How Rough or smooth should the gas pedal feel?

[AndyMenon]

Guys,

I just installed my gas pedal. But something seems off.

I will post some pics, but I used this bracket to install the throttle linkage.The installation was a breeze on my Edelbrock 1406.
The cable runs straight, and yet I do not feel the smooth movement in the set up. The spoon-style pedal feels awfully weak and stressed. But there is no binding of any sort.

How smooth or rough should I expect the gas pedal to be?

thanks,
Andy

 

[benT]

In my opinion it needs to be smooth. If it is binding, I'd check to see if the carb linkage is the culprit, or the throttle cable.

I would also add (from experience) that the pedal needs to be solidly mounted and stout. I mounted a sweet-looking adjustable spoon type pedal on my '27 and within 2 hours of running my car (and mashing the gas!), it was bent. I cut it up and used the spline to make my own out of some much heavier steel plate. No issues since.

 

[AndyMenon]

In my opinion it needs to be smooth. If it is binding, I'd check to see if the carb linkage is the culprit, or the throttle cable.

I would also add (from experience) that the pedal needs to be solidly mounted and stout. I mounted a sweet-looking adjustable spoon type pedal on my '27 and within 2 hours of running my car (and mashing the gas!), it was bent. I cut it up and used the spline to make my own out of some much heavier steel plate. No issues since.

Thanks Ben!

Looks like I will need to scrap that gas pedal.

 

[Hot Rod Todd]

If your carb has two return springs on it, remove one and take the car for a short ride. If the binding is gone, and the engine returns nicely to idle, then replace the two springs with lighter ones. If the binding/harshness is still there, then have a good look to see if the accelerator cable moves freely inside its casing. If thats tight, lubricate it and if that doesnt work, look at replacing the cable

 

[2old2fast]

Just a note of caution , many cable housings are lined w/plastic...some petroleum based lubricants will "eat " plastic...
dave

 

[AndyMenon]

Just a note of caution , many cable housings are lined w/plastic...some petroleum based lubricants will "eat " plastic...
dave

Agreed. But my set up has a braided steel cable.

If your carb has two return springs on it, remove one and take the car for a short ride. If the binding is gone, and the engine returns nicely to idle, then replace the two springs with lighter ones. If the binding/harshness is still there, then have a good look to see if the accelerator cable moves freely inside its casing. If thats tight, lubricate it and if that doesnt work, look at replacing the cable

Got it! Let me run through this check list and see what works.

 

[Joe-405]

is the throttle cable new ? And if you had to shorten it you might have fraid or unraveled the cable ?

 

[AndyMenon]

is the throttle cable new ? And if you had to shorten it you might have fraid or unraveled the cable ?

Yep it is new, and I had to shorten it by cutting it on the end that goes on the Carburetor . But I did not fray the end. I'm sure because had it frayed, I would not have been able to insert it into the cable end, and thread it in. Here are some picks of the set up

 

[EX JUNK]

How about some shots of the pedal side. Perhaps there is something wrong there because on the engine side I can see nothing wrong.

Jim

 

[Mike]

Other than there is zero slack in the cable, on the engine side of the firewall. Andy, if you're not running solid mounts, you better make sure you run a tight torque strap on that driver's side, because you have that cable as taut as a G-string.

 

[AndyMenon]

Other than there is zero slack in the cable, on the engine side of the firewall. Andy, if you're not running solid mounts, you better make sure you run a tight torque strap on that driver's side, because you have that cable as taut as a G-string.

Right. I'm not running solid mounts. I have at least an inch that I can unscrew on the cable end to add some slack.

How about some shots of the pedal side. Perhaps there is something wrong there because on the engine side I can see nothing wrong.

Jim

Hi Jim,

Here are the pix of the gas pedal from the driver's side. This is the best I could do in 5 minutes. I can post more pix if required.

Also, per Mike, I do not recall seeing any instructions on the torque strap. Is this something that is applicable in all cases, or just my project?

thanks,
Andy

 

[EX JUNK]

Right. I'm not running solid mounts. I have at least an inch that I can unscrew on the cable end to add some slack.



Hi Jim,

Here are the pix of the gas pedal from the driver's side. This is the best I could do in 5 minutes. I can post more pix if required.

Also, per Mike, I do not recall seeing any instructions on the torque strap. Is this something that is applicable in all cases, or just my project?

thanks,
Andy

View attachment 8130View attachment 8131View attachment 8132

If you are able to put a little slack in that line, do it. You might also disconnect the cable from the accelerator arm and the move the pedal and see if there is any drag that may be causing your problem. Then pull on the cable from inside and see if it pulls smoothly. One of those two areas are probably the cause of your trouble. I have attached a picture of my set up to show you that you don't need a lot of slack.



Jim

 

[Mike J]

It looks like the mount going through the fire wall is higher than the carb linkage, so maybe when the arm pulls the cable it is pulling it down( like an arc) causing the added friction. Maybe lighter carb. springs also. I.M.O.

 

[Dino]

Where the pedal mounts at the fire wall looks like the pedal rubing at the mount? May need a spacer at the mounting points

 

[Mike J]

What Dino said could be true. Without cable tension on the pivot point of the pedal , it might seem o.k. with tension from the cable, the pedal gets pulled against the firewall maybe causing the bind. Just thinking out loud.

 

[Screaming Metal]

OK this is starting to get painful.
1. Disconnect your cable from the carb. Move your pedal. Things should move free. If there is a slight drag, get some powered graphite, elevate the end of the cable sprinkle some between the cable and the housing. move cable back and forth, add some more graphite, do the same thing, Do this 3 times until quite a bit of graphite has been worked in. Get your airhose, where you were adding the graphite, hit it with a quick burst of air. This will drive the powder to the other end....then the cable will self lube as you use it.
Also, check everything at your pedal the same way also. Fix any binding there....Make sure the cable is centered to the pedal pull point. If not, fix it so it is....you want a straight pull, not off at some angle.
2. Now, work your carb linkage. Things should be free. If not, check for binding on your bushings or secondary linkage. Also, make sure your not stacking your pump(s) up solid. If there is still a issue, check to make sure your throttle blade aren't dragging in their bores.
3. Now, put 1 and 2 together, and you should have a smooth movement. If not, check any other outside influences, like trans kickdown cables, etc.
Be sure that your cable is pulling staight on your carb bellcrank. Put the cable on a straight line to where its attached on your carb. You should have free movement from idle, to full throttle. When at full throttle, make sure you can take your foot off the pedal and it should return quickly and solidly.

One of my customers lit off in his altered, down the track he went, he came back to the pits, car being pulled, his eyeballs were as big as saucers, and he was still panting....he said his throttle hung wide open midtrack....but he did win low ET in his class.

Having your throttle hang in a street car can get you in severe trouble as light as these cars are. Mine has a kill switch that grounds out the ignition circuit....old habits die hard....



Only add enough spring to return everything to close, then enough to have a slight resistance to push agianst....so it won't feel like a hair trigger. Any more, those shafts will wollow out the the alum. bores they ride in on the carb bases. A little graphite there will work wonders also.....

 

[Screaming Metal]

Loose throttle shafts have been the source of many a mysterious vacuum leak....even to some professionals. Check them periodically....

 

[AndyMenon]

Painful indeed. But again, we aren't exactly having a hobby that sounds like doll making.So I guess pain is definitely part of getting to the final result . Thankfully, I see a lot of feedback and therefore, I will try to cover them all here:

1. To Jim's point, I will add that slack by loosening up the cable.
2. Testing the pedal bind: When I detach the cable end from the throttle linkage, the gas pedal simply drops to the floor . This indicates that there is no bind in the pedal by itself.
3. To Dino's and Mike J's points: The cable I think is rubbing to one side of the fire wall mount. I may have to look into that and make some adjustments.
4. To Scream's list of items:

• Carb linkage is absolutely free. I cleaned the carb with carb cleaner, and none of the blades or the linkages were binding.
• The kickdown-cable isn't attached yet. So this possibility is eliminated.

Additional Item: Another thing I noticed are the 2 holes in the Jegs bracket where the 2 springs attach to the throttle arm of the carb. These holes have been machined, but not filed . When I depress the gas pedal, I can hear the springs twang because the curved ends of the springs are moving inside the straight edges of the holes in the bracket. Here's an illustration.
Maybe I should file around those holes and smooth the edges.



Happy Sunday to All!

 

[RPM]

Try unhooking the trans kick down cable. It might be the problem and not the throttle cable.