What valve springs..
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Racer
Joined: Nov 2004
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From: Greenville Texas
What valve springs..
Are the cool kids running these days? A number of years ago, it was the Patriot Gold spring/retainer/lock combo. Has anything better come out yet? I was thinking about going with a trex, ms3/4 or an LG cam. Something fairly big.
Tech Contributor
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Le Mans Master
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From: PNW
If you don't mind doing a little reading, I would suggest this thread. It covers a number of the key items needed to pick a proper valve spring.
The PAC 1518 springs have micro blasted surface and are nitrated for increased strength and reliability over the 1218s.
And actually a little stiffer spring should control the valve train more and reduce the chances of valve float.
Last edited by ZeeOSix; Sep 6, 2012 at 01:45 AM.
Tech Contributor
Joined: May 2008
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From: Howell Michigan
St. Jude Donor '09-'10-'11
It all comes down to a choice. For me, if I'm going to maintain a stock engine I would choose the GM spring. If the cam is changed to something different then by all means the springs and other valvetrain components should be picked to match the application and that might very well be an aftermarket spring.
The key point, you need to pick the springs to match the cam lift profile, the mass of all the valvetrain components and intended operating rpm. Just picking a spring without taking into account the whole system means something less than optimum and greater risk for component failure.
Team Owner
Joined: Mar 1999
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From: At the beach in little Rhody
Sounds like the OP is planning a very large cam.
I would find out what the required seat force is for the cam selected to start with. From there you need to sort out what is required to control the cam. Over the nose forces can deflect pushrods and loft the lifter. I have seen many with damaged cams blamed on the cam itself when in all likelihood there were other mitigating factors involved.
Also, the MS4 (not sure on the TREX) is well below PTV clearance minimums. Be aware if you don't plan on fly cutting, a missed shift or some minor valve float will not have a very happy ending. Valve train control and rigidity will be very important.
I would find out what the required seat force is for the cam selected to start with. From there you need to sort out what is required to control the cam. Over the nose forces can deflect pushrods and loft the lifter. I have seen many with damaged cams blamed on the cam itself when in all likelihood there were other mitigating factors involved.
Also, the MS4 (not sure on the TREX) is well below PTV clearance minimums. Be aware if you don't plan on fly cutting, a missed shift or some minor valve float will not have a very happy ending. Valve train control and rigidity will be very important.
Le Mans Master
Joined: Mar 2002
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From: PNW
Zee, when I wrote the above there were differences. I don't know if the PAC spec's have changed since. The updated GM spring was validated on engine dyno and durability vehicles. Some of the most thorough testing anywhere.
It all comes down to a choice. For me, if I'm going to maintain a stock engine I would choose the GM spring. If the cam is changed to something different then by all means the springs and other valvetrain components should be picked to match the application and that might very well be an aftermarket spring.
The key point, you need to pick the springs to match the cam lift profile, the mass of all the valvetrain components and intended operating rpm. Just picking a spring without taking into account the whole system means something less than optimum and greater risk for component failure.
It all comes down to a choice. For me, if I'm going to maintain a stock engine I would choose the GM spring. If the cam is changed to something different then by all means the springs and other valvetrain components should be picked to match the application and that might very well be an aftermarket spring.
The key point, you need to pick the springs to match the cam lift profile, the mass of all the valvetrain components and intended operating rpm. Just picking a spring without taking into account the whole system means something less than optimum and greater risk for component failure.
This is why I chose the PAC 1518s, because after all my research the force specs were a good match to the OEM springs IMO, plus the 1518s had the nitride treatment for increase reliability. I don't want to change valve springs again, so went with ones with what I felt was the highest reliability factor in a stock LS6.
Last edited by ZeeOSix; Sep 6, 2012 at 08:09 PM.
Le Mans Master
Joined: Mar 2002
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From: PNW
Here's a pretty good article about beehive valve springs.
http://www.enginelabs.com/engine-tec...-work-for-you/
http://www.enginelabs.com/engine-tec...-work-for-you/
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Tech Contributor
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From: Howell Michigan
St. Jude Donor '09-'10-'11
Here's a pretty good article about beehive valve springs.
http://www.enginelabs.com/engine-tec...-work-for-you/
http://www.enginelabs.com/engine-tec...-work-for-you/
The primary reason people fear using beehive style springs is breakage. The spring has to be properly selected for the valvetrain system. When the proper beehive spring is used it will greatly improve the total valvetrain performance and out perform any other style spring along with better durability.
Last edited by Eric D; Sep 10, 2012 at 12:23 AM.
Race Director
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From: Haymarket VA
FWIW: I've been running the same set of PAC 1521 springs on a couple of my builds. I've run cams up to .660 lift and now run .643 lift on both sides. When I did the 427 the springs had about 10k miles on them and when Richard at WCCH checked them out they were still within a couple of lbs of new specs and that was with the .660 cam. They've been controlling a 2.165 and a 2.200 intake valve. Not exactly small. They are in my 427 now and still going strong.
The PAC 1518 and 1521 are both nitrited and will last a VERY long time. the diff is the 1518 is a beehive and the 1521 is a dual.
The PAC 1518 and 1521 are both nitrited and will last a VERY long time. the diff is the 1518 is a beehive and the 1521 is a dual.