replace valve springs or send it ?
TECH Addict
Joined: Oct 2016
Posts: 2,513
Likes: 480
From: PDX-OR-USA
I've seen more than a dozen engines blown with broken valve springs after being pulled out of storage.
The higher pressure the spring the more likely it is to happen.
On some sprints the springs are trashed about every 20 races..
Nobody I know road racing a top shelf motor stores their engines with the rockers on.
I've measured springs that have been in storage and found 50+ lb differences between the ones that were tight and the ones that were loose. Also can often measure significant differences in unloaded spring height..
Attention to Details for the win...
The higher pressure the spring the more likely it is to happen.
On some sprints the springs are trashed about every 20 races..
Nobody I know road racing a top shelf motor stores their engines with the rockers on.
I've measured springs that have been in storage and found 50+ lb differences between the ones that were tight and the ones that were loose. Also can often measure significant differences in unloaded spring height..
Attention to Details for the win...
I've also broken a valvespring in the first 300 miles!! Happened as I came to a 4 way stop at 5:00 A.M. on my way to work. Might have been turning 1,400rpm. Had a good part of my savings in that engine. So it's not always age. Thank God for dual springs!! There is something to be said about a part, or part, that has proven reliable. On a really high lift cam, say .650"+, yes, you'd be foolish to run them year after year. Since my cam is close to stock lift, and I believe PAC springs are superior in quality-and they have better quality control, than the GM springs, I figure my springs are pretty safe. But even if I had warned somebody, and they didn't listen, there's no way I'd stuff salt in their wound as they lay there hurting, even if they wounded themselves! ! That's like visiting somebody in the ICU with Covid, who didn't get vaccinated. I'd never stand there and tell them "you asked for it". That's who I AM.....
grinder11
Poking fun at somenone who had an engine grenade on them isn't funny and it's certtainly not who I am. As for the valve springs there hasn't been any heat cycles ran through them and they're likely okay but I still recommend checking them. Otherwise it will be in the back of your mind as to how long before I really do need to change them and from what I've gathered so far the engine is on an engine stand.
Poking fun at somenone who had an engine grenade on them isn't funny and it's certtainly not who I am. As for the valve springs there hasn't been any heat cycles ran through them and they're likely okay but I still recommend checking them. Otherwise it will be in the back of your mind as to how long before I really do need to change them and from what I've gathered so far the engine is on an engine stand.
If this is a high rpm race build, I’d say change them out. If this is a street car that’s just gonna cruise on weekends and occasionally see 6500 rpm, run it as is, no worries.
https://www.guntalk.com/video-post/m...weaken-springs
Finding replacement springs for my Automag and Coonan won't be easy.
Finding replacement springs for my Automag and Coonan won't be easy.
TECH Enthusiast
Joined: Sep 2019
Posts: 532
Likes: 630
Its an over-simplification.
Basically in order to deform a spring, you have to compress it past its elastic limit, but the thing about spring steel is that its elastic limit is not a strongly defined value, and the tension on every part of the spring wire is not even, with it being much higher on the outer surface than inside the spring core. And if you have a high-lift cam, you need high lift valve springs that have few coils per inch. This means the torsion on each little part of the spring steel is higher than stock or lower lift springs, so in use it can be more likely to lose tension.
Also, valve springs, whether stored under compression or run in heavily used engines, will 'relax' and are expected to lose something like 10% of their tension, and a small amount of spring height, and then maintain that final 'relaxed' tension more or less indefinitely. The same phenomenon happens to suspension springs, leaf springs, all sorts.
Basically, from what I know about this, if you took your valve springs and compressed them all .600" and then stored them at that compression, or installed them in an engine with a .600 lift cam and drove them 100,000 miles, you will have your springs creep and relax somewhat. Its kind of unavoidable.
A potential issue is that in the stored engine the spring relaxation can be uneven, but if you run the springs they will even out eventually.
Please swap them if they are even slightly rusty, or they will crack.
Basically in order to deform a spring, you have to compress it past its elastic limit, but the thing about spring steel is that its elastic limit is not a strongly defined value, and the tension on every part of the spring wire is not even, with it being much higher on the outer surface than inside the spring core. And if you have a high-lift cam, you need high lift valve springs that have few coils per inch. This means the torsion on each little part of the spring steel is higher than stock or lower lift springs, so in use it can be more likely to lose tension.
Also, valve springs, whether stored under compression or run in heavily used engines, will 'relax' and are expected to lose something like 10% of their tension, and a small amount of spring height, and then maintain that final 'relaxed' tension more or less indefinitely. The same phenomenon happens to suspension springs, leaf springs, all sorts.
Basically, from what I know about this, if you took your valve springs and compressed them all .600" and then stored them at that compression, or installed them in an engine with a .600 lift cam and drove them 100,000 miles, you will have your springs creep and relax somewhat. Its kind of unavoidable.
A potential issue is that in the stored engine the spring relaxation can be uneven, but if you run the springs they will even out eventually.
Please swap them if they are even slightly rusty, or they will crack.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
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 https://www.guntalk.com/video-post/m...weaken-springs
Finding replacement springs for my Automag and Coonan won't be easy.
Finding replacement springs for my Automag and Coonan won't be easy.
TECH Apprentice
Joined: Feb 2010
Posts: 370
Likes: 138
Heat cycles is what causes valve springs to lose tension. There’s a guy on the Chevelle forum that clamped a couple valve springs for 11 years they are the same 460lbs of pressure and length from the first day he clamped them.
By checking them..
Can't agree more. It never hurts anything to check something, and maybe even double check. I'd pull the springs, bag them, with the retainer, 1 at a time, and mark which cylinder#, and which valve, I or E, the spring was installed on. Most engine/machine shops have the checking capability. If I placed a bet, OK/not OK, I'd say he's gonna be fine.....
TECH Senior Member
Joined: Jun 2016
Posts: 22,298
Likes: 3,619
From: Central Cal.
Can't agree more. It never hurts anything to check something, and maybe even double check. I'd pull the springs, bag them, with the retainer, 1 at a time, and mark which cylinder#, and which valve, I or E, the spring was installed on. Most engine/machine shops have the checking capability. If I placed a bet, OK/not OK, I'd say he's gonna be fine.....
