im looking too build an h22 head and im blueprinting my plans. im now on my "valves" section.

im looking too go oversized about 1mm or so. i was reading on some cams (but cant remember where) and it said not too use oversized valves. are oversized valves only good for 9k+ Or will it produce power throughout the whole ROM range?

im still loooking for a vlave. ive seen the skunk2 black nitrate valves warp and bend all out of shape. i thnk it was do too the boost. id like nitrate valves for the help with preventing detonation. as of now im going too call ferrea and have some flat, swirl polished, ss valves made.

comments please.


p.s. this will be a heavy street N/A motor. planning on 8500.

 

Well unless you're pushing a LOT of power and have heavily invested in the intake and exhaust manifolds/turbo you don't need OS valves.

FWIW you can get over 500whp on a stock head. It also seems that when OEM valves hit a piston they tend to bend where a lot of aftermarket ones seem to snap and gobble up the engine.

That's just my opinion and observations. Take it for what it's worth.

 

If you talk to most head porters, they'll tell you that with your goals, stock size valves are the best choice. H22 valves are already quite large out of the factory.

Pirate is right, OEM valves are constructed much better than aftermarket valves for their intended operation, and your setup sounds like it will be just fine with them.

 

valve diameter isnt a matter of how high you can rev...it depends on the cam choice you have. If you have a cam with alot of overlap you gotta be careful of valve to valve contact when they are both open. If they touch, your f*cked.

If you have a set of camshaft degree kit, you can determine Valve to Valve clearance and you can adjust the cams to clear.

 

Blake you're right about V2V contact, but, valve size is classically a major determinant of the engine's rpm band and hp output, check out some of the stuff in the Superflow manual, pretty interesting.

I can email it to you if you want it.

 

well duh, im saying that it doesn't effect how high you CAN rev...not how much power or how far you make power, lol. Of course top end is going to be enhanced with an engine that can actually make use of the larger valve.

email it to me anyway

 

If I remember correctly, John's motor doesn't have OS valves. You guys would know more than me. Just trying to further gauge the sort of application that would require OS valves for the OP. I do believe JUNs are somewhat overlapy.

 

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email it to me anyway</TD></TR></TABLE>


ooohh me too

 

and keep the stock size valves.

 

this thought never crossed my mind. it never hurts too ask......after searching.

as of now, the crower stage 3's and mahle pistons (11:1) are going too be my 2 main components.

 

I hear those crower stage 3 cams are tough to come by these days.....

 

thanks for the email. Looks like a promising read

 

...yeah right

 

it all depends on the application if you do go o.s. dont go more than .5mm on both sides oversized seat installations can get pricey especially out here in the boonies...

 

one reason i was pondering the o.s. valves is because one of my friends owns a cylinder head shop and owes me a favor. i think ill just get a stardard job with a few slight mods.