Piston clearance in LS/VTEC frankies

**skywings** · 15-10-2004 02:12 PM

Hey. I've heard that LS/VTEC conversions have low piston to valve clearances but can be (partially?) remedied by "grinding the piston's valve reliefs with a die grinder with carbide burrs and polishing the result with cartridge rolls" (hondatuningmagazine.com).

Assuming all parts are stock, does this mean it is pretty much pointless to shave the head? Are there any other ways to increase the clearance ie. aftermarket parts/headwork? Will any of these have an unwanted effect on compression?

When does the low clearance become a problem? With what mods? Or at what rpm?

**tinkerbell** · 15-10-2004 02:20 PM

search for 'claying' of the engine.

this is what you will need to do if you thing your set-up is going to face issues with a shaved head.

(the reason why the frankies have issues with stock pistons is because the non-vtec vales are only 31mm vtec ones are 33mm so you have to enlarge the piston valve relief - not necessarily deepen it...)