Black Fiber Synchros on all 5 gears?

[blodi]

This was the kit I purchased and supplied btw. 

http://m.ebay.com/itm/371349852020?_mwBanner=1

I left a message for the trans guy today so we will see what he finds when he dives in further. 

 

[Zed Head]

That's the same not-quite-right kit that's been out there for as long as I've been aware of rebuild kits.  Notice that the name/ID of the transmission is wrong, it should be FS5W71B, not 71A.  Also notice the two different types of synchros (aka baulk rings, look at the number of teeth if you use the magnifier in the eBay link) in the picture when other places call for 5 synchros of the same type (even though some also call for a different 5th gear synchro).  The ones in the kit picture (called out as the actual parts), show two different styles.  Plus, too many exclamation marks.  And why would you call a baulk ring a "crush ring"?  Don't get that.

Here's a reference, also look at the other link  I posted.  Part #45.   http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-gears/5-speed

The Z car trans rebuild market is kind of messed up.  I think that some parts shop created a list of parts many years ago, with the wrong trans ID number, and everybody uses it.  Kind of weird how that wrong ID follows the various "different" sellers around the internet.  Seems like somebody would have the details figured out by now.

Don't want to be a buzz-kill.  But you'll probably pay more in labor than parts.  Just some odd things I've noticed.

[Zed Head]

Browsing around, I find that Courtesy has discounted the synchro prices.  Not terrible.  http://www.courtesyparts.com/oe-nissan/32604p0100

[Zed Head]

Hope you don't mind but I tend to pile on when this topic comes up.  Here's a good thread from Hybridz.  duragg is the guy that rebuilt his transmission many times and knows most of the inner workings.  Full disclosure, I'm in there as NewZed (unintended multiple identities).

http://forums.hybridz.org/topic/113022-syncro-difference-btw-closer-ratio-and-wider-ratio-fs5w71b/

Here's another link where the guy, who seems to know some stuff, was disappointed in the kit parts - http://zhome.com/ZCMnL/tech/240SX5spd/transmission.htm

[blodi]

Gotcha. Ok. So do you think id be ok just getting the nissan synchros? Do you think the bearings and seals are ok from the kit I ordered? 

Thanks for the Courtesy link too. That certainly shaves a chunk off of the price. Thanks for all the help.

Maybe I just need to stop back by the shop and take a look for myself since he's hard to get on the phone. 

[Zed Head]

I can't really say.  As the guy in the second link notes, the kit synchros were okay for average driving.  But stock worn synchros probably are too.  The bearings in your eBay kit are Nachi brand which seems reputable and is what comes in factory boxes, I think, so those look okay.  But as duragg noted, some of the kit seals were wrong.  So, some of the kit parts are probably fine, but you might need others.  And, since you only saw problems in one gear, maybe you only really need one synchro.  Four worn and one new Nissan synchro might be the way to go.  You said 2nd was grinding like crazy but didn't say at what RPM, and only you know if the others were fine.  Personally, I found that the fluid used had a big affect also.

I tend to collect a bunch of information then put my own plan together.  In short, all I'm really saying is that the rebuild kits that are out there aren't known for making people happy.  Don't expect a like-new transmission, even if your guy knows what he's doing.

[blodi]

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. 

[blodi]

And yeah, I realize the labor will be the more expensive part.  I've never torn down a trans before and figured I'd have enough on my plate doing the engine swap...now...turns out I'm mainly just waiting on the trans.

[Chickenman]

As well as worn synchros, you could also have a bad Clutch Master Cylinder. Being made out of aluminium the bore will pit from water absorption in the Clutch fluid. Then the seal lips get damaged and the fluid will bypass internally. You end up not getting the full " stroke " out of the Slave cylinder and the clutch " drags " when shifting.  Second gear is always the worst. Note that you may not see any fluid leaking from the M/Cyl pushrod area, as it is an internal leak, usually in the part of the cylinder bore that wears the most.

It's a fairly common problem and typically rears it's head after a clutch change. The new Pressure plate will have a stronger diaphragm than the old one  and the extra pressure is more than the Clutch Master Cylinder can handle. It's the " tipping Point " so to speak. The slave cylinders are less prone to corrosion and pitting because they are made out of cast iron.

It may be a good idea to replace the Clutch Master Cylinder while you're at it. Especially if it's old. Probably the slave cylinder as well. Suppliers such as MSA and R**k - A*T*  sell them . RA has very good prices.

[blodi]

Clutch master, slave and clutch itself are all a year and half old with maybe 3K miles on them as I put all new stuff in when I swapped the car from auto to manual. 

[Chickenman]

^ OK that's good then. BTW... X2 on the Nissan synchros. They are very good quality.

[blodi]

Ok so I stopped by the trans shop today to have a look at things myself. Just as he described the synchros were all black. I don't know if these are what "black fiber" synchros are, they seemed to be metal. The 5th gear synchro looked exactly the same. The brass ones that came with the kit I bought indeed seemed to be too small. So I ordered up the Nissan ones from Courtesey and hopefully they can be installed. If the ones in my trans currently are the NLA 5th gear black fiber ones...well I'll have 3 for sale soon.