Car in signature developed a dead #2 miss out of the blue, has fuel, has spark, has good compression, has less than 3% leakdown... I found that the #2 exhaust valve lash was zero, no feeler would fit whatsoever. The others were within spec. I tried to loosen the tight one, and backed the screw until it stopped, and still, no clearance!? WTF bad valve seat or something?

 

up

 

the cam lobe wasn't pushing the rocker when you measured it, was it?

I don't know....it doesn't make sense to me because compression/leakdown came out good. Maybe try taking the manifold off and looking down the port.

 

I honestly wouldn't have thought of looking through the exhaust... mani has to come off for the head to come out anyway, so ill have a peek. Thanks.

anyone else?

 

You could take a plug out and shine light through the spark plug hole and watch through the port while you turn the motor. If its sealing like you say though, I doubt you'll see light.

 

Its possible but IMO if everythings in spec I'd pull the head to further inspect.
i had an intermantent missfire and the next day it was a dead cylinder turned out to be the valves

thank god the no piston damage was done