Sounds like a Comp box to me. although one that is not very desirable.  Most racers want a direct drive 5th with the middle three gears much closer together. I might have a customer for it - we are building an endurance rally car for them.

43 minutes ago, John Coffey said:

Sounds like a Comp box to me. although one that is not very desirable.  Most racers want a direct drive 5th with the middle three gears much closer together. I might have a customer for it - we are building an endurance rally car for them.

Well, let me know if they are interested. It'll be a little while til I get the right synchro ring and get the trans back.  Once I have it back though...I'll be wanting to just put it back in the car with the new engine. Then I'd have to find another standard wide ratio 5 speed.

OK, so I got the measurement of the synchros...they are the 78.0mm versions mentioned above. Part#  91130230108  for those in the future. 

Ordered one up and hopefully that does the trick. I'll keep you guys posted as to how it works. 

I'm also going to order that Swepco 201 fluid to put in. 

Edited January 14, 20169 yr by blodi

Where did you order it from?  Pictures?  I'd like to see what, exactly, a servo synchro looks like.

Found some pictures on the interweb.  So you're going to test JMortensen's old boss's theory, that a Porsche synchro ring is a direct fit in a Nissan transmission.  Should be informative.

Edited January 14, 20169 yr by Zed Head

Got it from Autohausaz. So, yes, going to test the theory. I'll confirm if it works or not. Hopefully it does and it helps others down the road. 

Synchro came in yesterday...going to drop it off tonight at the trans shop on the way home. I'll keep everyone posted if it works....

IMG_5907 by blodi, on Flickr

IMG_5909 by blodi, on Flickr

IMG_5910 by blodi, on Flickr

Another update on this saga.....

My trans guy installed the Porsche ring...but realized it had a bit of play. He then took it back out and found that the diameter was correct, however, the width was too narrow. The rings in the trans are 8.5mm and the Porsche ring was 7.5mm.  So...after searching even more and looking into the Roadster rings...I stumbled accross this pdf for the old Nissan Motorsports catalog with a schematic for every comp trans.... https://docs.google.com/folderview?id=0ByCvxnHNk90SZTAwYTI4Y2YtNWM4Yi00ZjUxLTkyZTYtNjQ2YTJjOTcxNDAw

Finally got a part number! 32611-14600  Found it online and ordered it last night. Hopefully this is right this time. I'll post with updates. 

 

 

Thats a shame it didn't work. Would have been nice and given you and others the opurtunity to source new parts for these transmissions.

I have had similar problems with the EFI fuel pumps. They look so very identical, but Hitachi changed the dimmensions ever so slightly. The parts that wear in the pumps, Bosch or Hitachi are not interchangable.

Ok, got the Nissan part. It does measure 8.5mm in width. Dropped it off today at the shop...hoping to have it back this week and get the engine/trans back in the car. I'll confirm for sure once the car is up and running, but it looks like this should be it! 

IMG_6038 by blodi, on Flickr

 Been thinking about the 2nd gear grinding issue. My first Z had this problem. When I tore it down, I found pristeen synchros. No wear on any part of the assemblies inside or out. Didn't want to do the job again so I bought synchro assys from Nissan and sourced the bearings at a local b. supply co. Put it together and it shifted perfectly. For forty some years I had not come up with the reason for the previous 2nd gear problem until the subject of gear oil came up a few weeks back. The main subject was brass and gear oil compatibility but there was a mention of gear oil affecting the shifting. I'm beginning to believe my original problem could have been cured with a different oil brand. Back then, 1975, I probably used Kendall to refill the trans. I'd like to hear from the members what brands of gear oil (brass compatible) have caused balky shifting or what oils have cured it. Anyone with an opinion?

I found that Redline MT90 was better than Valvoline for a 3rd gear high PRM grind, and 75/25 blind of Swepco 201/AT fluid was better than MT90 for a 2nd and 3rd gear grind.  Both old worn transmissions. 

Forgot to say that this topic has been discussed in to minutiae in other threads and could easily add a few pages to this Porsche style synchro thread.

Edited February 8, 20169 yr by Zed Head