Who here is good at reading spark plugs?

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That's a LOT of difference between plugs. You sure you don't have an intake manifold leak? I'm guessing you have headers, have you taken the header temps with a heat gun?
 
Have you fouled those plugs in the past? Sometimes they just won’t come back. That is too much spread for me. I would not live with it. I would recheck the condition of the ignition system. Wires etc. if it is dropping a cylinder out, you could chase your tail thinking it is distribution.
 
If it were me the Leakdown gauge is coming out of the cabinet. Simple way to rule out any issues mechically IMO and super easy with shaft Rockers. I like to get the easy stuff checked off.

Have you ever considered a AFR gauge? It won't help you with each cylinder however it does give the overall AFR. Since a couple of those plugs look fat something you can have done and I don't know what a shop charges but a smoke machine really eliminates the vacuum leak issue. But I am not sure that would be at the top of my list to get done....

JW
 
furrystump said:
Have you fouled those plugs in the past? Sometimes they just won’t come back. That is too much spread for me. I would not live with it. I would recheck the condition of the ignition system. Wires etc. if it is dropping a cylinder out, you could chase your tail thinking it is distribution.
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Nothing wrong with watching the motor run in darkness..... I have fixed a whole bunch of secondary issues from doing just that.... And it's easy to do....

JW
 
6PakBee said:
That's a LOT of difference between plugs. You sure you don't have an intake manifold leak? I'm guessing you have headers, have you taken the header temps with a heat gun?
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I'm pretty sure I don't have an intake manifold leak but I could be wrong. I did shoot the headers with a heat gun and there is a 70+- difference between the front (cylinders 1 & 2) and middle headers.
 
Im no pro but what im seeing is too much timing and its rich. On the 2md and 3rd photos is the black on the plugs sooty or wet. Kinda looks like you have a leaky valve in those cylinders. If its sooty black its fuel deposits from being rich if its wet or gummy feeling its oil.
 
dartfreak75 said:
Im no pro but what im seeing is too much timing and its rich. On the 2md and 3rd photos is the black on the plugs sooty or wet. Kinda looks like you have a leaky valve in those cylinders. If its sooty black its fuel deposits from being rich if its wet or gummy feeling its oil.
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More sooty than wet. I'm going to pull all the plugs, photogaph them, and keep track of which cylinders they came out of so I can begin the process of figuring out how to tune the engine.
 
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