Quote:
Originally Posted by mickmate
So the correct original linkage with non adjustable connecting rods, not like the Mustang adjustables people have added, with the little sheetmetal bellcranks use a threaded stop but that thread isn't used to adjust the stop position???? The footboxes, engines and gas pedals are all put in exactly the right position relative to each other on a hand built car for that threaded stop and don't need to be adjusted on that thread.
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I'll expand on what hand built means in regards to this subject. A collection of standard parts required fitting upon installation. Under throttle mechanisms for Cobras Nick covers it, the pedal stop didn't require a depth or length adjustment because other parts and processes required fitting. (The hardest part of throttle operation pieces to deal with on an assembled original car is the pedal stop as just about everything else close on either side of the forward foot box wall is in the way.)
The "adjustment(s)” were done by engine installers and remember Shelby American in California was just the largest volume shop not the only shop. There were several items to get right.
a) Foot box bracket location
b) Engine bracket location
c) Which hole to use in the throttle pedal drive lever
d) Where to set the throttle pedal drive lever itself as its lower end was an adjustable pinch clamp
The brackets for the foot box and intake manifold ends of the brazed bell crank assembly had to be installed by the engine installers. Both brackets required one car at a time fitment. The brackets were standard parts but:
1) Foot box side: the location for the bracket had to be fit and two holes drilled for fasteners.
2) Intake manifold side: the bracket for the spherical bearing for location and support had to be modified to suit. The normal method was to crudely slot and or enlarge one mounting hole so the bracket could be pivoted about the other. A little “swing” at one bolt hole meant longs of arc swing out at the end of the bracket.
Engine installers had to add the throttle pedal stop, which AC Cars did not provide with the chassis.
There are two last adjustments, which hole was used in the throttle pedal lever and slip fit adjustment of the pinch clamp made into the lower end of the lever on the pedal shaft.
When the installion is done hard foot pressure on the throttle pedal should not over pull the throttle lever of the carburetor. The small carburetor throttle shafts are no match for the strength of a human leg. When I adjust an original car I have somebody push the throttle pedal as hard as they can and I adjust the pinch clamp so that I almost but not quite get to exactly 90° W.O.T.; I stop just short. (I have repaired some carburetors used on original cars where attention was not paid to whether or not the carburetors were “over pulled” and their carburetor primary throttle shafts were twisted from pulling too far on them. )
The pedal stop is real important. I had the opportunity to work on a car that missed getting a throttle pedal stop day one in 1964 apparently as there was no signs inside or outside of the driver’s foot box that a hole had ever been drilled for a pedal stop. Throttle mechanism wise the car was a mess. The cast aluminum pedal arm AC Cars installed had been broken off at least once and crudely repaired, the lever on pedal shaft was bent and twisted, and the bell crank assembly was twisted. It appeared all those 1960s technology light weight parts suffered from a heavy foot or several with no stop to keep the pedal from literally being forced all the way to the forward wall of the driver’s foot box.
Dan