Crankshaft - Standard production crank identification

27 October 2003

 

Below is a list of crankshaft identification data by forging or stamped numbers - yes, contrary to what many say/express, all cranks are forged. None are cast. They wouldn't last 2 minutes in an engine if they were cast - they'd be way too brittle. The differences are in the material used, finish machining detail and any heat treatments applied. It is by no means complete and utterly correct/infallible since Austin/Morris, British Leyland, Leyland cars, Austin Rover, rover, et al were seriously prone to not adhering to specifications and applications lists. But it is better than nothing at all!

 

22A62

850cc

Early type with oil feed for primary gear, 1.375" dia. tail

22A63

850cc

Early type with oil feed for primary gear, 1.375" dia. tail

22A298

850cc

Early type thin-nose crank, 1.375" dia. tail

12A670

850cc

Later type with 1.5" dia. tail

12A298

997cc

Original Cooper crank

12A375

997cc

Cooper crank with oil feed hole for primary gear

12A595

998cc

Early EN16T spec

12A1451

998cc

Later, pre-A+ EN16T spec

BHM1436

998cc

A+ spec, 1985 onwards (12A1451 forging)

12G82

1100cc

Standard across the board transverse A-series EN16T spec

AEG330

970cc

EN40B forged, non-cross drilled

AEG171

1071cc

EN40B forged, non-cross drilled

AEG315

1275cc

Cooper S, EN40B forging, Nitrided, 1.625" dia. big ends, non-cross drilled

AEG316

1275cc

Cooper S, EN40B forging, Nitrided, 1.625" dia. big ends, non-cross drilled

AEG479

1275cc

Cooper S, EN40B forging, Nitrided, 1.625" dia. big ends, cross drilled

AEG480

1275cc

Cooper S, EN40B forging, Nitrided, 1.625" dia. big ends, cross drilled

AEG623

1275cc

Cooper S, EN16T forging, Tuftrided, 1.625" dia. big ends

12G1287

1275cc

Non-S, EN16T with 1.625" dia. big ends

12G1288

1275cc

Non-S, EN16T with 1.625" dia. big ends

12G1505

1275cc

Non-S, EN16T with 1.75" dia. big ends

12G1683

1275cc

12G1505 forging, non-S, EN16T with 1.75" dia. big ends, Tuftrided

CAM6232*

1275cc

Rolled-fillet radius on bearing journals, A+ with 1.75" dia. big ends

 

*Note: This crankshaft was used in all 1275cc, A+, transverse engines including the MG Metro Turbo. There are various un-confirmed opinions on the subject of whether the material was any different, or whether it was heat treated differently. It would appear that early Turbos had just the standard spec, EN16T, non-heat treated type fitted. Later examples certainly appear to have been heat-treated, probably an up-to-date, emissions-friendly version of 'Tuftriding' (a recognised ICI registered process) - possibly a forerunner to Nitro-Carburising. These crankshafts have a distinctly charcoal-grey/black finish - mostly detectable on the webs, water pump/alternator pulley end and in the rolled fillet radii. The later being fairly 'deep' and very even.

 

 

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