Cam wear? Engine was knocking.
11-28-2010, 08:31 PM
#1
Cam wear? Engine was knocking.
My engine was knocking at half the engine RPMs so I pulled the cam out and it is pretty beat up. Is this normal wear for a ~75k cam?
Most of the lobes looked like this
The worst one looked like this, the fourth from the back of the cam
The second worst one looked like this, the second one from the front
It started out slow and kind of loud like this one morning.
http://www.youtube.com/watch?v=DiZwsrWKHoc
The next day it got this much faster and louder.
http://www.youtube.com/watch?v=7hSWcpxP3jo
Now I have it torn apart. I pushed on each pushrod as I spun the cam and I didn't feel anything like a broken lifter. I plan to pull the heads next weekend and inspect them. Could the one badly worn lobe have caused this sound? Has anyone else heard a sound like this? Thanks for any ideas.
Most of the lobes looked like this
The worst one looked like this, the fourth from the back of the cam
The second worst one looked like this, the second one from the front
It started out slow and kind of loud like this one morning.
http://www.youtube.com/watch?v=DiZwsrWKHoc
The next day it got this much faster and louder.
http://www.youtube.com/watch?v=7hSWcpxP3jo
Now I have it torn apart. I pushed on each pushrod as I spun the cam and I didn't feel anything like a broken lifter. I plan to pull the heads next weekend and inspect them. Could the one badly worn lobe have caused this sound? Has anyone else heard a sound like this? Thanks for any ideas.
Last edited by CashDudeHomie; 11-28-2010 at 08:45 PM.
11-28-2010, 08:42 PM
#2
Is that a comp cam?
I bought a tr220 cam who comp builds for thunder racing that looked similar to that ...surprise look what junk someone sold me!
Sent it to comp said it was one from a bad batch of cams that the hardening procedure did not work correctly
Was given a new cam for the cost of shipping
Basically it was a soft cam and the metal would flake/peel off on the top of the lobe
I bought a tr220 cam who comp builds for thunder racing that looked similar to that ...surprise look what junk someone sold me!
Sent it to comp said it was one from a bad batch of cams that the hardening procedure did not work correctly
Was given a new cam for the cost of shipping
Basically it was a soft cam and the metal would flake/peel off on the top of the lobe
11-28-2010, 09:01 PM
#6
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New cam or a regrind??? Lifters are trashed.. I would def not reuse them... Just to say no def not normal.. There will be more damage to the top of the lobe, as it is where the most force is being presented to it during the valve opening..
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11-28-2010, 09:18 PM
#10
Does anyone have any comment on the last video? It doesn't sound like rod knock does it?
It is half the engine RPM, so I assumed it was valve train related.
EDIT: forgot to mention, the left dowel rod slid in easily, but the right one kept hanging up on the fourth lifter, even though it was being held up by the tray. I eventually got it in. Not sure if that means anything. The corresponding lobe is not one of the severely damaged ones.
It is half the engine RPM, so I assumed it was valve train related.
EDIT: forgot to mention, the left dowel rod slid in easily, but the right one kept hanging up on the fourth lifter, even though it was being held up by the tray. I eventually got it in. Not sure if that means anything. The corresponding lobe is not one of the severely damaged ones.