Perhaps the most interesting variety of A series engines was the AY12 engine. This was a special race-only Nissan factory (works) racing version with a crossflow cylinder head.
Overview
AY12 was used in under-1300cc class racing with 76 to 76.8mm pistons. Intake valve was 40-41mm and exhaust valves that have been used are 33mm and 34mm. The piston was also special design. Because of the hemi combustion chamber, the pushrod-activated valve rocker system was different from the regular A12.
Oiler