annuerysm

I am building an aux bridge motor it is an S4 core but will have S5 rotating assembly, I have put in new bearings into the S4 stationary gears (FD bearing in front and RB 3 window in the rear gear) I was wondering how much better the FD gears are than the the FC ones are. Thanks.

-Dan

rx7_re

86-88 stationary gears are not as strong as 89-93 ones.



I know that 89-91 stationary gears were hardened at the factory which just enabled those engines to rev higher. I am also pretty sure that the FD stationary gears are just like the 89-91 gears.



Unless you plan on reving past 8000 or so it might be a good idea to get them. You should be able to pick them up for a good price too.



Can anyone bacl me up? I am not 100% sure about the similarities betwwen the s5 gears and the FD gears.

annuerysm

yeah I am definately planning on revving high, anyone have personal experience?

mazdaspeed7

I had heard before that none of the FC stat gears were hardened, but i wouldnt exactly call it a reliable source. All of the S5 stat gears I have seen have the signs of hardening(discoloration where there is a change in the shape). SO I really dont know what to say. I would like to see confirmation from a reputable source.

rx7_re

I am almost dead positive that they were hardened, just need someone to confirm this. I have ssen those hardening marks as well, so there is no dout in my mind, and since the s5 engines and s6 engines are very similair....

annuerysm

It would be bad *** if the S5 and FD stat gear were the same. Can anyone confirm this?

mazdaspeed7

They are definately not the same. But they are both hardened, as far as I know.

88fc3sw/hx83

The 13BRE motor that I have had hardened gears as well.

andynogo

I think the FD gears are a bit deeper on the gear face. If ya know what I mean. My S5 gears were hardened too.

R100Extreme

If your going to "Rev" High I would put three window bearings in... Just my 2 cents.