How much power on stock valves

[mikejames27]

I just got the Brian Crower valve springs and retainer kit and Im wandering how much power/revs stock valves can hold up to. For now my little evo iii gt wont touch that but Im looking for much more power in the future.

 

[tjbiker031]

I don't know about anybody else, but i go by the rule of no more than 375-400hp on a stock engine depending on its mileage (but if your looking for that much HP and more, you would have your engine rebuilt anyways). And with regard to your question about revs, when you see your needle start heading to the red....STOP!!!! That's why its there, its not for decoration.

 

[mikejames27]

My car is not stock. Apparently you didnt look at my mod list which includes forged rods and treated pistons, ACl race bearings, etc., among every other single part in my engine bay brand new. Now back to my original question.

 

[jrohner]

I'm still on stock valves. I also hit 9700 rpms once like 3-4 years ago on a miss-shift with no issues.

 

[steve]

My car is not stock. Apparently you didnt look at my mod list.

Nobody should have to look at your mod list to answer a question. Please make sure to include all the important information in your posts.

 

[mikejames27]

You got it! It just seems obvious you wouldnt ask that without proper mods.

 

[mikejames27]

If stock valves can hit 9700 rpms what is the point of stainless valves? Heat properties?

 

[Rob10_99]

RPM has nothing to do with heat. You only assume 9700rpm is under full load.
I wouldn't rev a set of stock valves past 8500rpm if I were you, but that's just my opinion.

I'll wait for your parting thread to score some sweet ***!

 

[mikejames27]

Ill upgrade the valves then, might as well while everything is apart! I would definitely not want to destroy my motor over a few hundred bucks considering what I already have in the car. i just figured IF the stock valves would have no problem than a penny saved is a penny spent on other parts!

 

[tim4g63fast]

also cam size makes a difference.

if your building the head its not expensive to get a set of valves supertech or manleys are both cheap and get the job done, are not not two piece.


as far as hp goals.. I have seen people make over 600hp on oem valves... not just stock sized... just depends every situation is different...

cam lift/rpm/age of oem valve/condition of valve etc etc..

just buy some aftermarket ones

 

[mikejames27]

Just ordered 1mm oversized valves and bronze guides from Extremepsi.com

 

[tim4g63fast]

or you can go 1mm o/s

 

[mrTalonAWD95]

love how that solved the thread good luck with your build man

 

[Boomdeeze]

Sorry to bring up an old thread but does anyone know if you have 1mm oversize valves, will they still have enough valve clearance with EVO 9 pistons?

 

[JusMX141]

I would think so- the Evo pistons are still slightly shorter from the top of the pin to the top of the crown than OEM 2G pistons. Make sure the Evo pistons are installed in your block correctly- the dot faces the front of the engine no matter what.

Drag engine builders check valve tolerances using clay. You could probably do the same just to make sure everything is kosher before the engine is fully assembled.

Worst-case scenerio you'd have to get the valve reliefs on the piston crowns machined a little deeper.

 

[Boomdeeze]

So as in the front of the engine, do you mean the dots face the pulleys?

So you dont put the pistons in like they would be in an EVO? My machinest has never put them in before so wants to make sure he is putting them in right.

 

[LiquidX]

You would want them to face the exhaust manifold. Correct?

 

[JusMX141]

So as in the front of the engine, do you mean the dots face the pulleys?

So you dont put the pistons in like they would be in an EVO? My machinest has never put them in before so wants to make sure he is putting them in right.

Dots face the FRONT- meaning the pulley side of the engine...NOT the clutch side.

The dots face the front of the Evo engine as well, our engines just happen to oppose the Evo.

 

[Boomdeeze]

If i were to get the Cometic 1.6mm HG instead of the 1.3mm. Do you think that would help the clearance? And would the compression change much from 8.8 to 1?

 

[JusMX141]

If i were to get the Cometic 1.6mm HG instead of the 1.3mm. Do you think that would help the clearance?

Well obviously....to the tune of .3mm.

And would the compression change much from 8.8 to 1?

Not by any measureable amount.

 

[Boomdeeze]

Ok thanks i will try the thicker one and check the clearance when i get my engine back/