Valvespring cheating
Thread Starter
TECH Enthusiast
iTrader: (4)
Joined: Mar 2009
Posts: 648
Likes: 1
From: Smithfield, UT
Valvespring cheating Everyone confess, how far have you gone on the springs GM rates to 0.570"?
Yesterday I met a guy willing to prove he's running them to 6500 RPM on a 0.587" cam, and 6000 on a 0.612" cam.
Looking at the difference between installed height and coil bind spec, then subtracting a safety margin of 0.060", I'm seeing they should theoretically survive up to 0.655" of actual lift at the valve. That's impractical without more rocker ratio, and keeping the RPM down. Doesn't seem worthwhile to me.
Yesterday I met a guy willing to prove he's running them to 6500 RPM on a 0.587" cam, and 6000 on a 0.612" cam.
Looking at the difference between installed height and coil bind spec, then subtracting a safety margin of 0.060", I'm seeing they should theoretically survive up to 0.655" of actual lift at the valve. That's impractical without more rocker ratio, and keeping the RPM down. Doesn't seem worthwhile to me.
Lift isn't the real issue IMO. The ramp rates and the springs ability to stay out of surge or other bad harmonics would be the main concern I believe. Just because a spring will clear x amount of lift doesn't mean it should be used
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
I've shimmed LS6 springs and ran .598 lift XER lobes for a race day without issues. It was either that or withdraw from the bout but I was willing to take the risk. I would not do that for a long period and my PTV margins were over .080 on intake with the cam I had. I did that to finish that race day which was important to me.
My room mates trans am had a mystery cam in it (still have it just not sure where to send it for cam doctor) that was sold to him as a stock 98 ls1 cam.
Not sure what any specs were on it but it loped harder than the 230/238 113+2 that replaced it. It was in there for a long time with no apparent issues other than driving like **** because the tune was for a stock cam and horrible fuel mileage.
Not sure what any specs were on it but it loped harder than the 230/238 113+2 that replaced it. It was in there for a long time with no apparent issues other than driving like **** because the tune was for a stock cam and horrible fuel mileage.
Numbers came back with nothing everywhere I've looked and I haven't had the extra money to **** away sending it off yet (nor am I even sure who would be interested in messing with it)...will eventually get it checked just out of morbid curiosity.
Thread Starter
TECH Enthusiast
iTrader: (4)
Joined: Mar 2009
Posts: 648
Likes: 1
From: Smithfield, UT
I thought we all understood that the "squarer" the lobes, the more spring required, the shorter the spring life, and the less RPM. Squareness is easily approximated by looking at the lift versus duration.
I'm asking who has done what RPM with what cam specs. Anyone run these springs to 7000 with a common 224 grind over 0.570" lift? ( For one possible example. )
I'm asking who has done what RPM with what cam specs. Anyone run these springs to 7000 with a common 224 grind over 0.570" lift? ( For one possible example. )
Trending Topics
TECH Senior Member
Joined: Mar 2004
Posts: 14,620
Likes: 17
From: BFE
Man I've seen a guy punch his LS1 to 6.0 (4.0) bore. while it survived for awhile it doesn't mean it is alright to do it.
Please do it right and at least get the proper springs for your setup.
Please do it right and at least get the proper springs for your setup.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
