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Thread: Full Throttle!

  1. #11
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Full Throttle!

    Quote Originally Posted by Spacenut
    I was wondering about using brake fluid because of the one major flaw in ATF - it expands as it is heated!
    Sorry, having a total BLONDE moment (duh!). Of course brake fluid will expand if heated, same as ATF

    I rather foolishly assumed that because the brakes and clutch don't mysteriously jam on/de-clutch when hot that brake fluid was somehow immune from expansion. Of course it isn't; the expanding fluid merely moves into the fluid reservoir and the displaced air vents through the breather.

    The hydraulic throttle has all the same features, but works rather differently - a bleed screw prevents the expanding fluid from entering the reservoir, which doesn't have a vent hole and is only filled with fluid when purging the system of air. So the only way for the expanding fluid to go is to force the pushrod out!

    I'm such a dodo sometimes

    Lauren
    only Pythagoras can save me now!

  2. #12
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Full Throttle!

    Quote Originally Posted by NovaF4
    Hmm, I'm still trying to get to grips with your spring. Three things - What did it look like to start with? How strong is it? For example, how far apart could you pull it by hand? What's a mandrel?
    Hi Giles - the wire started life as an open "U" shape, about 3" across with ends about 8" long. I formed the coil around the mandrel by hand. The multiple loops in the coil allow more movement at the ends before the limit of elasticity is reached. A single loop, for example, would probably be permanently deformed with the first push of the pedal. Too many loops and the spring would have to have a couple of turns of preload to be effective.

    This spring is intended to work as a torsion spring - if you pulled the coils apart they wouldn't move far without becoming permanently deformed. But twisting the ends relative to one another causes no deformation whatsoever

    The mandrel is the offcut of M10 threaded rod I talked about. Mandrels are tool steel formers used in tube bending and similar operations.

    Lauren
    only Pythagoras can save me now!

  3. #13
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    Re: Full Throttle!

    Ah I see. Very cool.

    Mine uses the old VW Beetle accelerator pedal return spring which is useless in it's new adaptation. It looks like this:

    http://www.google.co.uk/imgres?q=vw+...9,r:3,s:0,i:71

    That's the same principle as yours isn't it?

    Maybe you could make me one? (hint hint). I'd have to guess the amount of coils mind you.

    Working on the accelerator pedal is a back breaker in a Nova isn't it? I also find that leaning over the side sill is a killer on the chest too. Usually I feel it the next morning.

    Giles

  4. #14
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    Re: Full Throttle!

    Christ look at that link! Maybe an idea for the forum - abbreviated links. It is possible.

  5. #15
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Re: Full Throttle!

    Quote Originally Posted by NovaF4
    That's the same principle as yours isn't it?

    Maybe you could make me one? (hint hint). I'd have to guess the amount of coils mind you.
    Hi Giles - yes, that does look very similar to mine, and I vaguely remember what the VW pedal looks like. Wouldn't you rather go for a different pedal design though? Organ type pedals are difficult to operate unless the pedal is leaning towards you. I reckon you could get a pendant pedal to engage with the bellcrank roller, you could hang it from the steering column support bar maybe.

    I'd need to know the diameter of the coils as well, but I don't see why a replacement spring couldn't be fabricated.

    Lauren
    only Pythagoras can save me now!

  6. #16
    Senior Member MicksRedNova's Avatar
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    Re: Full Throttle!

    Quote Originally Posted by NovaF4
    Ah I see. Very cool.

    Mine uses the old VW Beetle accelerator pedal return spring which is useless in it's new adaptation. Looks like this.

    Maybe you could make me one? (hint hint). I'd have to guess the amount of coils mind you.
    You could always buy one here: £2.50 doesn't seem too bad. http://www.megabug.co.uk/vw-beetle-t...979-1051-p.asp

    Mic
    Club Nova Member

    MicksRedNova2 may take longer than the original!!

  7. #17
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    Re: Full Throttle!

    Sorry I don't think I explained myself very well in my rush to type and run out the door. My Nova isn't using the usual VW Beetle accelerator pedal any more. I took all the parts apart, binned some of them (including the actual foot plate and it's ski jump back plate), retained a few parts and fabricated my own pedal. My foot plate I made out of aluminium with drilled holes. It's still floor hinged and uses a custom hinge bolted through the floor as opposed to the VW affair which was an odd contraption welded to the floor. Mine does utilise the original VW cranked arm that sits behind it with the original pastic roller wheel thing that rolls up and down the back of the pedal. Really it just an exercise to have a nice looking foot pedal plate. I've done a good job too. It looks like the Macca F1 clutch. Or possibly the foot rest. Whichever one it is I copied it's design anyway. The only problem is the return spring. I have the original one but it's not up to the job and I need to think of a better way to locate it. I'll better explain how it's located in a post on my re-build thread. Replacing it with the same verison is therefore pointless (thanks anyway Mic). I need a return spring that is similar in design but much stronger as the current one is pretty weak, especially in it's location. Basically it's not giving the pedal enough feel when pressed and then not returning the pedal firmly enough when taking one's foot off. But, like I said, I'll wait to see what Rusper do at the other end before I tackle it. For all I know it's springing a lot better as the cable will be connected to the throttle bar on the engine as pert of the new carb arrangement.

    Hope that explains it better.

  8. #18

    Re: Full Throttle!

    You can get spring steel wire from most good model shops it is sometimes called “piano wire” well it was 20 odd years ago when I used lots of it in the hospital
    Comes in 400mm lengths and lots and lots of sizes ….. only it work hardens very quickly and becomes brittle, there is a formula for the bend radius to cross sectional size …. But like I said it was 20 years ago.
    Like Lauren said “have a go” you don’t need fancy tools just a strong hand and wrist, a vice helps but is not an absolute requirement.
    It is best to use a smooth shaft as the mandrel a 10mm HSS drill (using the bit which goes into the chuck?) works or a long bolt try not to damage the spring steel as it will weaken the spring and can cause stress fracturing or a point where stress fracturing can start.
    RABS

  9. #19
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    Re: Full Throttle!

    I like the idea of an egg whisk. I might pop down to the cook shop for one.

  10. #20
    Senior Member MicksRedNova's Avatar
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    Re: Full Throttle!

    Quote Originally Posted by NovaF4
    My Nova isn't using the usual VW Beetle accelerator pedal any more ..... retained a few parts and fabricated my own pedal. Really it just an exercise to have a nice looking foot pedal plate. I've done a good job too. It looks like the Macca F1 clutch.
    I too re-designed my accelerator pedal, and did a good job of it. As the pedal is almost invisible hidden away under the dash I went for functionality rather than looks. It is very comfortable on long boring motorway drives, and only needs the original spring to make it bounce back.

    Here's a pic of my ugly but functional pedal.

    Mick
    Club Nova Member

    MicksRedNova2 may take longer than the original!!

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