I have just done a few 4th gear runs on the dyno and the car cooled down for about one hour and cylinder 4 the { the far left one when facing front of engine}seems to be running hotter than the others under WOT.
We first noticed the far left primary extractor (No 4) had turned purple and the other extractor pipes were bronzish after it cooled and now its gone whitish after cooling from hot!
so am i about to seize the rings inside the bore or what?
anyone having this problem with their extractors?
alll the car has is just Intake \4-2-1 thru 2.5 inches and Vafc?

Thanks

 

Typically, blue = rich