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Tom-
We have to watch out for the characteristics of the coating used on piston crowns. Just insulating can actually lead to total destruction of the piston. The key is that the coatings need to not hold heat and must be able to temperature cycle very quickly so as to avoid becoming a hot spot in their own right. Jet engine coatings so often used in the early days (25 years ago) of coating exploration are the worst deal here. What we need is something that is impervious to heat. It neither accepts it or rejects it. Can’t be done at present but modern coatings are much better at emulating this.
As Rookie implies coatings are a god-send when it comes to high boost, compression or nitrous. Since I have been using coatings on piston crowns I have not lost a single piston in a nitrous engine. Again a Rookie pointed out the tell tale sign of low heat transfer is the lack of discoloration on the underside of the piston.
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