Originally Posted by
Leo V.
I've had 2 sets of 7-port P/S with the same problem. the opening of the hole of the piston where the wrist pin goes into is chipping (looks like the edge of the hole is eroding and flaking off), exposing the clip. Eventually the clip comes off, gouging up and down the side of the piston.
Hi Leo - now please don't take this the wrong way, but ovaling and damage to the wrist pin hole in the piston can be the result of a short, hard (ie cold temperature) break in.
The wrist pin takes a hammering if the motor is broken-in not being pre heated, and run at low temperatures. This can quite often cause the damage you are refering to, or certainly weaken that area and make it susceptible to early wear.