Black Fiber Synchros on all 5 gears?

[Zed Head]

Groovy!  Looks like steel, not "black fiber" (who coined that term anyway?).

Found an old thread with pictures.  Edit - modified the link so that it can be opened.  something weird gonging on.

Change the space between community and ratsun to a .

community     ratsun.net/topic/51601-5-speed-id-help/page-2

 

 

Edited January 9, 2016 by Zed Head

[Zed Head]

Still weird that your guy couldn't tell steel from brass.  Oh well.

Note the conversation on the Competition transmissions in that link and the different ratios.  John Coffey probably knows what you have there.  Might reply if you sent him a message.

[Captain Obvious]

Brass sometimes tarnishes to a blackish  color. Maybe they are brass, but are just a little discolored?

[Zed Head]

They look like steel on my computer.  A brush with some Scocthbrite would remove any tarnish.  But they'll be out and on the bench soon anyway.

The outer part of the teeth is thicker also in the pictures, both here and my ratsun link.  Almost like tops have been machined down.  Pretty sure I saw a post from JMortensen about machining Porsche steel synchros to fit the Datsun transmissions.  Don't know where Datsun gets their steel synchros.

It's an interesting puzzle.

[Zed Head]

Found some old CZC.com threads on the steel Porsche-style, and actual Porsche factory,  synchro topic.  Haven't figured out if it's just the synchro/baulk ring or if you need the gear/cone that goes with it too.  Steel and brass might not be interchangeable.

It looks, though, that the gear ratios might tell if you have a Competition transmission.  The ratios can be pretty tight 1st to 5th.  Might not even be suitable for the way you plan to drive.  Here's one example, not sure if they're all like this.   2.906 / 1.902 / 1.308 / 1.0 / 0.864. 2.906 would need something like a 3.9 diff, which would make the .864 5th a 3.37 overall.  Compared to a .864 with a 3.54...3.06.  

Just playing around in your thread.  Good luck.

 

 

 

 

[Chickenman]

Talk about a wild goose chase. You should smack your mechanic up the side of his head!! Hadn't even taken it apart and was misidentifying parts.

Those definitely look like Steel Porsche Style Servo rings... not " Black Fiber " as your Tech called them. Those servo hubs  also look completely different from the standard Nissan Brass synchro ring style  You may have a bit of a rare beasty. It's likely a Competition Transmission as ZH noted or possibly a Roadster 2000 with a Competition Tail Housing conversion as listed in the link below. .

Either way I would not be throwing that tranny away. It could be worth a lot of money to a Vintage Racer looking for the correct transmission. When your tech gets it apart, I'm betting that he's going to find Steel Porsche style shift servos. . Those are the Porsche style and only came in some Competition boxes and I believe the Roadtser 2000. Brass Synchro rings from Nissan will not fit

Transmission ratios  will tell the big story. If 5th gear is a direct drive ( 1 to 1 ratio ) then that tranny is probably worth a whole HEAP of money. Those are high desirable Direct Drive Competition Boxes. If overdrive and still a Competition Box or converted Roadster Box, it's still worth a lot. Calculate the gear ratios for each gear and post them up. ( Important: Count the gear teeth to be accurate)

Here's an article listing the various versions and ratios of Nissan passenger car and competition 5 speeds. Check out the competition boxes carefully.  A lot of different gear ratio combinations in both Direct Drive ( 1 to 1 5th gear  ) and Overdrive. All the Competition boxes and Roadster 2000 boxes are worth big $$$

http://www.zhome.com/ZCMnL/tech/GearRatios.html

Whatever you do... hold on to that tranny till it's properly identified!!!

 

 

 

Edited January 9, 2016 by Chickenman

[Chickenman]

On 1/5/2016 at 6:08 AM, blodi said:

I was using Redline MT90 fluid in it the trans. I'm fine buying all 4 new Nissan brass synchros if it keeps the trans happy for a long time. 

2nd was pretty much impossible to get into without grinding while downshifting unless you were almost at a stop. From 1st to 2nd it would be "ok" if you really gave it a lot of time. 

If those do turn out to be Porsche Style Servo rings then the Redline MT90 may not be the correct oil.  Brass or Bronze synchro rings require a GL-4 or some other " Yellow Metal " compatible transmission oil. However... STEEL synchro servo's are a different matter. They may require a GL-5 High pressure differential gear oil. I would be checking with Porsche gearbox specialists about that or maybe some EXPERTS on Nissan Competition boxes. ( J Coffey where are you?? )

I'm thinking that the co-efficient of friction between a Brass synchro ring to a Steel gear cone is not the same as a Steel synchro  to a Steel gear cone. The MTL90 may be too slippery . Need to do more research.. but it's a thought. Going to research Porsche transmission oils...

And hold on to that Tranny !!!

[blodi]

Wow, ok, lots of info to digest here. Thanks guys!

So....can I get these same synchros anywhere? 

Good to know on the fluid...I just never knew what I was dealing with I guess. Probably why it started grinding.

I did run this trans for about 3K miles this last year. I can't remember what the rpm vs. speed was when cruising to give an idea of 5th gear. 

Here is a quick video of the last time I drove it with the L24...maybe this gives an idea or ratios roughly? I'm using the 3.54 rear end that came with the car since it's was originally an auto. 

Funny side note since now it sounds like this trans is rare....I paid $180 for it. It came with a Kamerai light weight flywheel (which I also didn't realize at first) ,which I sold for $250-300..can't quite remember, because i just wanted a stock clutch and for the car to be easy to drive on the street. Now all this...what a find! 

 

IMG_5260 by blodi, on Flickr

Edited January 9, 2016 by blodi

[blodi]

Another question....if finding synchros for this would be too hard/impossible....can I swap the worn 2nd one with 5th....and then using the correct fluid...would I be ok? 

 

[Chickenman]

You should be able to find Synchros... but at least take it apart to measure things first and be sure of what you have. If your tranny guy isn't familiar with Porsche style Synchro boxes.... take it elsewhere. If they are Porsche servo style, you're likely going to need pictures and measurements and take it to Porsche Tranny experts to find the correct parts. Although I'm sure that there are some Datsun Racers out there that know where to source these. Read ZH links carefully. A lot of the research has already been done. I believe that a Porsche " 915 " style transmission was mentioned as being the same parts as the steel Nissan Competition parts.

You should not swap used synchros from one gear to another. The Synchro and cone lap into to each other precisely  and must be kept matched.

You should count the gear teeth on the mainshaft and countershaft to determine transmission ratios if you want to accurately identify the Tranny.  Determining gear ratios by a video? ...Ummmm... NO 

And you want to accurately identify that transmission, because it could be worth a lot more as a used Tranny to a Vintage Racer than it is for a street car. You could pick up a used non-competition 5 speed ( FS5W71A or B ) with Brass synchros. Overhaul that and sell the Competition box to a Vintage Racer who is trying to find one of these.

 

Edited January 9, 2016 by Chickenman

[Chickenman]

You paid $180 for it??? Lucky SOB!!

If it turns out to be a Direct drive competition box, I wouldn't sell it for a penny less than $1,500 used. J Coffey mentions that a good used Nissan Direct Drive Competition tranny can go for REALLY big coin. Possibly $3,500 used for a top condition Ultra Close DD ( Ultra Rare ). Gear, Mainshaft and countershaft condition are the key determination. Synchro's can be found " relatively " easily. Ultra close gear sets are Ultra rare. Middle Close gear sets only slightly less so.   

http://www.zcar.com/forum/10-70-83-tech-discussion-forum/304300-nissan-competition-5-speed-direct-drive.html#post2114860

For comparison. Used Datsun 1200 Competition 5 speeds ( F5C56A )  fetch up to $2,500 these days. Uber rare Hall-Hewland conversions  ( straight cut Hewland gears ) for the Datsun 1200 fetch about  $4,500 these days. That's for a USED transmission!!

http://www.peterzekert.com/for-sale/transmission-rear-end/115-datsun-a-series-transmissions

 

 

 

 

 

 

 

[blodi]

Thanks! I found some porsche 915 synchro rings online...so the ring is separate from the gear part of the synchro on these, correct? 

http://www.ebay.com/itm/like/181976027736?ul_noapp=true&chn=ps&lpid=82

I do know that vs. my auto trans, this 5 speed has much lower revs (800-1000 less) on the highway in 5th than in 3rd in the auto. 3rd in the auto is 1:1...so this must be one of the two overdrive versions of the trans. I'll have him count the teeth on Monday or stop back by myself. I guess if someone is able to point me in the exact direction of what Porsche part i need....I'm good. 

Yeah, debating if I'd sell this trans or not now...Might be a nice match with the race built L28 that I'm currently putting in.