I am trying to replace the rear stationary gear seal on my 94 FD. I have been searching (the forum and fsm) for the better part of 2 hours and I have not found any directions on how to find top dead center. All I can find are references to doing it but no procedure.

So, is there anyone out there that knows how to accomplish this mythical task?

 

y are you trying this ?, i am curious ,
it has nothing to do with the seal ?

 

All the posts I have read about replacing the rear stationary gear seal have recommended putting the motor to top dead center before removing the housing. This is to minimize the chance of the rear rotor dropping leading to an unwanted rebuild.

 

Most people don't go through the time to get the motor at TDC when replacing the rear stationary gear o-ring. Make sure to take the pullies off the main pulley so there is no tension on it when you remove the rear stationary gear.

 

Is it really that much of a PITA?

Just for clarification, does the main pulley need to come off or just the belts?

 

I know how but I do not type well, PM me for the phone number and I will tell you .

 

Just the belts. Here's an old thread on the subject:

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/changing-o-ring-rear-stationary-gear-468305/

 

I did this about 4 weeks ago and followed the directions in a Mazda TSB,#003/98.
The procedure in this bulletin worked well for me and it was not necessary to loosen the front accessory drive belts.The key thing in my view was keeping one stud in the stationary gear so the gear did not come out in an uncontrolled fashion.
As far as top dead centre was concerned I just rotated the motor until the white mark on the crankshaft sensor plate was aligned with the indicator pin---close enough to TDC for me.
In my case the stationary gear came out easy and went in fairly easy----you have to be precise lininng up the slot in the gear with the pin of the housing.
In my case also the O-ring was so brittle it broke into several pieces as the gear was withdrawn.
I was a bit nervous doing this procedure but I was leaking so much oil it had to be done.

 

I found TSB #003/98. It gives great instructions on how to replace the rear stationary gear seal. However it references Section C of the workshop manual to find TDC. I have just gone through that whole section and I was not able to find this procedure. Do you know what page it is on?

 

Check here:

 

Ok.... So if I am understanding this correctly.... There has to be a spot somewhere on the either the front pulley or the back part of the e-shaft that can be aligned to show TDC.

If the e-shaft turns 3 complete revolutions per 1 revolution of the rotors, then one turn of the e-shaft would turn the rotors 120 degrees. In this case TDC on the front rotor will occur at the same point on the e-shaft for each rotor face. For example, the notch for the flywheel key would be pointing in the same direction in relation to a fixed point on the rear rotor housing, each time a rotor face gets to TDC. Or the same thing for the tab on the crankshaft position sensor plate or the timing mark. They are also going to be in the same position each time a rotor face reaches TDC.

My question is where would that point be?

Is the front rotor going to have a face at TDC when the timing mark is lined up with the indicator pin? Or is TDC going to occur 5 or 20 degrees after the mark passes the indicator pin?

Or am I completely wrong and TDC only occurs once per revolution of the rotors?

 

you have it right,there is a TDC for every face and yes 3 crank rotations for 1 complete rotor rotation.as for the last question my interpretation is that the rotor face is at TDC,but the spark plugs are not.(but I may be confused!)
In any event for the purpose of removing the rear stationary it did not matter in my case.

 

Well I went ahead and pulled the rear stationary gear housing tonight.

I loosened both belts on the main pulley and removed the spark plugs. I used a pen to feel where the rotor was in the housing (through the spark plug holes) and made sure to feel a face in both holes on the front rotor. The housing came out with a loud noise, almost made me drop a deuce.

The stationary gear seal was toast. It had a crack in it and it felt like a hard piece of plastic instead of a rubber o-ring. I had to use a screw driver to get it out of its groove.

I had the flywheel key notch pretty much straight down when I pulled the housing, the rear rotor was resting directly on top of the e-shaft. After I got it back in, I cranked the motor over by hand and it seemed to turn over just as easily as before I pulled the housing. I will update when I get my new clutch and get everything back together. Hopefully she will still be alive.....

 

Great success!!!

Everything is back together and she is running great!!!