Anyone ever popped a FRONT apex seal??
 

OK... why is it ALWAYS the real rotor seals that go when the engine blows?????
I'm not just talking about turbos, because I know that the fuel cut functions on the rear rotor only, causing a lean condition, but even on N/A's, when the motor blows for whatever reason, it's almost always the real rotor. Even with stuck seals, or other problems.. it still always seems to be the rear rotor.

Anyone have any theories???
I know the rear injectors are after the front on the fuel rail, but that shouldn't cause a lick of difference unless you are totally taxing the fuel pump!
Maybe something to due with a little more heat buildup? Harmonic frequency different beacuse of the flywheel?? Oiling discrepencies?
WHY???

My TII had a blown front Apex seal.

My 88 TII also blew a front seal :)

Try searching. Damn newbies! ;)
https://www.rx7club.com/forum/showth...hreadid=164694

In case you're wondering I blew my front rotor.

My '90 NA blew it's front seal. Maybe the rears pop more because the the trans retains a lot of heat??

Frankententh's blew the front seal in a big way

Did I just get called a newbie??????? Don't know what that's supposed to mean, oh well.

Anyways, That poll supports my point....
I thought about heat retention, via the output shaft and tranny/clutch... who knows.

Bambam, It's due to the fact the rear rotors coolant Is much more constant (hotter) than the front. Remember, the coolant follows the U path and finds It's way back to cooler temps In the Rad and repeats. The U being the bending point of the direction of collant flow and where the rear rotor Is.:)

I was just razing you because there was a very recent post on the subject (near the top of page 2). It was also a shot at the fact that newbies always get hell for this kind of stuff. It's not nessisarly fair.

I didn't know about the recent post... I don't spend as much time on this forum as I used to! Usually only to search for things.

As fo the coolant path.....that was one thought I had... wow.. I guess the difference in temp is substantial!

I think it's because the oil travels through the rotors front to back, so when the oil hits the rears it's already pretty hot.

It's largely due to two things:

1) There's a factory EGR passage that runs through the rear rotor housing and up near the lower intake manifold, heat-soaking the rear secondary runner
2) The factory fuel system on the Turbo II is in sequential flow (where there's pump, RP FP, FS, and lastly RS injectors, then FPR) vs. parallel rails. A slight drop in pressure by the time fuel volume hits the rear secondary injector will run the rear chamber slightly leaner.

B

Re: Anyone ever popped a FRONT apex seal??
 

How about the fact that the vacumme lines come of the rear secondary intake runner. Leaks in the lines cause it to run lean and over heat the rear rotor. Just throwing out ideas. I removed cleaned etc the intake manifolds etc on my car and replaced various lines and the idle dropped quite a bit. Must have been leaking some where.

Oh my '91 has a blown front apex seal.

This is what i always heard was the case: s5 motors tend to drop the front seals and the s4 motors drop the rear more often.

Anyone else see that trend?

I dont have any theories but I got an 86 na with no compression on the fron rotor. Then last week my TII dropped one of the apex seals on the front rotor.