My manual says to coat the piston liner with a water-proofing paint. I assume it is for where the coolant will be contacting the liner. But im not sure what kind of paint to use? I know that flat black tends to tranfer heat better than others, but will regular old krylon spray paint work? Does it need to be oil based? Purple, Green, ?? hehe. Any help would be appreciated.. Thnks in advance Garcol