easy fix or rebuild? oil fouled plug

[ugly]

changed the plugs 2000 miles ago and 1 plug was oil fouled, so I checked the compression- the #2 cyl was 125 and the rest were 150ish. I was replacing the valve cover and exhust gasket yesterday (leaking), so I pulled #2 and #4 and this is what I got- #2 on the left.

How do I test the valve seal/ piston rings? Could that have happened from leaking valve cover gasket #2 plug did have oil on the threads? Can I drive it this way or will it kill other parts?

So many questions from a newbie? thanks for the help!

 

[big83chevy4x4]

its prolly bad rings. you need to do a leakdown test to figure if its the rings or the valve seals.

we have almost the same problem with out van, it has 340,000 miles on a 4.3 vortec and we are replacing the motor.

 

[ugly]

help!

Maybe time to beef up the motor to get 500HP out of it.

 

[or2play]

I remember reading a way to determine if its the valves or the rings. Before checking the compression on that cylinder squirt a couple drops of oil in it then check the compression again. If it increases its your rings. If it stays the same its the valves.

 

[big83chevy4x4]

i forgot about that /forums/images/graemlins/thinking.gif

 

[diesel4me]

It could be just the valve stem seals--how many miles to a quart of oil do you get before you need to add more??.I was going to suggest it might be clogged oil returns in the head,allowing oil to puddle up around the intake valve stems,and get sucked into the combustion chamber--but if its #2,that would be the front passenger side plug,and it would be doubtful for enough oil to collect there,since the motor tilts back toward the firewall--the rearmost cylinders are usually the ones to foul plugs first when thats the case.If it still has 125 lbs of compression,the ring are probably ok--though not as ideal as 150 psi,but not the end of the world either.I have a motor that only has 85 psi in one cylinder,and 90 in another--it doesnt foul plugs,still runs fairly smooth and good power,gets about 500 miles to a quart--I'm in no hurry to yank it apart and fix it! /forums/images/graemlins/crazy.gif