What is this spark plug telling me?
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Joined: Mar 2007
Posts: 362
From: Bend, OR
What is this spark plug telling me?
For as long as I've been running this new engine it's had a wierd back and forth shake if I hold speed at an RPM below 2K in any gear. This last weekend I decided to focus on the spark plugs as a possible cause.
I have been running Autolite 103's by mistake this whole time and after reading many posts on this thread and others I realized I needed a hotter plug and bought a set of NGK TR-55's and gapped them at 0.045".
After about 50 miles of mixed driving, I pulled plug #4 and took some pictures with my cell phone camera. Sorry that they're kinda blurry but the only fine details you're missing are the "layers" of color change on the ground strap. The electrode looks new, the porcelain isn't discolored and the base ring has one full turn of color.
Looking at these pictures can you guys see anything I should be concerned about or does it look normal?
I have been running Autolite 103's by mistake this whole time and after reading many posts on this thread and others I realized I needed a hotter plug and bought a set of NGK TR-55's and gapped them at 0.045".
After about 50 miles of mixed driving, I pulled plug #4 and took some pictures with my cell phone camera. Sorry that they're kinda blurry but the only fine details you're missing are the "layers" of color change on the ground strap. The electrode looks new, the porcelain isn't discolored and the base ring has one full turn of color.
Looking at these pictures can you guys see anything I should be concerned about or does it look normal?
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Thread Starter
Registered User
Joined: Mar 2007
Posts: 362
From: Bend, OR
Is there something on the spark plug that's making you suspect cam surge or is that your explanation for my back and forth shake? I didn't know what cam surge was so I read up on it last night and it sounded like what I'm experiencing.
It doesn't feel as bad with these new plugs though. And the old ones were very dark when I took them out so changing them to something hotter needed to be done anyway
It doesn't feel as bad with these new plugs though. And the old ones were very dark when I took them out so changing them to something hotter needed to be done anyway
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Joined: Apr 2004
Posts: 282
From: Tx
Cam surge is not from the spark plug. If it stopped after you changed your plugs than you fixed it. If it comes back find someone with a tech II scanner or something and drive the car with it hooked up and see what cylinders are missing. I did it with my car when I didn't know what cam surge was and the scanner helped.
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Joined: Mar 2007
Posts: 362
From: Bend, OR
I agree cam surge isn't caused by the spark plugs. If I remember right it has to do with A/F ratio and cam overlap and can be corrected with tuning in a lot of cases. The new plugs seemed to make it less intense though.
As far as cylinders missing, all the old plugs looked basically the same except #2 looked like it had oil in all the threads while the rest of the plugs looked clean. Is that evidence of anything? I'll get some pics up later today so you can see the difference.
As far as cylinders missing, all the old plugs looked basically the same except #2 looked like it had oil in all the threads while the rest of the plugs looked clean. Is that evidence of anything? I'll get some pics up later today so you can see the difference.
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Joined: Apr 2004
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From: Tx
stick your finger in the hole to see if there is oil. If that is oil you will need to take off your valve cover and andcheck your spring, it could be hanging the valve open and allowing oil to drip and get on your plug.
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From: western ky