[Note: HB= Handbook, CC= Crankcase part number EN= Engine Number]

1922 HB353 CC BA1, EN 3658-69,000 magneto engine (oil filler hole next to dipstick hole also mounting for magneto)

1928 HB670a CC BA118 EN 69,001-97,599, coil engine (oil filler tube moved to top of crankcase and dipstick hole closer to fly wheel)

1931 HB888, CC BA140 NR 97,600 enlarged bearings in crankcase CC BA155 NR 141,868 enlarged camshaft bearing (for BA140 and BA155 you will need to check the bearing sizes as will look at a quick glance the same as BA118)

1932 HB888a CC BA160 petrol pump added other side of crankcase starter motor mounting added and dipstick hole moved.

1933 HB 1029a, CC BA174 EN 179,368 Rubber mounting, also screw in oil tube.

1933 HB1169 CC BA188 Sports models
1934 HB 1218, CC BA207 low frame BA174 high frame
1936 HB1406, CC C1-233 Nippy 3 bearing crankcase identifiable by the additional web next to the petrol pump with a bolt hole above
1936 HB1406a, CC C1-178 NR 249,001 3 bearing crankcase

The parts book images for crankcase BA188, BA207, BA174, C1-233 and C1-178 have the same image with the additional strengthening shown in the last image above, although I do not believe this strengthening is on all these crankcases. The last four BA part numbers are for the crankcase inc crank etc. The Low/High frame crankcase is a difference and can catch people out causing problems fitting the engine in the incorrect chassis.
The list of 12 excludes racing, marine and War Office, so this may not be a complete list, but certainly worth noting if you are looking for a replacement crankcase for your car as they are not all the same.  There are also cast iron versions which are easy to spot as they are much heavier.
Douglas Alderson (DA7C)