[200q20v] Reluctant Spark Plugs

[C1J1Miller at aol.com]

In a message dated 2/8/01 11:54:23 AM Eastern Standard Time, 
pjrose at frontiernet.net writes:

> At 11:32 AM -0500 2/8/01, Glen Powell wrote:
>  >As the seal between the spark-plug and the head is made by the gasket-
> washer
>  >way up they-ahh at the top of the threads, the threads themselves are
>  >exposed to combustion-chamber by-products and some gunk in the threads is
>  >normal and to be expected.
>  >
>  
>  Tom's post also described the gunk extending on to the insulator. 
>  It's been my experience that the plugs in the 3B head--even after 
>  cleaning and installation with proper torquing--will often become 
>  loose within limited amounts of driving (i.e. under 10K miles). There 
>  was a thread about this a few years ago on the qlist, in which it was 
>  concluded that the fineness of the threads (and, ultimately some 
>  "gunk") prevented any significant loss of compression. But it is a 
>  little disconcerting.
>  
>  Phil
>  -- 


Well, the plugs can loosen, and should be checked after about 1k miles.  You 
can develop some strange running problems should they end up loose...
Perhaps thread cleaning with an intake manifold cleaner?
Chris