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Rust on Plug Number One

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TR4

TR4

Jedi Knight
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I pulled the plugs so I could set the valves and there was a very slight coating of rust on the number one plug. I have driven the car about 100 miles already this season and it is running great, I only wanted to adjust the valves to see if I could get rid of what I thought was excessive tapping. The motor is quieter with only one valve tapping a little louder than I would like. Is that rust any cause for alarm? The motor has 102000 miles without a rebuild. My guess is the gasket is erroding away but I have no idea how long it has been like that. Of coarse, one of the previous owners could have changed the gasket and not torqued it down properly.
 
Where on the plug is the rust?? Is it on the threads or on the ceramic/electrode section? Can you take a picture?? Most of the time when a head gasket starts to leak, it doesn't make rust on the plug, it actually steam cleans it. They generally look very clean compared to the other plugs that are tannish or slightly sooty depending on how rich the engine is running.
 
The rust is on the ceramic/electrode section and not on the threads. I can take a photo when I get home tonight if needed.
 
I think a pic would help. A tan color to the ceramic insulator is normal with a good mixture, but not actual rust particles.
Tom
 
Sounds like you're describing fuel additive buildup.

Champion(the plug people) used to have a picture chart available at parts stores that showed the various calamities that plugs underwent and you might find it informative. Try a web search first, then a Champion catalogue at your local FLAPS.
 
The rear pages of any Haynes or similar manual (used to?) show how to 'read' plugs. Yes, a light tan colour is (was) indicative of good mixture and ignition, although with unleaded gas it's probably not as good an indicator as it used to be.
 
It's just the number one plug that has a different appearance than the others. I switched 1 & 2 plugs to see if the problem stays with the plug or with the cylinder.
 
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