To people with experience with the Datsun Comp. 5 speed, need parts for one

[KnightoftheRound]

I told Sam about this, and he said that the grooves in the selector rings wear out commonly on those transmissions. Only way to know for SURE is to wait for the fork hes sending me, go back, and see how it fits into the PORSCHE ring.

 

I haven't checked on the synchros themselves yet, I will bring a couple of the gears and synchros with me next time I go back to Don and see what he can tell me.

[JMortensen]

Keep it up! If this all works out I think you'll help a lot of people here.

 

It's been a really long time, but one thing I used to recall us doing to help wear here was to file the points on the gear clusters where the ring engages. If you grind the gears too much the points get mushed up and I think that contributes to the problem.

[Zgotrip]

MY apologies if this is a little off topic but I have been watching this one….

 

So I have the same trans in my car with bad syncros and JMort Had turned me on to the Porsche syncro thing. I had hoped to limp it till winter and deal with it then but it’s started to pop out of 4th so its gota go. I love this box when it behaves fun for sure but I wonder if they’re worth the trouble. Can this trans handle 260+hp? Like to see someone talk about how well this trans has worked out for them and in what application. Mine will be a street car so I think it won’t make it back into the car regardless, but I think I will miss it. The other Question is what are these things worth in this condition? Mine might be good for parts or? Love to trade it for a solid T5. Never seen a comp box for sale any condition…but I expect rebuilt well it would bring good $$$...or not?

[JMortensen]

All of the real hardcore road racer guys are using these transmissions, so they're usually in the 250-300 whp range. The T5 is a POS in comparison as far as I'm concerned, especially if you're comparing a close ratio Comp box to a T5 which has very wide ratios and you have a high strung NA engine. Parts are really the only problem. It's not really that surprising that it's hard to find a 35 year old competition transmission that doesn't need a synchro or has a broken shift fork.

 

I would say fix it and use it, and if it doesn't make that much of a difference to you what the ratios are, then sell it to someone that REALLY wants it and buy a T5 or something else. They do bring good money with the road race crowd because they are better.

Edited June 20, 2010 by JMortensen

[Zgotrip]

Well hopefully I will be pulling mine out this weekend and we will see how bad it is. After looking around and seeing all Jon’s posts on the Porsche syncros over the years I feel like doing it just to see…not sure I can live with the 1:1 5th in my street car though, so we will see…hopefully knightoftheround will have good luck and be able to get it done.

[Zgotrip]

Well i got mine out and apart... all the syncos are missing at least 2 teeth and 2nd is shredded. i have decided to let this one go as i really need an O.D. 5th. I will put it up in the for sale section in a few days but thought i would offer it up here first as it does qualify as "parts". In the car it would grind into 2nd, grind against reverse coming out of 5th, and occasionally pop out of 4th. I don't know anything about transmissions but this one looks fairly nice to me, i believe someone has rebuilt it before as the forks look to have double role pins. i have no idea what its worth, one guy told me i would be lucky to get $200 and another not to take less than $700, but neither wanted it.

[KnightoftheRound]

I would take it off your hands if you lived closer.

 

I am going back to see Don Schnieder tomorrow with my new shift fork, and a couple gears to confirm fitment. Sorry for no updates, I have been busy tearing down and stripping paint off my new 240Z.

[KnightoftheRound]

Here is what I found out today:

 

I took one of my gears, along with my dat-comp operating sleeve and the modified 240Z 4-speed fork I got from Sam.

 

 

As you can see, the Porsche ring (left), has a smaller groove than the Datsun one (right), so the only way to know was to try to stick the fork on.

 

 

Which ended in fail because the groove is too small. I was recommended to just have the groove machined out, as its a very minimal clearance issue.

 

Now, I haven't attempted to order the new operating sleeves (what Porsche calls them), but Don showed me the company he got them from last time he needed one, and its $220 or so EACH.

 

The transmission to source them from is a "Porsche 901 5-speed", he didn't give me a year, and I had forgotten to ask, if it matters. The Porsche ring fits nice and tightly over the gears though, which is nice.

 

Next step is to get new op. sleeves and fix the bent shift rod and put it back together and see how it works.

[JMortensen]

Seems easier to grind down the shift fork, especially if it is just .010" or .020".

[KnightoftheRound]

I was thinking that exact same thing, to be honest.

[janne]

Hi

 

I´m try to found opt1 or opt2 DIRECT DRIVE gear box to my historic rally car and found that way this topic. When I loked pictures in this page and previous, those where are showing all gears and plate between covers, I think both of these gear box´s are OVER DRIVE type. If I look these from front of gear box, The gears are: Main drive gear(4th) , 3th gear, 2nd gear, 1st gear, plate between , reverse gear, 5th gear. I think this box has normal shift patern: 1st up left and OD 5th up right and reverse down right. DIRECT DRIVE ( 5= 1/1) has patern: 1st down left and reverse up left.

 

What are you people think about that?

[datsnut]

I know this is an old discussion, but I picked up on it from a customer. The transmission shown is not the Direct Drive box, but rather the much more common FSC5C71B, or more commonly known as the steel servo Comp. box. If the owner wants to know what he has, he can contact me at Pettersen Motorworks 530 895-3606 during the business day. Please count the tooth counts on the first gear (main shaft), and the first gear (countershaft). That will tell me which ratio gear set it has. If the gear set is in usable shape, I've got pretty much any part it could need. Let me know, Steve Pettersen

[HS30-H]

57 minutes ago, datsnut said:

I know this is an old discussion, but I picked up on it from a customer. The transmission shown is not the Direct Drive box, but rather the much more common FSC5C71B, or more commonly known as the steel servo Comp. box. If the owner wants to know what he has, he can contact me at Pettersen Motorworks 530 895-3606 during the business day. Please count the tooth counts on the first gear (main shaft), and the first gear (countershaft). That will tell me which ratio gear set it has. If the gear set is in usable shape, I've got pretty much any part it could need. Let me know, Steve Pettersen

 

It'll be either an F5C71-B (5-speed, Direct Drive) or FS5C71-B (5-speed, Overdrive), because there's no such thing as an "FSC5C71B".

[primaz]

I have two of the Datsun competition trans in our two mild street cars and love them.  One tip I recommend is to get the parts cytogenetically treated to increase the strength.