Now, looking at the RB website for 12a front stat gears (Part number 10010 ) It says this:

TYPE I Modified Stationary Gears
12A Front

Our Type I Modified Stationary Gears are strongly recommended for engines which are regularly running near or above 8,500 RPM. These gears have had several machining modifications performed, as well as heat-treating of the teeth to improve fatigue resistance and yield strength. The front gear and the standard-ungrooved rear gear have the stock bearing installed. The “special grooved” rear gear includes a three-window bearing and is intended for high power output racing engines, while the standard-ungrooved rear gear is best suited for high output streetable engines. Additionally, we offer for a nominal charge the machining process that allows the Type I front stationary gear to accommodate the larger thrust washer and related components found on the 1992 and later engines.

Now the bold is all I am worried about. I found a place to cyro treat my front stat gear for uber cheap. All RB does to the front is heat treat it and a larger thrust washer/related components.

What does the 1992+ engine's larger thrust washer and whatnot offer that the 12a's do not? Is it just to keep it in line better? Also, is the RB hardening comparable to cyro treating? Which would be better, of the two?

 

Come to think of it wouldn't Mazda already harden the steel?

Can anyone get some verification on this? I have been searchin for a few days now.

EDIT: I am worried that if I get it treated it would only make it brittle.

 

IIRC the RX8 has the first factory heat treated stat gears. RB has been doing it for years for high HP applications. Actually, the RX8 gears have all the tricks RB has been doing.

 

i got a furnace at school used for heat treating, would i be able to use that for the stat gears?

 

I think it has to be like super accurate. I have access to 1500*C ovens but I do not know if I want to do that lol.

 

OEM stat gear hardening began with the S5, 3 window bearings began with the FDs. It's simply Mazdas continuing durabiity improvements. Can't comment on the thrust washer. If you buy the hardened gear, no further treatment should be needed.

 

So the stock S2 stat gears are not hardened?

 

no

 

I'm with trochoid. Buy the hardened 12A gears and feel happy that that's all you need.

 

but who has had a stat gear failure?

 

I've seen a few pics of failed stat gears. I think Midwest7s found a chewed up one in an engine he tore down. The point of hardening is to be able to rev/run above 8k on a regular basis. This however is just 1 step in building the entire engine so it will last with sustaind high rpms.

Since the cost difference is small between the stock and hardened gears, it's worth the upgrade. Using them doesn't mean the engine is ready for 8k+ though.

 

We've had them crack but not come apart. In fact that engine is apart right now, it happened last race. If the car wasn't brought in when it was there would be quite as few worthless parts.

Thanks trochoid on the hardening question, we just buy RX8 stat gears for our 13B's because of the improvements.

 

Cool, thanks guys. I can get them Cyro Treated for a little over $20

 

tt

 

Holy **** lol. Any ideas how that happened?

 

It was a Hayes motor. 'nough said.

 

They rebuilt the one that's in my car to be the Spec 7 20K miles ago... I found the paperwork in a folder in the back.

 

Man you got lucky. Glad it worked out in the end.

 

I had a front stationary gear failure in 2004. The gear was a new 20B front stat gear, on a new PP motor; it had about 6 hours of easy break-in then 3 racing hours on it when it broke.

I put another 20B front stationary gear in it, and a new '91 13B rotor, and it has held up great for the last 3 years of P-Port road racing (fingers crossed.)

 

In regard to the Rx8 stat gears, I believe only the six port engines have hardened gears, the four ports are not.

 

i don't know im looking at the center stat gear bearing an it looks like that **** didn't have no oil running through it and it locked...cuz that bearing looks pretty bad...

 

Just buy'em hardend because if you over heat the gears they may actually become brittle and you'll regret not forken out the extra $$$$. There is a reason why everyone isnt just hardening there own gears.

 

+1 on above...spend the money do it right the first time...

 

i have a set of racing beat hardened stat gears that i have been trying to sell if anybodys interested. they're for 13b only.
https://www.rx7club.com/showthread.php?t=682064