NA head on 951?
12-15-2011, 11:47 AM
#47
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I see, to clean the ceramic port, you have cut the head.
12-15-2011, 12:38 PM
#50
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Jeremy,
I fully agree about the velocity statement. It' not how much you remove but where you remove it from that counts.
Also I think I have solved (in my mind) the #4 cylinder issue. Having installed the stem vent tube and watching the bubbles I thought to myself this is rediculous. Why would I want to continue to allow such a difference in cylinder temps. I went ahead and used the turbo water pump and tapped into the same spot. Rather than having such a long way for the water to travel across the deck it now has freshly cooled water coming in from both the front and the back. I have no empirical evidence but have not burned a gasket either so it can't be bad
Originally Posted by blown 944
Having used both, My opinion is that the liners help spoolup.
12-15-2011, 06:35 PM
#52
I have heard that the NA cam has more lift on the exhaust lobe than the turbo cam..is this true??
I'm build a 2.5 but I had a bunch of head work/build done by a local Porsche Machine shop here....
I'm build a 2.5 but I had a bunch of head work/build done by a local Porsche Machine shop here....
12-16-2011, 07:15 AM
#55
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Endeed, it can give few more HP !
Sean rebuilt a NA head using 951 exhaust valves and Chevy intake valves. He felt his car gained more than a few HP.
I think that i will go ahead with the 951 head for the engine that i'm re buildind and take time to make a NA head for upgrade ...
12-16-2011, 11:15 AM
#56
We have used Chevy valves on several build ups. There a zillions of speed shops where you can orders them; like Summit Racing. Lots of manufacturers as well, so this stuff is really cheap. Usually you have to have custom made valve guides with Chevy valves, but it's not a big deal for any machine shop
12-13-2012, 06:43 PM
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We have used Chevy valves on several build ups. There a zillions of speed shops where you can orders them; like Summit Racing. Lots of manufacturers as well, so this stuff is really cheap. Usually you have to have custom made valve guides with Chevy valves, but it's not a big deal for any machine shop
