Initially both Supercharged and Unsupercharged engines had an 8 stud crankcase with a depth below the engine mounts similar to a standard engine and thus they had the same oil capacity albeit Castrol or Mobiloil R,The sump pan was tin plate with a circular inspection plate and a removable pot filter above.
To increase oil capacity Austins offered as an extra a deep unfinned aluminium sump,which most racers fitted but interestingly Austins themselves used the Sports tin sump on the Works 8 stud engines.(photos of Waites upturned car in the 1930 TT clearly show this)
Logicly when fitting the deep ali sump the pot filter would have to be dispensed with and a standard gauze fitted.
Austins introduced the 10 stud engines(S and US) early in 1931(theoretically and in one case in practice the VSCC will not accept a 10 stud as vintage.However the preproduction 500 mile 10 stud engine was produced in 1930 but this was very different and had a shallow depth crankcase .It also had a 9B no not 9C)The production 10 stud had a deeper crankcase depth for increased oil capacity and tin sumps with access to the pot filter were fitted.
The oil pump did not have an extended pick up.
Also the 10 stud pot filter was longer than the 8 stud type.

That VSCC date that cuts off the arbitrary vintage period for their purposes is 31st Dec 1930, so apart from the pre-production 9B numbered 10-stud (hens teeth?) engine, you are saying that the 10-stud engines were produced post-vintage and support the old VSCC reasoning?
I am curious to know what effect the post-vintage dating makes for a would-be VSCC competitor with a short chassis car now that these later short-chassis' are all eligible. This has been the case for some time, too.
What is the reason for a standard oil pump without an extended pick-up unless these were simply unchanged in works engines with shallow(?)tin sumps? How much was the extra depth?

Jim All 10 stud engines(other than the 9B engines 2 known) are post vintage .The vscc accepts them as they do post vintage short chassis but NOT as vintage.
Sports (Ulsters) have been accepted for many years made after 31 Dec !930 as PVT.Enter a 1931 car in competition and you are not eligible for Vintage awards.I have kept a Register of Sports (Ulsters) since 1968 and comparing some dates of registration given in the 60's with those now in the A7CA Chassis List shows some 1931 cars have become 1930 Dec.

Ulster(?) sump on ebay, I seem to remember talking about these before and the feeling being that there appeared to be more sumps than cars!

Austin,

I have a feeling that these were also fitted to military A7s. Perhaps someone in the know can enlighten us?

Cheers

Ruairidh