Two Piece Apex Seals?
 

This is just a random question, but what is the advantage to two piece apex seals? Ive never done a full rebuild myself and have heard many debates about one VS two peice seals. This has always made me wonder though Ive never thought to ask it in perosn for some odd reason.
Ryan

2-piece seals better.
You tend to get better compression #'s with multi-piece apex seals versus 1-piece apex seals.


-Ted

One piece is fucking shit :icon_no2:

Rotaries are bad enough for turning good fuel into heat and noise! what ever is left makes power........ 2 piece is the only type to use.

the rotary has 270 degree strokes, vs a piston engines 180 degree strokes, so there is more time to leak compression between chambers.

a 2 piece seal, can change length, so it always has the right end clearance vs a 1 piece seal that has to be set for "worst case" IE max temp. so the rest of the time it doesn't seal as well, because its too short.

a 3 piece seal can seal in the width of the seal groove.

So kinda like the verious (dare I say it) piston rings on a piston engine? And hell, I didnt even know they made 3piece ones.
Ryan

Not sure what you drive but Mazda used 2mm 3 piece seals (not in all). Your motor may still have the originals if it has never been rebuilt.
http://psychoapexseals.com/Images/24062010164.jpg

Mazda changed over from a 3-piece (2mm) apex seal to the current 2-piece apex seal sometime in the 1990's.

The 2-piece apex seal were more reliable and sealed almost as well as the original 3-piece apex seal back in the day.

I actually still run the older 3-piece 2mm apex seals in my '87 FC turbo when I rebuilt it back in 1996.


-Ted

Honestly I have no idea, right now I'm working on getting my original RX-7 back (an old 88 N/A) but with plans for a rebuilt RE-Swap. I'm just trying to do as much research on all the finiate details as I can.
Ryan

there are a couple of japanese shops that cut the 2 piece seal into a 3 piece seal!

-mike

The 3-piece seals are so fragile I'm afraid to use them in boosted engines. 2-piece seals fine anyway.