78 westy piston damage?

[metric Cwrench]

well, i was (am) cleaning parts today while i wait for my orders to arrive. i got out my cylinders, pistons and heads to wash with mineral spirits and/or carb cleaner. i think i may have a problem, and i may need new pistons and cylinders. i had previously measured the p's and c's with old and new rings, finding them within tolerance levels. they have been sequestered in boxes in my garage for a few weeks now. i fear something terrible has happened, as i looked at #1 piston and see things that were not there before. here's what i see:



on the right side, about halfway up the angle of the skirt, is visible a chip missing, or possibly a dent (darker grey area). it is about 1/32" deep on the skirt end, tapering up (in a triangular pattern) to the piston surface, about 1/4" in length.

am i getting new p's and c's now? i think my dad accidentally knocked it around when he was looking for something (he mentioned this later), and i can't rule out completely that i didn't do it myself (although i have been extremely careful, wrapped each piece in newspaper and stored them in boxes labeled for each set).

there is no corresponding damage to cylinder, as i rechecked again. woe is me, i fear...

[metric Cwrench]

could this be filed out? would have to re-balance with other pistons, but could it be done?

is this not as bad as i thought at first? maybe??

advice and help much appreciated.

[Westy78]

I wouldn't worry to much about that. It doesn't look that big. I would say if there are no high points on the outside that would score the cylinder run it. If there are high points sand until smooth and run it. Is it a dent or chip? If it's just a dent your not going to be off balance enough to worry about sanding a little. It's not going to affect the sealing of the piston, the rings take care of that.

[RSorak 71Westy]

That little thing was probably there before you took it apart and it nothing to worry about.

[metric Cwrench]

oh, that makes me feel much better. i've already put a lot of $ into this project (most of which have not yet arrived), and was hoping to not have to do new p's and c's also. you can probably relate to how relieved i am to hear this.

somewhere, i have pics of the p's and c's as i removed them and did my initial inspection. the mark is new, not there before. i think it's a dent, i don't see sheared or fractured surfaces that should indicate a chip.

as far as i can tell, there are no protruding points that might interfere with the smooth operation. i'll make sure of that when i get back to working on them (i put that on hold after seeing the mark and fearing the worst).

related question: how have others gotten thru that oil varnish build-up? i've been soaking the parts in mineral spirits for a while, then using shop towel to wipe off some of the varnish. much still remains, and i wonder if there are other means of cleaning them up.

thanks so much for the help

[RSorak 71Westy]

carb cleaner will remove that varnish much better than mineral spirits.

[metric Cwrench]

i didn't even think of using the carb cleaner. i'm a dummy sometimes...

got plenty of that lying around, will try it out this evening. got myself set up in a comfy chair, washin' tub, and throw in a movie. pleasant times...

i'll report back with the results, thanks again!

[Gypsie]

I would look close at the cylinder/case mating surface. This dent could have been made by bumping against the open hole. If there is a bump on the mating surface you will need to (very carefully) smooth it back down so the surface is flat.
2 cents