[Spenny_b]

Hi folks,

So....work is about to recommence on my 964 Turbo project after finding many shattered piston rings, horror-story all detailed in my signature link below.

One question I need to find a specific answer to, is that of the max temps I'll see down the spark plug holes.

We're trying something a little experimental on the ignition side, meaning I need to modify some coil-on-plug units by shortening them. As stock, they're a good 1-1.5" too tall.

The units can be broken down into 3 sections; the centre section is some kind of plastic. I'm planning on turning-up some new centre sections which will fit into the rubber boots at each end. But I need to know the max temp that a COP is likely to see in a Turbo application.

I've just spoken to an engineering plastics supplier I've used before, whose recommendation is PEEK for the max temp resistance. This is 4x the price of PTFE, not that we're talking huge $$'s for the small amount I need, but I am wondering if I can use material that I already have (Delrin), or something else, (OCD Mode=on....PEEK is natural white....I want black ideally, to look stock!)

I bought a rod of Delrin some years ago to make some collars for the Denso COP's, that hold the pencils central to the holes in the valve covers...they've survived very well, but valve covers won't be seeing the same temps as those down the spark plug 'ole!

Input welcome as always folks,

Thanks
Spencer