j9fd3s

the difference is the air injection ports. the air pump air is injected into the center houing and then thru the rotor housings into the exhaust port. if you mix the housings front and rear then it blocks off the air injection. some engines have both passages drilled so it doesnt matter if you mix front and rear. it is not a us only thing, they all work the same bascially.



mike

alvinb

For those of you who have been following the thread, I knew that it was an emissions thing, but I looked and looked and couldn't see the difference. I called K&D Rotary and explained to them my dilema. They stated that the two housings were in fact different, and I was not seeing it. He explained where to look, and lo and behold, I saw it! On the front housing, the hole is on one side, on the rear it is on the opposite side. NOW I understand why it won't pass emissions with 2 fronts or 2 rears. In case you are interested, here is a pic of the hole. You have to be looking up from the bottom of the housing to see it.

http://66.241.252.127/images/rotary/rotary020b.jpg

Thanks to all for the information provided. I am confident I'm gonna bring this car back to life soon, and the right way!

j9fd3s

its for the air injection. we have seen cars fail smog with the housings swapped

alvinb

I am learning. The only ppl I have to help me on this are you guys, Atkins Rotary (by phone), and K&D (also by phone). I wouldn't want to fail the smog. I know ppl who can get me around this, but they might not be here for too long. I want to build the car right, so I will build it the way it's supposed to be. I think one of my rear rotor housings are useable. K&D told me to take it there so they can have a look. I will try to do it this week. Maybe I'll post some pics to get you guys advice. It could save me a 2 hour drive to K&D. Today I feel Super Confident because I am understanding what is going on.

j9fd3s

yah even if the car doesnt have to pass smog it bugs me when the housings are swapped, its just sloppy

vosko

woops i used the wrong terminology but i was right about the not passing emissions thing

j9fd3s

well i think the 87-88 t2's might have an egr port, making you right

alvinb

Thanks, Vosko. Your post did get me looking in the right chapter in the Service Manual. Up until today, I didn't really know what an EGR port was used for, and now I get the idea. This has been a real learning experience for me. I hope when this is over I'll be able to share my experiences with somebody who is starting on their first rebuild. I was afraid to tackle the job at first, but now all the bits and pieces are starting to make sense to me.

setzep

I don't have a EGR (or even a place on the center plate to bolt it down to) or a airpump so I'm fine with two R or rear housings

j9fd3s

it might be the cosmo doesn have front and rear housings, its actually a matter of them drilling it out or not



mike