ENGINE BUILDING CRANKSHAFT QUESTION

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CFD244

CFD244

"THE NEW OLDSMOBILES ARE IN EARLY THIS YEAR"
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Hi Folks

Putting together a 340, getting ready to install the forged crank into a 1971 340. The crank measured up nice, and I got .002 clearance on all the mains with my plastigauge. I noticed on the #3 main, that there is a small scratch part way around the circumference in line with the oil hole. I can almost feel it with a fingernail if I try really hard. I have 2 questions:

#1 What do you use to remove the plastigauge from the bearing surface that won't damage the bearing face?

#2 I would like to attempt to polish out that scratch. I can chuck the crank up in my lathe, but I would like to know what speed to spin it, and what progressive grits I should use for the abrasives........Wet or dry?

Thanks
 
#1. Petrol or lacquer thinner.
#2. Scratch. Just make sure there is no high spot. I would NOT polish it out on a lathe because you will then create a depression over a large area [ journal will be oval ].
 
You should be able to use your finger nail to get the plastigauge off.

As for the scratch, make sure it doesn’t have any high spots and send it. You don’t want to try to polish it out because you won’t be able to keep the journal straight or round.
 
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