sj408

iTrader: (6)

Hey guys, have a customer's is300 were doing and the machine shop is warning me of piston to valve contact because of the vvti after they shaved off .020

I didn't think it would matter but I never messed with a vvti so here I am asking the experts.

am i safe with .020 decked off a vvti head? or do i need a thicker hg.

is3wagon

I would do it if I were using a thick copper aftermarket head gasket kit. Thats what we do with race engines. If its a daily driver, I probably would cut head until straight enough to where gasket could hide the rest. Good luck.

mitsuguy

iTrader: (2)

No need for aftermarket even, I would just do a GTE head gasket to make up for the difference... without doing real digging, if I recall, the stock headgasket is .3-.4 mm thick and the stock GTE headgasket is 1.2-1.3 mm thick... Since 1 mm is about .040, you could theoretically double what they are cutting off and be ok... I had .010 shaved off of mine and still running the thinner headgasket without issues, though I don't know at which point you run into issues with clearances... I think it isn't the valves necessarily, but deck height above the piston at TDC that becomes an issue...

MURPHY660

Maximum warpage: 0.10mm (.0039) in.

Says the Lexus manual

mitsuguy

iTrader: (2)

Right, that's maximum allowable without repairing it... Doesn't take into account processes to repair it...