'Ol =
Bob
might have been eating a burger while polishing your crankshaft.

Did you plastiguage the bearings as you installed them?  This is vital, =
as it
tells you whether you have sufficient bearing clearance.
This will also give you a clue as to whether you have mismarked bearings =
(it
happens).
=20
OR...........

You might have a bent crank (your shop should have told you this).

Regards,
Ray =20




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