tall port center plates
 

going to build me a custom 3 rotor using 13 b plates and was told to use tall port center primary plates which has the same volume as the secondary plate.Can someone tell me which plates are tall port center plates.

which 13B are you basing this on, the old ones or the new ones?

'74-'78 (for the older style)

and i believe the center housings from the 13B-RE, were the biggest ... however, i'm NOT really sure about that one. besides, i don't know if that engine came to Trinidad???? so i think your next best bet would be the REW.

at any rate, how are you planning to build a 3 rotor without the special plate that the 3 rotor engines use? did i misunderstand something?

If the engine is going to be based on a pre-86 engine then the ports in the 12A housings can be ported as large. I have one of them lying around btw! If it is based on the newer generation then the Cosmo 13B (13B-RE) are the largest as diabolical1 has stated. The guy that built hitman's engine does make custom 3 and 4 rotor eccentric shafts as well as modifying the intermediate housings for the 3 rotor center bearing. I talked to him once. He also said he can modify an eccentric shaft and intermediate housing for 2 rotors for a center bearing. Eamon Hurley from Hurley Engineering in England used to do the center bearing mod on his race engines and could crank them up to 14000 rpm due to lack of eccentric shaft flex! I don't know about bearing life though.

yes it is
 

Yes i am going to do a custom 3 rotor . I am trying to find out what 13b plates to use,was going with series 6 but then the problem was the center plates ,i need to find out which 13b came with the tall ports so that my secondary plates ports and primary plates ports would be all the same size,of course i have to get the shaft and install a gear on one side of the center plates,thats not the problem though.Any suggestions.

Contact Jeff Bruce in New Zealand. There is contact info for him on the hitman website.