what the hell is going on with Comp 918s????
06-02-2007, 08:01 PM
#41
Originally Posted by DeepBlueZ
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.
Anyone in SAC, CA area that wants them looked at I would be glad to inspect and change for them if only a few springs
06-02-2007, 08:11 PM
#42
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.
Note I used the Crane tool to uninstall and install my stock springs. The GOOD NEWS is the break appears to occur at exactly the same place on every spring (all reported occurences) that I know of. Its at the top of the spring which allows the spring to maintain a fraction of its original spring tension protecting the engine. In one case, a guy lost his engine as a result.
06-02-2007, 11:02 PM
#45
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Could the retainer itself be a problem? Are most people still using the stock retainers, steel retainers supplied by comp, or titanium retainers? Just wondering if any clearance issues between the retainer and the spring may contribute to where the spring seems to be failing. Just wondering......
06-02-2007, 11:31 PM
#46
Originally Posted by pewter99ls1
Could the retainer itself be a problem? Are most people still using the stock retainers, steel retainers supplied by comp, or titanium retainers? Just wondering if any clearance issues between the retainer and the spring may contribute to where the spring seems to be failing. Just wondering......
I used the titanium retainers in this case. I'll look at this and check the fit.
06-03-2007, 09:52 PM
#47
Originally Posted by thechef
I am going to say almost all of these problems are due to poor installations, and not checking installed heights etc
Nice...
A little more detail please, if you are going to declare the installer an idiot... otherwise why even post???
06-03-2007, 11:21 PM
#48
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Originally Posted by 03EBZ06
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.
Bingo, same here....my car still ran normally right up until I checked the springs myself.....
I REALLY doubt my failure was due to an improper install. The shop that did my car has a LONG-standing reputation for quality work and has turned out HUNDREDS of cars wearing those springs.
I honestly believe something went wrong somewhere along the line, be it a change in suppliers to Comp or whatever....
06-04-2007, 01:55 AM
#49
Is there any way to tell if the springs are broken while they are on the car? I pulled both my valve covers and all the springs looked fine. One wierd thing is at the drag strip I somehow lost 2mph for some reason the last time I went. I wouldn't mind putting a set of patriot platinums on my car since comp switched spring manufacturers and all these problems started happening. If I'm going to spend the time to pull all the springs to make sure they are fine I'm not going to just throw them back on, I might as well put new springs in.
If I'm going to spend the time to pull all the springs to make sure they are fine I'm not going to just throw them back on, I might as well put new springs in. 
06-04-2007, 09:50 AM
#51
Look at the pictures. It's stange how they all broke in exactly the same place on the top coil. Stranger still is the fact that none of the broken portion popped out from under the retainer, but all of them somehow turned ever so slightly the same exact distance without coming dislodged from the spring/retiner. That's either one hell of a coincidence or just dumb luck.
06-04-2007, 11:47 AM
#52
Think of it in another way. That is obvisously the weakest (smallest) part of the spring and therefore would break the soonest. If a spring were to break right in the middle of the coil, then it would almost for certain be a flaw in the metal, but seeing as how they all broke at the same point leads me to believe that they all recieved the same manner of stress, whatever that stress may have been.
If the springs had broken at different positions on the coil, then I would lean strongly to flaws in the processes by which those springs were made.
James
If the springs had broken at different positions on the coil, then I would lean strongly to flaws in the processes by which those springs were made.
James
06-04-2007, 12:33 PM
#53
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I have had the 918's in mine for less than a week but am getting nervous every time I give it a squirt. They were installed correctly but I will probably check em shortly to see if any are broken allready. The fact those springs all broke in the same spot could mean there is a flaw in the manufacturing process. The metal may be prone to fatigue and breaking at the weakest point.
cheers
cheers
06-04-2007, 12:54 PM
#54
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Originally Posted by Dr. Jeckel
Think of it in another way. That is obvisously the weakest (smallest) part of the spring and therefore would break the soonest. If a spring were to break right in the middle of the coil, then it would almost for certain be a flaw in the metal, but seeing as how they all broke at the same point leads me to believe that they all recieved the same manner of stress, whatever that stress may have been.
If the springs had broken at different positions on the coil, then I would lean strongly to flaws in the processes by which those springs were made.
James
If the springs had broken at different positions on the coil, then I would lean strongly to flaws in the processes by which those springs were made.
James
ummm.. if thats the weakest part on the spring and the whole spring is made out of the same faulty materieal it would still be the first place to break even with normal use... the weakest part of anything is always the first to break.
now if you had springs made out of **** material but didnt have a "weak spot" in the spring thats a first fail point then you would have random breaks all over on the springs.
who knows maybe comp designed them like this so that the weak spot would break first on the top and you wouldnt drop a valve due to it being the small peice right on the tip, kinda like the insurance running double springs like my 921's gives ya
06-04-2007, 02:20 PM
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I can't believe there have been almost a dozen cases of this mentioned lately and people are still so quick to blame the installers and/or the drivers (which I'm starting to take personally).
The 4 cars that I know of personally (including my own) had their springs installed by 4 different shops.
I find it hard to believe that, given this is a recent phenomenon, ALL of the shops simultaneously changed their install procedures and thus "caused" the failures by not checking installed height.
on the topic of installed height. Why would it be different car to car anyway? everyone buys the same cam kits. The only way to change the installed height would be to machine the spring seat in the head (which nobody's doing) or to use some kind of non-conventional retainer and lock setup.
I'm no expert, but I find it hard to believe that Comp manufactured the 918s (which are more or less for mild street combinations) in such a way that additional modifications would be required to achieve correct installed height.
The 4 cars that I know of personally (including my own) had their springs installed by 4 different shops.
I find it hard to believe that, given this is a recent phenomenon, ALL of the shops simultaneously changed their install procedures and thus "caused" the failures by not checking installed height.
on the topic of installed height. Why would it be different car to car anyway? everyone buys the same cam kits. The only way to change the installed height would be to machine the spring seat in the head (which nobody's doing) or to use some kind of non-conventional retainer and lock setup.
I'm no expert, but I find it hard to believe that Comp manufactured the 918s (which are more or less for mild street combinations) in such a way that additional modifications would be required to achieve correct installed height.
06-05-2007, 11:51 PM
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I think someone should do a quick check and see how many of the springs were broken on cars with a Manual vs. Automatic Tranny. A missed shift would certainly cause a tremendous amount of stress on the springs. No Rev limiter would be able to protect the springs from an accidental high speed down shift.
As far as where the springs broke, it certainly looks like the springs broke at the narrow side of the beehive at the edge of the grind point. This is the highest stress point where the spring would exhibit maximum deflection. This point is coincidentally also where maximum heat buildup would occur during the grind process to put the flats on. Improper tempering / annealing could cause it to be more brittle at that junction.
The only way to know for certain is to do a hardness test and possibly a metalurgical analysis on the springs to determine if the spring force was in spec. Another possibility is to check the spring rate and see if it is excessive, therby indicating a poor heat treatment process.
This problem could point to either side. It would be nice to have Comp Cams provide the failure analysis info. Otherwise I could see it seriously impacting future sales of the 918's. I also have a new set of Comp Cams springs - Batch 049045
As far as where the springs broke, it certainly looks like the springs broke at the narrow side of the beehive at the edge of the grind point. This is the highest stress point where the spring would exhibit maximum deflection. This point is coincidentally also where maximum heat buildup would occur during the grind process to put the flats on. Improper tempering / annealing could cause it to be more brittle at that junction.
The only way to know for certain is to do a hardness test and possibly a metalurgical analysis on the springs to determine if the spring force was in spec. Another possibility is to check the spring rate and see if it is excessive, therby indicating a poor heat treatment process.
This problem could point to either side. It would be nice to have Comp Cams provide the failure analysis info. Otherwise I could see it seriously impacting future sales of the 918's. I also have a new set of Comp Cams springs - Batch 049045
06-06-2007, 01:05 AM
#58
Originally Posted by Vette_Crazy
I think someone should do a quick check and see how many of the springs were broken on cars with a Manual vs. Automatic Tranny. A missed shift would certainly cause a tremendous amount of stress on the springs. No Rev limiter would be able to protect the springs from an accidental high speed down shift.
As far as where the springs broke, it certainly looks like the springs broke at the narrow side of the beehive at the edge of the grind point. This is the highest stress point where the spring would exhibit maximum deflection. This point is coincidentally also where maximum heat buildup would occur during the grind process to put the flats on. Improper tempering / annealing could cause it to be more brittle at that junction.
The only way to know for certain is to do a hardness test and possibly a metalurgical analysis on the springs to determine if the spring force was in spec. Another possibility is to check the spring rate and see if it is excessive, therby indicating a poor heat treatment process.
This problem could point to either side. It would be nice to have Comp Cams provide the failure analysis info. Otherwise I could see it seriously impacting future sales of the 918's. I also have a new set of Comp Cams springs - Batch 049045
As far as where the springs broke, it certainly looks like the springs broke at the narrow side of the beehive at the edge of the grind point. This is the highest stress point where the spring would exhibit maximum deflection. This point is coincidentally also where maximum heat buildup would occur during the grind process to put the flats on. Improper tempering / annealing could cause it to be more brittle at that junction.
The only way to know for certain is to do a hardness test and possibly a metalurgical analysis on the springs to determine if the spring force was in spec. Another possibility is to check the spring rate and see if it is excessive, therby indicating a poor heat treatment process.
This problem could point to either side. It would be nice to have Comp Cams provide the failure analysis info. Otherwise I could see it seriously impacting future sales of the 918's. I also have a new set of Comp Cams springs - Batch 049045
I don't know about you guys, but I learned alot about springs going through all this. Its dual springs or nothing for me now unless the cam is small as my stock LS6. Why chance it?
BTW, I talked to the comp rep and he was more than willing to work with returning my springs and issue a credit if warranted. For some reason I got the idea they were not totally aware of how much a problem this is. I think they are handling it well and if I had to guess, you will see a change in the spring or no 918 in the future.
06-06-2007, 12:21 PM
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A cpl of days ago one of the Aussie LS1 forum members dropped a valve fitted with 918's and caused serious damage as a result. 918's had a good record up until now or is this just a case of coincidence .
cheers
cheers
06-06-2007, 04:32 PM
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Originally Posted by 03EBZ06
Chad,
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?
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?
I asked a question in order to find and answer for myself and others. Not to embarass you. No offense but I don't care enough about you to go through the motions to cause you shame.
Now that the emotions of this discussion have been addressed I will say that I did NOT inspect every set of COMP 918s I installed after months of use. According to my records I DID have the valve covers off five sets of them after installation and use. The times of inspection ran from 1 month (about 400miles) on the earliest set up to 6months (1,200 miles) on the last. I owned a shop and kept decent records concerning this activity.
Does that prove anything scientifically? No, but it does show that when installed properly and to spec that they will not always fail. I KNOW the installed heights were correct on every set I installed. I know that every cam they were installed with was within their limits. I KNOW that every set was broken in with what I consider an appropriate amount of heat and stresss cycles.
I assure that under any circumstances that I consider normal I would be VERY aware of one or two broken springs. Every GENIII engine I have ever done a cam install on was tested,double checked,and scanned before every being handed back to a customer. Most were also DYNOed. If you are fairly competent and looking for problems in the valvetrain you will find them.
I agree that anyone with concerns should inspect their springs. The time spent doing it is worth the piece of mind you will gain from seeing them with your own eyes.
Again, I never attempted to attack you. What I wanted was information in order to make to rule out the most common cause of failure in automotive parts: User Error. One of the basic rules of troubling shooting is look at the most obvious possibility first. THAT and only that is what I was doing.
Questions for anyone that has had a 918 break on them:
What were the installed heights on your springs?
How did you check this?
How many heat cycles did the springs see before going to "redline?"
How many times have the engine been "overrevved?"
What rockers are you using and what is their ratio?
What method was used to set preload?
What cam are you using?
I think these are important questions and answers to them can provide alot of information.