If you want to find TDC use the flywheel. You can take the cover off the top of the engine in the rear and see the flywheel. Different year motors have different flywheels but generally speaking the numbers that identify the flywheel are oriented on the top when the engine is at TDC. GSL-SE for me probably knows which flywheel timing marks are where.

If you manage to get the front bolt off and you don't want to risk a front stack rebuild; you can locate the keyway on the front of the e-shaft without removing the pulley. When the key way is facing the exhaust the engine is at TDC (I'm pretty sure on this one). You can confirm TDC by sticking a pencil or something soft into the leading spark plug hole and feeling for the passing apex seal on the rear rotor. EDIT: I'm an idiot. It doesn't have to be the rear rotor since this engine fires on wasted spark; either rotor is fine.

Shoot I think I set my timing last time with the flywheel... just cause its easier to point a light at it than the front cover. I just lined it up with the seam on the transmission. I might have re-checked it with the front cover at some point, but these motors will let you know if you're out of time (the exhaust overheats at the headers pretty bad and you can hear the pinging).

 

I run the under drive main and alternator pulleys from RB on my car as it makes a difference when you run at a constant 5-6K for long periods, like mountain driving in my case.

To the OP, you don't need to change the pulley to get the timing marks. Just run the engine and apply some sandpaper to the edge of the pulley. Those marks will jump out at you and then you can time it.

 

Wedge the clutch pedal down so the torrington bearings won't slip down and get crushed once you tighten the bolt up. With a 2x4 or whatever you can find.

Heat the bolt with a MAPP torch or use the nice impact wrench aforementioned. Or both. Be aware someone may have used loctite on that damn bolt. Possibly even a gratuitous amount. I had one motor that was rebuilt by a PRO shop and lets just say using the breakerbar method, I had to slide a 8 foot pipe over that breaker bar, use heat and Conan that damn thing loose. I think he used this as a 'warranty void prevention method'. This is the worst bolt the loosen on the car.

Make sure the oil bypass thingy in the e-shaft, or its plug replacement do not fall out. Clean the threads with brake cleaner and a toothbrush. Lube the o ring at end of the bolt with motor oil. Use a torque wrench during re-assembly. Torque to 90 ft lbs. The RB pulley is underdrive and at idle you may notice the voltage being low due to the alternator being underdriven. But, it's a real nice machined aluminum pulley.

 

If this happens to pop up in anyone's inbox, I removed my radiator to fit a 600ft/lb air-powered impact in, and it's still not getting it. I've tried heating it with a propane torch for about 5 minutes at a time, and it still, won't, come, off. I'm speaking of course about the 19mm bolt that holds the eccentric shaft pulley hub to the shaft itself

 

Have you tried soaking with PBlaster or similiar with alternating heat. It may take days to get it off. Its the worst nut to remove on the engine.

 

What you're driving the impact gun with is just as important as the gun's capability. A gun like that needs minimum 125 psi to develop that type of torque. What kind of air compressor,hp/tank size are you working with? Also,the less adapters on business end of gun allows full torque to be transmitted. A shallow socket with an extension on it will "waste" torque,use one deep socket to transmit 100% of gun torque. If you have a good supply of high psi air,try a different air gun. Some guns don't put out rated ft lbs.

 

Take more than 5 minutes to heat it up. Buy a front main seal and o-ring and let that thing heat up to cherry red. And the for mentioned shorter sockets and more air.

On the thrust bearing thing... Try lifting the front wheels and angle the car back; that might keep the thrust washers in place when you pull the front hub.

 

the e-shaft needs to be pushed forward to keep that bearing from falling out, like holding the clutch in.

 

Is it too late to turn back? If all of this was to replace that pulley because the timing marks were rusted and you didn't want to redraw them, you can just get a good condition (used) OEM two piece pulley from Ebay:
https://www.ebay.com/itm/Mazda-12A-l...EAAOSwPa9dvhgW

All you need to do is undo the 4 small bolts (M6, 10mm wrench) holding it to your OEM pulley "hub" and install the replacement. (Item on the left in above ebay Ad picture). That will be a five minute job.

Is it too late to return the RB pulley? Messing with the main pulley while its in the car scares me and doesn't seem worth the effort or $$ for a 0.001% gain in performance from the lightweight RB.