Originally Posted by unclemat
There are two places you apply coatings on pistons: skirts and crown. Stock pistons have skirt coatings, and you want that on your forged pistons as well. Swain tech skirt coating is rumored to be very good and robust, better than "stock" coatings e.g. by CP.
Crown coating should be used only in race applications. It keeps piston cooler, maybe "too cool" under regular low load driving. Even if it's not detrimental, it's really not needed.
Thanks for clearing that up. I would never use a piston in a DD without the skirt coating, it works wonders. My 83,000 mile pistons hane no wear on the skirts at all. I was just wondering about that heat coat for the top, I agree it is probably overkill for a 300whp DD.
What I did notice was the underside of my pistons have a brown "burn" spot right in the center, like oil was cooked a bit slinging off the small end of the rod. Thats why I was considering the top coating.