View Full Version : Help please


mlewisjr1035
11-08-2011, 09:04 AM
I'm in need of some advice. I have a 2005 lq4 short block, that is disassembled, i purchased for a budget build for a 240sx swap. The previous owner tore the engine down and someone removed the coating from the sides and tops of the pistons. I plan on running stock bore and stroke with l92 heads and a cam no bigger than .618 lift. Im trying to figure out what pistons to use to not have any p to v problems. any help would be greatly appreciated.
thanks in advance
mark lewis

Jim85IROC
11-08-2011, 12:09 PM
You never mentioned what your anticipated cam duration is, which is more important than your maximum lift when determining PTV clearances. If your duration is such that you may encounter PTV issues, then you should consider a set of pistons that have the appropriate L92/LS3 valve reliefs, or a set of flat top pistons that have been fly cut. Due to the larger combustion chamber in the L92 heads, a flat top piston (such as an LS2/LQ9 piston) will give you a much better compression ratio than stock LQ4 pistons.

mlewisjr1035
11-08-2011, 03:09 PM
207/220 @ .050 plan on using lingenfelter GT2-3

Jim85IROC
11-09-2011, 08:08 AM
I would expect that mild duration not to cause any PTV issues regardless of what pistons you choose, though it's still smart to measure to be sure.