Riddle me this Mechanic Man?

[savatreatabvr]

Yeah, I thought that cylinder with the tight valves would have been a big issue once I adjusted them correctly but not the case, the cylinder I have problems with is #4, that one fouls plugs, has 90lbs comp. and has oil on the threads and outside of the spark plug hole.

Originally Posted by raws67

No Problem!
Ive used this methood before and it was right on the money with a valve problem I had. One other thing that makes me interested is how tight that valve was that you were talking about. That almost sounds like the valve sunk in to the head or a po who didnt know what they were doing over adjusted. Either way you did say that that cylinder seems to run fine. Let us know what you come up with.

[savatreatabvr]

Yeah, I thought that cylinder with the tight valves would have been a big issue once I adjusted them correctly but not the case, the cylinder I have problems with is #4, that one fouls plugs, has 90lbs comp. and has oil on the threads and outside of the spark plug hole.

Originally Posted by raws67

No Problem!
Ive used this methood before and it was right on the money with a valve problem I had. One other thing that makes me interested is how tight that valve was that you were talking about. That almost sounds like the valve sunk in to the head or a po who didnt know what they were doing over adjusted. Either way you did say that that cylinder seems to run fine. Let us know what you come up with.

[rs72z]

Originally Posted by savatreatabvr

Yeah, I thought that cylinder with the tight valves would have been a big issue once I adjusted them correctly but not the case, the cylinder I have problems with is #4, that one fouls plugs, has 90lbs comp. and has oil on the threads and outside of the spark plug hole.

What's the rest of the cylinders have for compression? 90 is a little low imo.

[savatreatabvr]

The other ones are about 110 to 120lbs.

Originally Posted by rs72z

What's the rest of the cylinders have for compression? 90 is a little low imo.

[rs72z]

Originally Posted by savatreatabvr

The other ones are about 110 to 120lbs.

I know its been mentioned but you need yo do
Leak down in it.
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[BMERDOC]

Using the 15% rule for a compression test and considering you highest reading was 120 then you lowest reading should be around 102. You still need to further diagnose the improper sealing. Rings or valve not seating properly because of worn guides?

[csb#356]

I always learned that it was 10% but either way thats a little low. And no hydraulic lifters are adjusted one time when the engine is assembled and thats it. If they have too much lash, valvetrain compenents are worn. You could tighten the nut down again and take the lash back out I guess but then your just covering up other problems.

[savatreatabvr]

You're right but the reason I adjusted them in the first place was not because the rocker arms were tapping, it was to see if I could get it to stop smoking and run better which it did but #4 cylinder still fouls plugs so I betting on the valve seals being the problem. I replaced the valve seals with the head still on the engine on a Ford Bronco I had, it smoked worse than my BBC but the Bronco never fouled plugs so that's why I was thinking my BBC had other issues.

Originally Posted by csb#356

I always learned that it was 10% but either way thats a little low. And no hydraulic lifters are adjusted one time when the engine is assembled and thats it. If they have too much lash, valvetrain compenents are worn. You could tighten the nut down again and take the lash back out I guess but then your just covering up other problems.