Worn down cam
 

Hi folks,

I pulled off my valve cover to change the valve guide seals tonight and found two lobes on my cam worn to nubbs. I've got a '87 300e and I'll be looking for a cam and at least a couple rocker arms.

Does anyone have any idea why this may have happened? I ran a compression test right before taking the motor apart and they ran from 162 psi to 175 psi. The motor has very good oil pressure.

I'm trying to decide whether to replace the whole head vs just the cam and the damaged rockers. Any opinions?

Thanks!!

Bob Kopicki
Massillon OH

A worn cam has no impact on compression readings or oil pressure.
I has to replace the cam and 3 rocker arms when I did a valve job at around 250K.
Lubrication failure? defective material?.
I don't know why, but I've seen this problem reported at a few occasions on the 103 engine.
The cam is about $450. , rocker arms, about $45. ea

it would be neglect of the oil changes somewhere along the line i believe.

actually a very worn cam can affect the compression test. if the cam doesnt hold the valve open long enough it can prevent the cylinder from drawing a full cylinder of air, thus giving a false low reading. false in the sense that the valves and rings may be fine.

tom w

It appears that some crud got into the oil line that sprays oil onto the cam lobes. The holes that supply oil to the lobes are tiny and it seems that sludge can build up in the supply line that runs above the rockers and cam. That said, I feel pretty comfortable replacing the cam and the rockers and leaving the head where it is.
Bob

i would in that case replace the oilers for the cam or if they are metal at least clean them out thoroughly.

i might be tempted to drop the lower oil pan to check for sludge there too.

tom w