Scored piston bores?

[rich201283]

I have an engine with slight scoreing to the bores, How much scoring is ok?

 

[Norman_E]

You need a compression test. If compression remains OK for the type of engine, then the scoring is not too bad. You must however remove the cause of the scoring. If the scoring is due to a broken piston ring then it is no good compression testing without replacing the rings first, and running the engine for long enough to bed in the new rings. Diesel engines require high compression ratios and may run badly or refuse to start if compression is low. Petrol engines are a bit more foregiving in that regard.

 

[mtb]

is as already suggested re piston ring or is it carbon deposits ?
you dont say what engine also how it ran before strip down and why the strip down

cheers
Mick

 

[Heckler]

Borrow a honing kit, Ive got one, run it up and down the bore and see what happens, would need to have a look to give a definite opinion, pix?
Stu

 

[rich201283]

Ive honed each cylinder however whats caused it is each gudging pin which had moved to touch the cylinders in each pot, the engine design does not have circlips in each piston

 

[leomagill]

If the gudgeon pins are not circlipped or held with a pinch bolt they should have a plug(probably aluminium) in each end to allow them to run on the bore without damaging it, they need to be free to rotate as they run to avoid bad wear.

 

[tross]

Was it running before you stripped it down - if so, that amount is OK