I remember reading this on here, and today me and my buddy removed my engine from my R2, due to o-ring leak @ dowel pin. we stripped the ball down and what do you know; i have mitch matched the HOUSINGS!! front was S6 and rear was S4. Leading plug was way lower on the S6 than S4. i never knew this!!!

I cant believed it ran, and ran good!!! no problems whatsoever, so im glad that the o-ring failed, so that i noticed this.

So breaking down the ball, all apexes were in perfect condition, i did have some 93 corner seal springs go flat and 2 broken side seals. im pretty sure it is from the timing being off, kinda like the rotor were fighting each other and running out of balance.

So my question is how many degrees are they different? im thinkin atleast 15 degrees.
And im thinking it robbed some good HP, and my r2 was smoking 03 cobras on 11 psi, T04R powered. So im gonna rebuild with S6 housing front and rear, prolly gonna run alot better.

Just wanted to get the word out, hopefully im not the only dumbass that didnt know this :-)

 

it's fine as long as you use the same for front/rear.

on s5's they also moved them down.

 

As far as I can tell S5 TII housings are the same as the FD housings expect for one thing. The TII has a coolant passage where the intake manifold bolts up. There might be some other things but havnt noticed them yet. But i have head they differ in they way they are coated making the S6 ones better.

 

https://www.rx7club.com/showthread.p...t=rotorhousing

 

Rotary Ressurection: after reading your link, i can run 86-88 in my fd if i use front and rear?? wont the ecu fire the plugs different time, due to the plug closer to trailing?

 

^^^ or is timing the same, just the position is different?

 

True timing is based on the relative location of the rotor to the housing side were the plugs are and to the crank angle sensor.

Since the plugs are in a different location, the EFFECTIVE timing would be different. If the plugs are lower, this would act like advancing the timing.