ATD Retaining Nut?

cinquecento

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Just fired up with the refurbished mag ' for the first time no problem, blipped the throttle and all sounded sweet. Shut down thmotor to tweak the idling speed and when the motor was started again it was missing at higher rev's.

'Touch wood', I'm thinking the ATD has slipped and will re time in the AM. Question is, how tight do people do up the retaianing nut. I've read elsewhere that a good taper fit in theory should have to be held on by a nut no more than finger tight. In practise do member's tighten until the horse shoe washer just starts to distort, what's common practice?

Thanks.
 

vibrac

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I can see you spending Christmas with fine grinding paste
then finger tight will hold it
no more distorted horse shoe washers (Anyway they are only flat washers with a section removed)
 

chankly bore

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By all means lap in the taper, but by doing so the inner face of the A.T.D.will progress inexorably toward the timing chest wall. We have had one local thrasher whose A.T.D. actually fouled at this location. The horseshoe washer can be replicated with a washer in better steel and shaped with a hacksaw and file. Missing at higher revs. may be a faulty pick-up. Turns the lights off and check. A lot of these items are dodgy nowadays. Let us all know what you find. Happy Christmas!
 

cinquecento

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.
'may be a faulty pick-up. Turns the lights off and check' ?

you mean look for arcing at the points, the money i've just spent on the mag' rebuild it better not ~@>% be!
 

chankly bore

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No, I meant a faulty pick-up, PR22/2G (Comet) or PR22F or G (twin). These are probably made in Taipei or Darjeeling and look O.K. but leak zaps. I have known many to fail although I cast no nasturtiums upon your rebuilder! My suspicion about this is because had the timing slipped I would not have expected the machine to re-start. Five degrees either way and you are through the garage roof or cursing Joe Lucas. Also, (and I keep on about this) your H.T. cable must be routed EXACTLY like the pictures in "Richardson" pp 88 or 95 otherwise evil will befall you.
 
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cinquecento

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thanks for that clarification, my 'Richardson' must be a different edition as it does not have the plates referred to but the routing of the HT lead has been experimented with by using general photos available. With regard to leaking zaps i guess i can just 'feel' for that; ouch!
 

chankly bore

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O.K.then, on a Comet the pick-up must point downward to lessen ingress of water or other nasties into the contact area at the end of the H.T .lead.It needs to be clipped to the return pipe A54ASF in such a position that it cannot touch any fins. Then along that return pipe clipped again then around the back of the FT3 or FT3/2 and back along forward to the plug. I have found it useful to put another clip on A53ASF such as to allow removal of the plug cap without dislocating it from the area where it does its work. This stratagem is of benefit on dark nights miles from the nearest illumination. It fairly peeves me to see H.T. leads going through the head finning or loitering about near the exhaust pipe or port.Twin rear lead straight along to the plug.The obvious plan is to keep the H.T. lead from frying and for you to be able to connect and disconnect it without cooking yourself.
 

cinquecento

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thanksthat' a clear explanation of the routing. Regarding the pick up outlet facing downwards, I did try that today but was far from happy with the tight loop in the HT lead necessary to exit the top of the cover ( F113 ) and also the risk of chafing the lead. Could have lived with this had it meant the HT lead was able to run well clear of fins or exhaust clamp but after multiple trys it doesn't. So will go for best fit clip combination and protect lead with heat resistant bandage if necessary; ugly, yes but I can't be bothered to have to check the lead is not melting at every set of traffic lights.
 

cinquecento

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just to bring the thread to a proper conclusion should someone in the future do a search.

it would seem that setting the points and locating the ATD on taper can be a fickle operation that needs to be checked and attempted several times.

This is not helped by the fact that it became apparent that PO's had b*asterdised the ATD in more than one respect, requiring oe back plate and rivets to replace nut and bolt lash up that was thought to be imposing localised load on the fibre pinion that could possibly lead to an early catastrophic failiure.

Ears on the ATD had been bent, were missing and had random material at the corners removed; how the machine ever fired when I bought it is a suprise. I have built these up with weld and to date firing up the motor seems to be possible on a regular cycle although a high speed run will be necessaary to confirm full advance is acceptable at 35 deg and if any pinking does occur it can be 'managed' or re timed.

The routing of the HT cable was not seen as a must do, however now I am able to pay attention to the recommendations for the pick up orientation and cable routing. This willbe made more feasible as some nice silicon flxible cable is on order.

Last but least , thanks for a great resource, particularly MartynG's posts which have given me plenty to cogitate on. Wishing a happy and peaceful 2014 to all.
 
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