The Stovebolt Site Forums The Shop Area Engine Shop black carbon on the #1 cylinder

After a long run (100+ miles) I pulled the plugs. the #1 plug is black carbon. The number 2 plug looked text book perfect tan. The subsequent plugs were good, not as good as #2 but much better than #1.

Am I correct in assuming this is valve related...possible maladjustment?

My second question is spark related. If the plug is too fouled to spark...like one covered with black carbon.... would the timing light register the voltage? In other words if the timing light is on plug 1 and the plug is too fouled to spark .... the timing light would not flash...correct?

Sorry for the complex questions. Am I over thinking this?
RB53

Best thing to do now is do a compression test and that will give you a better idea of whats really going on in there,if no.1 is lower than the rest put some oil in there and take another test if the cly. is still low it's the valves,make sure of the valve adjustment frist.

Pete

It'll still spark. The timing light don't care if the plug is any good or not. It may or may not spark if the plug wire is questionable. So if your timing light is not flashing it is not the plugs fault.

Check your valve adjustments and put in a new set of points and plugs. Check your cap and rotor and replace if there are signs of uneven wear on the pickups. in other words perform a basic tune up.

Describe the black carbon you are seeing. Is it just coating the spark plug more or less evenly, or is it a little chunky looking? Chunky or black on one side more than the other, or evenly distributed?

Does it have a big miss when driving?

It is pretty heavy black carbon but seems pretty revenly distributed on the #1 plug.

It runs pretty good on the road and even seems to idle pretty smoothly. It is responsive to the throttle but I know it misses as the timing light flashes irradically when I set the timing and does so on every wire...is this not an accurate way to determine a miss? i just assume that if you put the light on any wire it should give you a steady pulse of regular light. If not it is missing.

Builder
Waht is the significance of even versus un even carbon distribution???

Heavy clumped up deposits on one side of the plug could mean oil deposits from a valve guide. When the plug is in place in the head, the side with the heavy deposits would be facing the leaking valve.
A more smooth even distribution would likely suggest carbon from fuel.
In your case, if the deposits are even and only on one cylinder, I would try replacing the spark plug wire and spark plug.
That would be the simplest thing to try and also the cheapest. Simple things are not always obvious.

Thanks Builder
I will try that