Here you can see the substantially smaller skirt area and the Xylan skirt coating on the Cosworth piston (top). Xylan works wonders and we use it extensively in our race engine components when they are not DLC coated. As far as I know only Cosworth and Capricorn offers Xylan skirt coatings. It is expensive and despite its green color, the chemicals involved for the application are NOT very green at all and require special equipment to spray, vent, filter, and store, but it’s all worth the trouble and expense.
Assuming the block has not been decked, the pistons sit will sit approximately .013″ underneath the deck. This was done to improve quench and optimize combustion. With a factory thickness or Cosworth 0.8mm head gasket, the overall deck height will be in the neighborhood of .044″ which is greatly improved over a stock engine’s almost .060″. The valve reliefs have been optimized for Cosworth high lift camshafts (coming soon). If your block has been decked or ruined by a hack machinist when installing iron sleeves, there’s no need to worry either. Cosworth is releasing big bore and thicker gaskets to remedy your situation.
The underside of the piston is extensively milled to reduce weight.
The outer pockets are also milled to further reduce the reciprocating mass. It’s all about the details.
EN24B tool steel wristpins are included with the VR38DETT piston set.
Here is everything that is included in an engine kit. In the Cosworth USA world, piston rings are sold separately. You have the option of using factory rings, but ultra trick Cosworth rings are coming very soon.