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Old 01-12-2016, 09:07 AM
tomw0 tomw0 is offline
Ford Ranger Driver
 
Join Date: Aug 2015
Posts: 1,086
Default Re: Spark plugs backing out

I cannot say if it is needed, but if the cylinder head was made of Al and the plugs their normal Fe, the I would use anti-seize. For Iron to Iron, I never used it, BUT you want to make sure the head & plug threads are clean to insure that the torque is tightness, not just overcoming friction from crud on the threads.
You should be able to thread most plugs in using a piece of vacuum line onto the plug ceramic, all the way to where the plug seats on the head, and then tighten them that portion of a turn to apply proper torque.
Plugs back out if the threads are damaged in some cases. If you cannot torque the plug to the proper measure, and it keeps turning, likely the threads are too worn, and a repair is necessary. There are two brands of thread repair, and both names escape me. They can be used to ream out the old threads, cut new ones, and leave the head as it was before. Not exactly a $5 repair, either, so be prepared to cough up some bucks.
I always treat aluminum heads plug threads as if they were made of angel hair... Remove when the engine is cool to warm, not hot. Replace when cool, and use anti-seize AND a torque wrench.

heli-coil & timesert ... google works when brain does not search: thread repair kit

tom
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