Correct me if I'm wrong ,but you can use the stat gears froma FD correct? Also arent they multi window bearings ,and arent they hardend?

 

I don't know. I thought the fd/fc stationary gears were the same... But I do know that the rx8 stat gears are factory hardened w/multiwindow bearings and can be used in fc's...later

 

I am pretty sure that there were changes between S4 and S5, but they remained the same into S6.

 

so the s5 also has the multi wondow bearings too?

 

we need one of the gurus to answer this for me

 

I'm not sure about the FD stationary gears, but the the S5 gears are an upgrade in an s4 motor.

 

also can the FD tension bolt be used in my s4 irons?

 

The FD gears will work in the earlier engines. They do have a multi-window bearing. They are nitrided for wear but are not induction hardened.

 

the FD gears and tension bolts will work fine for any 13B.

 

So could I just buy the Rx8 front and rear hardened stationary gears and use them without any problems in my 88 n/a rebuild?

 

why would you need to use them in an 88 n/a rebuild? are you planning on doing some serious HP mods?

 

There is some debate about using RX-8 gears with earlier rotors right now. Apparently the 8 gear has a different profile than the rotor gear in the early rotors. The 8 gears and bearings are much cheaper than the FD parts however.

 

The other difference is the O-ring placement on the stationary gears. RX-8's use them on the iron, whereas all other 13B motors use the O-ring on the gear itself. I am pretty sure this is solved by the use of some silicone sealant.

 

you can use the FD gears, yes.
however i think just going with the RX-8 stat gears is the best solution. cheaper than the 13b ones and i haven't heard of any downsides to using them, other than having to do that simple modification on the rear stat gear. advantages...
- comes with multi-window bearing
- treatment and manufacturing process is best so far compared to previous generations
- there is something about the way the teeth are cut to better handle high-RPMs (i forget exactly)

from mazdatrix:
"If using the RX8 rear gear in an earlier 13b engine, you must add sealant where the rear gear o-ring WOULD be. There is no groove to hold the o-ring because the Renesis engine mounts the o-ring in the side housing rather than on the gear. We recommend using Hylomar, but a THIN layer of silicone sealant will also suffice."

 

I'm re-building my motor and have been giving serious thought to oiling. My NA shot craps due to rear rotor failure and I understand that that is common. I've researched the mods like 85 PSI rear reg. up-grade pump, windage tray, etc. Here's my questions; Why did Masda cross-drill the front e-shaft bearing supply, and not the back? Has anyone cross-drilled the rear bearing feed? Does this signifigantly weaken the e-shaft?