Would a main dealer recognise cam wear?

[groucho]

I have just been in my garage warming up my Griff and I heard a tapping noise. Actually it has always had this tapping noise since I've had it, but has got no worse in 14 months.
You can't hear anything whilst you rev the engine, but as the revs drop to about 1500 you can hear a tapping sound somewhere in the engine, quite hard to pin down the exact location. I have read threads about cam walk and other camshaft horrors, but it maybe that I am over paranoid as the confinement of the garage may accentuate the noise.
The car has done 16000 miles, of which I have done 6000 and had a 12000 mile service last month at a reputable TVR garage.
Getting back to the title of my thread, if there was a problem with my cam, wouldn't they have picked it up in the service? They said that the car flew through the service with no problems whatsoever, which they said was rare.
Since then I had one of their mechanics under the bonnet insulating my air intake and he was playing with it for a while.
I have had no trouble with the car and it goes like a dream (I hate saying that, it's the only thing I'm superstitious about).
Am I being paranoid or is there room for worry?

Grouch.

>>> Edited by groucho on Thursday 19th August 17:27

[Guillotine]

couple of guys on here have had this.they found the pre-load wrong on the cam/tappets.

shouldn't cause any serious wear.

easy to set, cheap to do.

symton is ok at idle/rev but as revs come down at about 2500, a slight tap is heard from the centr front of engine.

get it check but that'd be my bet.

[groucho]

Guillotine said:

symton is ok at idle/rev but as revs come down at about 2500, a slight tap is heard from the centr front of engine.

Thanks Guillotine I would say that is a fair description of the symptons. The noise is quite faint.

Grouch.

[stesrg]

No a dealer would not reconise cam wear, as when i 1st brought my car the engine was quite, no ticking or other unusual noises however when i took out the cam 3 lobes were completly worn out this had not happened recently lookes like a few years of wear.

[2 sheds]

Cams can wear very quickly, in a few hundred miles once you've pierced the case hardening.

[gruff500]

Not sure if this helps but I had the exact same problem on one of my banks - nothing at revs but at idle a tapping noise. The garage checked the camshaft and lifters but they were fine - it actually turned out to be one of the rocker arms, where one of the arm covers had completely worn out. Replaced all rocker arms as the engine had been taken apart anyway - hey presto purrs like a kitten!

Worth a look anyway...