Cam Damage! - PICS
Feb 16, 2009, 07:52 PM
#1
Cam Damage! - PICS
UPDATE - Mar 9 2009 Click here!
So yesterday i noticed a ticking had developed that sounded like valvetrain issues, so I pulled the cover off today to see what was up and here is what i found:
Has anybody had experience with this type of damage before? It looks to me like the down slope of the lobe has been smashed repeatedly like valve float. Several of the lobes on the intake sides showed signs of severe beatings. But springs and retainers were upgraded when these GSC 272s where installed and I've never had it above 7000rpm???
Any insight into what could cause such damage? How to prevent it from happening again? And what cams (for street driven/occasional roadcourse) I should go with to replace them?
Clarification: My cams are NOT GSC S2's they are old GSC 272's from 2005, probably some of the first sets that GSC released for the 4g63. The S2's are being made by a new manufacturer so this particular failure should not be tied to the S2's, only the old original GSC 272's.
So yesterday i noticed a ticking had developed that sounded like valvetrain issues, so I pulled the cover off today to see what was up and here is what i found:
Has anybody had experience with this type of damage before? It looks to me like the down slope of the lobe has been smashed repeatedly like valve float. Several of the lobes on the intake sides showed signs of severe beatings. But springs and retainers were upgraded when these GSC 272s where installed and I've never had it above 7000rpm???
Any insight into what could cause such damage? How to prevent it from happening again? And what cams (for street driven/occasional roadcourse) I should go with to replace them?
Clarification: My cams are NOT GSC S2's they are old GSC 272's from 2005, probably some of the first sets that GSC released for the 4g63. The S2's are being made by a new manufacturer so this particular failure should not be tied to the S2's, only the old original GSC 272's.
Last edited by ktk; Mar 8, 2009 at 10:29 PM.
Feb 16, 2009, 07:57 PM
#3
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bummer!!!!!!!! i have the same cams.... i guess i know what i'll be doing on my day off weds... i'll let you know what i find cause i also have some tick
Feb 16, 2009, 08:45 PM
#6
Actually, it looks as though the follower remained compressed for an instant as the nose of the lobe rolled past it, and then slammed down on the closing ramp, revolution after revolution. It looks as though it isn't isolated to just one cam lobe either. If the metallurgy were at fault, I would expect to see an abnormal wear pattern all the way around the lobe.
If this is the case, it indicates that something may be sticking in the valvetrain, which prevents the follower from accurately tracking the lobe. I wouldn't expect to see valve float with upgraded springs, but when one gets valve float, the same type of situation occurs.
If this is the case, it indicates that something may be sticking in the valvetrain, which prevents the follower from accurately tracking the lobe. I wouldn't expect to see valve float with upgraded springs, but when one gets valve float, the same type of situation occurs.
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Feb 17, 2009, 12:51 AM
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Damn!? I used to work in a machine shop that delt with parts with hardened surface treatments. The metal was so hard that when they were hit just right, the surface would break off like just that. That would definately go with Ted B's theory too.
Feb 17, 2009, 04:47 AM
#11
Actually, it looks as though the follower remained compressed for an instant as the nose of the lobe rolled past it, and then slammed down on the closing ramp, revolution after revolution. It looks as though it isn't isolated to just one cam lobe either. If the metallurgy were at fault, I would expect to see an abnormal wear pattern all the way around the lobe.
If this is the case, it indicates that something may be sticking in the valvetrain, which prevents the follower from accurately tracking the lobe. I wouldn't expect to see valve float with upgraded springs, but when one gets valve float, the same type of situation occurs.
If this is the case, it indicates that something may be sticking in the valvetrain, which prevents the follower from accurately tracking the lobe. I wouldn't expect to see valve float with upgraded springs, but when one gets valve float, the same type of situation occurs.
Feb 17, 2009, 06:56 AM
#12
From what I see, I am still thinking TedB's explanation seems to make sense. It definitely looks like the closing edge of the lobes have been beaten on, like float. I hadn't thought of it but perhaps sticking could have been the issue too...I'm not sure how to tell.
I didn't do the valvetrain build, it was done by the great peeps at JAM.
There is no way it was a loose bolt or anything like that the cams have been in the car for 38k miles. I checked the torque on all the cam bearing caps to see if they were loose or something, but they were fine...
It may just be a repetitive stress failure. Too much beatings over time...
I didn't do the valvetrain build, it was done by the great peeps at JAM.
There is no way it was a loose bolt or anything like that the cams have been in the car for 38k miles. I checked the torque on all the cam bearing caps to see if they were loose or something, but they were fine...It may just be a repetitive stress failure. Too much beatings over time...
Feb 17, 2009, 07:05 AM
#13
I would go with TedB's response and link the problem with something external to the cam itself. I have over 55,000 miles on my 272 intake cam but the rest of the valvetrain is stock. Cams were out a year ago when I serviced the lash adjusters and showed no abnormal wear.
Feb 17, 2009, 07:14 AM
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I've not seen lobe pitting and damage like that since the mid-70's on motorcycle cams. Definitely incorrect metallurgy. Replace the cams and followers.
It's probably also a good idea to disassemble and clean the engine to get all the assirted pieces out of the internal passages.
It's probably also a good idea to disassemble and clean the engine to get all the assirted pieces out of the internal passages.
