289 build

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Roger King
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Re: 289 build

Post by Roger King »

Yes, it's for a long return spring. The other end connects to a steel tab fixed under one of the three mounting screws for the footbox fresh air vent, which is not usually fitted to Hawks. I'd rig something up to fit the spring to if I were you. That is a very heavy pedal and the simple return springs on the carb will not do it easily - and if they are strong enough to do so, you will be getting some serious wear on the carb spindles. It's not good practice to have throttle return springs on the carburettor(s) only, the pedal should have its own spring to ensure full 'off' is achieved.
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Roger King
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Re: 289 build

Post by Roger King »

amulheirn wrote:I think as a throttle stop, I will be fabricating one rather than buying one of these!: http://actoncobra.com/index.php?main_pa ... cts_id=401
Yep, it's just a bolt with a stop washer half way along and another disc welded to the head, bolted through the front of the footbox wall to engage with the back of the pedal. Original AC.
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amulheirn
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Re: 289 build

Post by amulheirn »

Roger King wrote:Yes, it's for a long return spring. The other end connects to a steel tab fixed under one of the three mounting screws for the footbox fresh air vent, which is not usually fitted to Hawks. I'd rig something up to fit the spring to if I were you. That is a very heavy pedal and the simple return springs on the carb will not do it easily - and if they are strong enough to do so, you will be getting some serious wear on the carb spindles. It's not good practice to have throttle return springs on the carburettor(s) only, the pedal should have its own spring to ensure full 'off' is achieved.
Thanks Roger - did you fit the air vent on your old Hawk? I was going to leave it for the time being. That's a project for after IVA I think - even if it would be easier to do now, the price of the air vent stuff from Acton is a bit eye-watering for me a the mo!

I'll probably make a little L-shaped tab and find a suitably long spring from somewhere.

Ta,

A.
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Roger King
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Re: 289 build

Post by Roger King »

I did - but it's not easy and the original air vent bits won't fit without extensive modification. The reason for this is that the Hawk footbox is much taller, to allow for leg room apparently, and as a result there is less clearance between the top of the footbox and the underside of the bodywork above. I had original Cobra air vent 'cans' as nothing else was available. The only way to fit them with the correct tubing on top was to cut and weld the body of the can so it could sit at an angle - a tricky job. It worked fine, but as you never use them anyway if it's not an 'original build' I wouldn't bother. Plenty (some would say an excess) of fresh air finds its way into these cars anyway, and the only time I ever felt I could do with extra air in the footwells was at Pau Nogaro in 2011 when stationary in an ambient of 42°C. And when stationary, the vents don't do anything.....
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Migge
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Re: 289 build

Post by Migge »

Or mount a small blower the the fender area in between the tube :-)
Special customized BRA289
catsx11
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Post by catsx11 »

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Last edited by catsx11 on Wed Aug 23, 2017 3:13 pm, edited 1 time in total.
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Roger King
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Re: 289 build

Post by Roger King »

and a bigger dynamo
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Roger King
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Re: 289 build

Post by Roger King »

That confused me for a moment - 'don't remember posting that photo'...

Wonder why Colin's throttle shaft mount is that way round?
IainS
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Re: 289 build

Post by IainS »

Roger King wrote:Yes, it's for a long return spring. The other end connects to a steel tab fixed under one of the three mounting screws for the footbox fresh air vent, which is not usually fitted to Hawks. I'd rig something up to fit the spring to if I were you. That is a very heavy pedal and the simple return springs on the carb will not do it easily - and if they are strong enough to do so, you will be getting some serious wear on the carb spindles. It's not good practice to have throttle return springs on the carburettor(s) only, the pedal should have its own spring to ensure full 'off' is achieved.
The spring needs to be quite strong as the pedal hole is close to the fulcrum so the leaver doesn't work in its favour. So bear in mind when securing the fixing for the other end. Just trial and error with springs. As Roger says better to spring the pedal than put unnecessary load on the throttle actuation rods by loading the carb end.

Iain
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amulheirn
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Re: 289 build

Post by amulheirn »

IainS wrote: The spring needs to be quite strong as the pedal hole is close to the fulcrum so the leaver doesn't work in its favour. So bear in mind when securing the fixing for the other end. Just trial and error with springs. As Roger says better to spring the pedal than put unnecessary load on the throttle actuation rods by loading the carb end.
Thanks Iain. Roger's spring looks about 5 inches long in those photos. Most box sets of springs on eBay don't offer anything like that length - do you have any recommendations on suppliers? I've bought most of my hardware from Namrick, but I don't think they do springs.

Cheers,
Andy
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