Rotor housings
 

Hi.i need a help i have a Fc t2 1991 s5 series. can i mix a rotor housings? one s4t2 and the other one s5t2? thanks

well, i can only speculate as my experience is pre-86 so unless there's some difference that i'm unaware of like port timing between the two, i don't see why u can't.

thank you, but on s5 housings the holl for L spark plug is lower than s4, does that have any difrences? Sorry for my english :-D

It changes timing slightly between the series. If your going for high hp #'s, i would keep the series the same

Here are some links to rotor housing comparisons, if you want more information.
https://www.rx7club.com/2nd-generati...-s4-t2-816116/
FC3S Pro v2.0:&nbsp FAQ - Zenki Versus Kouki 13BT

Mr. Stefan13bh is right, the spark holes separation are different. And it will change timing.

The spark plug position does NOT change timing. TDC is TDC is TDC. If that were so then S4 CAS wouldn't work in S5. That's not the case because the timing is the same. It will change the dynamic forces though. Im not sure if I'd recommend it but I would be comfortable mixing housings.

I agree with Iduley that if it's a high HP application I wouldn't take any chances but if you're just wanting a car that won't be pushed too hard then I wouldn't worry.