Turbo II-FB

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?

slomo85

iTrader: (8)

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

MrDirt

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

Turbo II-FB

so the s5 also has the multi wondow bearings too?

Turbo II-FB

we need one of the gurus to answer this for me

Smoken'

iTrader: (1)

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

Turbo II-FB

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

C. Ludwig

iTrader: (27)

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.

RotaryEvolution

iTrader: (30)

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

ageman

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?

RotaryEvolution

iTrader: (30)

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

C. Ludwig

iTrader: (27)

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.

MrDirt

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.

coldfire

iTrader: (1)

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."

TonyD89

iTrader: (10)

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?