Zx 5 speed rebuild

[EuroDat]

4 hours ago, Patcon said:

I was noticing that the 5th had parts that looked like the Porsche synchro

Its not. The porsche type synchros are steel and this one is a fibre type clutch synchro.

I think they changed somewhere in the 79-80 model 280ZX. About the same time they dropped the 4 speed. Of course all close ratios have the 5th warner synchro, but the 2+2 variant still used the wide ratio FS5W71B.

Btw. Very bad idea for a manufacturer to mix servo type (porsche) and warner type synchros in the same transmission. The brass rings require GL-4 and the steel servo type requires a GL-5 lubricant like the diff.

[EuroDat]

1 hour ago, Dave WM said:

I ended up using the one ZH mentioned that he sent me (on yet another trans rebuild I did). That being said, I doubt those chips will make any real diff, even with the good gear installed its "balky" at times. this is most likey due to design, its a crash box setup. I would recommend you just dress them up a bit, a flat file to take off the sharp edges, but again I don't know if it will matter any.

I agree. The only concern I have is the chipped teeth can crack further and (even though small) a chance the small pieces end up between the gears on there way down.

Charles: You mentioned in another thread it has 23 teeth. I have only seen 21 and 22 teeth. Didn't know they were also with 23 teeth.

[Patcon]

11 minutes ago, EuroDat said:

I agree. The only concern I have is the chipped teeth can crack further and (even though small) a chance the small pieces end up between the gears on there way down.

Charles: You mentioned in another thread it has 23 teeth. I have only seen 21 and 22 teeth. Didn't know they were also with 23 teeth.

We counted twice but I will count them again. I will also take some time to pin down the ratios and the year

[Patcon]

We double checked, reverse idler is 23 teeth. Is it possible it was replaced with the wrong part?

It appears this tranny has had work. The rear staked nut is also peened

Also that nut is a standard threading (RH)

[Patcon]

X Main Shaft Nut Datsun Nissan FS5W71B FS5C71B Overdrive & F5C71B Direct Drive 5-Speed 32354-A7400 32354-E9800 32354-E9802 32354-E9804

I think I'm gonna need to find one of these or get it made. Can someone provide a cross reference for what vehicles these would have been in. Do the 4 speeds have this nut? they don't do they?

[EuroDat]

4 hours ago, Patcon said:

32354-A7400 32354-E9800 32354-E9802 32354-E9804

That is the correct nut for your main shaft. It is an M27x1.00mm right hand thread nut. It fits all the 5 speeds FS5W71B from 1977 to 1980.

After 1980 the nut changed to left hand thread. I think that is when they also changed the 5th synchro. I think fibre synchro is right hand thread and brass synchro is left hand thread.

You don't need to replace it. There is a trick to recover an old nut and safely reuse it. The section that is hammered down to lock it in place doesn't have any thread inside. It doesn't add any strength to the nut, just a way to lock it in place.

Remove the nut using a small srewdriver or similar, you can drive it in between the nut and shaft to open it enough to remove it without too much damage. Side the nut over something like a socket in a bench vice and use a small hammer to peen around the burred section. You want to get it to point where it doesn't bind too much when you screw it on.

When you rebuild the transmission and fit the nut. Tighten the nut and check where the burred section lines up. It probably won't line up with the groove, but if it does then have the face contacting the gear hub washer machined 0.5mm. This will turn the nut 180 degrees to the groove. Every 0.25mm will move the nut 90 degrees around the shaft, 1mm being the pitch.

You can do this with the overdrive nut as well.

Edited December 19, 2020 by EuroDat
Rht and lht

[pogden]

@patcon, I saw your post earlier today and was wondering the same thing. I have a 4-speed in the shed, will try to find time to have a look. I haven’t started on my wide ratio yet, and I know mine came from a 79 ZX. It will be interesting to see whether mine has a RH or LH nut.

This page has some interesting data, http://mmerlinn.com/catalog/dox_angel/dt_w7b/dtw7b010.htm and the company itself sells recycled parts. For what it’s worth, my transmission guy said they were very helpful in finding a “good” input shaft for my close ratio.


Sent from my iPad using Tapatalk Pro

[EuroDat]

1 hour ago, pogden said:

@patcon, I saw your post earlier today and was wondering the same thing. I have a 4-speed in the shed, will try to find time to have a look. I haven’t started on my wide ratio yet, and I know mine came from a 79 ZX. It will be interesting to see whether mine has a RH or LH nut.

This page has some interesting data, http://mmerlinn.com/catalog/dox_angel/dt_w7b/dtw7b010.htm, and the company itself sells recycled parts. For what it’s worth, my transmission guy said they were very helpful in finding a “good” input shaft for my close ratio.


Sent from my iPad using Tapatalk Pro

The 4speed nut is an M30x1.00mm. Right hand thread. Well it should be iirc.

Edited December 19, 2020 by EuroDat
Photos

[Patcon]

10 hours ago, EuroDat said:

That is the correct nut for your main shaft. It is an M27x1.00mm right hand thread nut. It fits all the 5 speeds FS5W71B from 1977 to 1980.

After 1980 the nut changed to left hand thread. I think that is when they also changed the 5th synchro. I think fibre synchro is right hand thread and brass synchro is left hand thread.

You don't need to replace it. There is a trick to recover an old nut and safely reuse it. The section that is hammered down to lock it in place doesn't have any thread inside. It doesn't add any strength to the nut, just a way to lock it in place.

Remove the nut using a small srewdriver or similar, you can drive it in between the nut and shaft to open it enough to remove it without too much damage. Side the nut over something like a socket in a bench vice and use a small hammer to peen around the burred section. You want to get it to point where it doesn't bind too much when you screw it on.

When you rebuild the transmission and fit the nut. Tighten the nut and check where the burred section lines up. It probably won't line up with the groove, but if it does then have the face contacting the gear hub washer machined 0.5mm. This will turn the nut 180 degrees to the groove. Every 0.25mm will move the nut 90 degrees around the shaft, 1mm being the pitch.

You can do this with the overdrive nut as well.

How would deal with the punched spot? I thought I would drill it out some to make it thin and then try to thread it off...

[Patcon]

10 hours ago, pogden said:

@patcon, I saw your post earlier today and was wondering the same thing. I have a 4-speed in the shed, will try to find time to have a look. I haven’t started on my wide ratio yet, and I know mine came from a 79 ZX. It will be interesting to see whether mine has a RH or LH nut.

This page has some interesting data, http://mmerlinn.com/catalog/dox_angel/dt_w7b/dtw7b010.htm, and the company itself sells recycled parts. For what it’s worth, my transmission guy said they were very helpful in finding a “good” input shaft for my close ratio.


Sent from my iPad using Tapatalk Pro

I couldn't get the link to work

[pogden]

1 hour ago, Patcon said:

I couldn't get the link to work

Sorry - late nite post on my iPad, must've somehow fat-fingered in an extra comma at the end of the URL. I fixed it in my post above, and here it is again: http://mmerlinn.com/catalog/dox_angel/dt_w7b/dtw7b010.htm

[EuroDat]

3 hours ago, Patcon said:

How would deal with the punched spot? I thought I would drill it out some to make it thin and then try to thread it off...

The punch spot is from a previous rebuild and not doing anything. The only spot you can lock the nut is where the groove is on the shaft.

Someone has already reused the nut.

I would rebuild the transmission and if the nut lines up where it is aready used, then take action the move it to new metal by facing the nut or adding and extra shim.