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Discussion Starter #1
I'm seriously considering installing a Rostra cruise control in my '73, 350ci, 350 thm, 4160 Holley. It appears that the best place for the control unit is on the left side inner fender liner. If anyone has done an installation on a 3rd gen car, do you have any words of wisdom or suggestions?
 

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I'm seriously considering installing a Rostra cruise control in my '73, 350ci, 350 thm, 4160 Holley. It appears that the best place for the control unit is on the left side inner fender liner. If anyone has done an installation on a 3rd gen car, do you have any words of wisdom or suggestions?
I bought the kit from Dakota Digital, which I believe is the same, for my LS with cable operated throttle.
I mounted it to the driver inner fender and fits nicely.


Sent from my Pixel 2 using Tapatalk
 

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Discussion Starter #3
Yes, Dakota Digital's is the Rostra (I plan to buy mine from DD). It looks like the driver side inner fender will work fine for mounting the control unit.
 

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Not a Rosta, but I did the same in the '70 with an original 'dealer option' cruise system from an '80s GM van.



Since this system uses a vacuum actuator, I also needed a vacuum reservoir:
(And check valve - not highlighted, but you can see the line zip-tied to the radiator hose for initial testing.)




Man... from that angle, the under hood wiring looks terrible. :(
 

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Discussion Starter #5
Thanks for the photos. Did you also use the control stalk from the donor?
 

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Thanks for the photos. Did you also use the control stalk from the donor?
Yes, but only temporarily - and it's just tucked under the dash for now. I didn't have time to properly remove the stalk, as I remembered it at the very last moment while a tow truck was hooking up to drag the van's carcass away. So, I had to break it and fish the harness out.

I've seen several tempting replacement candidates in junkyards, but don't really like the idea of a fat GM cruise control stalk on the Nova column.
I intend to scratch-build a control panel for the system, at some point (to go near the radio). I may be wrong, as the last stalk that I probed with a multi-meter was 15 years ago in an '88 S-15, but it seems pretty simple. A few switches and possibly a resistor array should do it.
 

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The newer cruises are a lot easier to install.

The older ones required different speedometer cables and then the aftermarket came up with the ones like Squigie showed and had magnets glued to the driveshaft that a coil mounted to the floor close to the magnets would pick up the magnetic field when the flew by to create a vehicle speed. The ones that worked off of vacuum sometime required storage tanks and also had vacuum dump valves attached to the brake pedal to disengage the cruise when the brakes were applied.

The newer cruises still require a vehicle speed sensor input and to fit them onto older cars, Rostra and others have VSS generators that go inline on existing speedometer cables.

As far as activation controls some replace the turn signal stalks, some piggyback on top, while another style are for console/dash mounts. Basically the switches make or break connections and some do very resistances between wires one needs to check before making their own custom circuits.

Here's a dealer cruise I bought years ago and eventually will put it on a 74 Nova of mine. It came with the standard underdash control but could be upgraded to a stalk/turn signal control.


Jim
 

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The newer cruises are a lot easier to install.

The older ones required different speedometer cables and then the aftermarket came up with the ones like Squigie showed and had magnets glued to the driveshaft that a coil mounted to the floor close to the magnets would pick up the magnetic field when the flew by to create a vehicle speed. The ones that worked off of vacuum sometime required storage tanks and also had vacuum dump valves attached to the brake pedal to disengage the cruise when the brakes were applied.

The newer cruises still require a vehicle speed sensor input and to fit them onto older cars, Rostra and others have VSS generators that go inline on existing speedometer cables.

As far as activation controls some replace the turn signal stalks, some piggyback on top, while another style are for console/dash mounts. Basically the switches make or break connections and some do very resistances between wires one needs to check before making their own custom circuits.

Here's a dealer cruise I bought years ago and eventually will put it on a 74 Nova of mine. It came with the standard underdash control but could be upgraded to a stalk/turn signal control.

https://www.youtube.com/watch?v=9hTcdIaDYN4

Jim
Thanks for sharing. I enjoy seeing different iterations of the same type of systems.

The cruise system that I plucked from the van chassis was a bit newer.
It uses a transducer between the speedo cable and transmission.
And the brake pedal trigger is like most mid-'70s-and-up GM cars that have a dual-circuit brake switch. One circuit is for the lights, the other is for the cruise control. (There are some out there with 3, and even 4 circuits/poles in the brake switch.) Since GM used the same mount style for brake light switches for 30+ years (and terminal arrangement and type), a switch from many, many years and models of vehicles will plug right in.

I did open up the brain box (ehemm.. 'control unit') once. It has several jumpers that can be cut to make it compatible with a manual transmission and clutch pedal switch (with another wire harness), and AC compressor load (pre-set automatic throttle increase)**.
But, overall, it appears to be little more than a voltage comparator that, somehow - via the other unidentifiable chips on the board - compares the current transducer voltage to a 'stored' value of some kind and adjusts to match.


**(The van had factory AC, so this is something that I believe I actually need to patch. It over-compensates when the cruise is initially set, and "stomps" the throttle to about 4-4.5 MPH over what is intended. Then it eases off, coasts to the setting, and then "stomps" the throttle back to what I assume is the AC load preset. It only does this a few times, but was never a problem when working in the van. I suspect it's the AC compensation circuit having a seizure. When the time comes, I'll experiment with grounding the wire intended for AC input, providing +12V, and just jumping the cut jumper with the AC input disconnected [as it is now].)
 

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Discussion Starter #9
Thanks for comments and input. I'll probably go with the Rostra system sold by Dakota Digital. I should have plenty of room for the control unit on the driver's side inner fender. I'll have to come up with a way to connect to the Holley 4160, but that shouldn't be a problem. The cruise will help a lot on long distance trips -- of which we do a fair number.
 
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