Check out this sparkplug.

[InvisiBill]

This is my #4 plug. All the others look like advertisements when they come out. I've had crud on #4 before, but this is the worst I've ever seen it. It did sit for a while during the trans rebuild, so that could be the reason it's so bad.

So, does this look like coolant? And therefore headgasket issues, I'm assuming?

 

[SY2455]

Looks like oil deposits, I would do a compression test, leak down test on it. I gave my son a 1969 Camaro SS that was using oil & he drove that thing for 2 years without doing a tune-up on it. One day he came to me & said dad it not running right, so I said start it up, you know it sounded like it was running on 3 cylinders. I said do a tune-up & we found 5 plug that look like your #4 & of the 5, 3 had deposits that totally filled the plug. I never knew a chevy would run on 3 cylinders when it has 300,000 miles on it. It soon to get a new motor.

 

[Ian Turgeon]

the plugs in my hurt crx motor (one cyl pulling <90psi) dont look that bad.

 

[InvisiBill]

In the grand scheme of things, I don't know a whole lot about engines. What would cause oil deposits like that? Rings or something? It doesn't burn any noticeable amount of oil.

Even with whatever this condition is, it still runs great and has relatively low knock for a SyTy - I rarely see more than a few ° of KR, with absolutely none most of the time.

 

[Larry]

Check out this spark plug

Check out this spark plug

Well it could be a simple valve seal but if the motor has some miles on it, maybe 70,000 or more, it would more likely be a worn valve guide in the head, or possibly blow by past the piston. Have to do a leak down test to see exactly where it is coming from. Good luck, Larry.

 

[SY2455]

In my sons case there was alot of blow by, futher testing show that valve seals were shot on these 5 cylinder & rings were worn too, driving the car on a hot day on the freeway & let off the gas on the off-ramp would cause the oil press to go up about 20lb.Being you are not using oil & your truck runs good I'd would say valve seals like I need to do on my Syclone but when I change plug 2 times a year none of mine look like your #4 yet. I just have that puff of blue smoke at start up with 73,500 miles.

 

[InvisiBill]

Hmmm, looking at the guide in one of my many Haynes manuals, it appears to match the "Ash Deposits" picture. They say to do valve guide seals...

Since I've got a custom Oxidized brand race exhaust =) I can't see the tailpipe when I start it up. I honestly don't know if it's doing the startup puff of smoke. Guess I'll look into that.