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Evening

Removed my intake camshaft to sort out the variator and discovered the first intake lobe is gone (as per the photo). The lobe is almost completely round.

This is one of the oddest failures of a camshaft i've ever seen, if the valve was seized I would expect the belt to snap before the lobe would wear away. My thoughts are this is a faulty cam that was either always like this or that lobe missed a hardening process.

Has anyone seen this before on a twinspark engine?

936547
 

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Not on a TS but have heard of it. Seen similar on our Lycoming O-320 and more lobes almost gone. Engine was still running! Once the case hardening wears through the underlying metal wears away very quickly. We had to have the engine overhauled including new camshaft, of course, new bearings and new oil cooler and pipes. Etc. Bill came to £10 000.
 

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Cheers for the reply

What I find so odd is that it's just one lobe, all the others are in good condition and the exhaust shaft is fine.

I'll probably just end up changing the camshaft and checking the oil pump catch filters.
 

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Not on a TS but have heard of it. Seen similar on our Lycoming O-320 and more lobes almost gone. Engine was still running! Once the case hardening wears through the underlying metal wears away very quickly. We had to have the engine overhauled including new camshaft, of course, new bearings and new oil cooler and pipes. Etc. Bill came to £10 000.
Not uncommon on a Lycoming. Camshaft is at the top and tends to suffer from oil starvation. Lycoming used to recommend a special additive back in the days when I ran lycomings.
 

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Yes you will have metal particles right through your motor. Not heard of it on a TS motor but I had a camshaft follower bucket crack on an early 2 litre Alfa engine (chain drive) once which would have worn the camshaft except i picked it early because of the strange clacking sound it was making. Never seen that one before or since.
 
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