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Cruise control, anyone? anyone?


DonaldSmith

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I have a 47 DeDoto, with the semi-automatic "TIp-toe" Fluid Drive.  The leg gets tired after driving any distance. 

I looked on line for after-market cruise controls, and saw an array of possible ways of putting a system together. 

Things to consider and work out include:

 

-  6 volt, positive ground (Some 12 volts available through a rectifier, but what amperage would be required?)

-  Speed pickup - can attach to the speedometer cable.  Otherwise, magnets on a moving part. 

-  Controls - On turn signal stalk? separate buttons? 

- Setup for semi-automatic upshift?

-  Actuator cable connecton to carburetor linkage? 

- Pause circuit to brake switch (6 volt again)?  to clutch?

 

Has anyone gone through this on a car of our vintage?  

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other than the voltage issue, the aftermarket kit by DANA was one of the better all around universal set up with magnet on driveshaft for pick up coil to sense,  controls were stem or pad.   Many years ago I installed 1 or two of these a week.  That is the age old battle between staying 6 volt and going 12 is for accessories and creature comforts such as these.   Unfortunately, I have not seen a kit of this style for a long time...not sure if available anymore.  Finding a NOS unit is not impossible I would think.

Edited by Plymouthy Adams
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I saved the setup out of a mid 60's Oldsmoble to install on my 72 Dodge Coronet, but couldn't find a speedometer cable that would make the connections I needed.  That was back in around 1980, but I do still have the unit.  (I know I could have gone to the salvage and found a MoPar setup that would have worked, but this one I got for free off of a car we were stripping out to scrap.)   It was the type that used an electromagnet (12 v, of course) to lock the governor in a set location, which mechanically opened a vacuum valve, which in turn controlled a vacuum servo connected (by cable) to the throttle.  I think I also have the vacuum servo out of a 93 Chrysler T & C, but I don't know if the diaphragm is still good in either of them, especially the older one.  I am also sticking with 6V on my 46, and yeah, it can be a challenge.  It would be interesting to see if this electro magnet would hold its position with only 6VDC power supply. 

 

When were the first speed control systems installed on vehicles?  (I remember that in 61 Oldsmobile had a buzzer alarm that would sound if you went over what ever speed you set it at.)

 

Edited to add   -    From Wikipedia:

Cruise control[edit]

Teetor was inspired to invent cruise control one day while riding with his lawyer. The lawyer would slow down while talking and speed up while listening. This rocking motion so annoyed Teetor that he was determined to invent a speed control device. In 1945, after ten years of tinkering, Ralph Teetor received his first patent on a speed control device. Early names for his invention included "Controlmatic", "Touchomatic", "Pressomatic" and "Speedostat", with "Speedostat" becoming the trademark name. The common name became "Cruise Control". The Perfect Circle device wasn't used commercially until Chrysler introduced it in 1958.

The throttle was controlled by a bi-directional screw drive electric motor, the two connected during use by an electro magnet. A 12v post would stay nearly centered between two throttle mounted electric contacts, one for turning the motor's screw for more throttle, the other for less. The floating post would "guide" the motor (and throttle and vehicle speed) with input from 1) sprung leveraged spinning weights driven from the transmission's speedometer cable, and 2) a counter-spring tension set by a cable from a dial near the steering wheel. This first-mass-marketed design was the industry standard for just over a decade (GM changed to vacuum-actuator/turn-signal-engage-button in 1969, though still a "Speedostat" product).

 

So that Olds was later than mid 60's.  Maybe early 70's.

Edited by Eneto-55
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the electromagnet generates its own voltage and is supplied to the controller...the pickup voltage is the reference voltage supplied and the purpose of the controller is to maintain this reference voltage which represents X speed at set trough varying the supply of vacuum to the cable linked servo to the throttle...the problem is these units is not the pickup but rather the voltage supply to the controller circuit. 

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I had a 68 Mercury with a clunky speed control.  It had a vacuum leak and would not hold the speed.  I put a speed control in a Datsun that worked.  

But for my DeSoto I'm interested in what experience anyone has had with the current devices in a vintage car.   i presume that the devices are all electric, no vacuum. 

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one of the largest makers of aftermarket cruise controls, I called and talked to Brian...unfortunately NONE of their products even those slated for install on 50's model cars will work with 6 volt.....their website mentions products for the 50's car but again, they do not address the voltage requirement thus the phone call.....12 volt upgrade is required.

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Not ready to consider a 12-volt upgrade.  If I knew the amperage required for a speed control, I would consider an inverter of the necessary oomph.  I assume there would be a steady amperage for holding the speed, and more for increasing it. 

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10 hours ago, Plymouthy Adams said:

the electromagnet generates its own voltage and is supplied to the controller...the pickup voltage is the reference voltage supplied and the purpose of the controller is to maintain this reference voltage which represents X speed at set trough varying the supply of vacuum to the cable linked servo to the throttle...the problem is these units is not the pickup but rather the voltage supply to the controller circuit. 

I'm not knowledgeable enough to understand all of the terminology you used, but I'm convinced you are correct. 

Here is a picture of the inside of the Oldsmobile speed control.

A reed switch prevents it from engaging at really low speeds (when the weights are close to the shaft), and when the weights swing out sufficiently, a contact is made through another reed switch, to allow the electro magnet to be engaged.  I'm guessing that the coil in the upper right of this photo activates it, but I don't know enough about such devices to know how.  (Older washing machines used a similar device to turn the water on, if I'm not mistaken.)  My 3 amp battery charger produced enough current to engage it.  But set to 6 volts, it just chattered.  I would image that with any of these 12 volt systems a small battery like those in emergency lighting or computer power back ups would do the job for a long time, to be recharged when back at home on a trickle charger.  To do it with 6 volts, I think a person would need a larger coil, but someone with more electrical knowledge than I would have to answer that.

HPIM0985-small.JPG

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6 hours ago, DonaldSmith said:

Not ready to consider a 12-volt upgrade.  If I knew the amperage required for a speed control, I would consider an inverter of the necessary oomph.  I assume there would be a steady amperage for holding the speed, and more for increasing it. 

On the mechanical speed control in the photo I posted, I suspect that it did not have the feature to increase the speed setting by holding down the button. like the electronic ones do.  I think you would have to speed up, and then reset it.  To set a slower speed, I think you could put an interrupt switch in the circuit, so that the controller would disengage the magnet until you released the button again.  (During that time the car would be slowing down, so then you would just release the button at your desired speed.)  I don't know if this controller could 'hold the car back' while going down a hill like the modern Cruise Controls do, either, but I would guess not.

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   Using the throttle control will keep the car running at speed, except it’ll slow down going up a steep grade, and speed up going down a steep grade. Also, in an emergency situation, should you slam on the brakes, the engine’s speed is set by the throttle control, and it’ll work against efforts to slow down unless manually released—not necessarily a good situation.

Edited by DrDoctor
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Yes, a person would definitely need to install an interrupt switch on the brake pedal, so that any time you hit the brakes it would break the circuit.  On the one I've been talking about, that would release the magnet, and shut off the speed control setting.  Also, on this one, since the governor is tied to the speed via the speedometer cable, the system will increase vacuum to the servo any time the governor weights are starting to spin at a slower speed.  I just don't know if it could reduce the vacuum flow if the car is running down a steep hill.  (I never set this up on any vehicle, and I didn't have a vehicle with any type of speed control for many years after I saved it, thinking to put in on my 72 Coronet.)

Edited by Eneto-55
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I mulled over the problems of adding cruise control to my 47 DeSoto (a real mind game).   Cruise control: 

 

o  Would Need 12 volts, 10 to 15 amps.  Either convert the whole car to 12 volts, a large project, or get an inverter, which would draw up to 30 amps from the 6-volt system, or add a 12-volt alternator for just the new stuff.  Whew.   Starting to gert complicated.  And expensive. 

 

o  Would need slack in the pedal-to-carburetor linkage, so that the cruise control module could open the throttle without pulling down the pedal.  At present, a large spring closes the throttle and pushes up the pedal when the foot is removed.  The linkage would have to be reworked to provide the necessary slack, and a separate spring would be required, to close the throttle.  I came up with numerous ingenious ideas, each requiring careful design and fabrication.  (We don't want the throttle staying open.)

 

But wait!  The problem is the right leg getting tired from working the gas pedal on the occasional extended trip.  (For me, an hour-long trip is beginning to be extended.)

 

Why not push the pedal down by hand?  What do the handicapped do?  I saw a portable pedal pusher available for about 180 bucks.  Why, I could make something similar from junk (precious recources) around the house.  Stick, flexible connection to a small base, and lugs or downturned edges of the base to keep the base from slipping off the pedal.  Place the base on the pedal, rest the stick against the edge of the seat cushion, and push and pull as necesary to modulate the speed.  Lift off and set aside to resume foot-pedaling. 

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As I said in my post on the 15th, the speed control module I have (out of an old Oldsmobile) engages fine off on my 3 amp battery charger.  Maybe it actually puts out more than that?  I don't know.  I was going to test it again with a 110AC adapter that is rated for 1 amp (I think I have one like that), but I haven't messed with it anymore yet.

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If you have to have up to a 12 v 20 amp power requirement you can get a small alternator for a yanmar or kubota tractor that is quite small. These will require an external regulator to match them. They can be used to operating a 12v car stereo with up to 4 speakers and no amp(an amp can require up to 40 amp power), as well as other 12 v accessories that don't have a lot of power requirements. I suggest using it in conjunction with a small 12v battery such as a motorcycle or garden tractor battery. For power requirements above 20 amp you may as well go with a full size alternator such as the GM 10si. 

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