Running a compression check on an XIO-320 D1A (200 hours since rebuild) with .010 overbore steel cylinders shows that #3 compression is down to 68/80 cold and 70/80 hot (last year it read 74/80 cold.)
During compression check air can be heard in the case by opening the oil filler, I assume is blowing by the rings on #3.
Armed with a newly acquired eBay dental camera marks can be seen at the 12 o'clock portion of this cylinder (within the nice hone/hatch marks.)
The spark plug was generally clean but did have a couple very small kernels of lead. The wear appears to be barely deeper than the cylinder cross hatching but is hard (impossible) to discern w/the magnified images.
Here is an image of the 6 o'clock position of cylinder #3.
During compression check air can be heard in the case by opening the oil filler, I assume is blowing by the rings on #3.
Armed with a newly acquired eBay dental camera marks can be seen at the 12 o'clock portion of this cylinder (within the nice hone/hatch marks.)
The spark plug was generally clean but did have a couple very small kernels of lead. The wear appears to be barely deeper than the cylinder cross hatching but is hard (impossible) to discern w/the magnified images.
Here is an image of the 6 o'clock position of cylinder #3.
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