Do valve springs "go bad" without use?
09-08-2010, 03:51 PM
#1
Drifting
Thread Starter
Do valve springs "go bad" without use?
I have the Comp 921s...they do not have that many miles on them (I would guess about 1000 to 2000 or so track miles), but they have been in the engine for almost 5 years. The car sits most of the time, sometimes for 8-9 months at a time...So I was wondering if the springs would/could go bad, just by being compressed for such a long period of time? or does it really require "banging" on them to make them wear out?
Input is needed
Input is needed
09-08-2010, 04:37 PM
#2
Safety Car
Member Since: Nov 2000
Location: Shenandoah Valley Virginia
Posts: 4,549
Likes: 0
Received 27 Likes
on
24 Posts
The repetitive movement of opening and closing the valves many times a second is what causes fatigue of the spring material and breakage. I have never heard of springs "taking a set" and going bad from disuse. Don't worry about it and run them hard.
09-09-2010, 07:32 AM
#5
Racer
Member Since: Jun 2000
Location: Lehigh Valley,Pa.
Posts: 394
Likes: 0
Received 0 Likes
on
0 Posts
My comp springs "went bad". After 5-6 yrs and 6-7000mi of use. Their fatigue was first noticed on the track , then reproducible on the street only with track like acceleration. After chasing what I thought was a fuel delivery problem, I discussed the symptom with the Cartek, who put the springs in. They said "it's your springs" just freshen them up. They were correct. Maybe one of the more "Learned Ones" here can explain why a stronger spring fatigues before stock springs. Cartek said to replace them every 3 yrs. minimum. The price for speed. ....the weak springs did present a dangerous situation as I was loosing power in high G tight turns on comp tires...lucky to not have gathered up the car on my rear bumper
09-09-2010, 09:41 AM
#7
Drifting
Thread Starter
My comp springs "went bad". After 5-6 yrs and 6-7000mi of use. Their fatigue was first noticed on the track , then reproducible on the street only with track like acceleration. After chasing what I thought was a fuel delivery problem, I discussed the symptom with the Cartek, who put the springs in. They said "it's your springs" just freshen them up. They were correct. Maybe one of the more "Learned Ones" here can explain why a stronger spring fatigues before stock springs. Cartek said to replace them every 3 yrs. minimum. The price for speed. ....the weak springs did present a dangerous situation as I was loosing power in high G tight turns on comp tires...lucky to not have gathered up the car on my rear bumper
09-09-2010, 09:42 AM
#8
Drifting
Thread Starter
I called Comp and they said that they have a new 926 spring that is supposed to be better (can handle more pressure) than the 921s, and at a cheaper price. Anyone have any input on the 926s??
09-09-2010, 01:11 PM
#9
Team Owner
Member Since: Sep 2003
Location: Raleigh / Rolesville NC
Posts: 43,084
Likes: 0
Received 25 Likes
on
25 Posts
Unless your cam lift is above .650 there are some great beehives that work up to .650.
Too much spring pressure leaves HP on the table with too much spring seat pressure.
Too much spring pressure leaves HP on the table with too much spring seat pressure.
09-09-2010, 01:28 PM
#10
Le Mans Master
5 years, I say replace them. Some of them had to be compressed for a long time. It is just good insurance.
Jim
Jim
09-10-2010, 07:25 PM
#11
Former Vendor
Member Since: Aug 2005
Location: Lewisville TX
Posts: 16,898
Received 406 Likes
on
300 Posts
St. Jude Donor '03-'04-'05-'06-'07-'08-'09-'10-'11-'12-'13
921's and our cams should be mileaged out or timed out.
Track cars, I would do it once a season for insurance. You never know if you buzzed the motor during a day at the track unless you have telemetry on board. Couple missed gears here or there can take their toll real quick on springs.
Street cars, depending on use, should be changed every 20,000 to 30,000 miles.
If it sat for a very long time, it can almost put a 'set' into the spring but it would have to not move at all for quite a while.
Track cars, I would do it once a season for insurance. You never know if you buzzed the motor during a day at the track unless you have telemetry on board. Couple missed gears here or there can take their toll real quick on springs.
Street cars, depending on use, should be changed every 20,000 to 30,000 miles.
If it sat for a very long time, it can almost put a 'set' into the spring but it would have to not move at all for quite a while.
09-11-2010, 10:20 AM
#12
Race Director
921's and our cams should be mileaged out or timed out.
Track cars, I would do it once a season for insurance. You never know if you buzzed the motor during a day at the track unless you have telemetry on board. Couple missed gears here or there can take their toll real quick on springs.
Street cars, depending on use, should be changed every 20,000 to 30,000 miles.
If it sat for a very long time, it can almost put a 'set' into the spring but it would have to not move at all for quite a while.
Track cars, I would do it once a season for insurance. You never know if you buzzed the motor during a day at the track unless you have telemetry on board. Couple missed gears here or there can take their toll real quick on springs.
Street cars, depending on use, should be changed every 20,000 to 30,000 miles.
If it sat for a very long time, it can almost put a 'set' into the spring but it would have to not move at all for quite a while.
09-11-2010, 10:36 AM
#13
09-13-2010, 12:49 AM
#14
Drifting
921's and our cams should be mileaged out or timed out.
Track cars, I would do it once a season for insurance. You never know if you buzzed the motor during a day at the track unless you have telemetry on board. Couple missed gears here or there can take their toll real quick on springs.
Street cars, depending on use, should be changed every 20,000 to 30,000 miles.
If it sat for a very long time, it can almost put a 'set' into the spring but it would have to not move at all for quite a while.
Track cars, I would do it once a season for insurance. You never know if you buzzed the motor during a day at the track unless you have telemetry on board. Couple missed gears here or there can take their toll real quick on springs.
Street cars, depending on use, should be changed every 20,000 to 30,000 miles.
If it sat for a very long time, it can almost put a 'set' into the spring but it would have to not move at all for quite a while.
09-13-2010, 07:15 AM
#15
Team Owner
Member Since: Sep 2003
Location: Raleigh / Rolesville NC
Posts: 43,084
Likes: 0
Received 25 Likes
on
25 Posts
for any type of track use, put on new springs each winter.
expecting 15-20,000 miles out of a set of springs, even 5,000 miles, that are dong only 3000 to 6500 rpms all 2-3 times every 2 min for 20-40 mins
I wonder if this is partly the best road race cams, have lifts under .575, for valve train life.
expecting 15-20,000 miles out of a set of springs, even 5,000 miles, that are dong only 3000 to 6500 rpms all 2-3 times every 2 min for 20-40 mins
I wonder if this is partly the best road race cams, have lifts under .575, for valve train life.
09-13-2010, 12:15 PM
#16
Drifting
There are WWII firearms that the springs still work just fine. They sat for a long long time! Also there are cars that sit for long periods. Some of the springs will be compressed for many years while it sits. I haven't heard of springs wearing out from sitting or "almost taking a set". Additionally I've never heard of a valve spring taking a set. I would be interested to learn about this!
Look at this way, if they do go bad, and you float your valves, aren't you going to wish you'd changed out the springs instead of building a new motor?
