Read a post a while back about the placement of the trailing plugs on the S5 differ from the location on the S4.
Curious-What is the difference, and if Leading is in same location on both models.
Anyone know the the distance between L & T on each model?

 

Dunno what they were talking about but leading is leading and trailing is trailing on ALL rotaries. Unless yours spins backwards They may have been speaking about using trailing plugs in the leading holes.

 

Thanks for the reply, but it was stated that the housings are different (S4 & S5) because of the placement of the Trailing plug hole is different on the S5. They may be further apart on the S5...That's what I'm trying to determine.

 

I've have never heard anything like that and I know plenty of people who mix and match housings. I don't have any different housings on hand to measure though.

 

Following taken from thread questioning S4 & S5 housings....If they are the same:
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Quote from Aaron Cake:
Spark plugs are in a slightly different place. You could use them as long as you used BOTH '90 housings.
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Quote from RX7 Ragtop:
No problem as long as you swap out the exhaust sleeves. The relevant difference is in the trailing sparkplug location- that effects emissions more than anything else.

 

I believe the S5 trailing plugs are slightly higher on the housing, so they are closer to the end of the chamber. This would only effect emissions.