question about valve springs
Thread Starter
Burning Brakes
Joined: Jul 2002
Posts: 1,126
Likes: 99
From: Nova Scotia
question about valve springs
i noticed lots of people running radical cams on the ls1 are having issues with breaking valve springs. do old SBC's have this problem too?thanks
Race Director
Joined: May 2000
Posts: 12,712
Likes: 2,264
The OE SHP cams including mechanical lifter types used the same valve springs as two-barrel 283s, and the valvetrains are bulletproof. But when you start pushing acceleration and lift higher you need better springs and you may take a hit - even a significant hit - in valvetrain reliability and durability. That's why I like OE cams.
If you use an aftermarket cam, use their recommended springs or other components they recommend for the valvetrain and keep your fingers crossed.
The LS-X engines have, overall, a stiffer valvetrain, and modern CAE allows for excellent prediction of valvetrain behavior, so they are able to operate it closer to the ragged edge through the entire event. The relatively short durations and higher lifts compared to OE vintage SB cams means more aggressive acceleration and closer to the reliability limit, so they won't take much more "action" than the OE cam provides without sacrificing reliabililty and durability.
The secret to the vintage mechanical lifter cams is that Zora's original design recognized that the standard valvetrain components would have to be used, and they would have to live, so he increased duration, while simultaneously REDUCING acceleration to achieve what is called "soft action". A shorter duration higher lift cam might make the same peak power with more peak torque, but it likely will not live as long.
Duke
If you use an aftermarket cam, use their recommended springs or other components they recommend for the valvetrain and keep your fingers crossed.
The LS-X engines have, overall, a stiffer valvetrain, and modern CAE allows for excellent prediction of valvetrain behavior, so they are able to operate it closer to the ragged edge through the entire event. The relatively short durations and higher lifts compared to OE vintage SB cams means more aggressive acceleration and closer to the reliability limit, so they won't take much more "action" than the OE cam provides without sacrificing reliabililty and durability.
The secret to the vintage mechanical lifter cams is that Zora's original design recognized that the standard valvetrain components would have to be used, and they would have to live, so he increased duration, while simultaneously REDUCING acceleration to achieve what is called "soft action". A shorter duration higher lift cam might make the same peak power with more peak torque, but it likely will not live as long.
Duke
