Valvespring replacement time??
Thread Starter
Joined: Apr 2005
Posts: 4,085
Likes: 1
From: N. Falmouth MA
Valvespring replacement time?? I think I'm either at or getting close to 10k miles on my PRC dual Golds running a PatG Tq cam with LSk lobes. I know I should replace the valve springs around 10k miles, but not sure how to tell if they need it or not. (other than an obvious problem)
When you install higher lift camshafts valve springs do become a maintenance item. There is nothing magic about 10k miles or any other specific frequency since the maintenance interval depends on several factors. These factors include how much lift the camshaft has, the quality of the valve spring, how well the valvetrain was setup, and how the engine is operated. The bottom line is that with aftermarket cams and springs you can longer ignore you valve springs for a 100k or more miles.
I just finished a top-end rebuild due to weak/fatigued springs...could have neen $200 in springs and seals versus nearly $1200 in parts, gaskets, and machine shop labor if I'd replaced them proactively.
Thread Starter
Joined: Apr 2005
Posts: 4,085
Likes: 1
From: N. Falmouth MA
And is the maintenance issue just weakening of the springs? I was more/less fearing a broken spring..
And the cam is 224/228 .637 .639 110 quicker lobes.I'm still getting my sewing machine noise and haven't noticed any drop in power, so I guess I'm still good.
Thanks for the help guys!
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TECH Regular
Joined: Jul 2011
Posts: 452
Likes: 2
Testing for weak spring pressure is possible of course.
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I would wait until around 20k miles personally, and check your pressures. Like was said, there is no indicator except a spring break that will show you anything but low pressure. Ive had 2 spring failures, in 2 cars, months apart. Both were setup by the previous owners, and i didnt know the importance of spring maintenance until it was too late.
My 2001 WS6 broke a 918 (#8Intake valve) and completely FUBAR'd a piston after i went from the reverse split cam, to a 224R. I checked the spring pressures (unknown miles) and they were nearly 100lbs too light at installed and open height. I couldnt even get the right pressure near coil bind height.
My wifes 2000 WS6 broke a 918 a few months later (#8 Intake valve too, what are the odds???) These also had an unknown amount of miles on them, and were run with a TSP 231/237 cam. Checked the spring pressures, and they were within a few pounds of proper spec.
Basically, you can watch for a drop in spring pressure, and replace when weak, or replace them before an issue arises.
In my car, i now have AFR 205s/AFR springs, and a 224/228. In my wife's car, it now has a PatG/EPS 227/230 w/PRC EHT .675 Duals.
My 2001 WS6 broke a 918 (#8Intake valve) and completely FUBAR'd a piston after i went from the reverse split cam, to a 224R. I checked the spring pressures (unknown miles) and they were nearly 100lbs too light at installed and open height. I couldnt even get the right pressure near coil bind height.
My wifes 2000 WS6 broke a 918 a few months later (#8 Intake valve too, what are the odds???) These also had an unknown amount of miles on them, and were run with a TSP 231/237 cam. Checked the spring pressures, and they were within a few pounds of proper spec.
Basically, you can watch for a drop in spring pressure, and replace when weak, or replace them before an issue arises.
In my car, i now have AFR 205s/AFR springs, and a 224/228. In my wife's car, it now has a PatG/EPS 227/230 w/PRC EHT .675 Duals.
TECH Regular
Joined: Jul 2011
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From what I've read in the past, there was a bad batch or two of Comp Cams 918 valve springs - can't recall the time frame those springs were manufactured. If these were them or not is hard to say.
Do you have prc duals or do you have patriot gold dual valve springs? I don't know where you heard 10k miles with the prc's because I have been hearing great things about them with there long life. These are one of the best springs thats out now I beleive. If you have a 918 or spring like it you would probably need to change them every 20k, but the prc's are much better
Well when it comes to springs there are MANY factors on deciding when to do a spring job. Once a cam is installed, it will be considered matience like any other thing. The more lift and duration as well as how much the engine sees RPM will decide when it's time. Also a thing to consider is simply just time, as some cars are not seeing the milage but after 5-6 years, it maybe just a good idea to do.
The only thing you can do is pull random springs to get them checked but then how far are you away from just putting new ones in. See my point. If you question them, just do them esp if they are bee hive design.
My own exp: LT1 383 with a LT4 hotcam (***** cam) managed to have a Comp 987 Dual (see heavy) spring let go @ 30k miles on the build. This being a Automatic car as well so it only saw RPM when I was racing and not like a m6 car that could see that every gear.
The only thing you can do is pull random springs to get them checked but then how far are you away from just putting new ones in. See my point. If you question them, just do them esp if they are bee hive design.
My own exp: LT1 383 with a LT4 hotcam (***** cam) managed to have a Comp 987 Dual (see heavy) spring let go @ 30k miles on the build. This being a Automatic car as well so it only saw RPM when I was racing and not like a m6 car that could see that every gear.
I agree. LSKs are quite a bit harder than XERs on the whole valvetrain. They might still be ok, but the only sure bet is to pull a few and check them. That 48,000 mile info is good fodder to run them longer than 10,000 though.
Check them for pressure, but I'd bet against them having lost any real pressure at 10K miles!
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Largest Stocking Distributor of LS-x Engines / CHECK OUT OUR NEW WEBSITE!
COMP - FAST - PACESETTER - DIAMOND RACING - EAGLE SPECIALTY PRODUCTS - CALLIES - COMETIC GASKETS
RAM CLUTCHES - MOSER ENGINEERING - KOOK'S HEADERS - ARP - GM BOLTS AND GASKETS - MSD - NGK
POWERBOND - ASP - AND MORE!
