12 replies to this topic

[Cloonatic]

Hi all

I am currently fitting a su hs6 to my 1275 and I’m having a problem with the mounting of the accelerator cable.

There doesn’t seem to be an off the shelf abutment plate to suite my needs so I’m going about making one. 

I can’t measure my own car as the body is away being sprayed.

What I need to know is the travel of the accelerator cable so I can make a linkage to the butterfly.

My mini is a 67 mk1 originally an 850

 

 

[croc7]

Not sure what you mean but why not buy the longest one available and cut it to fit?

[Cloonatic]

So as the saying goes a picture is worth a thousand words, I’ve done a little drawing.

Basically, I want to know the length D1-D2

 

 

[Ethel]

I did measure that when I made my own accelerator pedal. Annoyingly, I'd have to reinstall a drawing package to see if I have it jotted down - so see if somebody can measure it of a car first.

 

If you're up for it, just chock the pedal down & put a marker on the inner cable where it goes in to the outer at the carb end. Let the pedal up & measure between the marker's new & previous position.

 

I do remember it's different enough to stop Metro carbs being a direct swap - and of course the pedal will stop pulling when it hits the floor/carpet/mat .

[GraemeC]

That'd give you the length of cable movement at the carb, which is obviously a function of the angular change of the butterfly multiplied by the length of the throttle lever/cam.

However the pedal stroke could be slightly different - mine would be as I have a little bit of free play at the beginning of the pedal movement and I have full throttle before the pedal hits the carpet, after which it just puts tension into the cable.

[nicklouse]

It does not matter.

 

I have made many and never needed the distance moved.

 

But some of the carbs have a none linear pull as the carb spindle actuator is a spiral. But even so that is right for the cable pull so your mount for the end of the outer can still be anywhere.

[Ethel]

That'd give you the length of cable movement at the carb, which is obviously a function of the angular change of the butterfly multiplied by the length of the throttle lever/cam.

However the pedal stroke could be slightly different - mine would be as I have a little bit of free play at the beginning of the pedal movement and I have full throttle before the pedal hits the carpet, after which it just puts tension into the cable.

Whatever amount of cable you pull through one end has to come from the other end. The OP wants to know how much cable the pedal will pull so he knows how much he'll have to gor from idle to what - if I understood.

 

 

I loaded up that software & found I used 35mm of cable pull, but that was with a Turbo HIF44 that left the standard Mini pedal still some way above floor at what.

[GraemeC]

Sorry, don't agree Eth,

 

Arbitrary numbers but.....

 

First 1mm of travel at the pedal takes up slack - throttle lever/shaft/butterfly hasn't moved.

2-36mm of travel at the pedal opens throttle - cable at end of throttle lever has moved 35mm

37-39mm of travel at the pedal stretches cable - throttle is already fully open, cable at end of throttle lever hasn't moved any further

 

So 39mm of movement at the pedal end has only resulted in 35mm of movement at the throttle end.

 

 

And as Nick says, the throttle movement has no bearing on the abutment bracket he's trying to make anyway (other than ensuring it is far enough away from the throttle lever to allow full cable pull, but generally they are much further away than needed).

Edited by GraemeC, 28 September 2022 - 06:44 PM.

[nicklouse]

One I made earlier 

[DeadSquare]

Slide a suitable compression spring onto the cable before threading it through the pedal.

 

I used to make a quadrant out of the crown of an old piston.

[sonscar]

What you should do is have a pedal stop to prevent overtaxing the cable which can be set when you have achieved full opening,Steve..

[Ethel]

Firstly I'm very likely using a different carb linkage to the OP, so my 35mm isn't likely to be exactly right for him.

 

All the other bits aren't relevent, you'll need a bit of free play in every case. If he's using a standard pedal he just needs to know how much cable it will pull through, measuring it as suggested will give the answer, but not allowing for carpet thickness & other variations car to car.

 

I made my own pedal because the original was an inch or so above the floor. Yes, I could just have made a travel stop, but that would have reduced the sensitivity of the throttle control.

 

Making an abutment plate can vary the required cable pull by varying the angle of incidence with the throttle lever. Ideally, it'd be perpendicular for minimum force & maximum travel, but you'd need a sector/quadrant/cam to have that.

[stuart bowes]

the pedal travel does seem a bit dismal doesn't it, I was just going to bend mine up a bit and make a butterfly lever to suit so I can have a greater degree of movement and therefore more 'accuracy' 

 

how much difference that will really make I don't know I suppose it depends how responsive the engine really is

 

Probably add a strong spring (or springS) as well because I like the pedal to fight back a bit not just flop straight to the floor

Edited by stuart bowes, 29 September 2022 - 10:44 AM.