Mrblu

aftermarket cost more than stock, so got some flat std size valves from Supertech. what is the differnce in flat and disc?

LostMotion

A flat valve adds a bit of compression.

HvRRZ

This man speaks the truth!

They won't add much though...the only gains you'll see is maybe a bit of torque.

LostMotion

I am gong to throw out a wild ass guess of .2. It's certainly not more than .5, but .1 seems a little low. .2 CR increase would imply roughly 1 CC decrease in volume or about .25 CC per valve.

You can probably call supertech and find out how much volume is in the dish, it will be different for the intake and exhaust valves.

yorkman1

Carrera4 I really am glad you know whats going on. Always great advice, and you help us all in many ways. IYO Is it work doing a top end over haul ( vavles, springs, retainers, seats) for the reduction of mass and CR increase, plan of going stand alone in the near future and would like to rev higher.

Back S2k

I would think you get less then .2 doesent the spoon head gasket only adt .2???? You might as well thrwo that into the mix while the head is off this way youll get a combined cr increase with flat valves and thiner head gasket. just my 2cents

LostMotion

Hmm I just took a look at the stock valves. They are basically flat. You wouldn't gain anything.

Back S2k

^ in that case the op should stick with flat valves if he decides to go aftermarket. Still do the headgasket though.

yorkman1

So over all with gasket and vales max would be in the rage of .3 CR will that be a gain of anything or will the lighter stronger valve train just be good enuff to handle the extra 1k RPM!

HvRRZ

Stick to the OEM head gasket. You can rev a little higher even stock with no real issues. Upgrading the valvtrain is a good idea if you want to rev a lot more. The head gasket isn't really worth anything, and if anything may cause a problem down the line the higher rpm you climb.