Hello,
I found a post about the switch pitch controller that a member has developed to help with the converter control. Please advise Thank You

 

I don't understand the need for a "controller". The factory control was an on/off switch. Why make it more complex than it needs to be?

 

Just dialing in my ‘66 big car throttle switches.

It’s taken me a while to figure this out, and all of this assumes you have good functioning switch pitch/kickdown switches to begin with. Bench test your switch, then get onto cleaning the throttle mounts and greasing up all rod pivot points for smooth throttle movement. Then finally spend a few hours adjusting this. When it’s right, the gas pedal feel should be very responsive (for the 60’s…), not rubbery, have very little creep at idle, and kickdown when you stomp on it.

When you’re adjusting, if you have a qjet, remove the accelerator pump roll pin and pop out the pivot arm. Otherwise every time you open & close the throttle in testing you’ll be pumping gas into your engine. This can cause a flood, or worse.

The 65-66 switch combines 2 functions: switch pitch converter angle and kickdown. It has 4 positions, by adjusting the throttle rods, you can set where these functions kick in.

65-66 Switch Pitch / Kickdown Switch positions:
1) Closed throttle - the first 1-10 degrees of carb throttle opening — i.e. just off idle the converter should be in high angle to reduce stoplight creep
2) Part throttle - 10 - 40 degrees of carb throttle opening - the pitch switches to low angle (test light off) to improve acceleration
3) Heavier throttle - say 45 degrees and up - the converter switch pitch again (test light on) - maybe for economy?
4) Heavy throttle - say 70 to 90 degrees - the transmission will kickdown to a lower gear, unless you’re doing 70+ mph

When I was adjusting it the other day I learned a bunch. Not only did olds do 3 switches (see my posts on this elsewhere), but they also made fixed length and adjustable throttle rods for the throttle control. On top of that, they made at least 2 widths of the firewall mounting bracket - I suspect one of these may be for Cutlass/442 and the wider one is for the big cars.

There are 3 throttle rods to adjust. Rear vertical, Block connector rod, and carb connector rod

Rear Vertical Rod (nearest the firewall):
The rear vertical rod connects the cabin foot pedal to the combo kickdown/switch pitch switch. If you have a fixed one, great. If you can find an adjustable one, you’ll find that lengthing it raises the foot pedal-to-floor distance for your gas pedal. Shortening it, conversely, shortens the pedal throw. But — this also pulls downward on the switch pitch switch and puts a lot of play in the throttle. Too short and you increase the travel degrees of the switch so much that you might not open your carb all the way. Plus it makes the carb throttle action “rubbery”. I opted to set the length on the longer side so that the gas pedal is roughly the same height as the brake (not lower) and the switch pitch is in high angle for just a very few (maybe 2-5) degrees off idle. The second effect if you’re too short is that the switch won’t pull back far enough to kick the transmission down, so you want the test light on basically at idle and turning off when you lightly touch that the gas.

Block Connecting Rod
This is a relatively short rod of fixed or variable length that connects the forward upper hole of the switch mount to the spark plug wire separator hole. If you can find a variable length one, you can hook it to a 1/4” ball stud (from your hardware store) mounted in the forward upper hole. Otherwise, well, you’ve got a fixed one and one less thing to worry about. I went adjustable since I’m using an aftermarket intake (Edelbrock Performer) and a later era 170 quadrajet. If you’re more stock than that, fixed should work just fine.

Carburetor Connecting Rod
This is the longest rod with 2 45 degree bends in the middle to connect the switch pitch switch to the carb. The bends lower the vertical height of the switch rod end so that it mates cleanly to the higher mounted carb. The bends allow the carb rod to clear the spark plug wires. My carb rod is above my wires, which I think is how its supposed to go, but I have an aftermarket manifold so your carb may be lower and routing the rod under your plugs may work better.

The key is to let the carb rod move free of _any_ impediments so all the tension on the rod is just your foot pressure against the return spring. Ideally you want this rod loose enough so that when your foot is off the gas your carb is resting at warm idle, but tight enough so that 1 degree of gas pedal movement = 1 degree of carb opening (or maybe a little more…). If you’re foot is off the gas and the car is idling high, this rod is too short. If you can’t get the transmission to kick down it’s too long. If the test light is off at idle, too short, if it stays on to 50% throttle or more, too long.

If anyone would like more painful detail, I can get some shots in the next few days, or see my other posts on these throttle controls. They’re totally obsolete now, as Joe taught us, because when motor mounts broke in the 60’s, sometimes they’d stick open. So GM went to throttle cables later on.

Hope that helps,
Chris

 

Bruce Roe makes (made? I bought mine in 2013) an electronic controller for the switch pitch. From our email:

The factory SWP control only worked at idle & near full throttle.
Some use a manual switch. But you would never be willing to work
as hard operating that switch on the street, as a controller does.
For a lot of driving, I use an electronic controller. It gives the
brake function, midrange enhancement with smoother shifts,
and maximum throttle response. With torque sensing and adjustable
timers, it far out performs the crude OEM mechanical switch. Its
primarily designed for street use, but there is a race mode too.

I haven't had the car operable for some time now (currently has no interior or paint), but when I had it running the controller operated the switch pitch seamlessly. His email at the time was: bcroe@juno.com

 

His switch has a vacuum sensor to measure engine load, and automatically turns off and on to make best use of the different stator positions. I suppose you could do the same thing with a switch, but you'd be flipping that switch more often than you'd be tapping the brakes. It would probably get tiresome.

 

Sorry Joe, I did not explain the system is in a 1970 w30, and I had used a roll control switch to activate it but was thinking of somthing a little more automatic.
Thanks for your reply
Carl

 

I've used the switch pitch in later cars with a radical cam. Wire a relay to the brake switch so that the trans goes to high stall when your foot is on the brake. That helps with idle in gear and also with launching off the line. I also had a separate toggle switch that allowed me to select high or low stall manually. The "controller" was my finger.

 

Thank you Joe!

 

Joe,
Not to hijack, and please feel free to move the question, but can you shed any light on why the factory ‘65-66 switches go back into high stall at fairly heavy throttle?

I’ve only observed the design of the switch as it moves across degrees of throttle opening is that it goes high - low - high as you increase demand, then at the extreme goes to kickdown.

I’m fairly certain mine is working as designed, I’ve read the factory literature on high angle at a stop, but I’ve never seen anything as to why it would go back to high stall past part throttle.

I can easily imagine a vacuum pot as an alternative throttle demand-source and potentially better design, but I don’t get the logic yet.

Thanks
Chris

 

The trans is designed to go to high stall at W.O.T. to improve passing gear acceleration. If you're cruising along the freeway at light throttle and want to pass a car, higher stall lets the engine get to the torque peak more quickly and also increases torque multiplication for better acceleration.

 

I had a switch pitch trans behind a 455 Olds. I used an extra high beam switch on the floor. Worked perfectly. Simple and effective.

 

Thanks. That makes sense.

At least on my big car switches the high stall position is 10-20 degrees of throttle opening before the kickdown.

Is it reasonable to think of part-throttle high stall as a pre-kickdown passing assist? Or is it more designed to make the kickdown more effective?

Sorry to bug you. I’ve been messing with these pot-metal switches for decades and never really ‘got em’ other than to observe and repair the electrical functions.

Early on in the 80’s I destroyed 2 or 3 or them by not understanding the relationships among the rods. I put so much stress trying to max the carb opening that the pot metal just cracked under the strain I stupidly put on them.

I may finally be careful and knowledgeable enough to keep them alive!

Cheers
cf

 

I dimly recall Kenne-Bell offered some kind of switch-pitch controller way back when, along with being one of the few sources of reworked SP converters..

 

Hello All,
I just spoke with Bruce and he is sending me the info on his device, the email address listed above is still valid, it has been a very interesting to read what everyone is saying about the original system as the general designed it. Thank you all
Carl