chris_barry

Yes, but it takes really bad seat leakage to drop the compression back to 170psi. Suppose if they have bits of sparkplug stamped between the valve and seat its going to be really bad enough.

I would still suggest a leakdown before strapping everything back on the motor. It just confirms the top and bottom are in good order.

If the plug has got hot enough to disintegrate the tip, chances are its got hot enough to cause pre-ignition. It doesnt take much to crack a top ring as they are thin rings. It hard to spot looking down the edge of the piston, whereas a leakdown will show the problem straight away.

Marcon

Looks like that was it... Leakdown was clear so she's all back together. Injectors seemed okay so they were cleaned, new valve seats and guides, oils and filters now running on it. Idle now sits properly, she doesn't choke as much off the line and power through the rev range is back to great.

Of note.... was that a knock sensor had managed to rust itself up and was cluttering around.... probably not great for my timings, and a plausible explanation for the CEL. Waiting on a replacement to try to get that dreadful light to disappear In any case.. feels like new again so this, in fact, may not have been that unfortunate at all.

chris_barry

Glad its working out.