Chassis dating mystery

[agmatthews]

Hi,
I have an Austin 7 with no obvious chassis numbers that I'd like some help to date.

This is an Australian car, so Austin made chassis and Australian made body

Chassis:
Short wheel base - 6'3"
No longitudinal chassis brace
Two bearing brake cross shaft
Z profile riveted chassis rear extensions
Rear diff dated July 1931 
(as this does not match the rest of the chassis I'm guessing it's a later replacement)
Chassis rail appears a millimetre or two deeper than the other chassis I have

Body:
Steel 'chummy' body
No body-line mouldings as you see on Holden bodies.
Hole for battery under passenger seat
Running boards Type B (possibly Type C but bolt holes run along parallel with the edge of the board)
Front guards / wings Type D ( these are new - reproduction)
Rear guards / wings Type C (possibly Type D but they match the dimensions for the Type C)
Steering wheel - no splines

Engine:
The engine I have with this chassis is numbered M24012
(appears to be a September 1926 engine - but no guarantees it is originally from this chassis)

Photos below
(the sanding on the chassis to look for the chassis number was a light flap wheel sand just to remove the paint)

My best guess, using Woodrow, Purves, and Google as a guide, is that this is a chassis from somewhere between August 1926 and July 1928

So my questions are:
How do I confirm if this is the "deeper chassis side frame" from August 1926 onward? 
What do I measure to determine this?

Are these the rear chassis extensions and damper brackets from August 1926 onwards or the "improved type" from December 1927 onwards
How do I tell?

Is it fair to say that the rear axle is not originally from this chassis - based on it's date?

Does anyone know what the story is with a number of Australian chassis with no obvious numbers stamped on them?

-Andrew
Melbourne 
Australia

   

   

   

   

   

   

[Chris KC]

Didn't this come up a few days ago?

Check this thread http://www.austinsevenfriends.co.uk/foru...sis+number

Or perhaps some clues here http://www.austinsevenfriends.co.uk/foru...p?tid=2189

I think you're right 1931 axle sounds like a replacement, it is generally regarded as an 'upgrade' over earlier types. I'm not the person to ask about originality though!

[JonE]

any stamped number on the front of the transmission tunnel on the body?
Could this be another chassis that was supplied to a coachbuilder... I think there are some comments by Hedd about the location of a "suppled to" plate on a GE chassis somewhere....

[agmatthews]

Didn't this come up a few days ago?

No, same person, but this is different chassis!

The "pull rod brakes" chassis from a few days ago has no obvious numbers either but it has been significantly butchered during its long life - so it's hard to tell if the numbers were obliterated in the butchering.

This one is a completely different chassis, much cleaner, no obvious mods (not obvious to an Austin 7 novice like me that is)

-Andrew

---

any stamped number on the front of the transmission tunnel on the body?
Could this be another chassis that was supplied to a coachbuilder... I think there are some comments by Hedd about the location of a "suppled to" plate on a GE chassis somewhere....

Nothing obvious, there is some patching in the floor area, so any original number might be long gone.

Does any one know if the Australian built chummies came from the UK with floors, or if they were built here in Oz?

   

[Chris KC]

Sorry Andrew, failed to spot you are the same person!

[Hedd_Jones]

are there 4 rivett hole on the rear crossmember. slightly inboard of the lefthand chassis rail?

[JonE]

Hedd - two? or is this a different one?
https://gordonenglandregister.wordpress....rousel-194

[Hedd_Jones]

ah yes. 2 rivett holes

[agmatthews]

ah yes. 2 rivett holes

Hi Hedd & Jon,

No obvious holes at all to be seen on the rear cross member.
No visible stenciled number either.

The mystery continues
Thanks for your help

- Andrew

   
   

[Tony Press]

ah yes. 2 rivett holes

Hi Hedd & Jon,

No obvious holes at all to be seen on the rear cross member.
No visible stenciled number either.

The mystery continues
Thanks for your help

- Andrew

Hi Andrew,

The upturned lip along the lower chassis edge was extended forward past the front crossmember (as on your chassis) in May 1929 at chassis number 86511.

The additional longitudinal chassis frame member and coupled brakes were introduced in June 1930.

I would think your chassis is a 1929 number around 8700 with the uncoupled brakes.

Would have been originally fitted with a screw in torque tube differential.

The Chassis came to Australia with the floorpan and as far as I am aware no Chassis exported to Australia for locally built bodies ever had a factory ID plate.
 
Cheers, Tony P.