12 valve head and 24 valve head

SmokinRamMike said:
I have to disagree, depending on the tolerence's, there has to be some differences in size.

What are you confused about Zstrokin?
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How are u to ensure that the gasket thickness will be the same if u plan to balance the combustion chamber which the gasket is not a machined part and it will vary, he is confused cause me and him are curious how the 12V head is far superior to a 24V we just are wondering. I had a talk with a good friend and member on here earlier and we both agreed that some things can be over thought and over engineered............
Brandon
 
97' CTD said:
How are u to ensure that the gasket thickness will be the same if u plan to balance the combustion chamber which the gasket is not a machined part and it will vary, he is confused cause me and him are curious how the 12V head is far superior to a 24V we just are wondering. I had a talk with a good friend and member on here earlier and we both agreed that some things can be over thought and over engineered............
Brandon
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Okay, as you can see above I have retracted the statement about there being no CC's. I said something with out thinking so I apologize. The gasket thickness is somthing I did not take into consideration, seeing as I am asking an ass load of questions, you should be able to pick up that I am lost in the sauce here and I am trying to clear up what I dont know.

So how would you go about balancing the top end of these motors to the fullest extent? Given that you can not balance everything, I am sure you can get it as close as possible to make some difference. And if you think I am wasting my time then please tell me, I have nothing to base my questions off of, but some ideas I had.

BTW, I was saying the 12v head was far superior due to the fact that Mr. Fulmer had stuck his pecker out on the line to prove that it was, plus he has the information to back it. Again I dont know SH*T about this so teach me something so im not as ignorant in the future.

Thanks in advance.
 
I had think think about it for a min then the gasket thing hit me also :hehe:, I dont think I have EVER seen flow comparison charts between the 2 on here or in person....once my P&P 4 valve head hits the flow bench I will gladly show the flow numbers....

If you take the diameter of the single valve in a 12V head then take the 2 valves in a 4 valve head it would seem to me that the 2 would flow more due to if you did the math the 2 would crate a larger flow of air compared to a single valve..but then again I HAVE NO EVIDENCE to prove this.

I will be running a 4 valve head from last years 2 valve head which also means nothing.......
Brandon
 
pi r^2 for diameter.
I have the spread sheet at work with the diameters, and calculations.
 
97' CTD said:
I had think think about it for a min then the gasket thing hit me also :hehe:, I dont think I have EVER seen flow comparison charts between the 2 on here or in person....once my P&P 4 valve head hits the flow bench I will gladly show the flow numbers....

If you take the diameter of the single valve in a 12V head then take the 2 valves in a 4 valve head it would seem to me that the 2 would flow more due to if you did the math the 2 would crate a larger flow of air compared to a single valve..but then again I HAVE NO EVIDENCE to prove this.

I will be running a 4 valve head from last years 2 valve head which also means nothing.......
Brandon
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I think what you are trying to explain is that pushing the air into two valves will almost "funnel" the air better then if you were to push the same CFM of air past the 4 valves. Again I think that what you are saying. I guess in a way the 24 valve head is able to flow more then it is capeable of producing?
 
Interesting thread. . . a couple comments to throw out from stuff I've read on the boards, but as I understand it the durability of the valves on 24V head can be challenged in competition situations because of the thin stems (7mm) and the fact they are actuated by the triangulated bridges (which can flex and spread slightly and don't apply force in a perfectly vertical manner onto the valve stems). Getting upgraded bridges should be part of the package on a 24V head, plus upgraded springs, all big bucks compared to the minimal expense of a spring upgrade on a 12V head.

I remember some long 12V vs 24V discussions in the past and at that point the all-out p-pumped 24V motors fell short of the most powerful 12 valve engines, but that was several years ago. That would be the question to ask, hos strong are the most powerful p-pumped 24V and CR engines compared to their 12V cousins . . . something I can't answer since it's something I haven't been paying attention to.
 
Well I think this got a little off topic, due to some random brain farts of mine. But really the #1 question was will the flow of a 12 valve out match the flow of a 24 valve. And I believe I have my answer.
 
A crude way to put what I was trying to explain is take a 2" hole flow it....
Take 2- 1.5" holes flow them seperatly add them together which one will flow more I still belive in stock form and in a mild P&P form the 4 valve head will out flow a 2 valve head but I HAVE NO PROOF Just a uneducated opinion.
Brandon
 
just a thought,

While the 24v ports may flow slightly better, it has significant restrictions on #1 and #6 the way I understand it.

The 12v head has less restriction to #1 and #6 so possibly the 12v head may flow a higher average with a port that flows a little less, making more power.

On an all out ported head the 24v would probably flow more air once restrictions in #1 and #6 are removed, most likely a bolt on intake too.
 
As far as flow potential, the valve diameter is only relevant insofar as it establishes one of the factors in the equation for actual gas flow.

The annular window presented at valve lift of .450" is far greater than the area comprised by the valve seat I.D.

Mathematically, curtain area will always trump face area as long as the cam still has lobes... that's one of the fundamental reasons why 4V engines have higher power densities than 2Vs.
 
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