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KnightoftheRound

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

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Hey, I have this Datsun Competition close ratio 5-speed with the direct drive 5th gear, and need a couple parts to repair it with.

 

It needs the first/second shift rod and fork, all four synchros, and both couplings, I took pictures of the needed parts.

 

"Coupling"

IMAG0166.jpg

IMAG0165.jpg

 

Synchos

IMAG0164.jpg

 

Rod and Fork

IMAG0163.jpg

IMAG0162.jpg

 

Any help sourcing parts is greatly appreciated, I had heard that the Datsun 2000 Roadster 5-speeds were very similar.

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Thanks Titanium, I ordered a Nissan Motorsports Schematic Catalog that is supposed to have a blown up view of many of their vintage parts, including the comp. transmissions. I also PM'd TonyD on Zcar.com to ask him about it, but he hasn't replied.

 

The transmission looks awfully similar to the Datsun 2000 Roadster, Servo-syncho boxes that utilize steel synchros, at least the picture I have with all the parts numbers for the 2000R tranny looks pretty damned close.

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Another person to check with is Steve Pettersen at Pettersen Motorworks. He was building a Roadster five speed yesterday 5-28-10 when I talked to him. If, Steve does not have the parts he may know where to locate them.

530-895-3606

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Thanks 310Z.

 

I spoke with Sam Neave today. He informed me that the fork is NLA period, and that the couplings and synchros are somewhat obtainable, albeit hard to get. He recommended me to the parts manager of Lynchburg Nissan here in VA, named Riley Curtis. He said that he has been able to source parts for the transmissions he overhauls from old stock in warehouses or some such. He told me that the fork can be made from the shift fork of a 240Z or 510 4 speed, he said that they are the correct width, but the "mouth" part needs to be machined out to fit.

 

Keeping my fingers crossed for Tuesday when I speak with Riley I guess.

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There are no markings that I can tell on it, other than a number "#21227" stamped into the tail housing, and the number "7Z22620" stamped into the bell housing.

 

Would also like to know any other identifying markings. I just know what it is due to being in the family awhile, we even have the flanged drive shaft that goes with it still.

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Check into the Porsche synchro thing. I know I've posted about it here probably 7 or 8 times, some on classiczcars.com as well. 901 transmission has a servo synchro that is so close my boss when I worked for a Porsche shop was convinced it would work when we looked at them side by side on the bench. I ended up giving the trans to a friend who flipped the rings (they wear more on one side) because he didn't want to take a risk on using the Porsche parts. Do some searching you'll find more info on that. I want to say that somewhere along the line someone did use them and posted that they worked fine, but it doesn't come up that often.

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Sorry JMort, I haven't found any of those posts unfortunately. I've searched here, Zcar.com, and google up down and sideways on this transmission. Would love to find a confirmation on the Porsche rings if they can be bough from the dealer still (although they probably cost on hell of a lot).

Aftermarket are cheap and readily available. Search for "comp box" "comp transmission" "roadster transmission", etc.

 

Here's one thread:

http://www.classiczcars.com/forums/showthread.php?t=18577&highlight=comp+transmission

 

According to that thread, the Nissan synchro ring is cheap from Nissan too, if you can still get them...

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I see my memory is failing, I said 915 trans previously and 901 in this thread, so best to look at the servo in person (Porsche dealer parts dept?) before buying. The older 911's snap these things all the time just like yours did, so I would be surprised if they didn't have them in stock.

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You can't still get them unfortunately, Riley Curtis, who was extremely polite, helpful, and KNOWLEDGEABLE sadly informed me of this. He has ONE that he can get his hands on, lying in the parts department there, but its $238 for ONE and I need TWO.

 

So I need to ask for a mid 70s Porsche 911 "915" transmission coupler (what its called in the Datsun manuals)?

 

Thanks Jon!

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It's a synchro ring. I don't know if it's 901 or 915, so like I said I'd take a good one down to the Porsche dealer and figure it out that way. The 5th gear is smaller than 1-4 as I recall so bring the right size.

 

You might call Nissan Comp too. Sometimes things have been posted as NLA here and elsewhere on forums and they're still in stock. Doesn't hurt to check.

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Used to be Nissan Motorsports. I haven't called them since they were in SoCal. I think they sold off a bunch of stuff and moved to Tennessee. If you can't find a number for them directly, try Courtesy Nissan. They know their stuff and should be able to look and tell you if the synchro is still available.

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Just called Courtesy Nissan. Gave them the part number for the ring, they said its NLA and there is no dealer in their registry with one in stock.

 

Still going to go to a Porsche dealer and let them look at it.

 

You can try Skip at Durabild in Nashua NH. He knows a lot about the old Nissan comp transmissions as he was part of a Datsun race team in the early 70s. He probably doesn't have what you need, but he might be able to find it.

 

Pete

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Sent Sam some money for a modified 4 speed fork, haven't tried to bend the rod back yet. To put a rest to the Porsche synchro "coupler" thing (the piece the fork goes over, and slides over the synchros to engage gears), I took my GOOD ring to Abacus Racing here in Virginia Beach, they have an EXCELLENT exotic car repair team, and when I went in that section of the shop, all they HAD were old British, German, and Italian cars, engines out, transmission apart, etc, including a full blown race setup 911, and a GORGEOUS 964 Turbo...anyways I spoke to the mechanic there, and he said that they were the same ring, but he didn't have one to compare with at the time.

 

From there, I was sent Don Schneider of German Autowerks, also here in Virginia Beach, who DID had some of the rings lying around for matching purposes. We compared the rings and he confirmed for me that the INNER part of the ring with the teeth was identical, and it really was. The GROOVE that the fork fits into on the other hand is NARROWER, but he said that any good, reputable machine shop SHOULD be able to machine the groove out larger without much trouble, especially if you have the fork or ring that came out of it for the shop to look at.

 

The transmission parts would be from a early-mid 70s Porsche, but I have forgotten the kind of car, I have to go back up to see him when I get the fork in to compare some more things, but this is a good start! The only downside is that the couplers are $225 each new through him, and are probably even MORE expensive through a dealer, but are in fact available.

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OK, I misunderstood your PM. So the "selector ring" that the fork fits onto is the same but the groove needs to be opened up. Got that. How about the synchro ring itself? That's the piece that usually wears out or breaks. Did you even check to see if that fits? I would guess that a worn synchro might have caused a jamming of the selector ring into the dog teeth which broke it in the first place.

 

I'm a bit embarrassed to admit it but I didn't open up the pics at the start of the thread. Porsches commonly break the synchro rings, and I assumed that's what I was looking at when I saw the three broken pieces of the selector ring that you showed in the pics. Oh well, I guess I turned you onto a solution.

 

What is kind of funny is that in another thread I was told that the selector rings didn't fit. Maybe they just didn't think to open up the groove on the outside.

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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.

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

 

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.

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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?

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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 by JMortensen

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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.

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