The air filter is 11" dia by 2" tall, so on the small side. I believe the combustion chambers are 64cc and I calculated the CR to be 9.7 static, 8.1 dynamic. I have the Comp XE268H-10 cam.
I pulled the engine out and removed the heads. Generally the plugs looked worse than previous (more deposits, darker color) except #8 that was very white (need to investigate potential coolant leak into #8). There was nothing noteworthy about the combustion chambers or pistons, and bores still have some of the cross hatch. Cylinder #1 looked about the worst for deposits on the plug so I may pull the intake valve to evaluate the valve to guide clearance.
Until I pull pistons and check the rings it is a guess but I suspect that the rings are stuck (not free floating) in their grooves and it may be a result of the long delay between engine assembly and first firing ( roughly 3 years).
Last edited by WICruiser; 11/02/20261:58 PM. Reason: added pictures
