piston chipped

[rentthis]

I have tried to post a picture. Yeah right. I have given up in hopes that you will all forgive my lack of digital acuity.

I bought a 300 hour engine for my L3240. The center piston has places chipped out of the piston around the edges. The chipped places are probably 1/16th of an inch wide in a jagged pattern. The other pistons are fine and there isn't any cylinder damage. Is this a known issue? Many times people here can say "I have seen that before". The engine dealer doesn't think it's a problem. I would appreciate input before we put this thing back together.

Thanks, Mike

 

[ShaunRH]

I would think a chipped piston could cause uneven pressures, gas flow, and heating issues. I could be wrong.

If you have it all apart, just put a new piston and rings in. It won't hurt anything and they are usually pretty inexpensive. Turn the old piston into a pencil cup.

 

[rentthis]

It looks like a replacement piston is in order. My problem is that I may never know what chipped the piston.

 

[ShaunRH]

If it made it back out of the cylinder, nope, you'd have to find some forensic clue on the piston head itself. I've seen small pebbles, rust chunks, and in one instance- a crimp terminal pounded into a flat aluminum chunk.

The worst is when a keeper or a valve stem breaks and it sucks the valve into the engine... that's a mess and a half. You are lucky if you get it shut down fast enough not to break the connecting rod and damage the crankshaft. Then it's fixing the damage you KNOW you will be facing... ugh.

 

[Diydave]

Dinged up pistons can also happen when a valve head drops off or, like one of mine did, crack in half, and the chunk of the former valve drops into the combustion chamber. I heard mine start missing, and pulled it right into the barn. There weren't many dings, so I just cleaned up the loose and dinged piston top, and re-used. Been running a coupla years now, no apparent problems...