wargasm, Any particulars on that 5th gear you mentioned?

What is the stock 5th gear synchro made from?
Is it possible to buy a stronger one?

Re: 5th gear synchro
 

jkekeisen

How did you get the nut off the countershaft?

Sorry didn't see this before.

This is a 5th from another model of RX-7 in Japan. PM me if you want more info.

Brian

Where in MA are you? Wanna help me do mine sometime? :D

Once the synchro is fixed consider getting a B&M short shiter. They are cheap(~$150) and have an extra lateral spring that centers the shifter making it damn near impossible to hit 5th when doing a 2-3 shift (the common cause of sychro failure). In the 2 years (40k miles) I've had the B&M in I can honetly say I've never missed a shift.

Jon
'93 SSM base
working 5th gear synchro since '01

Re: Re: 5th gear synchro
 

There are two ways I know of to get the nut off. The problem is that the shaft will want to turn the transmission shafts rather than back the nut off.

option 1 - put the transmission in 1st gear and hold the input shaft in a vise (using wood or cloth to avoid damaging it). Now that it's secured from moving, take off nut.

option 2 - remove one or more of the roll pins that are set in the 1/2 or 3/4 or 5/R shift select spindles. Now that you can move the shift selectors independently of the shift rods, you can put the transmission into a double engaged condition. For example, select 1st gear and 3rd gear at the same time. This will lock the two shafts of the transmission so they can't turn. Now remove the nut.

Brian

Coming from Wargasm...that just sounds bad.
Ok real question...Has anyone heard of any custom ratio sets? Just curious because my friend has an 86 and there are several custom gear sets for his tranny.

There are 3 5th gear ratios I know of for the FD:

0.719 : 1 - stock
0.762 : 1 - From Turbo II
0.806 : 1 - From RX-7 Type R Bathurst model in Japan (I have this one in my car now)

There are also COMPLETE gearsets you can get such as the HKS transmission or the Guru Racing transmission, but those are MUCH more expensive and a LOT more work to install.

Brian

how much did the new 5th gear syncro cost you? did you buy it from the dealership?

another way to remove the countershaft nut, use an impact wrench.

I think the question was how to hold the shaft still, not how to put torque on the nut.

Dave

By using the impact wrech, you do not have to hold the shaft still.

Btw, the TurboII 5th gear has 2 ratios depending on the year. 89-91' is slightly taller and the 87-88' is lower.

5th synchronizer gear part # W501 17 725c was what I used I think and it was around 20 dollars from Ray Crowe/Malloy Mazda. Ray is the only Mazda person I deal with and he always makes me happy :) Give him a jingle at 888 533 3400 and ask for Ray.

Brian

thank you this thread was very helpful

My t2 'box does this also. I have to double clutch into fifth. Should i be worried about the syncro letting go and going throughthe gearbox?

So I'm in the reassembly stage of this, how do you press the bearing back on? The one you use the extended pullers to get off?

^ Problem solved, found a big enough pipe in the basement and hammered it on.