Magneto bolts?

dynodave · Feb 2, 2017

I am curious to survey for magneto mounts.
At some point the NHT went from... 3 studs(T2245) to... 2 studs and 1 stepped bolt(115163).
The 63 parts book shows the 2-1 combo.
My (65) 20-115163 is with the 2-1 combo. This continued through the end of 20M3 commando although rear points distributor.
My (63) 20-106471 is with the 3 stud configuration
I'd appreciate if folks could check in here, or PM me, with their data from above my 63 vin.
TIA

texasSlick · Feb 2, 2017

Dave:

My Atlas titled '63 but dispatched 1962 (102833) has three waisted studs.

Slick

Burgs · Feb 3, 2017

Hi Dave
Just checked my 1963 650SS and the three studs are stepped 5/16" into the case 1/4" through the magneto.

18SS/1048X/?P

Burgs

Rohan · Feb 3, 2017

Wouldn't Nortons/AMC have issued a Service Advisory or Bulletin for a change like that ?

robs ss · Feb 3, 2017

Dave
My '64 650SS (110425) has the 3 waisted studs
Cheers
Rob

dynodave · Feb 3, 2017

robs ss said:
Dave
My '64 650SS (110425) has the 3 waisted studs
Cheers
Rob

Thanks Rob
interesting the 3 studs went that high into 64 vin , yet the parts book for 63 calls out for 2 stud -1bolt.
any more data points between my 106471 and 110425 :?:

robs ss · Feb 4, 2017

Dave
I agree - and it's not as if they're interchangeable. The crankcases are clearly made for a lower stud or bolt as the case may be.
I suppose the only weakness in the argument is the magneto fits to the timing side - i.e.: the one without the engine number.
Cheers
Rob

Bernhard · Feb 4, 2017

Re magneto; the bottom is quite normal to be an non wasited bolt as mag only has to swivel on the bolt to tighten/adjust the chain. Mine had a nut and bolt on the bottom ….for obvious reasons.

dynodave · Feb 4, 2017

Bernhard said:
Re magneto; the bottom is quite normal to be an non wasited bolt as mag only has to swivel on the bolt to tighten/adjust the chain. Mine had a nut and bolt on the bottom ….for obvious reasons.

It is not a straight 5/16 bolt = non wasited bolt
5 of my engines 1950-1963 (20) are with 3 studs
My other 5... 20 and 20M3 engines are all stepped bolts style.
I would describe the later 2 waisted stud and a stepped bolt. The basic bolt shaft is 5/16 and exits the case as 1/4" which functions exactically like the waisted stud except the nut thread is 1/4-26 cei and is easier to manufacture than a waisted bolt.....this survey is to better determine the transition point, I have not yet figured why norton made the change. A published norton change point and reasoning would be my only further interest.

texasSlick · Feb 4, 2017

dynodave said:
I have not yet figured why norton made the change.

C'mon, Dave, surely you have taken the nut off that bottom PITA stud. It is something that one wants to do only once in a lifetime.

I guess you are being facetious :mrgreen:

Slick