Stripped the head off the crossflow after it developed and metallic banging everything looked OK except number 4 piston had been banging against the head? both head and piston having matching 'polished' areas where there is no carbon. every other cylinder has a good coating of carbon.

It didn't sound like bigends. what do you reckon? broken end cap bolt allowing the end to open up enough to hit the head.
Will find out this weekend in the meantime anyone got a crossflow lump they don't need?

Cheers Alan

Hi

Piston snapped above gudgeon pin??

David

quote:

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Originally posted by davidwag
Hi

Piston snapped above gudgeon pin??

David

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Polished as in steam cleaned polished or contact polished?

If contact polished then suspect little end bearing.

[Edited on 18/5/06 by jollygreengiant]

We had that happen once - found little dents all over the top of the piston. After pulling the piston, found a 1/8" long piece had broken off the end of one of the compression rings. No other damage - just rotated the ring a little by hand, screwed it all back together, used it for several years (including racing) after with no ill effects!

Big end bearing is run -- probably be gone for while and hammered the bearing shell.

Does it do this?

http://www.irvined.co.uk/component/option,com_gallery2/Itemid,3/?g2_view=core.ShowItem&g2_itemId=3490

If so, your big end bearing has broken up.