this is the engine notice how big the four ports are the oil injection nozzles it as 2mm apex the end houseing are 12as rotory houseing are 85 86 13bs and the rotorys are the later ones (I'm working on 100 postings) and there will be more pics to follow

 

The rotor housings have to be '85 or earlier. After that, the "O" ring grooves were moved to the intermediate housings.

 

got the years wrong