[Grigio_F80]

Hello, so i had a slight knocking at lower rpm, although engine is still running, slapping on acl race bearings just wanna know if i should attempt to polish the crank journal (refer to pics). There is no scoring just marks as what you see, nail doesn't catch any grooves. Any input would be appreciated thank you!

[77_wenz]

huh they look just like how mine did. I put in new bearings without polishing because I am worried about out of round clearance. I determined the marking to be from aluminum smearing and measured 0.035mm. put in new rheingold bearings. Its been going strong about 5k since, no issue yet. Sometimes let it bounce off rev limiter heh

[77_wenz]

hmm mine look a bit better than yours. It looks like you have a bit of metal transfer on the bottom from the copper layer judging by its coloring. Maybe some light polishing and then take the clearance again? this amount of smearing may have changed the surface property. I recall that these cast steel cranks also have a directional micro-ferrite-burr.