Can anybody tell me if polished cylinder bores are a good thing or a bad thing. I was lead to believe it is bad as it allows unburnt fuel to go one way and oil from the sump to go the other. What doe's a polished cylinder bore imply? Is it a lub problem?

Any help appreciated,

Craig.:D

????? Why? When the block is bored, it should be left with a fine matt finish, so that the rings bed in to form a gas tight seal. Why polish it? No one can see it at the shows :D

323GTR,

I think you misunderstood what I was asking, I meant polished bores from the piston rings rubbing againt the cylinder bores. I was unsure if overly polished bores was bad or not.

Cheers,

Craig.:D

They should look polished when you take the head off, depends how many miles the engine has done. There should be no scores or radial marks (ie going round the bores, not up and down). If you fit new rings, you need to deglaze the bores (remove the polished finish), other wise the new rings won't seal, but if you're keeping the existing rings and the engine was in good nick before you took it apart, all should be fine. HTH

Thanks for the advice.

Craig.:D