factory stamping: fr. axle, gearbox & G'box tops

[Mike Costigan]

151217 is fine for a 3-speed; first four-speed was fitted to 166315.

[JonE]

two more stats from Changes book...
112,127 boss for handbrake no longer drilled (presumably?) as coupled chassis comes in
c.116,000 - 1st reverse forks change (so does that mean back to modern pattern?)

[JonE]

Bingo. Parazine was correct. Was this your source though?
What is interesting is that this confirms the further change at 160,000, but it's just the first/reverse fork ROD, not the lever. So what happened in practice? What is does show is that 1A 3100s are very rare!    

[Russlin]

Happy New Year to all. The following numbers appear on my early 1928 Mag model which I believe to be reasonably original although with unknown history. Please forgive me if I have supplied too much information.
Body by Propert, Newtown, Sydney.
Engine no, M52800
Number stamped on trans. tunnel 46309 below which is a large '3'.
Front axle top, 52396.
Front spring small leaf, 'y', below to the right '4', below '31', below 'IA5047'.
Chassis no, 58320 nearside rail front engine mount.
Gearbox, 3-speed, first at lower right
Gearbox top, '2565E'
Gearbox case, 'SM 4020' with 'L' above Austin name RHS.
Differential, 2/4/28
Differential,  5290/9
Dynamo, CAV 6V 17691 12/27
Starter motor housing, 58726
Starter, CAV SE 35, 3 28, B 55 28.
Lucas cutout, 1 28
Steering box, 6796

The gearbox case numbers appear vertically on the right side flange near handbrake boss, would any of our readers know whether SM 4020 is a significant number?

Thank you.

[JonE]

Russlin, with Parazine hypothesis, that would make gearbox 52565. Its very interesting that the engine, box, and front axle top are all in the same ballpark, but that the chassis is this case is slightly higher than the engine number, when one might consider it was normally the other way round? Will be interesting to assess the chassis build date against the diff date...

[Parazine]

Gearbox case, 'SM 4020' with 'L' above Austin name RHS.
The gearbox case numbers appear vertically on the right side flange near handbrake boss, would any of our readers know whether SM 4020 is a significant number?

The number on the gearbox is stamped on the near side front "ear" of the bellhousing on early boxes.

   

This one is 283A which translates to 10283 (assuming the missing zero), which is 1925 I believe. The box has XL + 3 digit part numbers all over it.

The number was stamped above the output shaft on later 3 speeds.

SM 4020 may be a casting number or foundry reference??

[JonE]

is there any way that box could be as low as 1283, or do physical characteristics preclude? It's just so odd that while the system does seem to be working with boxes and cars that people are volunteering, the taking off the zero muddies it a bit... how does one know when the rule changes etc.

[Parazine]

No muddle really, 283A is 10283, 1283A is 11283 and so on.

Presumably there was a 1A, representing 100001! Or perhaps they started at 100A....

[JonE]

just seen a 159M box. Perhaps where there are 3 digits rather than 4, there is always a zero inserted, as per Parazine's very old box above. So 159M becomes 13 0 159 which is very close to engine number.
I wonder what happens on the very early boxes though - are there any cars which could be checked?

[JonE]

Two more to report:

3 speed with undrilled boss, 2R/31 ball pattern, 8714N, meaning 148714 - seems correct.

3 speed XL marked, no speedo drive, 208IG. It also has an X marked on the front top of the lid. AF852 on the rear facing vertical of the casing.

The latter is an I rather than a 1. If it were a 1 then 72081 is too late for an XL. So what WOULD the range of possible chassis' be for that spec, and how can the formula work here?