Bowtie.
Before you slip the cylinder on, check those piston sir clips out real good. It might be just how the pic makes them look, but that one sure dont look like its deep enough in its groove.
Its not impossible, that something could have happened during machining & the clip groove not be deep enough in that piston, but just check them out.
Wrist pin clips can come out sometimes, just ask anyone that has used several Mercury outboard engine over the years.
Neil
Also check your wrist pin for endplay between the installed circlips. Check your circlips so that they appear to be expanded to at least half their wire thickness below the wrist pin bore. Check to see if the expanded circlip is not below the pin bore surface. Spending an additional 30 seconds when installing a piston will allow one to catch shallow circlip grooves, improper circlip wire diameter and wrist pins that are too long for the space between the circlip grooves.
Wiseco had a batch of wrist pins a few years ago that were about .010" to .020 too long. The circlip would start to expand in it's groove but the end of the wrist pin touching the circlip would not allow the circlip to fully expand and seat in the circlip groove. The wrist pin would eventually push the circlip out of the pin bore. If you have a lathe with carbide tooling, it only takes a couple of minutes to machine the wrist pin to fix the problem. Customers doing their own top ends that did not pay attention to the above detail did not catch this problem and it destroyed their top ends.
A bevel on the ends of the wrist pin is also a design where the bevel exerts additional circlip expanding pressure to hold the circlip in a properly machined circlip groove. The circlip groove depth needs to be at just a little bit more than half the thickness of the circlip wire.
The circlip wire diameter needs to be large enough to prevent the circlip from relaxing at high RPMs as the piston approaches top and bottom dead center. Installing the circlip so that the opening of the circlip is facing up or down will also raise the RPM limit where the circlip experiences enough acceleration that it will relax and come out of the groove. We had a lot of problems with circlips coming out of the grooves on some of the highly modified Kawasaki Quads around 1986 or 1987. Kawasaki cured the problem by increasing the wire diameter of the circlip and machining the circlip grooves for the larger wire diameter.
Damn, thanks Neil and Jerry, sure enough, the one in the picture had not completely landed in the groove. I turned it a little so the gap would be towards the crank more and bam, fell right into place. Checked the gap and it was good. Thanks so much for noticing and saying something. It looked good to me when I first put it in, but I wasn't at the best angle. You probably just saved me from that failure. Definitely owe you both a beer!!!
