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Thread: Roll frame / escape routes

  1. #21
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    I don't believe a pressure release valve was part of the factory set-up. The earliest hydraulic systems were installed by owners (all of the ADD cars were manual from the factory, and so were the majority of Elam Mk1s), and were based on the Cadillac convertible roof pump. Although quiet in operation, these systems were slow in operation (except going down!) and had no negative holding pressure. There are even some cases of owners converting back to a manual roof!

    The Smiths Mini-Pack was used on the first factory hydraulic systems. This is a very powerful pump, and makes a lot of noise because of the reciprocating pistons used to pump the fluid. If the ram seals are in good condition the canopy can stay open for weeks on end!
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  2. #22
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    The Smiths Mini-Pack effectively closes both the "up" and "down" solenoid valves when not in operation, but a bypass valve connecting the "up" and "down" hoses together should allow the ram to be manually operated in an emergency. I say should because the effective volume of the "down" circuit is less than the "up" circuit due to the fluid displacement by the pushrod in the "down" circuit. Hopefully that makes sense.

    The other way of doing this would be to energise both "up" and "down" solenoid valves simultaneously, allowing the fluid to return to the reservoir in the pump.

    The later Smiths Quiet Pump and Hydro Products systems use a twin-gear type of pump, similar to the early Cad pump, and have a different valving arrangement from the Mini-Pack, but a manual bypass valve should still work.
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  3. #23
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    Yes, my car originally had the smiths pump, but now have a new quietpak in a box to use this time...
    The manual valves (I'm guessing mine was similar with only one valve fitted in the car by the seat) I was wondering about are the ones that can be seen in the last two pics at the bottom of page 1 here http://www.euro-nova.co.uk/vb/showth...l=1#post106005

  4. #24
    Senior Member Phill's Avatar
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    Quote Originally Posted by Spacenut View Post
    The Smiths Mini-Pack effectively closes both the "up" and "down" solenoid valves when not in operation,

    The other way of doing this would be to energise both "up" and "down" solenoid valves simultaneously, allowing the fluid to return to the reservoir in the pump.
    Excellent idea and very simple to implement.
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  5. #25
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    Can anyone therefore clarify where you would fit a manual valve into the current lines if you are using a hydro product pump or quiet pump.
    Just trying to picture this in my head that’s all ..

  6. #26
    Senior Member Phill's Avatar
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    You would need to bridge between the up pipes and the down pipes - effectively bypassing the pump when the valve is opened but separating up from down when closed.

    pump diag.jpg
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  7. #27
    Has anyone actually tried this manual valve idea? Sounds great in theory, but I am concerned that there isn't enough space in the system to compensate for the difference in volume either side of the hydraulic actuators. Maybe you will only get a few inches of movement? I am wondering if there is a way to manually actuate the solenoids on the Smiths unit for example? Like fitting an extension on the solenoid plunger (but that could leak), or using ceramic magnets from a disk drive, pushing up the hood canopy and then removing the magnets (on a pump that is in the footwell)?

    I imagine total loss of power from the main battery is a common cause of the canopy failing to go up! It would be good if a 5 volt USB power pack had enough power to release the solenoids. You could simply leave a usb socket connected to both solenoids as backup, then make sure you have a power pack with you, and plug it in momentarily if you were stuck!

    [As I don't have a Nova or Smiths unit I could be talking complete rubbish here!]

  8. #28
    Senior Member Phill's Avatar
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    Quote Originally Posted by John90 View Post
    Has anyone actually tried this manual valve idea? Sounds great in theory, but I am concerned that there isn't enough space in the system to compensate for the difference in volume either side of the hydraulic actuators.
    The isolating valve should be a ball valve which overcomes this potential issue by not displacing any fluid in either direction when it is opened or closed.
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  9. #29
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    Quote Originally Posted by John90 View Post
    Has anyone actually tried this manual valve idea?
    I can confirm my car had a manual valve situated by the drivers seat that released the hydraulic pressure to allow the roof to be manually pushed up; It is extremely heavy to push up, and it won't stay fully up - i.e. it comes down again if you stop pushing! The lever has to be re-engaged before you let go, and the roof will come back down until the hydraulic pressure is high enough to support the roof, so don't expect it to be easy to lift the canopy and simply climb out... If you are lucky, the roof will be held about half way down. But then this is only in case of a failure...
    It is nothing like the manual canopys that may still be about?
    I have the original plumbing out of the car, but its at my friends workshop - otherwise I would post a photo of how it was. Not sure when I'll get over there next.
    Last edited by MartinB; 21-06-2018 at 06:50 AM.

  10. #30
    ***Euro-Nova Supporter*** Spacenut's Avatar
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    Quote Originally Posted by John90 View Post
    I imagine total loss of power from the main battery is a common cause of the canopy failing to go up! It would be good if a 5 volt USB power pack had enough power to release the solenoids. You could simply leave a usb socket connected to both solenoids as backup, then make sure you have a power pack with you, and plug it in momentarily if you were stuck!

    [As I don't have a Nova or Smiths unit I could be talking complete rubbish here!]
    No, not rubbish at all, although the Smiths pump solenoid valves are immersed in the hydraulic fluid, so not easy to get to.

    I would say though that complete battery failure is not a common occurrence - I did lose enough battery power through a slipping fan belt (in the rain, lights on, demisters etc.) to prevent the engine from re-starting, but even though there was not enough power to crank the engine, the canopy hydraulics still had enough juice to lift the canopy.

    Dodgy, intermittent wiring is probably the biggest culprit, based on personal experience
    only Pythagoras can save me now!

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