'74 CIS Throttle Linkage Adjustment

Sean A · Sean A's Garage

Im having a hard time getting the right adjustments on travel and such, and the Haynes manual is garbage at explaining what needs to be done.

I see two stops and a microswitch. Should i be getting full travel from stop to stop? Also, is the microswitch (for the CSV, if im not mistaken?) be adjusted with the screw so that it is completely depressed when the hand throttle is all the way down or barley not actuated?

If i adjust the length of the short linkage bar to barley rest on the idle stop, its not long enough to get to the WOT stop. Conversley, if i shorten the length so that i can get WOT, it is too short to reach the idle stop. This is with all the rods connected. Do i need to lengthen another rod somewhere?

Gogar · 12:59 PM

Hi Sean.

My suggestions:

The short linkage bar goes from the throttle to the bell-crank that is mounted to the engine. Undo that, and make sure that your microswitch engages when the throttle is at the closed stop.

While you have that short linkage off, reach back and fiddle with the bell-crank. There are nylon/plastic bushings in that bellcrank that can get old and fall apart. Does the rod move around in the housing? You could replace the bushings if it does. Sometimes if the bushings are old you may not be able to get the proper angle to bring the throttle to the WOT full stop.

Othersise, it's all about angles/length of the rods. Make that short throttle rod is just barely long enough so your throttle hits the idle-side stop and the bellcrank is extended all the way.. Then, adjust that little screw for the switch so it clicks when the throttle is at idle.

Only then should you put on the long throttle rod that goes to the relay rod on the transmission, and work your way towards the front of the car.

The most likely culprits are the nylon bushings on the bellcrank, like I mentioned, or the similar bushings on the 'throttle relay rod' that is on the transmission. It's unlikely somebody messed with the idle switch adjustment or the lenghts of the rods, but anything's possible!

Sean A · Sean A's Garage

Quote:

Originally Posted by Gogar

While you have that short linkage off, reach back and fiddle with the bell-crank. There are nylon/plastic bushings in that bellcrank that can get old and fall apart. Does the rod move around in the housing? You could replace the bushings if it does. Sometimes if the bushings are old you may not be able to get the proper angle to bring the throttle to the WOT full stop.

Othersise, it's all about angles/length of the rods. Make that short throttle rod is just barely long enough so your throttle hits the idle-side stop and the bellcrank is extended all the way.. Then, adjust that little screw for the switch so it clicks when the throttle is at idle.

Only then should you put on the long throttle rod that goes to the relay rod on the transmission, and work your way towards the front of the car.

The most likely culprits are the nylon bushings on the bellcrank, like I mentioned, or the similar bushings on the 'throttle relay rod' that is on the transmission. It's unlikely somebody messed with the idle switch adjustment or the lenghts of the rods, but anything's possible!

The bushings check out okay, so should i be able to go from stop to stop using the gas pedal? I messed with the rod length and small screw yesterday when i found that the nuts on the small screw were loose and the car wasnt idling properly. Have i mucked things up?

EDIT: If i adjust the length of the short linkage bar to barley rest on the idle stop, its not long enough to get to the WOT stop. Conversley, if i shorten the length so that i can get WOT, it is too short to reach the idle stop. This is with all the rods connected. Do i need to lengthen another rod somewhere?

Gogar · 02:56 PM

Sorry, I went out and looked.

Undo the rod that goes from the bellcrank through the firewall to the transmission relay rod.

Adjust that first short rod (throttle to bellcrank) so when you're at the wide open stop, the arm on the bellcrank it attaches to is almost flat as far as it could go. That should allow you to hit both stops. Then, reattach the long rod that goes from the bellcrank to the trans relay rod, and adjust the length of that rod so there's no slop in it, but not so snug as to pull the throttle off of the idle stop.

Then with everything connected, push your gas pedal all the way down and have someone hold it there or hold it with a broomstick or something. If you're getting to the WOT stop, then you're good. If not, then there's one last rod under the gas pedal, make it longer if you need more throw, shorter if you need less.

It is also important to not have it slamming against the WOT stop and causing too much stress. the gas pedal should hit its rubber stop the same time as you get near the WOT stop on the throttle.

Sean A · Sean A's Garage

Quote:

Originally Posted by Gogar

Sorry, I went out and looked.

Undo the rod that goes from the bellcrank through the firewall to the transmission relay rod.

Adjust that first short rod (throttle to bellcrank) so when you're at the wide open stop, the arm on the bellcrank it attaches to is almost flat as far as it could go. That should allow you to hit both stops. Then, reattach the long rod that goes from the bellcrank to the trans relay rod, and adjust the length of that rod so there's no slop in it, but not so snug as to pull the throttle off of the idle stop.

Then with everything connected, push your gas pedal all the way down and have someone hold it there or hold it with a broomstick or something. If you're getting to the WOT stop, then you're good. If not, then there's one last rod under the gas pedal, make it longer if you need more throw, shorter if you need less.

It is also important to not have it slamming against the WOT stop and causing too much stress. the gas pedal should hit its rubber stop the same time as you get near the WOT stop on the throttle.

Excellent, thanks a lot. I adjusted the transmission-to-bellcrank rod and i am getting the proper throw now. The rubber stop on my gas pedal also needed to be adjusted.

Is the microswitch actuated by the small screw an idle switch? Or the CSV switch? My car has a hand throttle so i was always wondering...

Gogar · 05-23-2010, 06:41 PM

I guess when I say "microswitch" I mean the switch you were pointing to in your pic. Just make sure it "clicks" at the bottIom of the throw, adjust it with that little flat head screw.