If a cam with a .551 lift was installed in a 5.3L, would the LS6 springs be sufficient enough or not?

 

that is what I am running with just a little bit more lift then you, so far so good but mine does not spend much time at wot.

 

yes they'll work. Im running .558 lift on mine. What I heard they'll take something like .600?

 

lingenfelter says they'll go to .580....im running my vinci .551/.551 without problems and it see's 6300rpm pretty regularly.

 

ls6 cam is .551 lift..i ran my tr224 .563 on ls6 springs

 

spring seat pressure is more important than lift rating.


and ls6 springs don't provide enough seat pressure for 90% of the cams people use them on.

 

I agree.. I would use a correct spring that is used for a particular cam. You can get away with running ls6's with that lift, but how long. i wouldn't risk it..

John

 

How can you find out how much open and closed pressure you should have for a certain cam and max rpm?

 

Here the LS6 spring details from the 2008 GM Parts Catalog on page 281. You have a choice of two different springs with the LS6.

12499224
LS Valve Spring Kit (not shown)
• Beehive style springs
• 1.800" installed height @ 90# pressure
• 1.250" @ 295# pressure
• Used on LS2/LS6 cylinder heads
• Max lift .570"
• Includes 16 of P/N 12586484

12586484
Valve Springs (not shown)
• Beehive style springs
• Standard LS6/LS3 springs
• 1.800" installed height @ 90# pressure
• 1.250" @ 295# pressure
• Max lift .570"

If you do in fact have LS6 springs, then I would say the answer is YES.

 

As long as the ramp rates aren't too agressive you'll be OK. If the cam is ground on Comp XER lobes, go with Comp springs or some form of duals. If it's one of the Crane/Vinci grinds, you should be fine. SDPC recommends the LS6 springs for their Z+220 cam which is 220/224 .551/.551 114, this is a Crane grind. Lingenfelter recommends the LS6 springs for their cams of .570+ lift.

Personally, I would run LS6 springs whenever possible; they're not as brittle as aftermarket performance springs and are less prone to breakage. They don't need to be heated up before they're romped on, and since the seat pressure is 90 psi as opposed to 130, they don't slam the valves into the valve seats, thus increasing valve life. Granted, an agressive lobe profile will require more seat pressure to prevent valve float and keep the valve from bouncing on the valve seat, but that's the necessary evil of that style of cam.

From what I've read on LS1Tech, it's recommended to replace Comp 918's at about 40K, but LS6 springs don't require replacement unless there's a problem. I haven't read of anyone running LS6 springs with moderate cam profiles and having problems, although I have read ALOT of threads about broken Comp 918's, both the blue stripe ones and the new "redesigned" silver ones.

Just my .02.