timing pinions

Information relating to the Matchless G80 or AJS Model 18 500cc Heavyweight.
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david pollard
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Joined: Mon Aug 08, 2016 9:22 pm
Location: WILTSHIRE UK

timing pinions

Post by david pollard »

on my machine when kicking over you can hear the camshaft timing pinions clicking on the engine pinion as the valve spring takes up the slack, has anyone produced an oversize engine/half timing pinion to overcome this?, I know Vincent had this annoying problem and they produced ones 10thou oversize. many thanks for reading!
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robcurrie
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Re: timing pinions

Post by robcurrie »

David, you could investigate hard chrome plating the gears to reduce clearances.

Rob C
John Jarrett
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Re: timing pinions

Post by John Jarrett »

For what it's worth, I would question whether you are sure its wear on the timing pinion?
Is there a chipped tooth or debris caught/wedged in one of the teeth?
Could it be loose tappets or wear in the camshaft bushes allowing the cam to "rock" under the force of the valves opening and closing?
MikeM.
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Re: timing pinions

Post by MikeM. »

It may be caused by end float on the camshafts in the timing chest, the end float can be eliminated by adding shims to the shafts.
david pollard
Posts: 41
Joined: Mon Aug 08, 2016 9:22 pm
Location: WILTSHIRE UK

Re: timing pinions

Post by david pollard »

many thanks for all your reply's, there is minimal end float, new bushes fitted, 10thou gap on each tooth between half timing pinion and camshaft wheels, so its got to be relative positioning betwixt the wheels! so the only thought is oversize half timing pinion! any other ideas please?
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dave16mct
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Re: timing pinions

Post by dave16mct »

Are you sure it's not the rocker shafts 'clacking' as it's easy to mistake where a noise is coming from? Also, how have you checked the end float on the cams?
Dave.
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