Revised Comp918 Failure!
05-20-2009, 10:43 PM
#1
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Revised Comp918 Failure! Just making it known of this particular failure...not to down on COMP really, just the fact that any single spring is really not worth the risk in my opinion!
When I did my cam swap in my 01 SS I used a new set of the "revised" 918s, not the old batch they had trouble with....
I personally never had trouble while I had the car, however I only had it for about 2-3k miles after the cam/lifter/spring install....the guy who owned it after I did had the motor "lock up" shortly after he bought it (Maybe 4-5k miles on the springs at this point)...recently the car came up repo'd and a local shop bought it....went and took a look at the tear down today:
Looks like a spring shattered..dropping the valve into the cylinder and smashing the head to hell, and even cracked the piston in half...cylinder walls beat up etc....
SO...thousands of damage caused from ONE spring failure...call it what you will, but I for one will have a hard time buying a single spring again!
When I did my cam swap in my 01 SS I used a new set of the "revised" 918s, not the old batch they had trouble with....
I personally never had trouble while I had the car, however I only had it for about 2-3k miles after the cam/lifter/spring install....the guy who owned it after I did had the motor "lock up" shortly after he bought it (Maybe 4-5k miles on the springs at this point)...recently the car came up repo'd and a local shop bought it....went and took a look at the tear down today:
Looks like a spring shattered..dropping the valve into the cylinder and smashing the head to hell, and even cracked the piston in half...cylinder walls beat up etc....
SO...thousands of damage caused from ONE spring failure...call it what you will, but I for one will have a hard time buying a single spring again!
Last edited by LS1Silverado05; 05-23-2009 at 11:35 PM.
05-21-2009, 03:03 AM
#2
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Was that for the 2001 SS with .603 lifts?
Did you install all springs at 1.800 height? What was the cam seat pressure requirement?
Most failures 95%+ are due to either missmatch, bad install or error on driver part while shifting or beating on them cold.
FYI, all OEM cars run single, LS7 run singles it is mostly in the building process. Set them right and you'll have very few issues.
Did you install all springs at 1.800 height? What was the cam seat pressure requirement?
Most failures 95%+ are due to either missmatch, bad install or error on driver part while shifting or beating on them cold.
FYI, all OEM cars run single, LS7 run singles it is mostly in the building process. Set them right and you'll have very few issues.
05-21-2009, 11:17 AM
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Was that for the 2001 SS with .603 lifts?
Did you install all springs at 1.800 height? What was the cam seat pressure requirement?
Yes the springs were at 1.800....but I didnt check any cam seat pressure requirement....never crossed my mind, in fact you are the first person to mention it, comp didnt even ask about it when asking for specs. So you think they could have binded if the installed height was off?
Most failures 95%+ are due to either missmatch, bad install or error on driver part while shifting or beating on them cold.
Agreed
FYI, all OEM cars run single, LS7 run singles it is mostly in the building process. Set them right and you'll have very few issues.
Surely GM isnt checking installed height of all 16 springs before they go out the door....While I welcome the idea, I highly doubt it
Did you install all springs at 1.800 height? What was the cam seat pressure requirement?
Yes the springs were at 1.800....but I didnt check any cam seat pressure requirement....never crossed my mind, in fact you are the first person to mention it, comp didnt even ask about it when asking for specs. So you think they could have binded if the installed height was off?
Most failures 95%+ are due to either missmatch, bad install or error on driver part while shifting or beating on them cold.
Agreed
FYI, all OEM cars run single, LS7 run singles it is mostly in the building process. Set them right and you'll have very few issues.
Surely GM isnt checking installed height of all 16 springs before they go out the door....While I welcome the idea, I highly doubt it
Last edited by LS1Silverado05; 05-21-2009 at 02:15 PM.
05-21-2009, 12:07 PM
#4
They can't be at 1.800 unless something was changed. Standard seat height is around 1.770. Leads me to believe no measurements were taken.
A double will not save a motor, maybe sometimes at a low RPM, but the center spring is not there to open and close the valve. It is there for harmonics and damping, with a marginal contribution to overall stiffness. So if you break a double at idle, it may work. Break a double at 6K RPM and you are no better off than a single at that point as it simply won't control the valve train.
A double will not save a motor, maybe sometimes at a low RPM, but the center spring is not there to open and close the valve. It is there for harmonics and damping, with a marginal contribution to overall stiffness. So if you break a double at idle, it may work. Break a double at 6K RPM and you are no better off than a single at that point as it simply won't control the valve train.
05-21-2009, 02:11 PM
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What I can lay out on the install is this :
Factory retainers and keepers were used....
Cam 231/237 592 603 111.5
Pushrods 7.425 (at the recommendation of Pred-Z for less noise over 7.400)
You guys think the combination of the 7.425 pushrods / possible short installed height, and the cam just pushed the binding limits to the max maybe? When I had the car it saw 6800 many times never any problems... all the pushrods are straight after tear down as well...
Keep in mind I never made this thread to bash Comp.... I simply think that I made a mistake by not going with dual springs... (true the second spring may not control valve events at high rpm, they MAY keep the valve out of the cylinder...I hear alot more trouble with 918s than PACs thats for sure.... but duals just seem safer...
You guys got me wondering what to do on my new turbo set-up. I think Ill start a thread on that.. I appreciate your input
05-21-2009, 03:16 PM
#7
The "revised" 918's are rated to .625 lift. I've used them on an XFI lobe and had no issues for 10,000 miles. As Predator said, it's in the assembly that makes the difference. Simply throwing the springs on the heads isn't always the best thing to do, especially for .600+ lift cams.
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05-21-2009, 04:55 PM
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A double will not save a motor, maybe sometimes at a low RPM, but the center spring is not there to open and close the valve. It is there for harmonics and damping, with a marginal contribution to overall stiffness. So if you break a double at idle, it may work. Break a double at 6K RPM and you are no better off than a single at that point as it simply won't control the valve train.
I find it odd though that the only singles breaking are comp 918's. There are plenty of others running around out there (pac and psi) that were not necessarily set up according to spec and you never hear about them breaking.
05-21-2009, 06:49 PM
#10
Patriot Extreme Gold Every one that I know that is doing a 600+ lift with a stout cam runs them and I have never heard anything bad about them. My set up is a 232/238 600/600 113 and there should be no issues. The guy doing my work runs the same springs in his LS1 414 stoker.
05-21-2009, 10:13 PM
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You are absolutely right... he could have hammered the hell out of it ice cold, I have no idea... even so it just seemed like a VERY short life for those springs...
05-23-2009, 06:54 AM
#15
Ive run the new 918s on many, many engines, making hundreds and hundreds of passes on each without failure. But I have all the tools and know how to setup springs correctly.
NEVER HAD A SINGLE PROBLEM!!! Im running 918s on my personal truck also.
BTW: If you truely didnt want to bash you should have left the company name out and truely made this about single vs dual springs.
NEVER HAD A SINGLE PROBLEM!!! Im running 918s on my personal truck also.
BTW: If you truely didnt want to bash you should have left the company name out and truely made this about single vs dual springs.
05-23-2009, 09:48 AM
#16
i dont see where he is bashing. Just jumped the gun a little.
I have always used comp 918's and will continue too. 3rd set on my T/a since 2001 and 3rd cam as well. I have a set on my Nova running 7200 rpms without any signs of valve float. I have never bought into the dual spring saving your motor thing as the inner spring wont stop valve float and therefore piston will contact valve anyways.
Comp told me the revised spring is good to .625 safely. more when set up properly but not to push it. I have a .612 lift cam turning 7200.
I have always used comp 918's and will continue too. 3rd set on my T/a since 2001 and 3rd cam as well. I have a set on my Nova running 7200 rpms without any signs of valve float. I have never bought into the dual spring saving your motor thing as the inner spring wont stop valve float and therefore piston will contact valve anyways.
Comp told me the revised spring is good to .625 safely. more when set up properly but not to push it. I have a .612 lift cam turning 7200.
05-23-2009, 10:03 PM
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**Update**
Ill be damned....this couldnt of helped my cause any?.... Keep in mind I even went with 7.425 pushrods after talking with Predator at the time (though I never specified I had put LS7 lifters in the car).... I did NOT know this little tid bit about the LS7 Lifters and that is what this car got!....good info from Predator-Z in another thread below!
LS7 lifters are official GM LS1/LS6 replacement lifters, wht GM fails to mention is that LS7 lifters have aproximately .060 higher cup and require shorter pushrods to re-establish preload in the correct range.
Ill be damned....this couldnt of helped my cause any?.... Keep in mind I even went with 7.425 pushrods after talking with Predator at the time (though I never specified I had put LS7 lifters in the car).... I did NOT know this little tid bit about the LS7 Lifters and that is what this car got!....good info from Predator-Z in another thread below!
LS7 lifters are official GM LS1/LS6 replacement lifters, wht GM fails to mention is that LS7 lifters have aproximately .060 higher cup and require shorter pushrods to re-establish preload in the correct range.
Last edited by LS1Silverado05; 05-23-2009 at 10:28 PM.
05-23-2009, 10:07 PM
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Lets assume for a minute a perfect 1.800 installed height (but I cant be 100%)
Springs claim a .625 lift....
Cam had max lift of .603....
7.425 Pushrods
LS7 Lifters (+.060 over LS1)
Stock Head and Gasket....
Could the LS7 Lifters and 7.425 even on a 1.800 installed height cause a bind or at least been way too close for comfort? I understand that they are hydraulic lifters and that its end user that should measure but damn .060 is alot to not know about...I wish GM advertised that!
Springs claim a .625 lift....
Cam had max lift of .603....
7.425 Pushrods
LS7 Lifters (+.060 over LS1)
Stock Head and Gasket....
Could the LS7 Lifters and 7.425 even on a 1.800 installed height cause a bind or at least been way too close for comfort? I understand that they are hydraulic lifters and that its end user that should measure but damn .060 is alot to not know about...I wish GM advertised that!
Last edited by LS1Silverado05; 05-23-2009 at 10:32 PM.
05-23-2009, 10:47 PM
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i dont see where he is bashing. Just jumped the gun a little.
I have always used comp 918's and will continue too. 3rd set on my T/a since 2001 and 3rd cam as well. I have a set on my Nova running 7200 rpms without any signs of valve float. I have never bought into the dual spring saving your motor thing as the inner spring wont stop valve float and therefore piston will contact valve anyways.
Comp told me the revised spring is good to .625 safely. more when set up properly but not to push it. I have a .612 lift cam turning 7200.
I have always used comp 918's and will continue too. 3rd set on my T/a since 2001 and 3rd cam as well. I have a set on my Nova running 7200 rpms without any signs of valve float. I have never bought into the dual spring saving your motor thing as the inner spring wont stop valve float and therefore piston will contact valve anyways.
Comp told me the revised spring is good to .625 safely. more when set up properly but not to push it. I have a .612 lift cam turning 7200.
05-23-2009, 11:34 PM
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There were some quality issues with the wire manufacture for the old blue strip Comp 918 springs.Comp actually identified batch numbers that were suspect and did reimburse individuals that had failures in the field.That is why the new (revised) 918 springs were put on the market.I haven't heard of any bad feed back due to breakage in relationship to the new Comp 918 springs.Hopefully,those issues are a thing of the past!!