This happened to me once when I re-used some old pistons. It seems the slot
where the rings fit was too wide (worn) and put too much stress on the ring.
Also, is it possible yours froze to the cylinder wall during storage? Did you
add motor oil to the top of the cylinders before storage?
Chris
>
> From: Scott Donnelly <oharajem@free.midcoast.com>
> Date: 2001/06/25 Mon AM 08:23:53 EDT
> To: Alpine list <alpines@autox.team.net>
> Subject: expensive engine noises - update
>
> Engine tear down in search of expensive sounding noises...
>
> Removed the oil pan - no chunks or pieces found.
>
> Removed rocker assembly. Push rods, rocker arms, valve springs and
> lifters all look good.
>
> Removed head - dents in number 3 piston top. Closer examination revealed
> a small chunk out of the top edge of the piston missing. Disconnected
> connecting rod and pushed the piston up through the cylinder from below.
> The top ring was in pieces. The head has small dents from a piece to the
> broken ring floating around in the combustion chamber. There is a fine
> vertical scratch in the cylinder wall. No ring ridge at the top of
> bores.
>
> Removed remaining pistons. Two others had broken top rings. Connecting
> rod bearings look a little pitted and one had started to "smear". Crank
> shaft looks good and should just need a polishing.
>
> Any ideas on why the top piston rings would break? Improper winter
> lay-up? Age? Compression was good at 135-150#.
>
> So, since the engine is nearly all apart, it looks like a full rebuild
> is the way to go. Assuming the cylinder wall scratch can be honed out,
> do I replace just the damaged piston or all four? I'll replace the
> rings, bearings and seals well as have the head rebuilt. Should probably
> replace the clutch...
>
> Any other rebuild tips or advice?
>
> Scott Donnelly
> SV
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