Last year during tear down when I was inspecting the pistons, I noticed a bit of piston rock had been going on. Not terrible, but just enough to scuff up the top of the piston near the top ring – more than I’d like. The piston skirts didn’t get knocked in, no excessive cylinder clearance – just big piston and a short skirt I guess.
After talking with Mike at Diamond, he recommended we try Line2Line Coatings – they offer a new Abradable Piston Coating that is applied to the skirts. Unlike regular piston skirt coatings, this is a thick coating designed to wear in during use helping reduce piston rock, reduce friction and maybe make a bit more power.
There are some videos on their web site that help explain the process if you’re interested. We’ll take a look at these pistons after next tear down and see how they fared. 6 of the pistons are used, 2 are brand new so I can get an idea if the coating actually made much difference in piston rock after it has broken in.