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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