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Piper vernier pully wear


tiddy1

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I have just been checking the cam timing on my k-series and note that the vernier pullys have worn considerably under the cam belt, i.e the anodising has been totally worn away, the tooth profile is still very good and there seems to be no chance of the belt jumping but I was wondering if this is normal.

 

I believe there are two types of piper vernier, one with harder black anodising on the tooth profiles but the ones I have are red all over.

 

the engine is running a 285H cam and has probably done 15K since the verniers were fitted.

 

Simon

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I'm not saying such a thing doesn't exist, but I can find no references to Hard anaodising in my technical books. It does mention that in and of itself, anodising is a hard coating because the aluminium oxide film that is formed in the process is a ceramic.

 

Maybe Hard anodising is a thicker coat - they leave it in the bath longer????

 

Well, here we go - slight differences in the process can give varying ultimate hardness here

 

BRG Brooklands SV 😬 It seems that perfection is achieved not when there is nothing more to add, but when there is nothing more to take away. (Antoine de Saint-Exupery)

 

Edited by - Tony C on 31 Jan 2007 11:38:57

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There is considerable difference between decorative anodising ( i.e the red coat) and 'hard anodising' used as a wear resistant coat, but hard anodising is a generic term. we use a lot of hard anodised components in the aerospace industry for things like piston and sleeves

 

SImon

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Yep Stu, the hard ones are gunmetal grey ( as Jacko says they are the Rally spec)

 

Running with the correct Timing belt profile and tension also greatly reduces wear. Piper has supplied me with all sorts of Timing belts for the K some with square teeth, grooved teeth and never consistent lengths. I now always buy "Gates" belts and count the number of teeth.

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