Weird issue with TFS heads

281pony

Active Member
Aug 31, 2003
2,681
2
46
Oly, WA
i have a set of the old casting tfs heads (unmarked). ever since i got the engine with these heads, one of the plugs (cylinder 1 iirc, front plug passenger side) has always had a couple drips of oil outside the plug.

i noticed today its not threading in as far as the other plugs it appears. car doesnt burn any noticeable oil at all, runs great, ect. it torques down great and consistant. doesn't seem as though is crossthreaded or anything.

my question is, has anyone had this happen? is there anything i can use to check the threads without pulling the head? im throwing a supercharger on thursday, so i was putting in my colder plugs tonight.

any suggestions or just see how it does?
 
The sparkplug should bottom out. They sell sparkplug chasers that will fix the damage threads most of the time. Just make sure the chaser is straight, using some type of lubricant and chase some then back off, then chase some more.

Since your sparkplug screws in atleast a few turns I say you won't have a problem with the chaser.
 
A spark plug thread chaser is different from a spark plug tap. A tap will cut threads (which you don't want to do) and a chaser just removes the carbon and trash from the threads. When you use a chaser, pack the flutes (spaces between the threaded sections) with grease. It will lubricate the chaser and catch the junk it cleans out of the threads. That will keep the trash from falling down into the cylinder.
 
Valve cover gasket is causing the oil. either that or when you change your oil you are spilling some and its running directly down to that plug. and for my third theory you arent running a vent tube on the filler neck and its crank case pressure is pushing oil out of the filler tube vent hole and running down.
 
thank you jrichker. good info on the spark plug chaser.

i went and picked one up, wow it got alot of crap out of there. i had a mix of carbon and some light shavings. i used alot of grease and feel that it grabbed almost everything. after i ran it in and out progressively, i torqued down the plug. then removed the plug again to inspect its threads, seemed free of any debris.

threads in completely now. good $7 investment to save me from possibly blowing a spark plug out. :nice: