cfair

Some of you will be aware that Olds experimented with a variable stator (switch pitch) torque converter in the mid-60's. To make it work Olds had no less than 3 different kickdown switches which had the added feature of electrically controlling the switch pitch converter. Why they had so many designs, I have no idea. Does anyone know?

The Cutlass/442 switches were not adjustable. That switch is not shown here.

The big cars (88's / 98's / Starfires) use 2 different designs seen here:

'66 Big Car kickdown switches: AC Delco variable and fixed Littlefuse styles. Both controlled kickdown and switch pitch angle.

Over time the electrical contacts in these switches wear down and can lose their conductivity. I took a few apart this week for servicing and thought I'd walk you through getting them back to working as the factory intended. You need a few hand tools, some good spray lubricant and a dremel with a wire wheel helps clean 50 year old grease out of brass contacts.

First let's get them open:

With a screwdriver gently pry open 50 year old pot metal to clean the electrical contacts and lubricate the throttle shaft.

Once you pry the crimps open, you'll see this on the AC Delco unit.

The inside of a Mid-60's AC Delco Olds switch pitch kickdown switch. It will need cleaning and contact points may be worn.

The principle is the same for the Littlefuse unit, but the contacts are different shape - rectangular, not triangular. All contacts are held fast against their terminals by small springs underneath. The springs hold up well and don't seem to need restretching. The deterioration of the function comes from the physical and electrical contact of the brass points.

Here are a couple of shots showing worn vs. good contacts so you have a reference about what might need replacing, or in a pinch, repositioning.

Brass points wear over 50 years. The best ones are in front here.

The points to the rear are burnt through and won't work well, if at all.

Years ago I found a few of these in a junkyard, so I took one or 2 apart and used the best group of 3 contact triangles to reassemble mine. With luck they'll outlast me. If you have to prioritize which terminal should get the best contacts, I'd go BAT for the best one, followed by kickdown function, followed by switch pitch.

Once the thing is apart, you can dip it in Evaporust for a few hours (minus most of the bakelite plastic which probably wouldn't fare well in the acid. Then the switch looks cosmetically good too:

Clean it up with carb cleaner, tooth brush, Evaporust and Q-tips. Then relubricate all the internals with Power Lube and/or Lithium grease like GM did.

I lightly wire wheeled all the brass electrical contact surfaces to clean them up for good conductivity. There are lots of ways to do this including Deoxit D5 contact cleaner. I just had a dremel at hand, so I shined it up.

When it's reassembly time, lubricate the metal (hidden) throttle shaft, then hit the middle circle and bearing bumps with a bit of Lithium grease. Next put in the springs which sit beneath the contacts, then put the brass contacts in as shown above. Triangle corners pointing outward. Then slip in the middle bakelite part and cover as one into the crimps. You can make clean recrimps by using a light hammer tap over the flatblade screwdriver angled down over the crimps. Nice & clean.

Before you put it back on the car, it's a good idea to bench test it. To do that, hook the BAT to 12v + source and ground the switch anywhere to the negative side. Then take your test light and ground the alligator clip to the switch. If everything is working, when you touch the point of the test light to each terminal and move the throttle back and forth, the light should light up at various points in the travel. For example, the kickdown terminal should light up the test lamp at the far rear of the throttle travel.

This is a fairly short project, maybe an hour or 2, but I thought posting some instructions might help some of you guys. I remember how mysterious these were when I started.

Comments, suggestions and criticisms most welcome. I'm an amateur...

Cheers
Chris

rocketraider

👏🤙 Excellent to Nth power!

Chris, parts book shows only two part #s, one standard duty and one for trailering. Any way to tell them apart re STDs vs trailer? Then there are two part #s for Toronado, std and trailer.

My experience is the Littelfuse switch is more common on Toronados.

cfair

From what I see above the part number for the AC Delco adjustable switch is 1993676.

looked at my Littlefuse switch today too and there was no part number on it.

Still odd that they used 2 switches to do the same function.

The terminal engagement points are a bit different from one to the other, but since the Delco one is settable to whatever pitch the fixed one uses, why have 2?

VC455

Chris, thanks for that explanation and walk-through.

May I suggest that you do not use lithium grease on reassembly.

Lithium grease oxidizes (hardens) fairly quickly and becomes useless. Look at the sad state of the factory grease in your freshly-opened parts.

Instead of lithium grease, use a synthetic grease that will not oxidize.

AmsOil is one of many sources of synthetic grease. They have spray and cartridge forms.

I've used synthetic grease for 45 years and have not had any hardening or parts corrosion in that time.

cfair

VC455
Many thanks for your recommendation.

I’m pretty ignorant of types and grades of lubricant, but completely agree that lithium grease dries out. I use it based on the ‘66 Chassis Service Manual, but surely better stuff has been developed since then. I just don’t know what the good stuff is.

As I’ve been digging in to speedo cables, switches, and other stuff that need lubrication, I’m becoming aware of my ignorance.

I’ve been naively using CFC Power Lube lately based on recommendation of a local locksmith who loves the stuff. Also lithium grease, and plain old grey brake grease.

Do you have any AmSoil product recommendations to share? I’m fine with synthetic, but wouldn’t want to buy & try the wrong stuff.

If you have a few minutes, school me up. What products do you recommend for which applications?

Thanks in advance,
Chris

Vista67

Chris:
Thanks for a great write up and especially for all the photos. I had to rebuild the round, AC/Delco style variable pitch throttle switch in my 1967 Vista Cruiser 10 years ago and your write-up will save others considerable time. As shown in your photos, many of the contacts points were worn flat. I was able to rebuild the contacts with electrical solder. I put a blob on each spot and then used some fine hand files to shape the solder to match the good contacts. The rebuilt switch has been working well for 10 years and 20,000 miles.

Even when fully functional, the OEM switch does not take full advantage of the high stall capabilities of the switch pitch converter. On the round style switch adjustment is fussy and you don't get much range unless you get really creative modifying the internals. If you want a much more sophisticated controller get one of Bruce Roe's electronic switches. His switch adds additional functions which will make more use of high stall under heavy load, while also adding timers that will prevent the high stall operation from running long enough to cook up the trans fluid.

cfair

Vista,
You’re most welcome. I’be been playing with these switches for 30 years. In my youth, I broke a bunch of them from not knowing how to adjust their position relative to the carb which I was always trying to open wide...

I like the idea of soldering new points on. Had I not had a few spare switches (some broken...), I think I’d have gone that route too.

I’ve heard about Bruce’s electronic switches before, but have never properly understood their advantage. I’m sure he’s gone one better on GM, but not quite sure how. So I’ve left things stock.

When you have a moment, can you explain converter stall ratios to me? I can feel the switch pitch in my cars, but have never really understood stall ratios and why a particular RPM stall would be good or bad for my heavy Starfire and heavy 98. Most of the stuff I’ve read has been about “tight” converters or related to much lighter Chevelles and Cameron’s (surprise...), so I’ve never really gotten the logic of how to use the converter to my advantage. Much less the switch pitch converter.

Thanks for your comments, glad the pictures helped. If you _really_ want an eyeful, go check out my write up on the Perfect Circle Cruise controls. Be warned, it’s a big post...

Cheers
Chris

VC455

Chris,

Amsoil makes NLGI 2 grease in cartridges for packing bearings or lubing chassis points. It's good when rebuilding power window mechanisms or anything that would have used lithium grease in the past.

There's an aerosol spray grease that's a little messy but handy when you don't need to be neat.

One of the most useful is MP (Metal Protector). It's also in a spray can. It has a carrier solvent and leaves behind an almost invisible film that provides years of anti-rust protection and light duty lubrication. It will also work as a penetrating fluid.

Here's my most radical MP experience... I bought some used 1970 W-30 heads in 1974 and sprayed MP in the ports and over the surfaces. The Minnesota spring weather was brutal on parts in my unheated garage. Warm spells in the spring would bring humid air in contact with cold parts--water would condense and drip off them.

I didn't look at those heads for 40 years, and when I unpacked them they still looked nice. That is, except for areas deep in two ports where I must have spaced out when spraying the MP. Rust grew like fur in those parts. So I know for sure how well MP protects.

Gary

Vista67

[QUOTE=cfair;1284361]Vista,
When you have a moment, can you explain converter stall ratios to me? I can feel the switch pitch in my cars, but have never really understood stall ratios and why a particular RPM stall would be good or bad for my heavy Starfire and heavy 98. Most of the stuff I’ve read has been about “tight” converters or related to much lighter Chevelles and Cameron’s (surprise...), so I’ve never really gotten the logic of how to use the converter to my advantage. Much less the switch pitch converter.

Chris:
A big heavy car with a stock engine will want a matching low stall converter for most of its routine around-town driving and highway cruising. The same car would also get improved performance under "less routine" driving if it had a higher stall converter. When you want to get underway faster a higher stall converter helps launch a big heavy car better than a lower stall converter. Higher stall allows the engine RPM to run up higher prior to the time the converter starts to grab. Higher rpm means more torque and horsepower to get things moving quickly. When the higher stall converter rpm approaches its stall speed the fluid coupling in the converter can actually multiply the torque the engine is putting out as if it was another set of gears. Even though the slipping is somewhat inefficient (putting lots of energy as heat into the fluid in the converter), when you are getting on the gas efficiency is not the priority. The switch pitch converter allows you to match both those operating conditions, cruise around town with low stall or get busy with high stall.

The stock switch you rebuilt has an additional feature to engage high stall when the engine is in idle and your foot is off the gas. This is a convenience feature not related to performance driving. High stall at idle reduces creep in Drive and takes some load off the engine at idle in gear. When you start to slowly press the gas, depending on the switch adjustment, it will stay in high stall just long enough to get the engine a little run up in rpm before the low stall kicks in. This provides a nice smooth transition into 1st gear. There is another set of contacts in the switch that energizes high stall when you jump on the gas pedal. I think it is set up to roughly coincide with 1/2 throttle. This will give you high stall when you are really stomping on the gas. Note that the switch kicks in high stall well before it activates the kickdown switch for the trans to use the "passing gear". If properly adjusted the pedal has to be on the floor at WOT to activate kickdown.

Gas pedal position is a decent control input for the switch pitch function but if you have a big cam and other high performance things going on with modifications then you might want to get or make a more sophisticated controller to take maximum advantage of the switch pitch. However, in the 60 plus years since the switch pitch was designed there have been tremendous advances in techniques for building high performance, fixed stall torque converters. A high performance engine and drivetrain will probably work best with a big $ fixed pitch converter with the appropriate stall.

Most of the converter vendors have tech sections on their web sites trying to explain stall without getting too deep into the guts of the trans and converter. Find some references showing how the converter couples the engine and transmission and how the fluid works to connect the two. GM had some great training publications (30 to 50 pages) for TH400 and TH350 that show up cheap on Ebay. Beautiful color diagrams showing fluid flow. The GM Chassis Service Manual also has some good descriptions at the beginning of the transmission section.
Some useful links:
Wild About Cars Switch Pitch Write Up

Car Craft Switch Pitch Article

Hemmings Torque Conv Tech Article Part 1

Hemmings Torque Conv Tech Article Part 2

cfair

A little, possibly important coda. These contacts which I've often found worn in kickdown switches




Harvest new brass contacts from turn signal switches to replace your aging throttle switch contacts.

Are also on the inside of reproduction turn signal switches like the 1993597. Here's a shot of the 1993597, courtesy of Charlie Jones


Inside here are new contacts you can use for your rare switch pitch kickdown switch.

Hope this helps. This is some detailed picky stuff.

Cheers
Chris

cfair

Here's how to disassemble the turn signal switches to get at the brass contacts: https://classicoldsmobile.com/forums...-wheel-138493/

cherokeepeople

i bypassed the switch on my 88 with a toggle switch.the high stall really helped that thing launch,then when i got up to 25-30 mph i would switch to low stall and it had this seat of the pants feel to it as it came in.

cfair

I was wrong. Wrong. Wrong, Wrong.

Contacts from the kickdown switch and turn signal switch are different.

Therefore you cannot harvest contacts from the turn signal switch and redeploy in the kickdown switch.

Here's the proof:

Turn signal switch contacts cannot be used in your 65-67 kickdown switch.

Sorry if I caused anyone any pain on this point.

Cheers
cf

cfair

I just got my Starfire back from various tasks, among them reducing a leaky TH-400.

When it got back, the transmission wouldn't kick down and it felt different. It was shifting well (better than in a long time!), but seemed to be missing the switch pitch feature too.

In the finest tradition of heading straight for the exotic solution first (dumb), I went straight for the switch. Since they're complex as you can see from above. Turned out it was just a blown fuse. As my wife says, "When you hear hooves, think horses, not zebras".

Anyway, just in case it was the switch, I had an adjustable throttle switch locating rod on my bench and wanted to add some flexibility to the switch adjusting. My '66 Starfire uses the squareish, non-adjustable littlefuse switchpitch/kickdown switch. Until today, the rod that connected the switch to the engine block was fixed like this:

65-66 Big Olds throttle rod (rear) and kickdown switch locating rod (front). I swapped in an adjustable locating rod to allow further adjustability of switch pitch and kickdown features.

Here's the set up on the car that I find desirable. Now both the throttle rod and the switch locating rod can be screwed in / out to get 'em just where you want them with a 3/8's open end wrench and 7/16's open end wrench to secure them into the correct position.


Two adjustable 65-66 Big Olds throttle switch rods offer more flexibility than one.

If you have a Chassis Service Manual, Olds has helpfully provided adjustment instructions under the Tune Up section. In my case for a '66 big car that's section 6C-6 (with pictures!). Unfortunately for me I'm using a much later era quadrajet so those instructions for more are more referential than rule.

Just a quick note on the 3 designs. I like the round adjustable on the best, but all 3 work fine and I've seen all 3 in big cars from 65-66. My 98 has the circular adjustable one, the Starfire has the square non-adjustable one. Point is, in a pinch a cutlass-sourced kickdown/switch pitch switch can work. Or at least that's what I saw in the junkyard last week. YMMV.

Anyway hope the on-car shots help a little bit.

Cheers
cf

Oldster65

This post is why these forums are so important! THANK YOU to the OP and subsequent posters as it is both informative and useful. With it, I successfully serviced my 1965 Delta 88 Switch Pitch throttle assembly. A couple of comments, then a bunch of pictures that I hope add to this resource on servicing these old, rare switch pitch assemblies.

1. I wholeheartedly agree - NOT NOT USE WHITE LITHIUM GREASE - there are better, more lasting modern solutions. The fully solidified original white grease was the main source of why my switch was seized - It was like cement on the shaft of my switch and it barely moved.
2. I was not able to determine how to remove the shaft/lever from the plastic in the switch pitch without grinding off the peened end of the shaft, so I did not disassemble it. I used carburetor cleaner to melt the hardened lithium grease (over and over), and then used a thick lubricating/penetrating oil on the shaft. I wish I could have used the good red synthetic bearing grease that I used on the rest of the throttle parts, but I'll just know I need to hit the switch pitch shaft now and then with oil. I also used high quality dielectric grease on the contacts when I reassembled.


All parts disassembled and lightly cleaned. I am maintaining the original, un-touched look of the engine compartment.

Contact points -- only a single contact point on the top contact is about 1/2 worn down. This unit has 17k original miles on it.

Opposite contacts are in very good condition. Lightly sand/clean to renew. I removed hardened lithium grease here, too. I used dielectric grease here on re-assembly.

Because I could not determine how to remove this shaft, carb cleaner was the solution. I soaked it several times, worked it back/forth untill completely free, then applied thick penetrating oil as lubricant.

How does this come apart? (for the future and readers)

Refreshed and installed - driver side.

Refreshed and installed - lower passenger side at firewall

Full assembly - driver side

Upper passenger side - spring config

Vistabrat72

Beautiful job on this! Yes, white grease can cause a person fits trying to clean it up. This original post from cfair - thanks kind sir! - and the book helped me to understand the workings of this rather complicated assembly on our 1966 Ninety-Eight LS. Our Switch-Pitch, it was off by a little bit, but studying the article and carefully adjusting the mechanism has it working perfectly on our Olds once again! We have a slightly sloped driveway, when the car is put into gear it will barely move, but just feather the throttle slightly, one can 'feel' and hear the converter switch from high to low stall, the car will move slightly faster when this happens. On the road, some pedal, about half way, maybe a bit more, the pitch switches, and you get pitched back into the seat! A bit more, you get that nice THM-400 kickdown! Hang on! This feature was a marvelous engineering feature from GM, I know this feature of switch-pitches was used on Dynaflows and Turboglides before the Turbo-400 was brought out, it just works so nice on the Turbo-400. One has to guess why it was discontinued after 1967.

cfair

Oldster65 & gang,
So glad you found my old post.

Engines, carbs, brakes, suspension are very well documented here on ClassicOlds. To the degree that I can contribute, I try to focus on weird little systems that would be otherwise forgotten to the sands of time. Like the goofy (but excellent) switch pitch, or the even goofier analog Perfect Circle cruise control. Or vacuum powered remote control door locks. Great for the time, but long since superseded by solenoids.

110% with you on avoiding lithium grease, there are much better modern replacements. I’ve been using the red stuff from an aftermarket vendor (Amsoil?) for a few years and it’s _better_. Period. But it didn’t exist in 1966, so as a nod to the purists (which I’m not really..) I cited it in the redo. But yeah, the Amsoil grease is way better.

Tell ya what though, when you have the throttle rods & switch pitch radius really dialed in, the throttle response is both subtle off the line & ready to jump all at once. Thanks Olds for good engineering all those years ago.

Took my ‘66 Starfire to SF today. Great road car. Lots of fun.

Cheers
cf

GCH

Very intresting , thread saved in my computer , thanks for info about this.

ourkid2000

As a side note, I found a couple tricks when setting these things up.

1. Disconnect the accelerator pump linkage so you can mess with the throttle and not worry about squirting fuel into the carb all the time. Common sense, I know.
2. Use a meter that has an audible continuity checker to help rig the switch, leaving the power off in the car. If you put one lead on the power supply and the other on the side of the switch you're working on, you can just use the continuity beeper to rig the switch rather than using a testlight. That way you're not running power through the points and the transmission solenoids, etc, all the time with the key on. Once you get everything rigged, then you can use the test light if you're looking to double check it and make any adjustments then.

cfair

Gang,
I had a request from one of our members on how the 1965-1966 big car factory switch pitch/kickdown switch would work with an Edelbrock Performer intake manifold. Let's call the combination switch a "throttle switch". Wrong, but convenient.

Safety
Joe P tells us that Olds/GM left throttle rods in the late 60's because if motor mounts broke, the throttle could stick wide open. This can kill you. GM moved to safer throttle cables after the rods shown here.

I've had a few stuck-wide-open carb surprises. When you bolt on a new carb, or change gaskets, check that the carb closes easily & smoothly before road testing. Then test the car on a quiet road when the car warms up. Metal parts can expand just enough to cause a carb to stick open. Test thoughtfully. If you get in trouble, shift to neutral, shut off the engine & coast to safety.

65-66 Big Car Switch Pitch / Kickdown Switch
Here's my Olds big car throttle switch as mounted. On the left there are 2 holes to mount the carb throttle rod to. My use of the upper one is custom. That hole was intended for a cruise control. I mounted a 1/4" round post on it to see if I liked the throttle response better vs. the lower factory hole. It was better for me.

The factory post is the lower one facing the distributor. Beyond pedal-feel, installing the throttle rod in the lower hole interferes with my HEI plug wires.

The lower rod you see in the photo below is slightly special - it's adjustable. Meaning you can set the fore/aft position of the bracket assembly to get really good range of motion for the switch pitch & kickdown functions. Your lower rod may be a fixed length. If you're handy, you may be able to cut off the rear end of a fixed lower rod, then run it through a tap to allow you to put one of these threaded ends on to build an adjustable lower rod.

Anyway here's what this ancient switch looks like installed:


65-66 Big Car combination switch pitch / kickdown switch

Switch Adjustment Goal
You want your throttle rod to rotate freely & move _straight_ back & forth. Not side-to-side. Side movement puts bending pressure on a fairly weak diecast throttle switch mounting ear. These switches are subject to 2 kinds of wear: side to side (solved with bushings/shims) & front/rear (solved with fore/aft adjustment). If you get it wrong, the metal tears from use & the switch separates from its mounting ear.

Along the way I was so focused on having carb _wide open_ that my switches were too tight and tore when I nailed the throttle. I broke a few.

Adjustment Procedure
Pop the throttle rod off the switch so it doesn't influence the carb at all. Next, to get correct fore/aft switch screw adjustment, remove the acceleration pump roll pin from the carb with the car off. That disables the acceleration pump. Then you can move the carb throttle blades & switch back & forth in testing without flooding the engine. Remember to put the roll pin back in when you're done.

Safety 1st
Make sure the carb closes (idles) completely. When the engine is off & cold (as it should be when you're adjusting), the cold-start-high-idle complicates things a little. To fool the engine into acting like it's warm while off, nudge the passenger side choke on the carb forward until you hear a "click" that represents the choke dropping off - i.e. acting like the engine is warmed up. The throttle rod should move slightly forward with the choke off. That's your normal warm-running idle setting.

Looking at the throttle switch, you want be sure that the threads on the switch are loose enough to allow the carb to close completely & smoothly. To test, pop the rear (switch) connector off. If the carb closes more, the switch is too tight. If it doesn't move (much), you're probably close - the switch isn't so tight that it's pulling the carb open at idle. Put another way, with the carb at idle, the switch connector should pop on to its post with no change in RPM. When you pop the throttle rod on the switch, if idle goes up, it's too tight. Even better - if the switch puts a little forward closing pressure on the carb blades, that's good.

O.k., Now Power
For WOT, you want to make sure that when the rear butterflies are at or near 90° open, that the switch is at the rear-most point of its travel. If the switch is not all the way back, you're risking tearing it. Your goal is to have the switch all the way the rear of its travel when the carb is all the way open.

Too loose: if it's all the way back & the carb isn't all the way open, you're giving up some HP/Torque. Legend has it that Pontiac fiddled with these angle relations to make the GTO king of HP/torque when other models had the same mechanical setup.

Too tight: if the carb is all the way open and the switch still has a few degrees of rearward travel. Avoid that - it's fatigue waiting to happen.

Aim for full function & good enough
Optimize: First make sure the carb closes all the way (idles) with no rod influence. Next see that it opens all the way & doesn't stick. Finally fiddle with any adjustability you have to set the kickdown point & switch-pitch "switch point".

Fitting teflon & nylon bushings
I used the factory 5/16's hole for the 1/4" throttle rod. In between are nylon or teflon bushings to make up the difference between the OD (outer diameter) of the rod & ID (inner diameter) of the carb hole. I used 5/16"s OD to 1/4" ID bushing with a lip on it to keep the rod from flopping around in the old. For best performance, you want completely free rotation, but no slop from wrongly-size rods/holes. Diameters control the "feel". Bushing widths & placement (fender side or carb side of the carb hole) control the angle of the rod relative to throttle switch. You want it as straight as possible - so get a few thicknesses and play. I recommend taking the carb and throttle rod to your hardware store and play around in the Hillman section. Get a bunch of nylon bushings in various thicknesses to allow to play when you get home.

Align the throttle rod with nylon / teflon bushings

Use nylon/teflon bushings for straightness, smoothness and no slop
Here's a shot of what you're aiming at from the front. The straighter you can make the throttle switch to carb connection, the better the gas pedal will feel and the longer it will last. Play around with a fat shim on the inside vs. outside to make the best connection in your car. My rod points at the driver's side fender. You can reverse this & point the end at the passenger if it fits better in your car. Spray some silicone or other lubricant to make the action smooth.

The rod & bushing design used here was also used by Olds to transmit driver gear choices to automatic transmissions. Snug, round, new bushings really make the car feel right. Even with worn rods - carbs &
transmissions alike.


What straight looks like between carb & throttle switch

Engine Bay Beauty Shot
While I was taking shots, I thought you guys might like a broader view of my past 25 years or so. I've tried to make the engine bay nice without getting gaudy. It's nothing big, but I like the red MSD plug wires & the better quality (at the time) red Napa heater core hoses. Since the heater core hose runs over my AC mounting bracket, I put a sponge sleeve on it to wear before the hose does. You'll also see the results of my tubing bender period. I got curious about this art and learned on fuel lines. Then I was having fun so I made a few vacuum lines.

You'll also see I've converted to a later alternator & eliminated the external voltage regulator. The "S" scrawled on the alternator is for the "Sense" wire, the "F" is for the Field wire. I ran the sense wire to the junction block on the driver's side fender to give me a good sample of the voltage in the system, as opposed to just jumping it like a 1-wire.

I'm no big show guy, but I polished these rods with #0000 steel wool and a Dremel with a wire wheel. If I recall I also ran the threads through a Tap to make adjustments clean & easy. Your call on aesthetics.

At least it's clean!


Hope this helps you all,
Chris