vimzzz

Anyone got any tips for adjustments on the gaspedal?

I bought myself a Holley 4150 carburetor, and a new gas wire for a C3. Now I find myself only able to open the throttle on the carburetor about 50% of what the carburetor can handle when the pedal is in the floor.

I had a look under the dash, and I see that my gas pedal is about half way down to the floor already compared to the brake and the clutch pedal. I can pull the gas pedal towards the drivers seat to align it with the brake and the clutch, but I wont get any pull on the gas wire from that position to about 50% down. So I have a big dead zone right there.

blue427

what year,did you switch from a q-jet to a Holley.You might want to look at cables and carb brkts first.

redvetracr

not sure what a gas wire is but the correct cable and cable bracket might help

DUB

WHAT YEAR?????? Throttle cable design changes and how the cable attaches to the support mount ...WHICH CAN MAKE A BIG DIFFERENCE!!!!!

YES...I have to 'tweak' the gas pedals when I find that I am not getting full throttle. BUT...understand I do this for a living and I make sure the throttle cable is CORRECTLY installed and connected to the carb....regardless if it is an original carb or an aftermarket carb. A LOT of it has to do with how and where you a re connecting the throttle cable to the carb linkage. I can ONLY assume that you are doing it correctly.

Photos would be nice if you care to do so.

DUB

vimzzz

Hi.

This is a 1968' model.
The carburetor is set up with a mounting bracket for the cable, and I have full stretch on the cable with my bracket. If I move the bracket any further backwards to the coupe, I start to tension the springs on the carburetor.

Here is a pic of my carburetor setup:



This is where I mount my wire on the carburetor:



As I said. I have tension on the cable to the point of mount on the carburetor. So my main problem is that I dont have enough "wandering" on my accelerator pedal to obtain full throttle.

redvetracr

you have the wrong bracket and probably the wrong cable...the factory stuff (while not as sexy) works just fine

vimzzz

The cable I have is like this one:
http://thumbs1.ebaystatic.com/d/l225...5YSeZLQKig.jpg

As I understand, it should be the original. All though that is not the orginial bracket, I still get to adjust it to the point where the cable is at full tension to the carburetor. As in, I cant put any more strain or tension to it with starting to accelerate the carburetor mounting point.

My accelerator pedal lever is pulled all the way to the firewall as it sits, but the pedal itself is only lifted about 50% from the floor. Which means I don't get enough leverage to pull the throttle on the carburetor enough to open it fully.

vimzzz

I'll try and run down to the garage and take a few pics / take a film as soon as my 1 year old decides its time to sleep.

vimzzz

Okay.

So here is a video showing the slack that exists between the pedal mounting bracket and the lever. The bolt that goes from the pedal mounting bracket is able to travel quite far before it grasps a hold of the lever and starts to move it. This is where I loose 50% of my pedals travel and why my pedal is so far down to the floor:

http://tinypic.com/player.php?v=ckqr...8#.VOwbKFOG8mU

Since the video had poor quality / light, here is a pic to shed some more light on it:

terrys6t8roadster

On both the 6t8 and 69, when switching to Holley style carbs I removed the pedal assy, bent the upper arm that attaches to the cable, to allow WOT. Then welded on a reinforcing piece. Also use Lokar cables. T

resdoggie

I have a '76 and put on a 4150. I also used the same throttle bracket which is just fine and the original accelerator cable. It has plenty of adjustment. Your problem is the gas pedal rod which terry has pointed out above. Rather than taking my gas pedal apart, I just grabbed my gas pedal firmly, crossed my fingers, and pulled it up towards the dash to bend the rod. Luckily, it didn't break the mounting bracket attached to the firewall. Looking at your picture of the carb, I used the larger diameter hole to the upper left to attach the throttle cable.

vimzzz

Thanks for the reply.
I found another post on this forum about ppl having problems with this gas pedal and its two parts getting ****ed up. Some of the guys recommended tack welding the parts together, and I think Im going for that solution. Just taking out the whole darn thing and tacking the stud in place. If any more movement is needed, Ill bend the pedal.

Street Rat

This is where I connected mine as well. You may have to get a bushing kit to fit the hole correctly (readily available). The hole that you are using is for the cruise control stud if you have cruise. This may be only part of your problem but is one thing that I see wrong for sure.

DUB

For one thing I might try to find or get a used accelerator pedal assembly and swap it out with what you have due to the design changed and it may be easier to modify. You can obviously try to get this one to work...but with the one bracket that bolts to the end of the other accelerator pedal part that has your pedal on it...It might be fun...and then again...it might work out perfectly.

No one can tell you which hole to use in your carburetor to attach the linkage because unless we can see a GOOD side view of your carb and linkage bracket...it is all guess work. The amount of throw of the gas pedal and which hole in the carb is best for this amount of throw (further away from the throttle shaft..the more throw of cable is required) and where it is in relation to your support bracket for the cable....TOO many variables.

For what it is worth...and not knowing if you know...and if you do...well this may help others who do not know....I take a horizontal line from the bracket where the center of the cable will be and see what hole it goes to. AND KNOWING that when you press on the gas pedal...the throttle linkage at the carb too turn and this attachment point will slightly raise up ( due to the arc motion it is traveling) and then it will come back down. SO..I want my cable in a position so when it is at idle or FULL throttle...my accelerator cable is even with this horizontal line or a little bit below it...BUT NEVER above it because it will not ever get to full throttle...it just cant.

DUB

nascar03

with DUB..
In 1998 I installed a ZZ4 cate motor e/w Holley 4150 into my '75 Coupe.
I had a bunch of problems trying to get the factory linkage to work correctly with this set-up. I tried 4-5 different throttle mounting brackets but nothing solved the issues. I finally used a generic mounting bracket and after much experimentation and many measurements I made an adapter(red) for the throttle bracket on the carb.

This adapter allows for the proper location of the pivot ball to correspond with the movement of the throttle cable. Prior to this the carb would either never shut-off(not good) or never fully open. This has been functioning perfect ever since.
Here is a wide-open throttle pic.

It worked for me.
I've been to many autocross events to find people having carbs that never fully open due to linkage issues. Free HP.
ymmv
graham

DUB

PERFECT EXAMPLE of what I wrote about 'nascar03'.

Thanks for the photos.

And I agree with you. I have lost count on the number of Corvettes that have been modified and I am looking around and checking 'stuff' and the throttle is one of them. I stop and shake my head. In so many cases the throttle cable bracket is able to move and all 'jacked-up' and can only get it if is LUCKY only 3/4 throttle. And I will not get started on the issues with the aftermarket air cleaner set-up and an air filter that is half as wide as what is called for.......and GOD FORBID they are using rubber hose from the fuel pump to the carb with some crappy plastic fuel filter in line.... Awaiting to happen.

DUB

scottjamison

Hi Vimzzz,

I know this is an old thread, but what was your solution?
I have a 68 with exactly the same issue and I am trying to figure it out.

Did you bend the original pedal?

terrys6t8roadster

There are two main parts in the pedal assembly; the lower rod which the pedal attaches to made out of round stock and then the upper which is made from sheet stock. The upper over the course of 50+ years has been bending closer to the firewall hence giving you less cable travel. As 'redoggie' mentioned bending the upper piece cures that problem, but if you notice in the under dash picture is that the piece that is bolted to the firewall [pivot] is plastic and 50+ years old, it can break. Safest bet is removal before bending, just don't loose the little piece that retains the cable to linkage. I also fabed up a piece for reinforcement and had it welded on. T