Unknown quantity - advice required | The Z Club of Great Britain
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Unknown quantity - advice required

Discussion in 'Drivetrain' started by Geoff-R, Jul 13, 2021.

  1. Geoff-R

    Geoff-R
    Z Club Member

    As I slowly work on my car I've dug out the original box. I've never had it running. The engine has been rebuilt and is sitting in the car but I've not driven it as it's far from roadworthy yet, however, the box needs to go in soon. Rather than pop the box in and hope for the best I wanted to open it up and take a look before fitting it to the car. Seemed a bit of a leap of faith to pop it in without knowing what I was up against. Attached are some pictures of it as well as the inside of the bellhousing. It seems clean, the oil that came out whilst dirty didn't contain any pieces of metal and the sump plug was quite clean, after all, it's been some 30+ years since the car ran. The car is a 74 UK 260z. I understand synchros are no longer available but what do people think of the internal condition? If good to go is there anything else I should replace aside from gaskets, o rings and bearings? Video attached below as well.

     

    Attached Files:

  2. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

    I think I would risk it. However pull the back off and check the reverse gear. I've damaged a few so I can't be alone (I hope).
     
  3. Geoff-R

    Geoff-R
    Z Club Member

    Cheers Rob, I'll try and get the back off. Any tips to getting the back off? Obviously remove the selector and then give it a persuasive tap as I did with the bellhousing? What's your thoughts on replacing the bearings whilst it's all apart assuming the reverse gear looks okay? Are there any UK suppliers for the bearings? Or is it an order to the States for those?
     
  4. jonbills

    jonbills
    ZClub Administrator
    Moderator

    I think the bearings are all relatively standard sizes, so should be possible to get them in the UK.
    But: to change them all you have to strip the whole box down which is quite a bit of work and tool acquisition. if they don't feel notchy, I'd leave them.
     
  5. Geoff-R

    Geoff-R
    Z Club Member

    Thanks Jon, I'll have a better look tomorrow evening and see what they're like
     
  6. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    I believe there is a guy in Auz that makes synchros, but you need to post on the AuZcar forum to find his details - unless someone here knows him.
     
    Geoff-R likes this.
  7. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

    I just think that you may be inviting aggro and expense. If you were an experienced gearbox man then fair enough. But don't blame me if it's knackered!
     
    Geoff-R likes this.
  8. Geoff-R

    Geoff-R
    Z Club Member

    Solid advice there Rob, if it ain't broke don't fix it. I think I'll follow Jon's advice. Check the bearings out. If all good I will probably just renew the o rings, seals, gaskets and throw out bearing. Give it a good clean and pop it in. If it runs and is usable for the time being I will be happy as I have an S14 box that will go in the car in due course. Whilst I have worked on gearboxes in the past I am by no means a gearbox man so while I'd be happy to pull it apart it is a bit of a journey in to the unknown and I could do more harm than good as you say.
     
    jonbills and AliK like this.
  9. Geoff-R

    Geoff-R
    Z Club Member

    Delved in to the rear of the box tonight. Couple of little horrors. One bearing is shot, it definitely needs replacing. One of the gears, am I right in assuming this is the reverse gear, or at the very least part of the reverse gear due to it being straight cut, seems to have suffered some wear on the edge of the gear. I'm assuming this would still work but would it cause any issues in engaging reverse.

    What's the opinion. Replace the bits that need replacing, pop it back together and hope for the best? Or does a shot bearing and worn gear spell further issues just round the corner?
     

    Attached Files:

  10. Albrecht

    Albrecht Well-Known Forum User

    It looks pretty good to me. Typical damage to the reverse gear idler teeth (you can pop that off, smooth them out a bit with a Dremel or even get them Stellite welded and re-shape them) but I'd even leave the bearings alone if they don't feel notchy (they are the original Nachis, which are superior to the usual replacements).

    I'd put it back together and use it, but make sure to use an oil that the Porsche/steel synchros like to take a bath in. Makes a big difference.
     
    AliK, Rushingphil and jonbills like this.
  11. Geoff-R

    Geoff-R
    Z Club Member

    Thanks for the advice Alan, some good tips there, appreciate it. Bearings feel good on the whole bar the one pictured where the internal rivets have just worn out so I think I'll heed that advice and keep the originals.

    Do you have any particular recommendation on oils? I quick search send to bring up a number of results with differing views.
     
  12. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

    That's exactly why I suggested taking the rear off. It's easy to get reverse instead of 4th. I wouldn't risk putting that back without fixing the reverse.
     
  13. Albrecht

    Albrecht Well-Known Forum User

    I use Swepco 201 in my Servo synchro 'boxes, and it really does make a difference. Like night and day.

    You might want to sit down before looking at the price though:

    https://type911shop.co.uk/epages/de...ca1-377e-432e-84fd-bdccf2206766/Products/2042

    Think of it like Greta Garbo filling a bath with Bollinger champagne and you won't be too far off.
     
    tyroguru, atomman and AliK like this.
  14. atomman

    atomman
    Z Club Member

    I did find a source in Oz for the steel syncro's a couple of years ago , As has been said further up ,

    I seem to remember the reverse idler is the same as a 4 speed and other 5's ? maybe change it out for one of those ,

    Check the snap rings as they wear on the thickness to, just check they are in spec,

    have a look on Simply bearings, you can search on size, part number etc and they stock Nachi's to . its what I put in my S14 box,

    here's a link to the '6204' that's knackered , it looks like a 'standard' clearance not a C3 , but have a check in the spec's

    https://simplybearings.co.uk/shop/advanced_search_result.php?search_in_description=1&keywords=Nachi 6204&
     
  15. Geoff-R

    Geoff-R
    Z Club Member

    I'm sure I saw you say that in another thread someone posted about their gearbox, that could be quite frustrating. For what it's worth I may as well pull the idler gear and get it sorted as suggested.

    This was the very oil that a few people were suggesting. Pricey, yes, however, has to be worth it so will no doubt go that route, I would rather have oil in the box that ensures the synchros are being looked after than save a few quid and run the risk of ruining the box altogether. Good job I was sitting down then!
     
  16. Ian Patmore

    Ian Patmore Well-Known Forum User

    I believe Stewart Watkins or Les Collins either can supply the steel synchros (or used to), or they are modified from some other model. The original synchros are still to be found, but it is getting harder, they are also found in the SP311/SR311 4 and 5 speed boxes, as the SR311 box is the same as the early S30. I managed to buy 4 for about 1/2 the price they should be. The Synchro on 5th shouldn't be too bad, as it doesn't get as much wear as the others.

    I have heard the synchros can be turned around, as only one side gets worn. Whether this is the case, I am un-sure.
     
  17. Geoff-R

    Geoff-R
    Z Club Member

    Thanks for that, good point on snap rings as well, got the specs from the workshop manual so will check these are within specs before popping back together.
     
    atomman likes this.
  18. Ian Patmore

    Ian Patmore Well-Known Forum User

  19. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

    If you work on the reverse gear to smooth the teeth test engagement before you reinstall it. Put the gear lever in and ensure reverse is easy. I thought about putting a mechanical reverse lock on my car - like a racing car.
     
  20. Geoff-R

    Geoff-R
    Z Club Member

    Haven't had a chance to look at a place yet that would be able to repair the reverse gear, locally would be ideal, thinking smoothing it out might be the best option. My hesitance is smoothing it out too much and then finding it's useless. I assume the mechanical lockout consideration is because reverse is too easy to engage whilst driving?
     

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