Broken Valve Spring
Comp Cams has admitted that their 918 valve springs have a quality issue, I have talked to them on the phone myself after breaking two springs. Now, dont get me wrong, I'm not bashing Comp Cams, its just that the earlier produced 918 are bad and need to be replaced. I am currently running the 921s.
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From: BFE
Originally Posted by Doc99SS
Comp Cams has admitted that their 918 valve springs have a quality issue, I have talked to them on the phone myself after breaking two springs. Now, dont get me wrong, I'm not bashing Comp Cams, its just that the earlier produced 918 are bad and need to be replaced. I am currently running the 921s.
Also something not touched so far are initial break-in heat cycles, and finaly that in any parts, there are some batches that have problems.
But as I mentionned, this is why 10K service is a must.
See problem is running heavy duals with too much pressures for a given cam is a power robbing scenario. I'm just not convinced about this single spring phobia. I'm also a big fan of light effective moving valvetrain mass.
I am currently running the PSI beehive spring setup that came with my Dart heads. I compared the weights to a dual setup I had siting around. The retainer was over two grams lighter, and this is a titanium to titanium comparison. The springs were about 20 grams lighter, and when you take into account how the beehive compresses and expands vs. a dual spring, these are actually quite large differences in accelerated mass.
There isn't much history on the PSI springs as compared to the Comp 918's as far as guys running them on the street and track, but I found it interesting that Katech did a bunch of spring tests and picked the PSI beehives for their LS7 heads.
There isn't much history on the PSI springs as compared to the Comp 918's as far as guys running them on the street and track, but I found it interesting that Katech did a bunch of spring tests and picked the PSI beehives for their LS7 heads.
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I had 23K miles on crane duals and the valve spring cracked....
Glad I had duals as it saved my ***...(didn't want to go with crane duals again though)
Now I have comp 921's in and its running well.
Considering the valve spring is a weak link in the ls motors...
Duals should be the way to go...
Which brand?
Patriotic golds are probably very good and cost effective..
Comp 921's have an excellent reputation and cost a bit more...
Dual valve springs are money well spent. (choose the brand you like etc)
Glad I had duals as it saved my ***...(didn't want to go with crane duals again though)
Now I have comp 921's in and its running well.
Considering the valve spring is a weak link in the ls motors...
Duals should be the way to go...
Which brand?
Patriotic golds are probably very good and cost effective..
Comp 921's have an excellent reputation and cost a bit more...
Dual valve springs are money well spent. (choose the brand you like etc)
Originally Posted by PREDATOR-Z
Those were the green stiped and that issue was over 2.5 years ago. Dead horse.
uhhh ive had my 918's in my car since 26k and i now have over 61k on em.....cam is a comp 224/224 .581,.581 112lsa...i havent even checked em but they car runs fine...PLUS I DO let the car warm and drive it easy until it reaches temp 2
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From: BFE
Originally Posted by gi8e7oi825
What about the ones with the blue stripe? I just broke two of those... and less than 3000 miles.
When I talked to Dart, they told me that the PSI springs in their heads are an upgraded version of the 918. According to them, there are only a couple of manufacturers of springs and that PSI supplies Comp with their springs.
Galen
Galen
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Originally Posted by mvvette97
same thing happend to me with the 918s. Half of mine broke at the retainers. We thought that maybe the retainers were too tight where they fit down in the spring. After that I used the stock retainers. Even then I didn't feel safe so now I have the Patriot Golds duals
I've got over 50,000 miles & 4 years on my 918s with the TR230 cam so yall are making me nervous with all the spring breaking info. I'm installing a new set of 918s when I get my car back. It has run fine this whole time with normal street driving. I havn't heard any ticking or anything strange from the engine but the car does feel slower from what i remember a few years back...could just be me though.
When I change out the springs, do yall suggest I pick up some extra locks or should the stock ones be fine forever?
When I change out the springs, do yall suggest I pick up some extra locks or should the stock ones be fine forever?
Originally Posted by PREDATOR-Z
Either wrong install, or cold start beating or just defective. Did you send them back to Comp for analysis?
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From: BFE
Well if Lingenfelter installed them, then you must be close by in a cold climate. Have you ever started the car and reved past 3K rpm before they got hot. Unless they were defective, I would almost bet that some incident like that happened, but only you would know.
Yeah it's cold here. It might have been revved past 3K. I read that you shouldn't go past 2K so I've always done my best to stay below that number. Most of the time when it's colde I let the car idle for 5-10 minutes 'cause the leather seats are too cold for my butt. I'll also add that I'm not the only one who drives my car... who knows. I'm probably going to send both heads back to Lingenfetler for replacement/repair. I almost don't care about the cause anymore, I just want some good heads back on my car.
02z 2 with 2 broke 918's My friend with an 02Z with a procharger (installed by us less than a month ago) has a 54-444-11 cam, with the 918s, and less than 200 miles on them, never got on it when cold, and dropped a valve tuesday, destroying a cylinder, when we pulled the valve covers off, there were 2 broke springs (seperate cylinders) toward the top, he's sending them to COMP tomorrow for a failure analysis. No install issues b/c they made it thru 10+ dyno runs.
Originally Posted by Doc99SS
Comp Cams has admitted that their 918 valve springs have a quality issue, I have talked to them on the phone myself after breaking two springs. Now, dont get me wrong, I'm not bashing Comp Cams, its just that the earlier produced 918 are bad and need to be replaced. I am currently running the 921s.
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From: Troy,MI.
Originally Posted by PREDATOR-Z
Well if Lingenfelter installed them, then you must be close by in a cold climate. Have you ever started the car and reved past 3K rpm before they got hot. Unless they were defective, I would almost bet that some incident like that happened, but only you would know.
