Who has the highest mileage so far with 918 springs? (cammed car)
07-30-2002, 02:48 PM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) I did my cam (.581/.588 lift) back in November. I'm guessing I've got around 13k-15k miles on 'em so far.
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07-30-2002, 02:48 PM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) Uhhh... I’m sure it’s not me, but I’ll put my .02 in. 1000 miles and yes I’m above .550 lift. I also have 772 retainers.
07-30-2002, 09:50 PM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) Be careful with these. I Just dropped a valve/lunched the engine (making a turn from a light, not racing!!!!!) on a recently completed 230/230 .591 112 setup. I'm waiting to hear from CompCams about this, but they seem reluctant to acknowledge the presence of a problem. Despite their hesitancy,several others on this forum have posted reports of valve spring breakage.
In light of reported problems with 941's and 918's, I'd be leary of high lift, fast ramp setups on single springs. Let the buyer beware, but it's an expensive lesson to learn. And CompCams doesn't seem to be in any hurry to stand behind their product.
<small>[ July 30, 2002, 09:53 PM: Message edited by: SPEED DOG ]</small>
In light of reported problems with 941's and 918's, I'd be leary of high lift, fast ramp setups on single springs. Let the buyer beware, but it's an expensive lesson to learn. And CompCams doesn't seem to be in any hurry to stand behind their product.
<small>[ July 30, 2002, 09:53 PM: Message edited by: SPEED DOG ]</small>
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07-30-2002, 10:48 PM
#8
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Re: Who has the highest mileage so far with 918 springs? (cammed car) I have about 6000 miles on my 918 springs, with .578" lift. As for dropping a valve, how do you know you just didnt snap a valve, most of the time at low speeds broken spring leads to bent valve head, and not much further damage.
07-31-2002, 09:09 PM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong>I have about 6000 miles on my 918 springs, with .578" lift. As for dropping a valve, how do you know you just didnt snap a valve, most of the time at low speeds broken spring leads to bent valve head, and not much further damage.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You're right, I don't. On the other hand, sudden failure at 6k rpms is more likely a spring, with subsequent valve/piston contact than much else. Remember, I was accelerating, though not totally at WOT close to it, from idle. I guess we'll never know for sure. Don't know why a valve, properly installed with ARE's guides, etc. etc. would "snap" as the initiating event. Seems that valve spring breakage would be more likely.
<strong>I have about 6000 miles on my 918 springs, with .578" lift. As for dropping a valve, how do you know you just didnt snap a valve, most of the time at low speeds broken spring leads to bent valve head, and not much further damage.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You're right, I don't. On the other hand, sudden failure at 6k rpms is more likely a spring, with subsequent valve/piston contact than much else. Remember, I was accelerating, though not totally at WOT close to it, from idle. I guess we'll never know for sure. Don't know why a valve, properly installed with ARE's guides, etc. etc. would "snap" as the initiating event. Seems that valve spring breakage would be more likely.
07-31-2002, 09:12 PM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) I wasnt trying to be wise, i just am trying to preserve 918 reputation in case it wasnt the fault of spring, did retainer and keepers stay in tact?
08-01-2002, 07:29 AM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong>I wasnt trying to be wise, i just am trying to preserve 918 reputation in case it wasnt the fault of spring, did retainer and keepers stay in tact?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes, the retainer and keeper were intact. I didn't think you were being wise, just wanted to post our view.
We build a lot of NASCAR engines as well as engines for GT1 and GT class racers. We're beginning to think there may be a harmonic on these heads, particularly with fast rate higher lift cams that put single spring setups in jeophardy. I had raised that subject with Nick before this last build, but he felt that he could port the LS6 head more aggressively with single rather than double springs, so we went with that. The output we got from the new work was terrific (see sig) and we were very pleased. The downside, of course, is what I've just experienced.
I'm rebuilding as a big block, with top drawer everything (don't want to do this again). I plan to use a double spring set, as well as double roller timing assembly, and so forth. By the way, ARE's racing oil pump seems first rate, and will go on this as well: 65+psi at all conditions off idle, with no pressure fluctations at all (vs. calibrated gauge).
<strong>I wasnt trying to be wise, i just am trying to preserve 918 reputation in case it wasnt the fault of spring, did retainer and keepers stay in tact?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Yes, the retainer and keeper were intact. I didn't think you were being wise, just wanted to post our view.
We build a lot of NASCAR engines as well as engines for GT1 and GT class racers. We're beginning to think there may be a harmonic on these heads, particularly with fast rate higher lift cams that put single spring setups in jeophardy. I had raised that subject with Nick before this last build, but he felt that he could port the LS6 head more aggressively with single rather than double springs, so we went with that. The output we got from the new work was terrific (see sig) and we were very pleased. The downside, of course, is what I've just experienced.
I'm rebuilding as a big block, with top drawer everything (don't want to do this again). I plan to use a double spring set, as well as double roller timing assembly, and so forth. By the way, ARE's racing oil pump seems first rate, and will go on this as well: 65+psi at all conditions off idle, with no pressure fluctations at all (vs. calibrated gauge).
08-01-2002, 07:53 AM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) Speeddog....at what mileage on the spring did this occur? You may very well be right on the single spring issue but Comp does state that the 918 is good up to .600 lift and you were pretty much right there. In the instances of failure on these, I wonder if the majority of the the few were all running close to .600 lift. Did you heat cycle the springs before you got on it?
08-01-2002, 09:34 PM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by StevieZ:
<strong>Speeddog....at what mileage on the spring did this occur? You may very well be right on the single spring issue but Comp does state that the 918 is good up to .600 lift and you were pretty much right there. In the instances of failure on these, I wonder if the majority of the the few were all running close to .600 lift. Did you heat cycle the springs before you got on it?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Hi Stevie: I had a couple of hundred miles on the car, with multiple warm up/cool downs. In addition, I wasn't "hammering" the car, simply accelerating forcefully through a light. Finally, we had done a couple of careful dyno runs to get A/F measurements fairly well along in the process, and hadn't any inkling of a problem.
I don't know how many of the breakages were on high lift setups. That would, indeed be interesting to know. Mine is as stated: a pretty stout package for the street, but nothing horribly radical.
The real question is whether these heads, fast rate, fairly high lift cams, and so forth, are a vulnerable package. If so, those of us running them are paying a price to find out. Seems to me CompCams should be asking this question as well, and standing behind their products: something they seem reluctant to do. While breaking things is part of the high performance world, I do think there should be some amount of responsibility from the folks who provide the hardware.
As a side comment, ARE is/has been first rate about this (so far) and is standing with me all the way. My engine is on its way to Toronto for a rebuild as a big block. This is not what I had planned for now, but I'm going to make the best of a bad situation.
<strong>Speeddog....at what mileage on the spring did this occur? You may very well be right on the single spring issue but Comp does state that the 918 is good up to .600 lift and you were pretty much right there. In the instances of failure on these, I wonder if the majority of the the few were all running close to .600 lift. Did you heat cycle the springs before you got on it?</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Hi Stevie: I had a couple of hundred miles on the car, with multiple warm up/cool downs. In addition, I wasn't "hammering" the car, simply accelerating forcefully through a light. Finally, we had done a couple of careful dyno runs to get A/F measurements fairly well along in the process, and hadn't any inkling of a problem.
I don't know how many of the breakages were on high lift setups. That would, indeed be interesting to know. Mine is as stated: a pretty stout package for the street, but nothing horribly radical.
The real question is whether these heads, fast rate, fairly high lift cams, and so forth, are a vulnerable package. If so, those of us running them are paying a price to find out. Seems to me CompCams should be asking this question as well, and standing behind their products: something they seem reluctant to do. While breaking things is part of the high performance world, I do think there should be some amount of responsibility from the folks who provide the hardware.
As a side comment, ARE is/has been first rate about this (so far) and is standing with me all the way. My engine is on its way to Toronto for a rebuild as a big block. This is not what I had planned for now, but I'm going to make the best of a bad situation.
08-02-2002, 05:40 AM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) Speed dog, your idea about damaging harmonics is a good one but Comp. has the equipment to test for this and can build spring wire that experiences this harmonic in a range that spring usually doesnt spend much time. Im sure i am not teaching you anything here on this topic, but comp also makes pushrods designed to dampen these vibes. Maybe a belt drive should be developed for LS1 also. I like single spring but maybe damper needs to be incorporated into it, doubles add much weight and will wear guides more rapidly.8mm stems are a poormans titanium and we need to make this light factory designed stuff work out in my opinion.
08-02-2002, 07:39 AM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong>Speed dog, your idea about damaging harmonics is a good one but Comp. has the equipment to test for this and can build spring wire that experiences this harmonic in a range that spring usually doesnt spend much time. Im sure i am not teaching you anything here on this topic, but comp also makes pushrods designed to dampen these vibes. Maybe a belt drive should be developed for LS1 also. I like single spring but maybe damper needs to be incorporated into it, doubles add much weight and will wear guides more rapidly.8mm stems are a poormans titanium and we need to make this light factory designed stuff work out in my opinion.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks for the reply. I do know this, but wonder if they've missed something. On my setup, at least, we installed push rods matched to the head's milled height and the cam's base circle, and which were supposedly antiharmonic. Failed nevertheless.
I also realize that occasional failures may simply reflect the variances that occur in any system. Anecdotal experience does not predict class effects. Unfortunately, when one is the victim of one of these "anecdotes" the subsequent cash hemorrhage is pretty depressing.
I always wonder if manufacturers read these forums. It would be nice if they did and could reply. It would also be nice if they had a sense of what's going on in the enthusiast community. Perhaps that would improve their commitment to customer relations, which could only enhance their business in the long run. Since most of these posts are met with deafening silence from all but the members, I guess they don't or fear posting from a liability standpoint.
<small>[ August 02, 2002, 07:43 AM: Message edited by: SPEED DOG ]</small>
<strong>Speed dog, your idea about damaging harmonics is a good one but Comp. has the equipment to test for this and can build spring wire that experiences this harmonic in a range that spring usually doesnt spend much time. Im sure i am not teaching you anything here on this topic, but comp also makes pushrods designed to dampen these vibes. Maybe a belt drive should be developed for LS1 also. I like single spring but maybe damper needs to be incorporated into it, doubles add much weight and will wear guides more rapidly.8mm stems are a poormans titanium and we need to make this light factory designed stuff work out in my opinion.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Thanks for the reply. I do know this, but wonder if they've missed something. On my setup, at least, we installed push rods matched to the head's milled height and the cam's base circle, and which were supposedly antiharmonic. Failed nevertheless.
I also realize that occasional failures may simply reflect the variances that occur in any system. Anecdotal experience does not predict class effects. Unfortunately, when one is the victim of one of these "anecdotes" the subsequent cash hemorrhage is pretty depressing.
I always wonder if manufacturers read these forums. It would be nice if they did and could reply. It would also be nice if they had a sense of what's going on in the enthusiast community. Perhaps that would improve their commitment to customer relations, which could only enhance their business in the long run. Since most of these posts are met with deafening silence from all but the members, I guess they don't or fear posting from a liability standpoint.
<small>[ August 02, 2002, 07:43 AM: Message edited by: SPEED DOG ]</small>
08-02-2002, 08:20 PM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) Have you ever considered Cryogenics for strengthening springs? I have used this for other engine components with amazing results, doesnt excuse COmp from wrong doing but i believe you may have had a "Bad Batch" spring that let go on you. Comp components are cheap in price in comparison to brands like Crower and Isky, i think this random part failure may have to do with where Comp saves money, allowing for better pricing.Quality control is the worst place to cut corners but it happens.
08-02-2002, 10:53 PM
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Re: Who has the highest mileage so far with 918 springs? (cammed car) </font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by LS1derfull:
<strong>Have you ever considered Cryogenics for strengthening springs? I have used this for other engine components with amazing results, doesnt excuse COmp from wrong doing but i believe you may have had a "Bad Batch" spring that let go on you. Comp components are cheap in price in comparison to brands like Crower and Isky, i think this random part failure may have to do with where Comp saves money, allowing for better pricing.Quality control is the worst place to cut corners but it happens.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Hadn't considered it, but wish I had. At this point, I'm about rebuilding a trashed setup. Hopefully, others will think about all this, and make decisions accordingly. Might save them money in the long run.
<strong>Have you ever considered Cryogenics for strengthening springs? I have used this for other engine components with amazing results, doesnt excuse COmp from wrong doing but i believe you may have had a "Bad Batch" spring that let go on you. Comp components are cheap in price in comparison to brands like Crower and Isky, i think this random part failure may have to do with where Comp saves money, allowing for better pricing.Quality control is the worst place to cut corners but it happens.</strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Hadn't considered it, but wish I had. At this point, I'm about rebuilding a trashed setup. Hopefully, others will think about all this, and make decisions accordingly. Might save them money in the long run.
