Is this camshaft done or still kind of ok??

[votan]

I'm right now checking all the top end things and found two cam lobes of the intake side being scratched. All others look fine and valve clearance is ok on those valves, too.
Can I still drive with this camshaft for a while is or is a top end rebuilt needed right away?

[1point7bar]

Has it worn through the nitride?

(Nitride is a treatment to harden the surface and reduce wear).

Worn cam lobes lift the valve less. You most likely realise this has an effect on power output.

[votan]

Seems to be not fully worn through yet.... and lift also still seems to be ok.
Surface is only damaged directly where the scratches are.. surrounding area is still nice an clean.
Would that mean, it's still kind of 'ok' to drive?
Just am affraid of an unexpected engine failure...

Edited by votan on Tuesday 24th July 21:11

[1point7bar]

The lobe is just less hardened on the surface.
I have run cams with the nitride completely gone from the nose of the lobe.
It did not cause any problems.

[votan]

Thanks, that is good news!

[nrick]

The original camshafts were composite cams, individual cams on a separate shaft. That cam looks like a chilled iron later camshaft, a single one piece cast iron where the outer skin of the camshafts is rapidly cooled through the use of chills (inserts in the mould). These cams are much better at reducing wear and most camshafts are made this way, we did use to make up to 7000 camshafts every 8 hours where I did work.

To answer the question this shaft has been damaged/scratched at some stage, it might have been recently or quite a while ago (even when fitted). It is not perfect but if the defect is not deep or the whole width of the follower then it should be ok for a while. Best thing is to keep an eye on it, if it gets worse then you'll need to change it. It could start to break up, and that would be terminal.........

[tuscanturner]

I have a cam (no 7) lobe which looks just like that! Ive known about it for the last three years now and it hasn't changed much in the last 10,000 miles. Engine has nearly 40,000 on it now so I'm saving up for a rebuild just in case

[MPETT]

Personally idcheck the finger followers contact patches for wear to be on the safe side. I think you can do this without removing the cam. They slide sideways if I recall.

See my video:
http://www.youtube.com/watch?v=sYt7aRXGZag&fea...

Cheers,

Martin

[votan]

Thanks nrick and tuscanturner! This makes me feel much safer.

I'll also take another look at the finger folower.... but looked fine on first impression.

[nrick]

Can you post a picture of the follower, it is important to know if it is damaged.

[votan]

I will try to take a pic tomorrow. Weather is way to hot right now to even think on working on the engine!