That could very well be a breach there due to erosion. The odd part is that the OP says this problem occurs with every cylinder and the compression readings are pretty decent on all cylinders.
I’ve got a few theories that I’m batting around but have no firm handle on what the cause of this is yet.
Unless there’s a breach on every cylinder (and not necessarily any metal erosion) and the coolant is artificially inflating those compression numbers up higher than what they really are. What do you think of that possibility?
It’s a good theory. And you make a good point about the “all cylinders”.
Man, with some of these threads I wish I could be there hands-on. My gut is telling me there’s something going on with that metal headgasket that was installed. I wouldn’t be surprised if the final result was that the gasket was installed incorrectly or even the wrong part number used.
If the design was meant to use a regular gasket with fire rings and a solid metal gasket were installed, could that compromise the ability of the cylinders to seal? Would the metal gasket require higher torque values?