cds00bsmg

iTrader: (1)

I recently acquired a 90 gxl motor for the nice sum of $50. I'm planning a full rebuild and was considering swapping 4 port end housings (13b late 70's large port) I had lying around onto this motor. I wasn't sure if this was a good idea/combination for optimizing power from this N/A motor. I'm going to be running a webber sidedraft setup and, I was also considering street porting the motor. I read in DRAG magazine I believe the best setup was what I'm planning on doing since the 90 motor has the desierable 9.7:1 compression ration and lighter weight rotors. Any suggestions anyone might have would help.
THANKS

Rx7carl

But mazda swapped the grooves for teh coolant seals to the side housings in 86. So with early sides (no coolant seal grooves) and late rotor housings (no clloant seal grooves) what will you do? I could be totally wrong though (as I often am, just ask my wife).

Siraniko

iTrader: (13)

I agree with Carl. It aint gonna work. Its either you find a GSL-SE block to mate with your old 4port plates. But I prefer to use the 79+ plates as it is nitrated.


OR
Find a TII plates to convert that 6port to a 4port.


BTW, please use the search button. This topic was brought up appx 2 weeks ago. Again, its free.

cds00bsmg

iTrader: (1)

thanks for your info. guys, well, heres a second question then. is it possible to use the rotors out of the 90 n/a in the entire 70's 13b motor? heres what i have to work with, you tell me if i can use it together.

1970's large port 4 port 13b

1990 n/a 6 port 13b

is there anyway i can make a 4-port motor with the high compression/lightweight rotors, or should i just start looking for TURBO II end housings?

thanks again

hornbm

All 13B rotors are swappable, you just need to make sure you have the correct front and rear (or stock flywheel for teh rear) counterweights that match the series of rotors you are using in your engine.

If I were you and those motors were the only ones I have to work with, I'd put the 90 rotors in the 70's block.

cds00bsmg

iTrader: (1)

if i put the 90 rotors in the 70's motor, can i use the 90 eccentric shaft as well? the 70's motor i have isn't complete, actually its just the end housings, int. housing, and rotor housings. the 90 motor is complete.