what the hell is going on with Comp 918s????
05-27-2007, 04:34 PM
#21
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Originally Posted by angel71rs
HOLY SH*T!!!!
I posted the other day when I saw a valvespring shifted like this and nobody answered me back....
I guess I have a broken one under there.....
05-27-2007, 07:01 PM
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Originally Posted by Project GatTagO
Funny how a little bit of internet hearsay turns into concrete proof. Magic...Lets do a poll shall we? Maybe that will be the statistical analysis that will prove this theory. 
As with any product, proper installation is key. How many people that use 918s actually check the install height? How many actually shim the springs so that they are at the proper install height. All of these things are important factors not only in the performance of a spring but also in its life. How many of these springs are being used with these ridiculously aggressive cam profiles that punish the valvetrain? So many variables....yet everyone wants simple answers....typical...
Andrew
As with any product, proper installation is key. How many people that use 918s actually check the install height? How many actually shim the springs so that they are at the proper install height. All of these things are important factors not only in the performance of a spring but also in its life. How many of these springs are being used with these ridiculously aggressive cam profiles that punish the valvetrain? So many variables....yet everyone wants simple answers....typical...
Andrew
cheers
That would be nice to know. Just bought a set form THUNDER!!! 
05-31-2007, 10:19 AM
#27
You can't go wrong with the Patriot or PRC duals..I put 44,000 miles on a set or PRC duals with a .598 lift cam in a DD and had no problems with them at all..I was still shifting the car at 6800 rpms till the day I replaced them..I just do not have that much confidence in a single spring compared to a dual spring ... I put a ton of miles on my car every year 
05-31-2007, 02:22 PM
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update: I've just heard a friend of mine has a broken 918 on his motor too....I don't know any details yet, but add another one to the list....
06-01-2007, 10:41 PM
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Great, the batch number on my box of 918's is 50808, that's pretty close to 49826. I bought these from Summit last November. I hate to waste money on parts never used, but I am seriously thinking of getting a different spring.
06-02-2007, 11:35 AM
#35
on the corvette forum ones.....i'd lean towards something else was wrong. Did the springs ever get baked? who put the springs on and the rest of the engine together?
10 broken springs I think is the result of something other than the springs being 100% at fault. what was the lift? shims? stock rockers? pushrods? heads milled? anything altered from stock? Theres got to be something else.
10 broken springs I think is the result of something other than the springs being 100% at fault. what was the lift? shims? stock rockers? pushrods? heads milled? anything altered from stock? Theres got to be something else.
06-02-2007, 12:17 PM
#36
Originally Posted by pwrtrip75
on the corvette forum ones.....i'd lean towards something else was wrong. Did the springs ever get baked? who put the springs on and the rest of the engine together?
10 broken springs I think is the result of something other than the springs being 100% at fault. what was the lift? shims? stock rockers? pushrods? heads milled? anything altered from stock? Theres got to be something else.
10 broken springs I think is the result of something other than the springs being 100% at fault. what was the lift? shims? stock rockers? pushrods? heads milled? anything altered from stock? Theres got to be something else.
Just my 2 cents.
James
06-02-2007, 12:28 PM
#37
It would appear to be more than just coincidental that all 10 broke at the 1st top coil. That has to have something to do with the fact none of them came apart before disassembly. He's real lucky he didn't have a catastrophic engine failure considering he was running that engine with 10 broken springs. I would have bought a Powerball ticket after finding out I had dodged a bullet like that.
06-02-2007, 04:31 PM
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Originally Posted by eallanboggs
It would appear to be more than just coincidental that all 10 broke at the 1st top coil. That has to have something to do with the fact none of them came apart before disassembly. He's real lucky he didn't have a catastrophic engine failure considering he was running that engine with 10 broken springs. I would have bought a Powerball ticket after finding out I had dodged a bullet like that.
Mine appears to be broken in the same spot.....the rest of the spring is intact....I'll know for sure wednesday when they get replaced.
06-02-2007, 04:45 PM
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I've installed over a dozen sets of these with no failures. The cams they were used with did not exceed COMPs recommendations.
Sorry to hear some of you are having problems. Any chance for user error here? Be honest please, everyone makes mistakes. I know I would like to know if the springs really are the problem here.
Sorry to hear some of you are having problems. Any chance for user error here? Be honest please, everyone makes mistakes. I know I would like to know if the springs really are the problem here.
06-02-2007, 07:52 PM
#40
Originally Posted by Cheatin' Chad
I've installed over a dozen sets of these with no failures. The cams they were used with did not exceed COMPs recommendations.
Sorry to hear some of you are having problems. Any chance for user error here? Be honest please, everyone makes mistakes. I know I would like to know if the springs really are the problem here.
Sorry to hear some of you are having problems. Any chance for user error here? Be honest please, everyone makes mistakes. I know I would like to know if the springs really are the problem here.
ZERO user error. Of those dozen, how many have you visually inspected AFTER installation, months later.
Remember, we are talking about a STOCK NOT MODIFIED LS6 engine. There was a 216/222 585 116 cam in the car for a few months, but I took it out planning to go turbo. The truth is when I started noticing the power loss was when the car was COMPLETELY STOCK w/stock cam. I even have the stock airbox. I RARELY hit the rev limiter and even when I do, its just a tap and I let off or shift.
Not only was there no error on install, but your theory of no failure on dozens of installations is flawed. Besides the orientation of the spring, it is difficult to see they are broken. The actuall part of the spring that is broken is under the retainer. The way I figured this out was after a quick sprint in 2nd gear to 6400 (stock cam), I noticed a loss in power the rest of the day driving the car. It was OBSCURE and difficult to tell the springs were broken except for the ones that were shifted upon visual inspection.
I would recommend before you apply the blanket state that you have not had problems with your installs/springs, you inspect them first. Note, that my car was probably still a low 12 sec ride even w/broken valve springs. After I personally changed them out to stock, it gained a lot of power and smoothed out on top end.
These springs, at least mine, were defective. This fact was verifed by Comp Cams, though they did consider a credit on return and inspection.
This post is for the benefit of those who wish to inspect their springs. If ANY disorientation of the spring is evident, it is likely broke. I seriously doubt you would recognize this fact since 1 or 2 springs broken wouldn't result in a huge power loss and the spring still has minimal tension on it.
Regarding corvetteforum ,spring breaks what is is reason for suspected incorrect install?