E: Engine Comet cams followers and idlers

greg brillus

Well Known and Active Forum User
VOC Member
If the retaining collar at the rear of the ATD has been pushed on a bit too hard it will restrict the movement, but the cam ring in the mag itself tends to give drag which can make the ATD feel stiff. Best to rotate the mag to a point where the points are closed and check the freedom of the ATD in that spot. The gear pinion of the ATD should have some in/out end float if this is not the case then the collar will be the problem. My preference is the original Tufnol pinion gears over the plastic ones.
 

Gene Nehring

Well Known and Active Forum User
VOC Member
I believe that Maughans will stellite cams at least I have been told to give them a call. If I use a stellite coated cam set on the Comet I will have to match that with Stellite coated followers to be consistent I am going to give Maughans a call on Monday. The story I have is that Stellite cams will quickly wear out standard followers am I correct. To be truthful the Alloy idlers look pretty good no real slop so might be sensible on the pocket to keep them on the other hand I have been told to get the ATD uprated with the superior Acetal wheel.

As noted above Gary was running the Stellited Cams on Maughans followers for the last number of years with few complaints. He told me not so long ago that this is what he would recommend for my twin build.
 
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stu spalding

Well Known and Active Forum User
VOC Member
A Tufnol gear should be rotated a few teeth in relation to the idler every 10,000 miles or so. It usually fails at the point where the maximum flux density of the mag loads the teeth up highest. Rotating the gear shifts the load and greatly extends it's life. Cheers, Stu.
 

Ian Savage

VOC Vice President
VOC Member
David, if the gears were bought from the VOC Spares Co why would they need to talk to John at Coventy Spares? If bought from Coventry Spares why did you say they came from the 'Club'. Sorry if I'm getting a bit grumpy over this but I had too many instances of the Spares Co being accused of supplying a 'faulty' part often by a 3rd party only to find the item wasn't bought from us and we didn't even make it.
 
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Chris.R

Well Known and Active Forum User
VOC Member
Hi photos attached show ATD, Cam and followers, the surface of the followers is worn I guess the hardened surface is worn away, the MK1 Cam end is best described as lumpy worn in ridges. The ATD looks ok apart from its movement being stiff, I note the comments made above, it will have to come off to be certain there are no problems, Given what Vibrac says about alloy idlers mine look pretty good and am now minded to keep them unless better advice comes forward. Remember that for most of its life this old gal from 1954 has been in a museum awaiting rescue.
 

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stumpy lord

Well Known and Active Forum User
Non-VOC Member
I believe that Maughans will stellite cams at least I have been told to give them a call. If I use a stellite coated cam set on the Comet I will have to match that with Stellite coated followers to be consistent I am going to give Maughans a call on Monday. The story I have is that Stellite cams will quickly wear out standard followers am I correct. To be truthful the Alloy idlers look pretty good no real slop so might be sensible on the pocket to keep them on the other hand I have been told to get the ATD uprated with the superior Acetal wheel.
To use old unknown alloy idlers is, in my opinion, a false economy. If you had seen the inside of a Vincent engine following the failure of an alloy idler you would not even consider using them, every nook and cranny will be full off alloy dust and that includes the upper frame member. The only way to sort that kind of incident is a complete strip-down and clean.
Stumpy Lord.
 
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