Re: RV8 valves
Actually, Art, I am using larger valves from an older 225 Buick. They are the largest valves that will fit in the heads without installing larger seats. They are also about maximum size for the ports with reasonable porting done. The stems are necked down and use the same keepers. Therefore the question. Thanks.
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Re: RV8 valves
The question about rpm is critical to the engine I am building at the moment. There are, unfortunately, a number of things to be determined that depend on the rpm available. I have generally, within reason, selected components that are capable of operating at reasonably high rpm. My target horsepower is 425. Somewhere, rattling around in my head, is the idea that I will probably need around 6500 rpm limit. Now I'm an old guy and a fairly conservative driver, but when I push the pedal down, I like to see results. Hopefully, the pair of KKK turbos will give me a fat torque curve. I have spoken to Dan Jones about designing a roller cam to do the job.
I would rather not be looking for custom valves. Thanks. |
roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: RV8 valves
425 "actual" hp., is a LOT, for an RV8 ! Say perhaps 20+ lbs, manifold pressure ? Care to describe your build plan ? Good Luck, roverman.
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Re: RV8 valves
The turbos are from a 996 that is 3.6l and makes 420 "actual" horsepower at 6000 rpm and 10.6 lb. boost. They have 4-valve heads, but I will be able to run a more aggressive camshaft. I also want a little more rpm to work with. Hence the original question. How many rpm will new stock valves handle?
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roverman Art Gertz Winchester, CA. (3188 posts) Registered: 04/24/2009 11:02AM Main British Car: 74' Jensen Healy, 79 Huff. GT 1, 74 MGB Lotus 907,2L |
Re: RV8 valves
IMHO, I would know what the RV8 heads flow, from .05" - max. lift. Buick Grand National/turbo valves, "may" have better suited metalurgy. I still suspect, with reworked RV8 heads, you will need close to 20 lbs. manifold boost. Understand, with ported TA heads, you would need much less boost to equal the output. You have a rotating assembly, that will sustain this-reliably ? Good Luck, roverman.
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: RV8 valves
It's a balancing act, enough spring to not float the valves vs enough lift to fill the cylinders and then there's the life of the valvetrain to consider, etc, etc. I've gotten 7 grand with less than 120 lb seated pressure...
Jim |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: RV8 valves
Buick 215
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: RV8 valves
No problem, hope it helps.
That was with CC's hottest SBB hydraulic which they don't offer anymore. The springs were the ones they sold with that cam. Back about 1985 or thereabouts. Jim |