Piston Deck Height LS2

[chook]

Does anyone know if the LS2 engine has the same type of Piston configuration (i.e Short Deck Height) as the LS1. Is it too prone to piston slap in the bores?

[Dacious]

All LS-series engines use hypereuctectic pistons = short skirt, short deck height. They pressure cast the pistons with silica (sand) which enables a smaller lighter piston which handles stress and temperature better than the old style steel-skull pistons of the 70's.

The short height/skirt and reduction in drag is one reason they produce big HP. Power losses due to friction are exponential i.e. the faster the motor revs the more power you lose, so if you can lose friction it's free HP; and you gain economy while lowering emissions. That is a design feature of the LS motors. Also why they run such low oil pressure compared to the 'old' motors.

In fact, so do virtually all modern motors. The deck height has little to do with pistonslap - that is/was a manufacturing quality issue. The LS2 uses a flat-top piston (best flame-front path so reduces ping) like the LS1 with a lower combustion chamber volume via LS6-type heads to bump compression. Basically the LS2 is a bigbore LS1 with the DoD technology designed in.

The LS2 has revised wristpin design which stops the pin floating in the rod little-end and supposedly reduces noise.

[chook]

Dacious, thanks for the explanation. Will still be watching with interest.

[Mongy]

Have a look at this article HERE (http://carcraft.com/techarticles/77899/) chook, it'll give you a better insight into pistons. There is another site HERE (http://www.idavette.net/hib/02ls6/page5.htm) that you will also find interesting as it goes in depth into reasons of oil usage and piston slap.

[MNR-0]

Might I add another question to this useful thread?

Can you bolt-on an LS2 casting #317 head onto our LS1/LS6 block? If so, will it not decrease the compression ratio - or raise it?

Cheers