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Cam walked backwards, how?

Old 03-26-2004, 03:48 PM
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Default Cam walked backwards, how?

I think we have solved my cam sensor problem. After pulling the plate that the knock sensors are in we were able to see that the cam had indeed walked, but not forward like everyone thought, it moved backward. Part of the roller lifters aren't ever touching the lobes! I know the cam plate keeps it from walking forward but what went wrong for it to slide back 1/4"? It wasn't making any noise from the front of the engine like I would imagine it doing if the timing gear were rubbing so what gives??
Old 03-26-2004, 04:32 PM
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The cam plate should keep it from walking fore or aft. Never heard of a cam sliding out the backdoor, especially not a 1/4 in!
Old 03-26-2004, 05:44 PM
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Anyone??
Old 03-26-2004, 05:53 PM
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http://www.iskycams.com/pdfcatalog/PAGE178.pdf

might help?
Dan
Old 03-26-2004, 05:54 PM
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Originally Posted by Steve98Z
Anyone??
dude. pull your front cover and check your timeing cam sproket! sound like your bolts on the sproket are backing out. thats what keeps the cam from going back
Old 03-26-2004, 06:20 PM
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This happened to GoFasTA but the bolts fell out and the cam walked inside and destroyed his motor.
Old 03-26-2004, 06:22 PM
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Originally Posted by BLUEBALLS ZZ
dude. pull your front cover and check your timeing cam sproket! sound like your bolts on the sproket are backing out. thats what keeps the cam from going back
Yeah I'd pull the front timing chain cover, you have to anyway.
Old 03-26-2004, 06:26 PM
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Yep, my bolts didn't come completely out, but they had loosened up enough to allow the cam to walk backwards. There was enough play that the dowel pin (index pin) on the cam was knocked out and ended up as a chewed up chunk of metal in my oil pan. The cam walking was enough to get a lifter jammed in the lifter bore. Block was toast.

Not sure what might have caused yours, if this is indeed what happened. In my case, I used an online install guide that listed the torque spec for those bolts at 18 ft-lbs, instead of the correct 26 ft-lbs. That was 3 years ago and I'm not even sure that guide is still around.
Old 03-26-2004, 06:30 PM
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Originally Posted by Go FasTA
Yep, my bolts didn't come completely out, but they had loosened up enough to allow the cam to walk backwards. There was enough play that the dowel pin (index pin) on the cam was knocked out and ended up as a chewed up chunk of metal in my oil pan. The cam walking was enough to get a lifter jammed in the lifter bore. Block was toast.

Not sure what might have caused yours, if this is indeed what happened. In my case, I used an online install guide that listed the torque spec for those bolts at 18 ft-lbs, instead of the correct 26 ft-lbs. That was 3 years ago and I'm not even sure that guide is still around.
Thanks for clarifying, Andy.

That was on ordeal
Old 03-26-2004, 06:31 PM
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Originally Posted by CANNIBAL
Thanks for clarifying, Andy.

That was on ordeal
Yeah, and not one that I ever want to live again.


I also had codes thrown that indicated a problem with my cam position sensor during my ordeal. I actually bought a new sensor and it didn't solve my problems (obviously).
Old 03-26-2004, 06:34 PM
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Originally Posted by Go FasTA
Yep, my bolts didn't come completely out, but they had loosened up enough to allow the cam to walk backwards. There was enough play that the dowel pin (index pin) on the cam was knocked out and ended up as a chewed up chunk of metal in my oil pan. The cam walking was enough to get a lifter jammed in the lifter bore. Block was toast.

Not sure what might have caused yours, if this is indeed what happened. In my case, I used an online install guide that listed the torque spec for those bolts at 18 ft-lbs, instead of the correct 26 ft-lbs. That was 3 years ago and I'm not even sure that guide is still around.
Torqued mine to 20lb and didn't use locktight This is surely the problem, looks like I will be gettin' dirty again, at least this will give me an excuse to put the Pete Jackson gear drive on it......
Old 03-26-2004, 06:37 PM
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Yeesh. Sorry to hear that Steve. I know the pain all too well. I just hope for your sake that the damage is limited to the cam and lifters with no damage to the block.

Also, please double check that torque spec before you reinstall. The 26 ft-lbs. is off the top of my head, and it's been a year or more since I last participated in a cam install.
Old 03-26-2004, 06:49 PM
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Originally Posted by Go FasTA
Yeesh. Sorry to hear that Steve. I know the pain all too well. I just hope for your sake that the damage is limited to the cam and lifters with no damage to the block.

Also, please double check that torque spec before you reinstall. The 26 ft-lbs. is off the top of my head, and it's been a year or more since I last participated in a cam install.
Luckily there was no damage, I was having cam position sensor codes and replaced the sensor, had the wiring and PCM checked and everything was good. We could not figure out why the cam sensor was not picking up a signal from the reluctor ring so we pulled the cover where the knock sensors are, and it was obvious the cam had walked back that is why the sensor couldn't pick up a signal. If would had listened to the GM tech and repalced the PCM or simply ignored the problem there is no doubt I would have ended up in your shoes.
Old 03-26-2004, 07:31 PM
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Steve, you can add moonwalking 3/4 cam to your cool sig now
Old 03-27-2004, 12:16 AM
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Andy..do you know of anywhere you can get a cam at a good price?

inside thing guys


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