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Old 08-03-2011, 01:41 PM
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Stiff-heavy gas pedal

I've finally started getting the Chevy back running again and one problem that I had was the gas pedal set screws had stripped. I currently have this, Mr. Roadster Spoon Pedal. The steel pivot at the middle of this pedal has been replaced since the old one deformed from the set screws spinning around it. The new one I made had holes drilled down into it to secure the set screws. When I went out and tested it today, it bent the set screws. This pedal connects to the carb through a generic steel braided cable.

Here are some pictures of my current setup, this is the 2nd version since the first time I did this I did a really tight s-turn from the firewall to connect to the throttle bracket.
http://www.hotrodders.com/forum/atta...id=57300&stc=1
http://www.hotrodders.com/forum/atta...hmentid=&stc=1
http://www.hotrodders.com/forum/atta...hmentid=&stc=1
I've tried this without the kickdown cable connected, without the return springs, I took the carb off and rebuilt it. I am ready to start from scratch but want some advice on anything else I need to check out to make sure this problem doesn't crop back up. The butterfly's on the carb feel kinda stiff, at least compared to my 30+ year old Q-jets. Before I buy a new pedal or make something new, I am looking for any advice on how others would approach this situation.

I was thinking about mechanical advantage and how my current pedal is pretty much 1:1. This pedal has a 3:1 advantage, but I don't want to put that much force into this until I know what is causing it to be so stiff.

Thanks for the help, I hope that explanation above makes sense.
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Old 08-03-2011, 02:30 PM
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I didn't see any pictures of what things look like at your pedal side, but i can tell that you're currently using a mr gasket universal throttle cable kit. I know this because I just pulled that same POS off mine. I was getting a lot of drag and it would actually stick at different areas in the tubing. Anyway, long story short I just replaced it with a Lokar universal cable setup last night and its smooth as butter. Not sure that this helps you any, but thought you might like to know someone else had a problem with setup.
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Old 08-03-2011, 02:32 PM
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Oh one other thing.....it appears that you could be using less cable housing as you have a short distance to go. Is there a reason you have it looped that way. You should be able to make a small S and still not create any drag.
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Old 08-03-2011, 03:48 PM
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2 things scare me in the first photo.
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Old 08-03-2011, 04:14 PM
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Thanks for the early response.
It does make me feel better that others have had stiff throttle issues like this. I will try and find a cable to test the pull resistance and rule out the current cable.

As for the loop, it's hard to see in the pictures, but the throttle exits the firewall 2 inches higher and about 4 inches to the side of the throttle bracket, it makes a very tight s-turn if that is attempted. This was the way I first had it setup, and ended up changing when I got the new cable. Ideally I would come out of the firewall in line with the throttle, but the firewall angles back into a 3" recess right next to the current exit point so if I moved to be inline it would come out pointed towards the distributor.

I came up with the loop idea because I thought a large gentle loop would create less drag than 2 small tight turns.

As for things scaring you in the pictures, please be more specific so I can fix the problem.
I think I know what you are referring to but and I didn't say anything about it earlier, but I just set the connections back in place for the pictures and did not complete everything (secure cotter pins, hook up second return spring) as I would if I was going driving. The pictures were hastily taken right before I had to get ready for work.

On a further note of design, the current pedal travels 3 inches inside the car, but I only need 1.5 inches of travel at the carb. I've tried adjusting the travel inside to decrease it to 1.5, but I've also thought about a new carb bracket that would be higher up giving me 3" of pull at the carb.
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Old 08-03-2011, 04:19 PM
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I was worried about having a tight S, but with the lokar cable it was fine and it didnt collapse.....i think you'll find out you like it better......also as far as the travel goes on the pedal just set it up so that when the pedal is floored your wide open......it might be closer to the floor but i dont think its a big deal.
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Old 08-03-2011, 06:38 PM
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Quote:
Originally Posted by guba_unus
As for things scaring you in the pictures, please be more specific so I can fix the problem.
I think I know what you are referring to but and I didn't say anything about it earlier, but I just set the connections back in place for the pictures and did not complete everything (secure cotter pins, hook up second return spring) as I would if I was going driving.
Thats what I figured. I just wanted to make sure before I pointed at anything.
Can you drill a new hole in the firewall in order to run a shortened cable straight out to the linkage?
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Old 08-03-2011, 08:26 PM
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Thanks for the concern. During a slow moment tonight I had an idea. My shop is finally getting to the point I can create pretty nifty things, so I was thinking of using 3/8" threaded rod and drilling out the center of it. Then cutting a pipe to sleeve the rod. The sleeve would be further cut in the middle with say a 45 degree angle (actually whatever angle matches the funky part of the firewall), then this would allow me to run the rod straight through the curved part of the firewall and still bolt it tightly to the firewall. I could run the cable through the rod, and I could put the new hole so it is a straight shot to the carb. I probably wouldn't even need to sleeve the cable as it is only 6 inches or so from the firewall to the carb bracket. I think my current pedal location would work for this too.
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Old 08-04-2011, 07:34 PM
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Have you tried to isolate the problem. Disconnect the cable hand pull it, without the carb attached. Feel the gas pedal, all the hacking you have done to that could have introduced binding. It should be a straight forward troubleshooting adventure. Process of elimination, you only have three items or systems if you prefer to check through. As one feels free connect the next and so on. A good smooth working throttle is key.

I like this style of throttle control hard link:
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Old 08-04-2011, 08:10 PM
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I've tried isolating things but I am unsure of what is considered excessive. I feel the throttle is pretty stiff to start with, but it seems ridiculous, possibly even ludicrous, to move once I add return springs and a kickdown cable.
What type of lube should I use for the throttle on the carb?
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Old 08-04-2011, 08:53 PM
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Throttle cable

First you can"t run a loop or sharp turns with the throttle cable.Ever tried to wire weld with a loop in the lead? Same principle. You said you could build something so why not just fabricate the place on the firewall where you need the cable to go.You can adjust ,grease,whatever on the present setup and still be cussing at yourself for not doing it right. Good luck.
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Old 08-04-2011, 09:32 PM
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I wouldn't run a rigid throttle with rubber isolator type motor mounts. If the mount separated and the engine lifted, the throttle could be pulled open.
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Old 08-04-2011, 09:34 PM
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Looking at Pic #1, with the home-built bracket ...

I see that neither of the cables appear to be aligned with the linkage.
IMO, that is the most crucial point ... where the cable interacts with the end of the cable housing. The throttle cable seems to be at about a 20° angle from the end of the cable housing, which will lead to a lot of friction, wear, and inevitable fraying of the cable.

The Kickdown cable is also offset in the opposite direction ... see how it rubs on the opposite side?

True that bracket up with a square ... then square the cables to the carb linkage. Like you said ... gentle "s" curves should be OK, but the more lineal the cable path the better.

Could you modify the pedal linkage end so that the end of it was more in-line with the carb somehow?
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Old 08-04-2011, 09:43 PM
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Quote:
Originally Posted by 1ownerT
I wouldn't run a rigid throttle with rubber isolator type motor mounts. If the mount separated and the engine lifted, the throttle could be pulled open.
In that case a torque strap from the engine to the frame should be used.

As far as the looped throttle cable goes, you need to go to plan B.
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Old 08-05-2011, 06:33 PM
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Quote:
Originally Posted by sqzbox
In that case a torque strap from the engine to the frame should be used.

As far as the looped throttle cable goes, you need to go to plan B.
You are right, that would be a great idea.
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