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.

 

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

 

id pull the lifters too buddy...that doesnt look good.

 

if it was a lifter problem the whole lobe would be trashed not just the top off the lobe

 

I'd throw the lifters in the trash and start fresh. Not worth wiping out a new cam after having the lifters run on that surface.

 

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..

 

It may be an old school practice thats out of date with modern rollers, but always replace the lifters with a new cam...

 

Grey, that's the same part# cam!! Just my luck.


But does it look like this have been causing the knocking sound? Maybe this damage caused a chip in one of the lifter rollers or something?

 

Ive come across three grooved cams from comp like that. One I installed in a buddy's SSS a few yaers abck and after 40K(i think) the lobe was grooved real bad. His didnt make any sound though, we were putting in a bigger cam.

 

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.