Tri power throttle question
 

Two questions today...….doing some adjustments on the 66 to make sure im hitting the stops on full throttle...…….when doing this by hand I can adjust everything fine...…...but when I put on the gas cable its always about a 1/16-1/8 off on the back carb.

The pic I have is where I was bending the one bracket trying to make it fit right, well that was a no go from the start...……….could get it to work right ONLY if I hit the gas pedal just right...…......so im guessing when I want to kick in the other carbs, hopefully my foot is in the perfect position to work. lol

Other question I have is when you guys are making adjustments how are you dealing with the carbs gas...……...ive been unhooking the lines to the center carb and pulling that off and draining it that way...……….but while doing adjustments the ends are squirting all over town...…………..so I take it I have to take off all 3 carbs anytime I want to make a slight adjustment.

So im thinking my issue is with the cable /gas pedal somewhere...…...I see ames sells a 3 eyelet one and a single, which I have now...……….im sure someone else has run into this issue...……...seems like a waste of money to buy god knows how many cable just to get this to work right.

Thanks

Rich

On my old ('61 SD) Tri-Power, I can unhook the accelerator pump links. I don't know if that can be done with later ones?

I guess I never will understand that logic (after working at Holley on their carb wet flow stands and seeing HOW LITTLE that additional airflow there is going thru the carb for that last .100" of throttle blade movement.

I never set the carbs linkage up for "Pedal to the Floor" and "Carbs on the Base Stops" as that is why you have loose carb levers and see threaded screws in many carb shafts vs tight Rochester Products "peaning" of the shafts. The floorboard does move under a "Gorilla Stomp" on the pedal occasionally and then you have put a lot more stress into the carb linkage/levers. The Throttle Cable could probably lift 75 to 100 pounds of material without breaking and with the carb lever arm helping with the force applied to the peaning, no wonder you see so many Tri-Power carbs damaged. All for 1 more HP from the additional .1 pound of air mass thru the carb. One pound of air mass typically will make 10 HP and I guarantee that removing that .100" of additional clearance before the carb base stops does not get you one pound of additional air mass flow or 10 HP. Maybe at most 1 HP.

Tom V.

But do it your way.

__________________
"Engineers do stuff for reasons" Tom Vaught

Don't want to be a wise A, but why do engineers put stops on carbs and shifters, must be some reason.

Pressing the pedal to the floor is a far cry from a "Gorilla Stomp"...…...im not looking for every last hp...…...im just trying to get this thing to work right...….I have a post in the 66-67 section to see if I even have the proper gas pedal linkage, I stopped by a friends house today, he has a 64...…...mine is not even remotely close to his, so I don't know if I have a throttle cable problem or the whole gas linkage problem.

If you don't mind looking at my post in the 66-67 section, maybe you could shed some light on that.

Better yet, I"ll post them here.

You can see in the # 8 pic, the pedal hits shaft which is already on the carpet, so something isn't right there, not to mention I can move the linkage any way without resistence.

Been like this since I got the car...……..wondering if its from a Chevelle .

Rich

Fascinating post Tom.
Nice problem to have Rich!

Maybe a spacer/washer under the bolts that hold the pedal down inside that plastic cup. This would raise the fulcrum away from the floor and let you press the pedal down a little more before it bottoms out - maybe what you are needing.

Experiment with spacer/washer thickness to get where you want?

Just a thought.

Thanks Jim, will try that, but before I mess around with this any more, I want to find out if this is even Pontiac related, not sure where I even got this gas pedal from anymore, thinking ames but not sure...……..I ordered the new throttle cable today, lets see how that goes.

Rich

I'd listen to Tom. A LIFETIME of experience and a ton of knowledge goes a long way.

As far mechanical stops, they are put in place as a last resort!!

"Bill"!

Bill, I agree, Tom has way more knowledge on this stuff than me...…….im learning as I go, but it would help if explained better...……….if I even have the right parts would be helpful.

Im just going by Mike Wasson and others who do this...……..they use the stops, right or wrong I don't know...……..im just trying to get this car running better.

Nobody at this time has even mentioned if I have the right linkage or not...…….

Rich

Can't explain about 1966-67 GTO parts on the body as I have only owned one 1966 GTO convertible and it had been converted to chevy power before I bought it in florida.
It had chevy accelerator linkage.

Here are some illustrations on the 64-65 parts which I am aware of and a illustration on the 66 67 GTO parts which as you posted are different. Whole system is a bunch different. Looking at the 1966-67 parts design your pictures show a 1966-67 accelerator rod assy.
Tom V.

I apologize for basically trying to keep you safe if your linkage broke and jammed the Tri-Power throttle linkage.
I am referring to the Tri-Power linkage that controls the carbs, not the accelerator pedal, cable, or the pedal rod assy.

Tom, thanks for the pics, quite a bit difference. Im gonna pull that pedal linkage out and see what I can do, im thinking the bushing are shot because I can move it either way. Question on the carbs linkage, if not using the stops, are you adjusting the linkage to say a 1/16 to 1/8 before the stops.

Thanks

Rich

Rich

I have my wife push the pedal to the floor (she drove the car in college quite a bit), and then adjust the 1965 linkage (much safer vs the 64 linkage) so that when the pedal is all the way down there is about a 1/16" (.060") of clearance from the stop on the rear carb.

The front carb has a oval slot in it and I adjust the connecting rod to get the same clearance on the front carb. I also make sure that if the rod gets hot it has room for more expansion so the blades are not slightly open and cause a higher idle reading.

Tom V.

Tom, thanks for that tip......I"ll have my wife do the same, because im getting nowhere doing this by myself trying to hold levers back with my hands and making adjustments.

Im not that far off the 1/16 mark now, im just gonna move them till I hit that mark. Just gonna get them so they are all equal.

But first I got to figure out what my issues is with the pedal assembly itself, because it all depends where you put your foot on the pedal where everything lines up on the carb linkage...……...if I press hard on the very bottom of the pedal, things are close linkage wise, but if just pressing regular, its not even close to anything.

Hard to explain, yeah, I know I don't explain things well anyways. lol...….but it seems like the pedal rod hits the carpet first then the pedal seems to lay on top of the rod. So something is not right there.

This was even worse with the GTO carpet pad in there.

I appreciate the help

Rich

Many think cable throttle systems are really easy vs mechanical linkage (like chevrolet) had on their vehicles. You need to have a nice smooth, (not sloppy) throttle control.
Your are a smart guy, between you and your wife, you will get it solved to your satisfaction. Have you looked to see how much slop you have between parts 11 and 13?

Tom V.

Tom, checked between those numbers, seems pretty good, I think I found part of the problem, it would be # 20 on that chart you posted. Looks like a plastic bushing, of course im missing one. On your parts list, does that happen to have the size of that bad boy, I checked at the hardware store , no luck with anything even near that size.

Not sure of the pic with the spring on the pedal, showing it both ways, but it seems you can push down on the pedal and it moves quite a bit before the rod moves...….not sure of that though...……..must work, been using it for the last 21 yrs. lol

Hoping I can just buy this part somewhere...………..my wife is out in the garage and says, Buy my A$$, im gonna get this to work...……...might just happen. lol

I ordered the new throttle cable, hoping this is gonna work...…….

Thanks again

Rich

I was pretty sure that #20 might be the cause of your issue.
I have seen that broken/missing nylon bushing in the past on 1964/65 vehicles.
Seems like your wife could buy a piece of brass stock or plastic stock and get the OD pretty close to the housing ID and then drill a hole for your pedal extension bushings,
you need two of the #20 bushings or one longer brass sleeve bushing.

Tom V.

Tom, you were right on that call, I was missing one of those nylon bushings, thought I could buy some # OER 3798256 says those are for a 67 firebird, we ended up making this, I got it started and my wife finished it up...……...tight as can be now, then I had my installer install it...……...she wasn't a happy camper. lol



Suppose to be getting the correct cable for a tripower Monday, hoping for the best on that deal.

Seems Chicago muscle parts has the bushings for $7 a piece # 106200...…..I don't think so.