I've been searching this for a while and the only thing I could come up with is that the s5 has higher compression rotors.
I'm asking because I'm trying to figure out if I can use my s5 rotors with s4 rotor housings.
Is there any advantage between the s4 and the s5 housings or rotors?
I basically have a s4 and a s5 engine that are both blown, and I have 2 good rotor housings out of a s4.
I'm trying to rebuild an engine using the parts I have, plus a rebuild kit I'm buying off a friend.
I'm on a budget and would rather not sell my sevens.

 

They're basically interchangeable.. The only difference I remember is that the spark plug holes are moved slightly on the S5 ones, so the timing will be *slightly* off if using in an S5 car.

 

if you use the S4 housing you also need 2 use the s4 hub,timing,main pulley assembly.

 

Is that because of the timing being off?

 

The timing is so slightly off it doesn't matter. You can use the S4 housings and S5 everything else.

The important part is that whatever rotors you use, you need to use that series front and rear counterweight.

 

Okay, I heard there is something you have to do with a knock sensor if you use s4 housings and s5 everything else. Will it run bad if you use s4 housings with s5 rotors.
I read a couple posts/threads about it but I haven't been able to find one that shows some results of if it runs funny.

 

It runs fine. I am not sure what you want to do with the knock sensor so you will want to look into that more.

 

I am right now actually. I just didn't want to put everything together and have it run funny. (Not that it might not run funny anyways, lol.)

 

Not true,The timing will be off almost by 20 degrees if you use the S5 front hub on S4 rotors.BDC confirmed that like 2 years ago and i did it myself 2.

 

That is the only thread I could find actually. I thought your picture looked familiar from last night. However, would the timing being off cause a lot of issues or would it not be noticeable.
I know I owned a miata for two weeks (I'll never drive another piston powered vehicle) and the timing was actually set a little bit off and it made it have an increase in power, but then the timing got worse and it felt like death.

 

And to really make this discussion interesting, what if you have s6 housings and everything else s4?

 

I'm not for sure on that, I haven't searched anything. I'll go ahead and search it up and we can just have a whole thread about mix-and-matching housings with rotors.

 

S4/S5 rotors have different compression and weights.
The housings have slightly different plug hole locations and S4 has an exhaust diffuser (either that or the N/As do, can't remember).

 

Yeah, I've been told the s4 rotors weigh a little bit more than the s5 rotors.
So does anyone know how the timing being will cause the engine to run?

 

Since s4 and s5 rotors both are graded A-F/E is it possible that a s5 rotor grade f/e might weigh the same as a s4 rotor grade A?

 

I've never understood how the TIMING could be off by moving the sparkplug hole location. TDC is TDC is TDC is TDC is TDC is TDC.

Both series four and series five fire at 5 degrees ATDC for LEAD and 20 degrees ATDC for TRAIL.

Did I mention TDC is TDC is TDC is TDC is TDC??????? I don't give a flip where the sparkplug is in the housing, if Mazda wants the thing to fire at 5 degrees TDC.........where the plug is in the housing does not matter.

Mazda did NOT change the timing when they moved the sparkplug hole. It's still the same on a series five as a series four.

 

no

 

Makes sense to me.

 

S5 and S6 rotor are the same with the only difference being some upgrades on the spark plugs area(coolant passages)TDC is TDC we all know that buddy but if you use the s5 housings with a s4 hub your timing wont be perfect,the hub size is different between series and the timing mark is in a different spot cause of the different spark plug locations.

 

Couldn't you set the timing off to counterbalance it then? Or can you set the timing in a rotary like you can in a piston engine? (I know there isn't a timing chain.) I just don't know how this aspect of the rotary engine works and would like to learn.

 

set the timing using the keyway

 

no. the location of the spark plugs and the ignition timing are two separate things

 

So you can just set the timing so that it will work correctly?
Correct?

 

Ignition timing is determined by the CAS. The geometry of the motor has nothing to do with it. The front pulleys are slightly different diameters, and they have to be mounted on the corresponding hub, S4 pulley on S4 hub, in order for the little marks to be in the right spot. You can put a S4 hub/pulley on a S5 rotating assy though. But you HAVE to match the rotors and counterweights for the series or bad things happen.

All N/A have the exhaust diffusers.

 

So... I was to use a s5 rotating assy I can use my s5 hub and pulley?
It won't matter that I'm using the s4 rotor housings?
Now I'm very confused.