Scratches and gashes on the piston...

[RaCinJason399]

I got a little problem on my .21 engins piston, the top of it has scratches and gashes on it but thats the only place in the engin with scratches.. the sleve is ok and so is the rest of the piston.. will this affect its preformance?

 

[NCNitro]

yes it will, are you running too long of a glow plug?

 

[RaCinJason399]

nope I'm runing a os #8 and the other night i wanted to clean it so i took off the head and there it was all scratched... there was also some tiny pieces of metal there too but i couldnt figure out where it came from...

 

[NCNitro]

thats definately not good. One tiny spec of metal in the engine will cause it to die. I strongly recommend a complete disassembly and look for further damage. That metal had to come from someplace.

 

[Akina'sMtx-2]

If it wasn't there before, then it's something you need to be aware of. If you bought the engine and it has scratches on top of the piston, that might be something the manufacturer did.

 

[RaCinJason399]

I took apart the engin and i found where the metal came from.. the one way bearing fell inside the motor... and with the rod it shaved a small section of metal off the rod.... but nothing else is scratched so why would only the top be? not the sides?

 

[RobH]

youch! I donno a lot about motors but I dont see how a piece of metal could mistically make it's way to the head without going up one of the sides. Maybe it happened a while ago and with the engine running it scrubbed the marks off.

good luck hope your motor isn't toast

 

[RaCinJason399]

well i hope it isnt toast too.. but if it is I can get another one for $100 at my lhs.... I'm thinking it was my fault.. using a poopy one way bearing that was already beat...

 

[AoD]

Originally posted by NoviceRob
youch! I donno a lot about motors but I dont see how a piece of metal could mistically make it's way to the head without going up one of the sides. Maybe it happened a while ago and with the engine running it scrubbed the marks off.

good luck hope your motor isn't toast

I know, the intake port creates a small vaccum on the compression stroke and when it happened, it probably sucked the metal, and when it came time to feed the fuel, there that metal was. As for the piston, if the sleeve and walls of the piston are ok, and compression is still good, then clean the hell out of the parts, get a new rod (if the balance of it is hurt in the least, that motor will die quick) and work it until it good. I'd run it as if I were breaking it in for a couple tanks to make sure the motor is ok tho... Just a piece of advice. As for the scratches.. It shouldn't hurt much if it's only on the top. If it hurt the walls or sides of the piston in any way, kiss it goodbye, or time for a rebuild.

 

[RaCinJason399]

Yeah AoDaLiZeD i was planing on taking it easy the firts couple runs.. I already cleaned it like crazy.. it looks practicly new... the rod is just missing a tiny piece of a edge... I dont think it will mess up the balance.... but if it goes I'm buying a whole new one not just a piston rod and sleve... its cheeper buying the whole thing... isnt that outrageous.. the price of replacement parts.

 

[AoD]

Yep yep. A small gash might not hurt it. All depends on the loss of balancing. hope it works alright for you.