The “AK” mount | The Z Club of Great Britain
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The “AK” mount

Discussion in 'Drivetrain' started by AliK, Jul 5, 2020.

  1. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    Given how bad my diff mount insulator was and the extra torque the L28 with “show and go” is throwing at it, I felt the need to protect the new one from the full stress of the diff lifting, to prolong its life - i.e. to never need replacing again in my ownership.

    Remember this?

    [​IMG]

    The R/T mount is a tried and time honoured way forward but there are two things I don’t like about it:

    1. Price to the UK is about £120
    2. The price to the UK

    https://www.technoversions.com/DiffMountHome.html

    So I made the AK mount for about £17 and a couple of hours of effort + stressing over perfecting the angles. Now I know it will never be as strong as the R/T but it will do a heck of a lot more than a giant rubber band above the diff!!! Have you ever tried to bend unheated 3mm steel? Also I’m not rallying the car so it will be plenty strong enough for my usage.

    I am writing this up in case anyone else is interested in making one. But if you do, I expect to hear about it and see your creation posted here.

    What you need is 400mm x 40mm x 3mm of bright mild steel, a suspension bump stop of your choice, a vice, a bloomin great hammer and a couple of rubber washers.

    The pics will tell the story:

    I used a threaded rod to keep the same separation as under the car and modelled it using CAD - Cardboard Aided Design.

    [​IMG]

    Then got the dimensions (that should be 393 total length, I was high on fumes from painting the petrol tank [emoji1787]).

    [​IMG]


    The angles ( edit: updated photo with angles in the right place [emoji6] as well as dotted line showing alternate bend per the CAD model).

    [​IMG]

    The mounting holes - they align with the bolt holes on the rubber strap brackets so as to keep the brackets on the car.

    [​IMG]

    [​IMG]

    An M10 thread is tapped at the top to allow the bump stop to screw against the mount. That way the lock nut will be, erm, a lock nut! I may have to go 11mm if it transmits noise so that the rubber can move more.

    [​IMG]

    I added a couple of rubber washers as the red poly bump stop is pretty solid and the rubber will take out some vibration / noise. You can use the original Mini’s suspension rubber bump stops if you prefer a softer less NVH intrusive solution. I wanted the hardness of the poly in stopping the diff but with a bit of give in the rubber.

    [​IMG]

    Fits like a dream under the car and when the diff is bolted up, I can trim the red stop if it’s too tight.

    [​IMG]

    Next, it needs a 60mm steel washer above the rubber washers, ‘cause I’m fussy; and some POR15 rust preventer nasty ass chassis paint to protect it.

    Oh and those brackets need a bloody good clean up!!

    I’m very pleased with how it turned out and how easy it was to fabricate. It feels utterly solid and is absolutely ROCK solid when bolted under the car, so I doubt the diff will be able to distort it in any meaningful way. Time will tell and I will update this thread after a good few months of thrashing, sorry, I mean my normal driving.
     
    Last edited: Jul 6, 2020
    Huw, toopy, Paul_S and 8 others like this.
  2. peter_s

    peter_s
    Z Club Member

    Well done!
     
    AliK likes this.
  3. Rob Gaskin

    Rob Gaskin Treasurer Staff Member Moderator

    Yes well done. If you were at school your angles would be shown wrongly! ;)

    41' is actually 139'
     
    AliK likes this.
  4. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    You know, I saw that this morning too ;) I will update the photo.

    Oh no!!!! I’ve been homeschooling maths and angles.
     
    MaximG likes this.
  5. uk66fastback

    uk66fastback
    Z Club Member

    What a great fabrication Ali - must have been a real feel-good moment to get that up under the car and see it fit like the proverbial glove ...
    I think in the style of the air-box, you could be knocking these out for the members. £20 a pop?

    Top man.
     
    AliK likes this.
  6. Paul_S

    Paul_S
    Z Club Member

    I love this kind of stuff. Great work.

    Cardboard Aided Design!! [emoji38]
     
    AliK likes this.
  7. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    Thanks dude. My time and wife’s patience are unfortunately too short. But if someone wants to make them and calls them the “AK mount”, then I’m not gonna object ;)

    Thanks chap, the CAD is fast and works well.

    I just updated the angles photo in the original post and with the original design shown in dotted pencil line.

    I may for a bit of fun create one that shape to compare and decide if it’s a better shape. I quite like the shape of the one I made though. I wanted a wider angle to leave tolerance for the bump stop and inability to produce pin sharp accurate bends.

    Mr Tenno pointed out that he has shot similar looking things playing Galaga [emoji1787] and he is right!!!!

    [​IMG]


    Another thought - I made this in such a way that I could keep the original brackets and rubber strap in place but there is no reason why you can’t reduce a couple of degrees of angles and bolt directly to where the brackets go.
     
    Last edited: Jul 5, 2020
    Huw, Paul_S and Mr Tenno like this.
  8. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    With a lick of paint the AK almost looks like a manufactured part ;)


    [​IMG]

    I originally went with 40mm for a few reasons: it reduces leverage with the offset mounting holes, it’s the max size I can get into the side of my vice for bending and is easier to bend than anything wider.

    But I’ve now decided to remake it using 60mm steel which makes it even beefier (not that I feel it needs to be) and will look a lot neater covering the whole of the top of the bump stop. Also, I may centre the mounting holes and put it between the bracket and body with a square spacer washer behind the other end of the brackets. Yes I’m absolutely set on keeping the brackets on the car ;) More of that anon. This gives me the pleasure that the fuel tank issues of late have taken away.
     
  9. Pete

    Pete Well-Known Forum User

    I know half the fun is in the making of this on your own but here you go mass production awaits.
    upload_2020-7-7_12-40-47.png
     
    WazzaJB likes this.
  10. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    Wow what a brilliant idea!!!! [emoji106][emoji106][emoji106][emoji106][emoji106]

    Let me get the design perfected and tested to make sure it actually works without transmitting too much noise etc and then let’s see how many people want one maybe we can get a batch done.
     
  11. Mr Tenno

    Mr Tenno
    ZClub Administrator
    Staff Member Moderator

    That's it Ali, your dreams of space-invader-diff-mount dominance dashed as soon as they started - you've put the design in the public domain now!
     
    AliK likes this.
  12. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    Well, it was for the benefit of all ;)
     

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