Quote Rui
“I recall the car has 110.000 km , was not often driven but every couple of months or less or so and he felt like new - performance , fuel consumption etc - before the problem showed up .”
From post
Panic reporting - valves expert opinion needed : sudden zero compression on cylinder 2, XJ6 1985 - XJ - Jag-lovers Forums
He also said the engine had displayed rough running and tappet noise after cold starts on three previous occasions, which cleared once the engine heated up.
Classic symptoms of sticking tappet due to too thick oil. First became prevalent when engines started to be fitted with hydraulic tappets.