I went rummaging through a small pile of Datsun cranks today as I figured it was time to move my A13 project ahead & since the entire engine has to be built entirely from parts, starting with the block, it was time to get a crank.

I laid out about 5 or 6 of the 1200/ A12 cranks on the floor, & since the 1200, A12, A12A & short stroke A13 all share the same 70mm stroke, then any crank from one of these will fit any other block from the group.
In Australia, pretty much any 70mm stroke crank that you find will be a 1200/A12 one.

Each one was tagged & surprise surprise, there's an A13 one. Better yet, it's the original one from my block.

When I compared it to all the other 1200/A12 cranks it became obvious that it is different. It's dimentionally interchangeable, but is based on a different forging.

This one has 'scoops' in the web in line with the main bearing journals & this would have the effect of reducing the weight of the crank.
The other cranks on the floor in front of me were all marked as A12 & all were machined straight in this area.

There are two versions of the A14 crank also & the more common one is the lighter one & it too has the 'scoops' in the forging.

I now assume that this design was a production revision after a certain date but would have coincided roughly with the B310 models as these are the cars that got the A14 in Australia & this version of the A13 in Asian markets.
The A12 & A12A were also used in B310 models at this time in various markets & both had the 70mm stroke so I wonder if they used the same crank.

I will try to get a comparison shot of the earlier A12 crank soon.
The grotty journals are just that, grotty with heavy oil & a lot of dust & dirt.

Should I knife edge it?