ive just done a rebuild on my engine, fully forged with V9 crank, steel crower rods, and weisco pistons, all standard stroke, but im using Sti 4 heads with 1mm over supertech valves. i know standard headgaskets are 1.6mm but the pistons are different to the early pistons, there like the later type. anyone know what thickness gasket to use on unskimmed heads. ive rung about and heard standard but it will be different ratio now

cheers

 

Do you know the volume of the pistons? If not they should be able to tell you. As an example Mahle pistons for the ej20 have a 14cc bowl, this would give 8.2:1 with 1.2mm gaskets with your heads.

 

would the bowl cc be on the spec sheet for the weiscos

 

If you assume that the block has never been surfaced, was actually line bored correctly yada yada yada. We trial assemble all of our engines to get an accurate compression measurement and modify if reqd before final assembly.