Throttle Stop Help Request

[Bud74]

CobraThrottleStopMy Car.jpgThottleStopOwnersManual.jpg

Problem: My gas pedal is very high with extreme amounts of free play. I started to study the Superformance owners manual re adjusting throttle linkage (the manual shows a four barrel like I have), when I started to wonder if I am missing a part - namely the throttle stop. Note the manual's photo of the linkage, particularly the red circle I have drawn around the throttle stop area, and the silver rectangular plate. Now note my throttle stop area - it has no plate, but it has a hole like for a bolt.
My question is: is this plate the throttle stop, and am I missing it? If this is true, do I need to get a plate and a bolt from Hillbanks? Is the hole for a 1/4-20 bolt? If it is missing, I might be able to fabricate a plate from odds and ends in my shop if I had the geometry and dimensions. Thanks so much.

[Silverback]

Bud, here is a picture of mine.



I did a lot of carb work on mine and I don't ever remember having to adjust the stop.

However it looks like a simple piece of metal so I would fab one up and install it. And since the car is built in SA I would guess it is a metric thread.

[Bud74]

Bud, here is a picture of mine.



I did a lot of carb work on mine and I don't ever remember having to adjust the stop.

However it looks like a simple piece of metal so I would fab one up and install it. And since the car is built in SA I would guess it is a metric thread.

Yeah, Silverback - you never had to adjust the throttle stop cause it really would never require adjustment if you were satisfied with the pedal height. I think I sussed out the problem correctly - I am missing that little plate. Its absence lets the pedal throttle lever go too far back, and that lets the pedal go too high. Thanks so much for the picture - worth a thousand polysyllabic words. I can easily check the bolt requirement - I have plenty of miscellaneous metric and SAE bolts on hand. And probably some piece of metal plate that I can work with - otherwise Fleet farm has a good collection of bar and plate stock. Thank you again!

[S_Reynolds]

Silver, when you look up the meaning of polysyllabic let me know so I can broaden my vocabulary horizon.

[DanEC]

It would probably be pretty easy to fabricate something like that out of some 1/8” aluminum stock from Lowe’s with a little saw, drill and file time.

[Silverback]

Silver, when you look up the meaning of polysyllabic let me know so I can broaden my vocabulary horizon.

Look it up? Hell I kan't eveen speel it.

[Morris]

Bud.....you should have a throttle stop on the bottom of the pedal.....and then work out the geometry for pedal height and full throttle openings of the throttle butterflies....

That way you can push the pedal to the floor or stop....and not be hunting for full throttle opening. The pedal height is controlled and by the linkage....and sometimes the linkage needs various extension at pivot points.

[Ron77]

What Morris said. My throttle stop is on the bottom of the pedal and I can adjust it. I adjust the linkage to get the return height of the pedal where I like it.

Ron

[Bud74]

It would probably be pretty easy to fabricate something like that out of some 1/8” aluminum stock from Lowe’s with a little saw, drill and file time.

EXACTLY what I did last night - I am going to finish file and sand it today. Now I just got to find the correct bolt for the hole that holds the plate. It isn't 1/4 - 20 but it's close. Got to find a metric size, I guess (assuming the hole is threaded).

[Bud74]

Bud.....you should have a throttle stop on the bottom of the pedal.....and then work out the geometry for pedal height and full throttle openings of the throttle butterflies....

That way you can push the pedal to the floor or stop....and not be hunting for full throttle opening. The pedal height is controlled and by the linkage....and sometimes the linkage needs various extension at pivot points.

The Superformance owners manual give detailed instructions for adjusting the throttle linkage, including pedal height, with no mention of a pedal bottom stop. It is done with that little plate I am missing. In other words, the pedal lever inside that starts the linkage is adjusted by the little plate (see Silverback's picture). The instructions also include adjusting for full open throttle when the pedal is floored without over-forcing the carburetor throttle arm. It is a four step process but very clear once you study the linkage visually.

[Carlewms]

Bud.....you should have a throttle stop on the bottom of the pedal.....and then work out the geometry for pedal height and full throttle openings of the throttle butterflies....

That way you can push the pedal to the floor or stop....and not be hunting for full throttle opening. The pedal height is controlled and by the linkage....and sometimes the linkage needs various extension at pivot points.

I like Morris's Idea ... It would seem to me that if you did push it to the floor intentionally or by accident, the weakest links would be subject to failure if there was not a positive stop on the pedal. Yes the spring should bring it back to the closed position ... but addition of a stop to prevent over travel would seem like a good idea.

Just my two cents ...

[S_Reynolds]

I fabricated a throttle stop for my accelerator pedal that mounted on the fire wall.

[dominik]

Typical Metric would be M6

[Morris]

Actually we made the pedal stops out of 5/16" bolt and Fender washer.... then screwed them into the pedals.... and set the height that we needed for Heal and Toe....
As you can see you have to have a stop on both the Clutch and Throttle pedals. When you are driving aggressively you can't have your foot feeling around if you are at full throttle or not.... it is a terrible feeling and you might be bending the throttle linkage.... so you need the stops so you can just push down flat to the floor.... same for the clutch... but most importantly ... you have to set the pedals first then set the linkage.... as you can see we had to extend the one linkage arm to get the full throttle opening at our pedal stop. This also helps when you are going around the corners as well as you know how much to squeeze the pedal on the exit of the corner....
Here's some photo's to see how we did it.... each car is different...

[Bud74]

Actually we made the pedal stops out of 5/16" bolt and Fender washer.... then screwed them into the pedals.... and set the height that we needed for Heal and Toe....
As you can see you have to have a stop on both the Clutch and Throttle pedals. When you are driving aggressively you can't have your foot feeling around if you are at full throttle or not.... it is a terrible feeling and you might be bending the throttle linkage.... so you need the stops so you can just push down flat to the floor.... same for the clutch... but most importantly ... you have to set the pedals first then set the linkage.... as you can see we had to extend the one linkage arm to get the full throttle opening at our pedal stop. This also helps when you are going around the corners as well as you know how much to squeeze the pedal on the exit of the corner....
Here's some photo's to see how we did it.... each car is different...

Thanks - , but completely different set-up than my Superformance.

[Silverback]

A couple items to keep in mind Bud.

Make sure that your linkage will not bind, including when the motor torques over under acceleration. I broke a motor mount on mine and while it did not hang the throttle, it did slightly damage the paint around the cutout where the side pipe went through the body.

I replaced my motor mounts with a set from Olthoff Racing.

http://www.olthoffracing.com/cobra

And make sure nothing will go over center and hang the throttle open.

Also like Morris I always ran double springs.

One more unrelated question.

Did you look at your rear shock upper mounts? If not, you really need to.

[Ron77]

Bud,

One thing that I did when racing was to put a short length of chain in the front of the motor. I bolted it into the head and then the frame and left very little slack. That way if a motor mount did break the chain would hold the motor down until I could stop. And as Morris and Silver said, I also used double return springs on mine.

Ron

[Morris]

Thanks - , but completely different set-up than my Superformance.

That’s the point......no car is the same....but you have to take idea’s from others an incorporate the ideas to improve your car....

There are always 100 different way to accomplish an idea or solution.....it all depends on how far you want to go and how much money you want to spend.....

[Silverback]

See Bud, we told you early on that there are a lot of smart people on this site.

Just wish I was one of them.

[RedBarchetta]

See Bud, we told you early on that there are a lot of smart people on this site.

Just wish I was one of them.

Silver, you have to think positively and view yourself as a counterweight. ;-)