This afternoon, I have taken off the cam cover on my poor old 500 SL I am trying to find what was making the tapping noise back in 1993 before she was laid up.
All previous work was done in a workshop under artificial lighting, so I am blaming this fact for missing the evidence of a camshaft repair that has been carried out at some time, on the third lobe in from the right, there is a line across the base of the lobe on both sides that looks like a very fine, straight crack, which corresponds with a slight change in colour at both sides, it looks like the lobe has been ground off and another one stuck on, to be fair, it looks good, with a good surface, and it does not look scuffed and worn.
This corresponds with the cam follower, third one from the right, having a scuffed and scored appearance with a slight groove across it, I am sure all looked good when I put it together in 1992, I am assuming this is the culprit, but what has happened? has the lines across the cam 'planed' off the surface of the follower?
Parts needed - 1 cam follower, and three of the weird 'o'ring diaphragms that cover the cylinder head bolt holes.
Possibly a good camshaft.
OR a good sei engine !!!!
Hi, it's possible the worn camshaft has been repaired in the past by metal spraying and re-grinding. The slight difference in colour would be due to a slight difference in the colour of the sprayed steel.and what appears to be a crack is just the joint of the two metals.
I haven't had any experience of this method of repairing camshafts but it might be worth looking into to repair the other damaged lobe(s)