tkklemann

iTrader: (6)

Damn, after seeing that, I know I am definately doing this. (Not because of this post, but have been planning on dong my EVO head for about the last 2 months.)

That picture gives me the confidence I needed because I was debating on grinding down the valve stems as well. Didn't know how much material it would remove from the over all length of the guide.

Awesome post!

xspsi4

iTrader: (67)

This has to be one of the most sensitive subjects ever, People get upset really fast for some reason. Everyone thinks they are right.

vwjeff

iTrader: (13)

yeah the guys that think they are right are always the ones that have never done it.

grenade

iTrader: (4)

Looking good. Got any flow numbers ?

Aby@MIL.SPEC

iTrader: (161)

is the picture of the guide that was removed/being measured a intake guide?

the exhaust guide looks to have a lot more removed, than what is in the picture being measured.

regardless, nice work

xspsi4

iTrader: (67)

AMEN to that.

240Z TwinTurbo

iTrader: (25)

Thanks, but the head has been completed for some time now. Prior to the guides being removed the head flowed 279.2cfm(intake)/273.7cfm(exhaust) at 0.400" lift, which is the lift of my HKS cams. Once it was determined the guides needed to be replaced they were removed and additional porting was done. Results were ~295cfm(intake) / ~285cfm(exhaust) at the same 0.400" lift. I also had the combustion chambers modded with a custom piston top. Oversized SS intake valves and oversized inconel exhaust valves. These results were obtained while maintaining port velocity.

Vigo

What turbo are you running?

240Z TwinTurbo

iTrader: (25)

If you are asking me it is a one-off GT4245R

Vigo

Oh, sorry I was asking xspsi4 on his Evo 8, but thanks anyway. So you are running a GT4245R on your Evo 9? Are you still 2.0L?

xspsi4

iTrader: (67)

20g and a little n20

Vigo

20g-lt/Evo Green?

xspsi4

iTrader: (67)

evo green

Steve_P

iTrader: (5)

shortening the valve guides give less surface area contact to the valve stem so there will be less heat transfer from the valve into the guide into the head into the coolant. This means the valves, esp the exhaust, will run hotter. For an OE application where longevity is important, this is probably not a good trade off so they use longer guides that protrude into the port. For this application the shorter valve guides might be fine.

Pics are nice, but you should always insist on before and after flow data.

xspsi4

iTrader: (67)

I do have the before and after flow data I am just not sure that that is something that the shop wants published.