I've been trying to track down a noise problem in a newly rebuild engine . My engine builder discovered wear marks on the front of the crank due to the chain coming in contact with it . They are little even nicks that are found all around the crank face (it seems to be from the roller pins coming in contact with the crank)). We took the crank gear off and chain and tried it on another GN turbo crank . And there also seems to be no clearence between the chain and crank face . How much clearence should there be ? And has anybody else come across a improper machined crank gear before ? It is a Sealed Power Double Roller # 220-3111.** and yes, the crank gear is on right** Help & thanks.!!!!!