Period or ace looking diff covers | Page 2 | The Z Club of Great Britain
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Period or ace looking diff covers

Discussion in 'General discussion' started by franky, Mar 19, 2021.

  1. franky

    franky Well-Known Forum User

    I might give you a shout on that, I've just got a 'hobby' solid works license for a year(£20!), so might give that a whirl, its got a post processor for hurco, however need to see if it all works etc etc.
  2. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

    Jason, you keep being distracted from finishing your 240Z. Has the Square 4 landed yet?
  3. SeanDezart

    SeanDezart Well-Known Forum User

    No point, I have 3x Perrin covers here with modified bars to support them BUT......there are other, much more cost effective ways of cooling diffs that 'works' cars were wearing back in the early '70s - here are some clues :

    Have fun. :)

    Attached Files:

  4. franky

    franky Well-Known Forum User

    I've(unfortunately) got a 1000 things at the minute that come before the 240z, its my house that kills things, young kids and work! Square 4 is a few weeks away I think.

    The 240z won't suffer from being left, all the others will.
    Rob Gaskin likes this.
  5. franky

    franky Well-Known Forum User

    3!? front, centre and rear diffs like a g wagon? If it’s the one I’m thinking of, they’re quite a pleasing shape.

    Im not sure if I’d call that cost effective, nor would I say it cooled diff temps?
  6. atomman

    Z Club Member

    thats a good deal! it might be worth looking at the Inventor HSWorks plug in for Solidworks (sure you can get a student version to use for 3 years) bit more user friendly than the solidworks CAM .

    HURCO's do have a good conversational controller (for Americans ) for pockets etc etc but I've always found it better to use CAM
  7. Albrecht

    Albrecht Well-Known Forum User

    Works race and rally cars (PS30-SB, HS30 and HLS30) first of all used a fuel-oil heat exchanger to cool their diffs, then went to an electric oil-circulating pump with a small air-oil cooler unit.

    None of that is visible from your photos.
  8. SeanDezart

    SeanDezart Well-Known Forum User

    Ah...thanks for that, then what IS visible in the photos is how we do it on the track today, keeping the weight down and the process simple and reliable. ;)
  9. Albrecht

    Albrecht Well-Known Forum User

    One of the cars in the photos you showed is a privateer racer - with later, but period, lightening mods. Not Works.

    Diff oil temp in a plate LSD-equipped car is a function of how high the preload setting on the friction plate stack is set. Doesn't matter how light the car is, its the LSD doing what it is designed to do that generates the heat.
    SeanDezart likes this.
  10. Paul_S

    Z Club Member

    Ah, I wondered if it was that the exhaust had been rerouted further away from the diff somehow.
  11. Albrecht

    Albrecht Well-Known Forum User

    In fact, they did the opposite. First race & rally iterations had twin pipe systems passing right underneath the diff, but I doubt they added too much heat to the diff oil whilst moving.

    Later iterations went to short, side-exit exhausts (exiting just in front of the rear wheels) but that was mainly about protecting them from damage.
    Paul_S likes this.
  12. franky

    franky Well-Known Forum User

    There's nothing in those pics that shows how you 'cool a diff', also I can't see how they'd be how you'd track prep a car today?
  13. SeanDezart

    SeanDezart Well-Known Forum User

    LOL, obviously you're right and I you've gone off on a tangent, misinterpretating my comment of lightweight. I meant less equipment so the car overall lighter - light is right when racing after all.

    Jason, with respect, remove the blinkers, look at the car again and apply the following physics lesson to diff oil :

    Expansion and Contraction in Liquids
    • When liquids are heated, their particles move around more, pushing each other apart slightly, causing the liquid to expand and contract by predictable amounts based on their temperature,
    • This is because the particles in liquids are not held in a fixed arrangement, as they are in solids, so this increased freedom of movement results in greater expansion.
    • As with solids, the expansion and contraction of liquids needs to be allowed for in certain situations eg car radiators are connected to an overflow tank to allow for the expansion of coolant as it is heated by the engine
  14. franky

    franky Well-Known Forum User

    Sean, I asked for some pics for inspiration. you replied with the following

    Theres Naff all in those pics about diff's. All I learnt is that you've got 3 diff covers.

    What part was constructive to this thread?
  15. franky

    franky Well-Known Forum User

    Thanks, I'll have a look. The conversational side of this is great, its got a DXF option installed also, so you can load DXF and build from there, however I want to use a post processor to proper 3d/3axis not just 2.5 type stuff.
  16. SeanDezart

    SeanDezart Well-Known Forum User

    Forgive me if with whilst suffering bad Covid-19 and the English/Kent variant I commentated out of context on your thread - like Alan but only I get 'the treatment' !

    I was happy to lend you a Perrin cover (do you need to see a photo of a Perrin diff cover or can you manage to Google it yourself?) if it helped and also began to say that, 'franky', you don't need to do all this to keep a diff cool, especially not on your car which it street-orientated.
    It's a Z club - I replied on-topic about Zs not software so please carry on - I'll keep my ideas to myself.

  17. franky

    franky Well-Known Forum User

    No one got 'treatment', Alans posts were about diff covers/diffs. Regarding my car, I'm happy with my direction. I wasn't aware you were across what it was?

    The discussion about software is very relevant to the thread.
    atomman likes this.
  18. Garaculas

    Z Club Member

    Always liked the look of the Greddy ones.


    Thing is though these things are normally machined castings and will need a fair old billet to be made out of one piece. Nice Milling machine for the garage too, Is that just for hobby car parts or do you have another primary use planned?

    Let us know if you need any on-machine probing, I know a few people :)
    franky likes this.
  19. franky

    franky Well-Known Forum User

    Thanks, the castings do look better I think. I might make a single billet then get it cast. The Billet can cost up to £120+vat alone. it'd be a chunk of machining time!

    Feel free to drop me a PM about probing.
  20. uk66fastback

    Z Club Member

    I don’t believe you’ve bought this just to make a diff cover, what’s the long-term plan behind the purchase?

    It looks a superb piece of kit, I wish I understood more about this stuff ...
    franky and MaximG like this.

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