Valve spring question
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Joined: Aug 2015
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Valve spring question
Had my heads sent out to American heritage performance for there stage 4 package. Not really thinking I got the btr dual spring kit too. I have a stock cam with an ecs blower at 8psi. Are these springs ok to run with a stock cam? Or should I send the heads back and have stockers put in?
2008 z06
Thanks!
2008 z06
Thanks!
Le Mans Master
Joined: Aug 2005
Posts: 5,375
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From: CA.
St. Jude Donor '13-'14-'15
Better valve springs are just that---BETTER------Longer life and valve train stability--Being you have a stock cam your engine would have been fine with the stockers as being supercharged has little affect on valve springs---Better valves are just a cheap insurance policy---
Thread Starter
Advanced
Joined: Aug 2015
Posts: 84
Likes: 1
Better valve springs are just that---BETTER------Longer life and valve train stability--Being you have a stock cam your engine would have been fine with the stockers as being supercharged has little affect on valve springs---Better valves are just a cheap insurance policy---
Last edited by Ajsegal; Nov 29, 2015 at 11:16 PM.
Drifting
Joined: Jul 2011
Posts: 1,822
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From: Boca Raton Florida
Originally Posted by Ajsegal
Thanks for your input, thats what i was thinking at the time of purchase. But....... I think I remember reading that stiffer springs with a stock cam can put a significant amount of stress on rockers,pushrods,cam, and lifters. More so that stock springs. Also read something about vavles closing to hard and bouncing with stiffer springs and stock cam. Ha, I'm probably over thinking it
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Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
If you even to more research you will find many many failures of STOCK LS6 valve springs on a STOCK cammed Z06----They don't hold up well under higher RPM running
or performance driving---Using weak stock valve springs to get more HP or avoid valve bounce is an old wife's tale---
Your supercharger will put more stress on your engine than anything else--Good valve springs will insure the valves will close properly and not allow boost to enter the combustion chamber when it's not supposed to---Again just an insurance policy---If it were my car ? I would absolutely keep the better springs---Insures catastrophic failures
from a valve that doesn't close--There may be more wear on your engine but not more than created by the SC !!!!--A valve job is much cheaper than a blown engine----
or performance driving---Using weak stock valve springs to get more HP or avoid valve bounce is an old wife's tale---
Your supercharger will put more stress on your engine than anything else--Good valve springs will insure the valves will close properly and not allow boost to enter the combustion chamber when it's not supposed to---Again just an insurance policy---If it were my car ? I would absolutely keep the better springs---Insures catastrophic failures
from a valve that doesn't close--There may be more wear on your engine but not more than created by the SC !!!!--A valve job is much cheaper than a blown engine----
Thread Starter
Advanced
Joined: Aug 2015
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After speaking with Kohle at AH I decided im going to keep the springs. Forget what he said to be honest, but it was along the same lines as everything else said in here (boost=more pressure, cheap insurance, etc) he also said something about seeting them higher(I'm sure im using the wrong verbiage) for less pressure because of the stock cam? They will Only at 120psi or something like that. Anyways he made me feel alot more comfortable with those springs.
Last edited by Ajsegal; Nov 30, 2015 at 09:36 PM.
Race Director
Joined: May 2004
Posts: 16,667
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From: Raleigh, NC
St. Jude Donor '15
If you take a stock intake valve, call it 2" diameter, 1" radius = 3.14 inch^2. Spring pressure, say it's 120lbs closed (I've seen these quoted as being closer to 80lbs closed, which makes this example even worse)
Say you're at 12psi of boost
Total pressure on the back of the valve is 3.14 inch^2 x 12 lbs/in^2 = almost 38 lbs of force pushing the valves open. So, about a third of your spring pressure is gone (half if you use 80 instead of 120 lbs)
Does it really work out exactly like that? Hell if I know.. but that's the math I was shown when I asked why valve springs are a good idea with FI applications.
Say you're at 12psi of boost
Total pressure on the back of the valve is 3.14 inch^2 x 12 lbs/in^2 = almost 38 lbs of force pushing the valves open. So, about a third of your spring pressure is gone (half if you use 80 instead of 120 lbs)
Does it really work out exactly like that? Hell if I know.. but that's the math I was shown when I asked why valve springs are a good idea with FI applications.
