Valves would not seal

[Alerosaint]

Okay over the weekend me and a buddy finished replacing the bad piston I had. We put the engine back together.

Problem:
No compression still in #4 cylinder.

What was done:
Did a compression check got no reading
Pressurized #4 cylinder and felt air coming out through the throttle body
Remove s/c manifold, re-pressurized and heard and felt the air seeping from the valve seat area

What was found: After spraying WD40 on both intake valves would not seal

Anybody have any ideas??

[Gr1m]

im gonna go out on a limb and say your leaking from somewhere

[Nate's Alero]

resurface the valves.... maybe when you detonated you burnt the intake valves

[Alerosaint]

yeah the intake valves for #4 is not closing all the way

[Nate's Alero]

yeah the intake valves for #4 is not closing all the way

so was the valve scored? or was the spring just worn form you bouncing in the 7 - 8K RPM range?

[Alerosaint]

yeah they were black

[Oldsman]

if this is a push rod motor it is one of the following

-bend push rod
-bad lifter
-bad valve spring
-bent valve
-bad valve seat

I would remove the head do thorough check of the head