Cylinder head questions
11-24-2003, 01:34 PM
#1
Three Wheelin'
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Cylinder head questions
Will a 944 NA head work on a 951? As I understand you cannot port the exhaust of 951 head. I have access to a NA head that has all of the valves bent but I can put all of my valves in it when I'm ready. I'm gonna pull the motor here shortly to freshen it up and I'd like to apply some of my magic to the head while I'm there. I'm gonna flow the head before and after for comparison's sake. Are any of the years different etc? Thanks, Mike
11-24-2003, 04:48 PM
#3
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A friend will have a ported NA head for a 951 for sale after he gets his new Milledge head. I think he also has a set of 4 into 1 'V' band headers to go with it.
Alan C.
Alan C.
11-24-2003, 07:34 PM
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Three Wheelin'
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So this will work? I have extensive porting experience thats proven itself on the dyno on many of my customer's cars (mostly american V8's) But's it about flow characteristics and there is alot of theory involved.
11-24-2003, 10:50 PM
#7
Three Wheelin'
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Yeah the turbo valves are different by their composition being as aforementioned sodium filled. I can put my turbo valves in the NA head when I get the motor out.
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11-25-2003, 08:46 AM
#9
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What is the largest valve that can be put into the N/A head and what is the biggest cam that can be installed? Also, what is the heads' bottleneck? Does the head respond well to polishing? Does the chip and header route gain the biggest first time improvement? Questions, questions, questions, just jump right it and tell me all you fellow Rennlisters' know, and don't about the head!!
Thanks in advance!!!
Steve E
Thanks in advance!!!
Steve E
11-25-2003, 10:51 AM
#11
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>>The question is, how bad is the ceramic coated exahaust ports and sodium filled valves needed?<<
I have often been skeptical about the need myself. Since racers are doing without, I bet you would be fine without them.
I suspect those features may be another example of Porsche misplaced engineering, i.e., make a cylinder head that can withstand 1000 freaking degrees of heat, but keep a timing belt/water pump design that can allow the valvetrain to be easily ruined, keep the battery at the base of the windshield where water runs right over it, etc....I love these cars but it's amazing the number of places where massive over-engineering was employed right alongside built-in Achilles heels.
I have often been skeptical about the need myself. Since racers are doing without, I bet you would be fine without them.
I suspect those features may be another example of Porsche misplaced engineering, i.e., make a cylinder head that can withstand 1000 freaking degrees of heat, but keep a timing belt/water pump design that can allow the valvetrain to be easily ruined, keep the battery at the base of the windshield where water runs right over it, etc....I love these cars but it's amazing the number of places where massive over-engineering was employed right alongside built-in Achilles heels.
11-25-2003, 12:39 PM
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Originally posted by 91S2
>>The question is, how bad is the ceramic coated exahaust ports and sodium filled valves needed?<<
I have often been skeptical about the need myself. Since racers are doing without, I bet you would be fine without them.
I suspect those features may be another example of Porsche misplaced engineering, i.e., make a cylinder head that can withstand 1000 freaking degrees of heat, but keep a timing belt/water pump design that can allow the valvetrain to be easily ruined, keep the battery at the base of the windshield where water runs right over it, etc....I love these cars but it's amazing the number of places where massive over-engineering was employed right alongside built-in Achilles heels.
>>The question is, how bad is the ceramic coated exahaust ports and sodium filled valves needed?<<
I have often been skeptical about the need myself. Since racers are doing without, I bet you would be fine without them.
I suspect those features may be another example of Porsche misplaced engineering, i.e., make a cylinder head that can withstand 1000 freaking degrees of heat, but keep a timing belt/water pump design that can allow the valvetrain to be easily ruined, keep the battery at the base of the windshield where water runs right over it, etc....I love these cars but it's amazing the number of places where massive over-engineering was employed right alongside built-in Achilles heels.
Ever seen a exhaust manifold on an turbo after a few hours of "spirited" driving? Bet you can light a ciggar on it...
That is why!
TakeCare