TECHNICAL INFO  

 CRANKSHAFT 

Crankshaft - Standard production crank identification 

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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