so, ive just pulled down a $10 998 engine to put new rings in, now the engine is really good, the bearings are perfect, crank is perfect, bores are good with no wear ridge at all (all standard size fyi) BUT, the pistons all have scratches down the skirts, this is not the first one i have seen like this, but the other engines were all really really past it.
what causes this?

the reason its getting new rings is that they broke on one piston after sitting arround for a long time.

jed

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speed costs....how fast do you want to go...

You know you can get engines a little cheaper than eleven grand nowadays.

I can't help with the scratch thing other than wouldn't it be easier to scratch them
where they have been done before the engine went together?

dont you read angusdog's posts? NZ minis are made from unobtanium, our engines are special

unless the factory scratch tem up, i assume the scratching occors in the engine, perhaps grit gets thrown up that isind hard enough to scratch the bore or dammage the bearings, just the pistons? itson all 4, not just the one with multi-piece rings

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speed costs....how fast do you want to go...

I`d say a lack of a good air filter
most common cause of scratched up piston skirts

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

really? hmmmm, im not going to worry about it, but its good to know what causes it...also explains why my las one was much, much worse than this one i havent used this engine!

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speed costs....how fast do you want to go...

......and/or running way too far between changes.. sludge is not a great lubricant.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

in the last one i blamed it on the bits of bottom end/block/gearbox casing! its barly noticable on this engine, it hasent done many miles judjing by the condition of everything else.

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speed costs....how fast do you want to go...

scratches and wear on the lower part of the skirts also point to a motor being thrashed from cold, no...