go to your nearest automotive repair shop and find
some plastigauge. it installs between the bearing
shell and crank surface. when you torque the
bearing to the recommended reading, it crushes.
DO NOT rotate the crank with this installed. use
some on each main and rod bearing surface. when
you have completed this operation, remove the
bearing caps and measure the plastigauge (keeping
track of where each piece came from). you will
need a micrometer for this operation. this will
tell you the bearing clearance for each bearing
surface. the macine shop should have done this,
unless you didn't have the bearings at the time.
you should have consistent bearing clearances
across all surfaces, which are in the shop
manual. for the 1275, main bearing clearance is
0.0010 to 0.0027 inches (0.0254 to 0.067 mm), rod
bearing clearance is 0.0010 to 0.0025 inches
(0.0254 to 0.063 mm). hope this helps
mike neff
60 sprite an534446
-----Original Message-----
From: Guy Weller <GuyWeller@compuserve.com>
To: spridgets list <spridgets@Autox.Team.Net>
Date: Monday, January 19, 1998 11:53 AM
Subject: Bearings - how tight should they be?
OK, I've got my re-bored 1275 block and reground
(-0.010) crank back from
the engineer's shop.
Assembled crank into block, without the pistons as
yet, so I am only
dealing with 3 main bearings.
The crank is tight. Not so tight that I can't
move it, but it certainly
dosn't "spin" Should it ?
I can just rotate it by hand -- two hands that
is, but it takes a lot of
force.
It turns smoothly with a bar as a lever between
the flywheel/ crank bolts.
No high spots, but just stiff.
Does that sound right to those who have done this
job before, or should I
scrape the bearing shells?
Guy
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