Technical Perfect Circle Speedostat

Anyone happen to have a wiring diagram for a vintage Perfect Circle Speedostat? It’s all vacuum operated.



Looks like this….

 

There were several versions of the SpeedOStat....that looks like aftermarket, from the 70s.

Might start by organizing the wires, see what you have.

Do you have the vacuum servo? it's a separate part. Do you have the vacuum brake switch?

 

I have the vacuum servo, no brake switch, that’s a picture I pulled off the internet, I believe the guy said it was out of a late ‘60’s early ‘70’s Chev pickup.

 

This is the closest to a diagram I’ve been able to find but it doesn’t show how the wires are connected, there’s different colors coming out then at the terminals if that makes sense…

 

No one has ever put one of these in something? Maybe I’m even dumber than I thought!

 

They're pretty rare these days...the later version from the 80s with a computerized box is getting hard to find today, but at least I have the instruction booklet for them.

Might look to see if there are any vintage motorhome forums where they talk about them? pretty common on the 70s MH

 

Chrysler used those back in the 70's.

 

So I think I have it figured out…found a diagram for cruise in an International. Seems to line up with what I have.

 

I matched up what I have with the wire colours here and here’s to hoping.

 

Well holy shit, the cruise actually works, I expected a certain amount of tinkering would be required to get it going, it is probably 60 years old. Not bad for a few hours and ten bucks. The speedo in the truck isn’t working so a cable issue between the cruise servo and the dash.

 

Good job getting it working. I retro-fitted a few 70's Mopar cruise control units for use in rods, and they worked good. Speedometer driven, vacuum controlled. Wish I could find another one to put in a friend's Dart. Hardly find 80's cars around here, rusted and crushed.