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Discussion Starter · #1 ·
Got my crankshaft back from the machine shop. Had it polished and balanced and I just noticed that at some point one of the journals was scuffed. The machinists says it’s fine but I think I should get a second opinion. Is this something that could be polished out?
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Here’s one sure way to find out if it will have a effect.
Clean off any oil from one half of the bearing that goes there, then color it up good with a big black marker.

oil up that whole bearing journal with just a light film of oil that’s enough to support the bearing , load the bearing on and spin it back & forth over that area.
If no scratches show up in the black coloring then your good, it’s just a low spot and as such is no different then the low spot of the oil feed hole.
If you do see scratches showing up in the bearing face then it’s time to cut the crank again because that scratch is to deep to polish out.

Also from your photo I also see a nice fat radius from the journal to the crank cheek.
This is very good for strength, but you need to make sure the sides of your bearings will not ride up on there, weather when the crank is in the block or the bearings are in the rods.
 

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If it's a cast Crank which it looks like it is then you can not polish it by the shoe string method, its critical that it's not done that way!!

It must be done spinning in a Crank polisher and it must be spun in the opposite rotation from the way it was ground also!

The reason for this is that course grinding a cast Crank leaves carbon nodules standing up and these need to be polished out in the reverse rotation from which it was cut.
If this is not done the bearings will be eaten up over time, and this will also increase oil temperature.

Only a steel Crank can be polished up at home with the shoe string method.
 
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