Hi all, I have been disassembling the "old" B16 engine from my 444 and have found the cause of the low compression in the #3 cylinder. Photos are below, I am not sure what happened here? It looks like maybe the top compression ring fractured and the bits rotated over time to one area of the piston, eventually compacting there until some small bits managed to blow out into the combustion area (small red arrow in the photo of the piston top) and there rattled around until blown out the exhaust? The large red arrow points to what I think is a chunk of ring embedded in the piston.
Strange that the engine did not make any noise or knocks, it just had very low compression on the #3 cylinder!
There is no sign of the top compression ring (except maybe the embedded bit mentioned above) and the lower ring was effectively "clamped" by the deformation of the ring groove, visible in the side photo.
Does anyone have, or know where to get, a servicable B16 piston (standard size - marked D)? I prefer not to go oversize/spring for a new set of pistons, as all but #3 are within service limits, and should only need a hone and new standard rings. I think currently that new standard rod and main bearings will be OK too from cursory measurements of the crank.
Thoughts - suggestions appreciated.


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Cheers!
OK