I'm in the middle of a s5 rebuild, and noticed the scarring from the apex corner seals on my rotor housings. I've searched the forum, and talked with Kevin about the matter, and am just curious what the other rotary experts out there do about this during a rebuild?

-Is it better to use an aftermarket apex seal with the wider corner piece in a rebuild (like atkins), to keep from grinding the housing out further? Or does it matter?

-If you use new Mazda seals, does the corner piece continue to grind the housing to the point that it ruins the housing prematurely?

-Or how about turning the apex seal around, so the corner piece is at the front?

I allready have new 2 piece Mazda seals, but am wondering if this is the best way to go now.

 

Ya know, I used to think it was corner seal and/or apex seal "tip" piece doing the damage, but when I tore mine down BOTH sides of the rotor housing had that "removed material" area, which rules out the apex seal end piece, and the corner seals just don't sit right to be the culprits either, IMO...The best explanations I've heard so far are: 1) the ends of the stock apex seals are harder than the rest of the seal, and 2) the OMP oil doesn't get to the edges of the housing, causing the wear...My recommendation- NEW rotor housings, that way you won't be "grinding" the new rebuild seals down to fit the old worn rotor housings...I know there are many out there that won't agree with this...

 

On my housings the groove is only in the back side, there is a slight taper on the fronts, but nothing like the back. I'll try to get a picture attached here:



The housings are in really good shape except for the groove. And for some reason it is only on the bottom half of the housing.

 

the exhaust stroke portion is always the rough area (that, and the chatter marks/ scratches near the plug holes)...those actually look a smidgen better than mine did (186,000 miles on 'em)...ya gonna re-use 'em?

 

Yes I'm going to take my chances with them, I'm just trying to make sure I use an apex seal that will perform the best with the housings like that, or at least not wear them out too fast.

This car had ~112k miles, and that is the aft housing. The fwd is in better shape.

 

Kevin (RotaryResurrection) could probably tell ya what kind of apex seals to use in this instance.

 

Here is a side by side pic of the old vs new apex. The new one measures .365" at the edge, and the old one ~.307".




Kevin thought the atkins style would not further grind the housing. I'm curious to hear what other people's experience is. You would think that if the Mazda seals continued to do this to a housing that everyone would use the wider atkins style 2 piece seals during a rebuild.

 

Anyone else have experience with this?

 

It's really not the corner seal that's causing the groove.
It's actually the triangle assist piece on the apex seal that's causing the groove.

It's true...all these "new" apex seal designs will minimize more grooving in that area, but you take a hit on compression sealing.  Think about it...the apex seal slides on the diagonal cut, and this causes one side or the other to run slightly lower than the other piece.  With the longer "assist piece, you lose this length of sealing with the rotor housing when it slides under the main apex seal piece - this hurts compression.  Loss of compression hurts power.

Since you're reusing old rotor housings, I'd rather use stock type apex seals with the triangle assist piece.

I can understand when you're using brand new rotor housings, but you're reusing old rotor housings so it's no big deal.


-Ted