Throttle rod and linkage geometry gone wonky

[Ride The Snake!]

After reinstalling the *same* carb and intake following a cam replacement and gaskets, water pump, among some other items--my throttle rod and linkage no longer align properly. For the life of me, I can't fathom why the throttle rod now requires that extreme forward angle in front of the firewall at closed position, in order to have adequate pedal travel inside the cab. Ideas?

Edit: I had to make extra threads on the rod connected to the carb in order to get the gas pedal to be resting in an appropriate position and not on the damn floor.
Edit 2: sorry I forgot to rotate the images

[LockDoc]

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I will have to do some checking in the morning but it looks to me like the throttle assembly that goes though the firewall got bent somehow.

LockDoc

[dmjlambert]

without pressing on the pedal (in other words, at idle speed) I've got about 3 inches between the carpet and the part of the pedal rod that touches the pedal. What do you have there on yours? (your picture, I've added the arrow)

[Ride The Snake!]

That's my only guess as well, but I don't understand how that's possible or would have even happened. Isn't the pedal rod a single piece of steel?

[Ride The Snake!]

I have about 5 inches along that arrow. 3 would feel low, and like the throttle isn't opening all the way at the carb.

[kwmech]

Flip the rod 180 so the adjustment is in the front so threads don't hit the firewall

[Ride The Snake!]

Originally Posted by kwmech

Flip the rod 180 so the adjustment is in the front so threads don't hit the firewall

I'm sorry, I don't understand at all what you're suggesting.

[dmjlambert]

Hi, Arrow Guy back again. :-)
I think you'll find that the maximum travel the carburetor's throttle linkage will have is a couple inches. Go ahead and move the carburetor linkage by hand and measure how far it goes. So there is no reason to have the gas pedal 5 inches off the floor. That's too much pedal height and you won't be able to use all that distance between pedal and the floor anyway.

[Sheepdip]

It appears by your pic that the piece inside the cab has been cut and welded and probably altered the clocking of the whole shebang. Here's one on ebay that would save you a bunch of time trying to figure out what someone did.

https://www.ebay.com/itm/Gas-Pedal-A...pe!95386!US!-1

[dmjlambert]

I don't see that alteration. Looks same as mine. I just don't have mine adjusted for an extreme pedal height.

[LockDoc]

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My '67 is three inches up at the arrow dmjlambert posted, and my '68 is 3 1/2". The pictures are the '68. I can't imagine that your pedal would even work the way you have yours now.

[Ride The Snake!]

The problem is, if I were to adjust it for only 3 inches inside the cab, the throttle plates at the carb wouldn't fully open. In fact, even as it's set up now, with the pedal all the way down, i can still pull the throttle plates open a little further.

Here's a pic of the pedal rod and throttle rod removed. Those angles seem weird, but the pedal is a single piece of steel and even if it's not stock, it worked fine before! Only after reinstalling the carb and intake and reattaching the throttle rod to the carb and pedal rod did it suddenly form this funky angle and force me to put additional threads on the throttle rod just to get it to work at all. And it sucks because the pedal isn't smooth and lightly binds up.

edit: or maybe the angle on the pedal rod is normal.

[dmjlambert]

Interesting. Well on mine the throttle rod travels 2 inches, nearly opening the throttle all the way, and the rod hits the firewall. If I disconnect the rod, I can get another 1/4 or so of travel of the lever on the carburetor. So I'm not getting to the tractor supply and back as fast as I could. Perhaps I'll cut the rod off a little bit. But then again, think of all the gas I'm saving. Maybe the General didn't intend for us to go full throttle...

['68OrangeSunshine]

I went to a throttle cable set up on my '68 C/10. But I was dealing with a 4 Bbl carb, designed for a V8, on my L6 292. The carb had to be clocked 90* toward the drivers side to put the primaries on the same plane. The bellcrank/boomerang deal was getting to be more of a Rube Goldberg than I wanted to deal with.

[dmjlambert]

You just told us a pretty wacky thing, I love it. Did you take pictures of the before and after bellcrank/boomerang to throttle cable setup? That would be interesting to see.

['68OrangeSunshine]

Originally Posted by dmjlambert

You just told us a pretty wacky thing, I love it. Did you take pictures of the before and after bellcrank/boomerang to throttle cable setup? That would be interesting to see.

Sorry. It was done in the Dawn of the Digital Age. We did start to chronicle the project with pics of Before, but my Buddy's digital camera got smashed in the door of his truck, and he was too pissed to get another camera.[They were expensive then.] We did complete the cable project though.
Unfortunately, no pix were salvaged. Especially sad, that our wildlife shot of a big Packrat sitting up on the valley of my 454 in the '67 K/10 Suburban, and seeming to say: "Yeah? Rat Motor? I got yer Rat Motor right here!"
Lost. All gone. Nevermore.
I do have a film shot, transcribed to a disc and uploaded of the After.

[dmjlambert]

That turned out quite neat. Good job!

[dmjlambert]

Ride The Snake! didn't mention if the problem is the rod hitting the firewall. I am just now realizing what kwmech meant by flipping the rod. I don't know how the rod connects to the steel lever that goes through the firewall, that connection is way back there and I can't get close enough to get a good look at it.

[RustyPile]

I've been following this thread and I am totally myistified. It has given me chuckles, frowns, and amusement.. There is no way on God's green earth the linkage geometry could have changed simply by changing intake gaskets and camshaft.. The carburetor is in the same location in relation to the fire wall..

Since Ride the snake is so interested in wanting the carburetor throttle blades to reach the absolute wide open position, I offer this procedure to accomplish this.. Disconnect the threaded rod from gas pedal lever.. Also disconnect it from the carburetor. Place the gas pedal in the wide open position and block it in place.. Do the same thing to the carburetor throttle plates.. Adjust the threaded rod so that it slips into place without moving either the carburetor arm or the gas pedal lever.. The "angle" of the gas pedal is what it is and cannot be changed without altering the linkage geometry..

[Ride The Snake!]

Thanks for all the replies and advice, guys. In the end, I just adjusted the pedal to have the 3" distance from the back of the pedal's tip to the floor at an angle drawn perpendicular to the lower pedal arm's shaft. This compromise works, and I agree the lower gas pedal feels better under my foot, and it doesn't feel like it's binding at all now.

However, the throttle plates don't open entirely before the pedal hits the floor. And to answer a question asked before--no, the throttle rod is not contacting the firewall. I don't know how much airflow and wide open throttle response this is potentially limiting the motor, and I guess it's not that important.

More importantly, I need to figure out why it's missing and bucking at mid and high RPM, under load and even sometimes at cruise. I can't imagine it's a spark issue since I have new plugs, good wires, new distributor parts (cap is only a few thousand miles old at most, new pickup coil, ignition coil, condenser, module). the 2g carb I bought rebuilt from a reputable shop a few years ago and has barely any mileage on it, after I could never get my old 2g to work properly despite rebuilding it and checking my work three times.

Aaaaand just discovered my heater core is bad after driving across town last night. Steaming up my cab and smells like sweet and fishy vagene. Super gnarly. I'll bypass it for now.

Bah, this should be another thread...

[Ride The Snake!]

Originally Posted by RustyPile

I've been following this thread and I am totally myistified. It has given me chuckles, frowns, and amusement.. There is no way on God's green earth the linkage geometry could have changed simply by changing intake gaskets and camshaft.. The carburetor is in the same location in relation to the fire wall..

Since Ride the snake is so interested in wanting the carburetor throttle blades to reach the absolute wide open position, I offer this procedure to accomplish this.. Disconnect the threaded rod from gas pedal lever.. Also disconnect it from the carburetor. Place the gas pedal in the wide open position and block it in place.. Do the same thing to the carburetor throttle plates.. Adjust the threaded rod so that it slips into place without moving either the carburetor arm or the gas pedal lever.. The "angle" of the gas pedal is what it is and cannot be changed without altering the linkage geometry..

I totally agree, it was not physically possible. But somehow, some way, the original threads on the throttle rod no longer extended far enough such that when we (my dad and I) initially reattached it to the pedal, and carb, at closed position the damn pedal was virtually to the floor.

So even with my acceptable, compromised adjustment now, the new threads we added were necessary. How this could be possible is indeed quite a mystery. All I can add is that during the truck's down time we also loosened the motor mounts and I jacked the engine up an inch or inch and a half in order to get the oil pan to come out. But there's no way that after tightening it down again the engine could have slightly shifted position... right? I mean, we got all the clutch linkage to line up easily, which I don't think it would have had the motor and bell housing shifted position.

[biketopia]

Can you put the rod in the lower hole on the carb? Might get you to full throttle with the different mechanical sweep. Also, get a bigger air cleaner, I know you're only feeding a 2bbl but that small of a cleaner can cause enough of a restriction that it could be contributing to your hesitation issues.

[Ride The Snake!]

I had considered trying the lower hole on the carb, but it's even further back towards the firewall. The way the linkage is, it would line up better if the carb hole was further forward instead. But you might be correct that the lower hole's mechanical sweep is shorter, which would help get the throttle plates open more with the same pedal stroke length.

I might play with it again and try it out, but the compromise I have now seems to work pretty well.

You're right about the air cleaner. However, it came with a tiny one when I bought it so I just replaced them with the same, and the motor wasn't misbehaving before. But you're right in that it's probably restrictive and should be bigger. I will do so.

I wonder if it's possible the carb isn't tuned right for a 350. I don't know what jets it has, and I haven't cracked it to check the float level.

[biketopia]

If you can get it to "act up" reasonably consistent. Take it to a section of rode and pop the air cleaner off as long as your not near a gravel quary you won't have issue of dirt hurting anything for a quick test. Drive your little course with and without the filter and see if it makes things better, cheap and easy test to get you in the right direction hopefully.