Throttle/ kickdown linkage

[Rooster27]

Hey guys and gals hope all is well and you have been soaking up the sunshine! Have a quick question on mostly the kickdown linkage. I have it disconnected right now as you can see in the photo. The carb is a 4bbl edelbrock 600 that sits on top of a weiand intake. Any help would be great!

 

[493 Mike]

I hope you are NOT driving with the linkage inoperable? That will burn up your transmission quickly! I'm not familiar with the E-brock carbs (except that they are AFB/AVS copies) but, if they're like Holley's you need the adapter for Mopar.
Mike

 

[R/T Boy 67]

 

[Rooster27]

View attachment 957615

Thank you!

 

[Geff McCarthy]

My new 63 Sport Fury has a replacement 400 with Edelbrock 1407 4bbl. I now realize that the transmission rod is the original Plymouth. I struggled to obtain enough length to direct the 727 properly; it would shift into 3rd by 20mph and no kick down. I was about to bend the entire rod to lengthen, then noted on the Edelbrock site, a MOPAR adapter: really just a lenght of rod and a hexagonal turnbuckle that, when twisted, shortened or lengthened. Not bad price, but I went to my local hardware store, purchased the correct 1/4" x 28tpi turnbuckle, and since no rod was available, bought a bolt and cut off the head. Bingo: adjustable shift points and kick-down. On the original cars, there s a"V" bracket that prevents sideways movement of the control rod. I need one of those, now too. Can send photo if you need.

 

[Rooster27]

My new 63 Sport Fury has a replacement 400 with Edelbrock 1407 4bbl. I now realize that the transmission rod is the original Plymouth. I struggled to obtain enough length to direct the 727 properly; it would shift into 3rd by 20mph and no kick down. I was about to bend the entire rod to lengthen, then noted on the Edelbrock site, a MOPAR adapter: really just a lenght of rod and a hexagonal turnbuckle that, when twisted, shortened or lengthened. Not bad price, but I went to my local hardware store, purchased the correct 1/4" x 28tpi turnbuckle, and since no rod was available, bought a bolt and cut off the head. Bingo: adjustable shift points and kick-down. On the original cars, there s a"V" bracket that prevents sideways movement of the control rod. I need one of those, now too. Can send photo if you need.

That would be awesome if you could send a photo im actually having the same issue shifting into 3rd too soon. I dont drive it very often and only had about 300 miles on it since the engine has been rebuilt. I just bought the adapter before I saw this message but a picture would be awesome just so I can compare!

 

[Nate S]

A common problem, even when the bracket is “correct” is the the distance from the centerline of the throttle shaft to the attachment point is different on the new carbs than the factory carbs. The old radius was 1.125”, typical Holley replacements are 1.5, not unlikely the Edelbrock is too. That means you have too much throw and when set to bottom out at WOT it leaves it far too lax for the whole early part of the motion. Best to measure that distance and drill a new hole in the right place. I have done this and it works soooo much better.

 

[Rooster27]

A common problem, even when the bracket is “correct” is the the distance from the centerline of the throttle shaft to the attachment point is different on the new carbs than the factory carbs. The old radius was 1.125”, typical Holley replacements are 1.5, not unlikely the Edelbrock is too. That means you have too much throw and when set to bottom out at WOT it leaves it far too lax for the whole early part of the motion. Best to measure that distance and drill a new hole in the right place. I have done this and it works soooo much better.

Could you show me what this would look like? What is WOT? Sorry for the questions, my wife inherited the 66 charger from her dad and im not super savvy when it comes to mechanical stuff on these old girls, but I can detail the **** out of them.

 

[Billccm]

Wide Open Throttle

 

[Rooster27]

A common problem, even when the bracket is “correct” is the the distance from the centerline of the throttle shaft to the attachment point is different on the new carbs than the factory carbs. The old radius was 1.125”, typical Holley replacements are 1.5, not unlikely the Edelbrock is too. That means you have too much throw and when set to bottom out at WOT it leaves it far too lax for the whole early part of the motion. Best to measure that distance and drill a new hole in the right place. I have done this and it works soooo much better.

Luckily I have a 65 fury here with a 318 poly and I think i know what you are saying now, with the edelbrok it seems where the throttle cable hooks to on the carb would be the place you would want it. I just looked at the fury 318 which is stock, and the kickdown and throttle cable are parallel to one another. I feel with the edelbrock if you were to do that, it would almost be too high of a "pivot" to attach it there.

 

[Nate S]

In this first picture I’m showing a 1971 carter AVS and the distance from the throttle shaft to the Cable and linkage attachment point.

figuring that the distance required to go from idle to WOT is related to the circumference of the circle it goes on, that 1.2” radius is proportional to that distance. Inside the transmission the shift points move based on the compression of a spring between the kickdown valve and the throttle valve. It’s designed to work with that throttle cable movement distance, ending with the kickdown linkage almost bottomed out.

Here’s a typical Holley with the correct bracket they sell for Chrysler products. See that hole above where the throttle is actually hooked up? That’s the hole they give you. It’s 1.5” from the shaft centerline. If you set the kickdown linkage to almost bottom out at WOT it’s pulled MUCH farther forward when at idle, this is because of that larger radius.

Part throttle acceleration isn’t much different than idle so the kickdown linkage with that outer hole position hasn’t moved to even where it would be at idle with the correct radius. The solution is to drill a new hole in the aftermarket arm that’s the same distance as the factory hole (like was done in the second photo). This allows the kickdown linkage to be compressed the right amount and the shifts to happen at higher points.

 

[Rooster27]

In this first picture I’m showing a 1971 carter AVS and the distance from the throttle shaft to the Cable and linkage attachment point.View attachment 957712

figuring that the distance required to go from idle to WOT is related to the circumference of the circle it goes on, that 1.2” radius is proportional to that distance. Inside the transmission the shift points move based on the compression of a spring between the kickdown valve and the throttle valve. It’s designed to work with that throttle cable movement distance, ending with the kickdown linkage almost bottomed out.View attachment 957718

Here’s a typical Holley with the correct bracket they sell for Chrysler products. See that hole above where the throttle is actually hooked up? That’s the hole they give you. It’s 1.5” from the shaft centerline. If you set the kickdown linkage to almost bottom out at WOT it’s pulled MUCH farther forward when at idle, this is because of that larger radius.

Part throttle acceleration isn’t much different than idle so the kickdown linkage with that outer hole position hasn’t moved to even where it would be at idle with the correct radius. The solution is to drill a new hole in the aftermarket arm that’s the same distance as the factory hole (like was done in the second photo). This allows the kickdown linkage to be compressed the right amount and the shifts to happen at higher points.

Thank you for this, ill be getting that bracket hopefully by Wednesday and doing some tinkering!

 

[Rooster27]

In this first picture I’m showing a 1971 carter AVS and the distance from the throttle shaft to the Cable and linkage attachment point.View attachment 957712

figuring that the distance required to go from idle to WOT is related to the circumference of the circle it goes on, that 1.2” radius is proportional to that distance. Inside the transmission the shift points move based on the compression of a spring between the kickdown valve and the throttle valve. It’s designed to work with that throttle cable movement distance, ending with the kickdown linkage almost bottomed out.View attachment 957718

Here’s a typical Holley with the correct bracket they sell for Chrysler products. See that hole above where the throttle is actually hooked up? That’s the hole they give you. It’s 1.5” from the shaft centerline. If you set the kickdown linkage to almost bottom out at WOT it’s pulled MUCH farther forward when at idle, this is because of that larger radius.

Part throttle acceleration isn’t much different than idle so the kickdown linkage with that outer hole position hasn’t moved to even where it would be at idle with the correct radius. The solution is to drill a new hole in the aftermarket arm that’s the same distance as the factory hole (like was done in the second photo). This allows the kickdown linkage to be compressed the right amount and the shifts to happen at higher points.

I just posted a video on you tube not sure if you are able to help me out a bit and seeing if I adjusted it right. I know you had suggested drilling a hole.

 

[Nate S]

I just posted a video on you tube not sure if you are able to help me out a bit and seeing if I adjusted it right. I know you had suggested drilling a hole.

Video helps. Had something very similar recently. Same description, almost exactly. Problem was as I described. Picture it this way, if the throttle lever on the carb was 4” long the cable simply wouldn’t have enough travel to pull it all the way open. Also for most of the time the kickdown wouldn’t be compressed enough. As the radius from pivot to connection point gets smaller it takes less cable motion to pull it open and with the same WOT reference point (floored) for the kickdown the linkage is more compressed more of the time.

I’d have someone floor it and you look at the carb. I’m betting it’s not opening all the way. The way I fixed it was drilling that hole closer to the pivot. Being closer to the pivot it now needs less cable motion to get to WOT. And the kickdown is more compressed more of the time.

 

[Rooster27]

So inwas tinkering tonight and had to do an oil change after the engine break-in. While I was under there I figured I woulf take a look at the kickdown linkage. What I discovered was that the end of the linkage that attaches to the shaft that goes into the trans was loose and not fully connected. That was one of the problems of it not shifting right and going into 3rd at 20 Mohandas also having a slight runaway. Got that all hooked up properly and shifts wayyy better. Kickdown still doesn't want to kickdown so I just need to fine tune the linkage I believe and all should be good. I may take a look at the kickdown adjust band as well and do that first or should I adjust the linkage first? Any advice is greatly appreciated! Thanks guys and gals!

Roost

 

[Nate S]

I would do both but the linkage first. Get it so it’s nearly bottomed out at WOT. Then jam the pedal to the floor (engine off) with a 2x4 or whatever you’ve got around and visually confirm the carb is wide open and linkage is nearly bottomed out.

Next. With it all adjusted nicely, pop the socket off with the throttle in idle position and move the kickdown rod. You should be able to feel the spring in the tranny and where it just initially touches as you push it rearward. Hopefully that’s just a tiny bit past idle, maybe 1/8-1/4”. If it’s not, look at the attachment position like I’d described. Compare it to your original AFB.

 

[493 Mike]

The KD band first.
Mike

 

[Nate S]

The KD band first.
Mike

Both need to be right to get very far so I can’t disagree with this. Do you know what to do with it?

 

[Rooster27]

Both need to be right to get very far so I can’t disagree with this. Do you know what to do with it?

Inhave the service manual, it says to loosen the lock nut 4 or 5 turns and checknto see if the adjustment screw turns freely, then torque down to 72 inch pounds if you don't have the adapter from Chrysler. Thats what it says in the manual anyway. Not sure after you check to see if the adjustment screw turns freely if you tighten the lock nut and then torque the adjustment screw? Its not specific in that regard, im guessing not or it would say so.

 

[Nate S]

Inhave the service manual, it says to loosen the lock nut 4 or 5 turns and checknto see if the adjustment screw turns freely, then torque down to 72 inch pounds if you don't have the adapter from Chrysler. Thats what it says in the manual anyway. Not sure after you check to see if the adjustment screw turns freely if you tighten the lock nut and then torque the adjustment screw? Its not specific in that regard, im guessing not or it would say so.

Just get the locknut free and loose enough to be out of the way. Then tighten the adjuster to 72 in-lb. I wouldn’t fuss about this very much, snug with the 1/4 or 5/16 open end you’ll use will be fine. Then back it out 2 turns. (Other trannys have slightly different number of turns but a ‘64 - big block with a 3.8 kd lever should get 2). Now keep the wrench on that little post so it doesn’t turn and wind in the locknut and tighten the locknut up. That’s it.