[tacticalogic]

A leak-down was one of my first tests, after watching the tailpipe on throttle up, then throttle-lift ... rings or valve guides - which would it be? ;-)

Generally if it's the rings you could tell by doing a compression test dry, then repeating after pouring a tablespoon of oil into the cylinder and turning it over a few times. If the compress increased after you put the oil in, that was a good indication the rings were shot.

Worn-out valve guides usually produce a lot of smoke at startup.

[Blueflag]

True.