broken cam bolts
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Teching In
Joined: Jun 2006
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From: Austin
broken cam bolts During a recent road race track event, I lost compression/engine during a 4th gear pull. I removed the heads to find 16 bent valves, ok, broken timing chain. After pulling the timing cover, I found I had sheared the cam bolts between the gear and the cam. I know of others who have done the same, ironically, we all share the ASP underdrive pulley. I'm going to replace the damper with a ATI unit. Is there any other recommendations to overcome this problem?
Originally Posted by pm supra
During a recent road race track event, I lost compression/engine during a 4th gear pull. I removed the heads to find 16 bent valves, ok, broken timing chain. After pulling the timing cover, I found I had sheared the cam bolts between the gear and the cam. I know of others who have done the same, ironically, we all share the ASP underdrive pulley. I'm going to replace the damper with a ATI unit. Is there any other recommendations to overcome this problem?
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From: Austin
Originally Posted by Mike94ZLT1
Honestly I don't see how an underdrive pulley could have anything to do with shearing cam bolts?! 
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From: Austin
My Z06 has about 12K on the odometer and 10K on the H/C. It is tracked for 20-30 minutes at a time at four times a day. I have only tracked it for about the last 2K of the 12k miles, that includes mainly street driving. I know street and drag racing quite well, road racing by far the most abuse a engine could ever endure.
There are some really good articles on the ATI web site about harmonics and their adverse affects. When I bought my ATI at Carlisle a couple of years ago, the guy that was there told me they couldn't get a 25% under drive to provide proper harmonic control and that is why they were only 10% under. Not sure if this is coincidence or not with the other cam bolt failure, but it is interesting. ATI also has a tech line, you could ask them the question.
