View Single Post
GJF GJF is offline
Slantnose from HELL
GJF's Avatar
Join Date: Dec 2004
Posts: 809
OK, Here is something I always do on a turbo motor. Especially 911/930 Porsches. When I have my pistons made I lower the rings as low as they can be on the piston so there is more meat at the crown. Typically when the valve reliefs are cut in IMHO there is too much material taken away, and IF you deck the piston higher and need to clearence the valve pockets further it will make the crown at the vale relief's even thinner. If the engine might lean out, the valve relief is the first place to melt. By lowering the ring lands, it gives the piston more crown and gives alittle insurance to the pistons. I also am a fan of the anti-detonation grooves at the crown. Just a suggestion.
87 911 Carrera platform
Twin Garrett's, Big Valve, Xtreme Cylinder Heads, JB Racing cylinders and machine work, custom JE pistons, GT2 EVO cams, GT3 oil pump, modified 3.2L intake, 80mm TB, custom Intercooler, equal length headers, DFI, KEP Stage 2 custom twin disc, G50 custom gear set, LSD, Tilton trans pump, Fluidyne cooler
Old 10-03-2008, 02:07 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #5 (permalink)