valves

[marklee77]

what are peoples views on standard vales I am building a new cylinder head have a fairly powerfull motor with a forged bottom end and a garrett 30 71 the cams I am putting in are 272 from bc is it worth getting new valves? bigger valves? or are stock ones ok?

[johnnyhillen]

The standard valves are sodium filled so are good for standard items. In relation to size I've no idea.

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[marklee77]

yes I read that thats whats making me think about keeping them I cant imagine plus 1 mm is going to make much difference? although the super tech are nitride and the tomei have a relif cut at the base of the valve has anyone had any experience with either of them?

[green_rs13]

im sure the NA heads have larger inlet valves. but they are not sodium filled.

I would think thee standard valves are ok for 3071 power levels.

port matching all the runners wouldn't be a bad shout.

[marklee77]

so what kind of bhp are standard valves good to? definatly gonna port the exhaust not really too much to do on the intake

[ANDY black s13]

mobnes CA did 705 atw on stock valves, and many an SR has done over 500 on stock valves
tbh you can squeeze a 1mm bigger valve in there but the gains V's costs for piston pockets machining/over size seats
+ time taken building it up to check clearance etc
or just do some head porting work, reshape valves radius seats etc and gain more flow than the 1mm valve size increase would offer on it's own
if your chasing every last bit of power and have a big budget then go for it
check the VVL intake ports to see the SRdet port has a lot to go to match them stock sized, imo port both sides for a power gain

[marklee77]

mobnes CA did 705 atw on stock valves, and many an SR has done over 500 on stock valves
tbh you can squeeze a 1mm bigger valve in there but the gains V's costs for piston pockets machining/over size seats
+ time taken building it up to check clearance etc
or just do some head porting work, reshape valves radius seats etc and gain more flow than the 1mm valve size increase would offer on it's own
if your chasing every last bit of power and have a big budget then go for it
check the VVL intake ports to see the SRdet port has a lot to go to match them stock sized, imo port both sides for a power gain

thats what I said I cant imagine 1mm will make much difference and would rather spend money on the track, porting polishing and shortening of the radius I will do myself got a pal with a milling machine might get him to relief the chambers. I would only spend time doing the exhuast cause theres not much to come out the intake plus leaving it slightly rough helps atomise the fuel, its gonna have seats cut at a shop cause the valves dont seat properly gonna do the valve guides as well cause stupid not to while the heads off the car if the valves can do more than 500 I think they will be staying cause thats more than enough for reliable track car. Do you own a supra?

[ANDY black s13]

thats what I said I cant imagine 1mm will make much difference and would rather spend money on the track, porting polishing and shortening of the radius I will do myself got a pal with a milling machine might get him to relief the chambers. I would only spend time doing the exhuast cause theres not much to come out the intake plus leaving it slightly rough helps atomise the fuel, its gonna have seats cut at a shop cause the valves dont seat properly gonna do the valve guides as well cause stupid not to while the heads off the car if the valves can do more than 500 I think they will be staying cause thats more than enough for reliable track car. Do you own a supra?

that reads as a good plan or route to take with the head,
not seen it on CA stock valves but SR stock valves can crack if they get super heated from a bad tune/timing/too much boost/detonation etc
anything tbh creating very high exhaust temps,
so if you had a exhaust temp gauge to monitor on track could save it if something goes wrong when on track and temps go to high

the Supra ain't mine, that's the original white beast @over 1200 bhp (one of my fav pics)
,I have a white '99 14a,my black s13 for RWD drags,a stripped out Yaris for daily duties + fwd drags,and a Honda vtr1000 for bike drags/fun toy