AY12 engine

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AY12 Engine

The AY12 is so rare it has been dubbed the Nissan Mystery Motor. It was used in works Datsun Cherry racing cars.

A12Y engine

Nissan Part Number 11041-M0820. See the FIA homologation papers for the PE10/A12GX E10 Datsun Cherry.

LTR was planning to create a new head casting: Remake of the Crossflow.

Benefits

Using a stock A12 engine block, here are some benefits of the racing-only A12Y cylinder hear:

1. It is crossflow, the inlet and exhaust are on opposite sides of the head.
2. Using a hemi cylinder head design, the valves are in better position than in the normal model. Racing trim was reportedly 220 gross horespower
3. The is no heat problem with twin carbs, because they are on diffent side than the exhaust manifold.
4. The chamber is hemi, it can take more compression without unintended pre-detonation (knocking or pinking/pinging)
5. The exhaust side is the same as normal head. The ports are not in same place but one can use standard A12GX exhaust manifold

Swap Notes

1. In a right drive, rear drive car, the rear carb is likely to cause interference problems with the brake cylinder. Solution: use Remote brake master
   • Left side drivers, however will immediately see the advantages
2. The exhaust can quite obviously be made in a more conventional style to allow a lot more room in there
3. The induction on this one precludes the use of a conventional distributor. One could use a right angle drive to lay the distributor down alongside the block, but it makes it hard to service.
4. In RHD, the carbs in the picture are causing a problem with the routing of the clutch cable. Again, LHD cars will have no problem

The head was originally designed for a transversely mounted engine in the Cherry range of cars & some of the clearance problems simply did not arise because of this transverse mounting.

The cure for some of these problems might just be a custom EFI induction with a cramk angle sensor made from a modified distributor & let the computor sort out the spark problem. Even a simple Pertronix conversion would very likely serve this purpose quite well for many aftermarket computers. Just make a flat[ish] cover for the distributor to replace the distributor cap, & run two coils in a wasted spark configuration.