Samuel---The Bentley manual doesn't come right out and specify how much
clearance there should be between the crank journal and its bearings. It
does give journal diameters in the 'data' section under 'crankshaft', on
p.109.
I can tell you from experience that even as much as .003 clearance will
work, but oil pressure will be down about 20% from clearances set at
.0015. The last time I had my crank ground I specified that the crank
at the main bearing journals to end up at 2.915 +/- .0005. (This was the
second grinding, and I used the +.020 bearings) The crank came back at a
perfect 2.915, and 1.855. They didn't need the + or - and both the
crankpins and journals were then fitted with .0015 tolerance.
I've never trusted Plasti-Gage but many rely on this type of measurement
for accuracy. I like old-fashioned mics for checking pins and journals,
and just replace the bearing (shells) if the crank 'is fit'.
A strip of Crocus cloth folded to match the width of each pin or
journal, will polish the bearing surfaces up to a mirror finish fairly
quick. Position the crank and see-saw this fine abrasive material. This
will give new bearing shells a fighting chance to seat properly. It's
the next best thing to a professional out-of-engine polishing.
Dick T.
CF11143
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