Cruise Control in a 240?

[AndysPlit]

....I stumbled upon an ad on craig's list the other day claiming that this 240Z for sale had cruise control. I e-mailed the guy asking about this and he said that the previous owner added it.

Is this rubbish? Anyone else done this to their S30? Very curious, not that I would. I barely use it on the 300ZX.

[DRBall]

Yeah you can buy a aftermarket kit from stores like J.C. Whitney etc as for why well my right knee kills me if I drive for long distances. The last rental car I had did not have one...And my knee let me know about it...

[AndysPlit]

..So how much does this conversion cost?

[240znz]

I wonder if this guy is getting confused with the ol' hand trottle ala "poor mans and outright dangerous cruise control" that came with the "series 1" HLS30's and sub VIN 1500 HS30's.

It is easy to fit replace the single choke plate and levers with the earlier model but welding is required on the accelerator pedal to fix the cable. The major potential lethal problem with it is that it doesn't release the pedal when the brake pedal is pressed. Nasty.

[e_racer1999]

my z had an aftermarket cruise control installed. pretty hokey one. next time i am at my g-ma's house i'll take a pic of some of the parts

[mdbrandy]

Back in the 80's I used to drive my 1975 280Z back and forth between Illinois and Los Angeles a couple of time a year, and I added an aftermarket cruise to it. It was vacuum-based. The '75 had a vacuum bottle that ran the HVAC vacuum servos that I tapped into. Used a magnetic pickup that you strapped to the driveshaft. Attached a magnet to the inside of the tunnel, and every time the magnet on the driveshaft came around, the cruise knew "one revolution" had happened. So you set the cruise at some speed, the unit knew the revolutions that were happening at that speed, and it keep speed constant through a vacuum valve and a wire-arrangement that you had to set up to pull on the throttle linkage appropriately.

I expected it to be mediocre, but from what I remember, it would keep my speed within about 1 mph.

Mark

[MikeW]

The major potential lethal problem with it is that it doesn't release the pedal when the brake pedal is pressed. Nasty.

I've often wondered about this. You hear stories about cars that took off like a rocket even though the driver claimed to have the brake pedal firmly pressed to the floor. While I'd never try it on any of my cars (pressing both pedals at the same time) I have a strong suspicion that the brakes would win and the engine would knock off. I'm certainly not claiming that having the cruise control not disengage upon braking isn't a problem; I just don't know how big the problem really is.

[e_racer1999]

Back in the 80's I used to drive my 1975 280Z back and forth between Illinois and Los Angeles a couple of time a year, and I added an aftermarket cruise to it. It was vacuum-based. The '75 had a vacuum bottle that ran the HVAC vacuum servos that I tapped into. Used a magnetic pickup that you strapped to the driveshaft. Attached a magnet to the inside of the tunnel, and every time the magnet on the driveshaft came around, the cruise knew "one revolution" had happened. So you set the cruise at some speed, the unit knew the revolutions that were happening at that speed, and it keep speed constant through a vacuum valve and a wire-arrangement that you had to set up to pull on the throttle linkage appropriately.

I expected it to be mediocre, but from what I remember, it would keep my speed within about 1 mph.

Mark

sounds exactly like the one i had. had a slip on thing that went over the turn signal arm, right?

[hd240z]

I installed one on my 71 240Z some 25 years ago and it is still working today. It was made by Dana and I probably got it from JC Whitney IIRC. It is similar to the one Mdbrandy described. It has just the basic functions, no resume or accel. I mounted the ON-OFF-SET rocker switch in the console next to the rear window defrost switch. The control unit is mounted out of sight under the dash and a magnet on the driveshaft. It has a brake pedal switch to cancel it when needed. The vacuum operated throttle actuator is connected the the linkage between the carbs. It has always worked reliably and holds the speed to within 1 or 2 mph.

[Walter Moore]

I've often wondered about this. You hear stories about cars that took off like a rocket even though the driver claimed to have the brake pedal firmly pressed to the floor. While I'd never try it on any of my cars (pressing both pedals at the same time) I have a strong suspicion that the brakes would win and the engine would knock off. I'm certainly not claiming that having the cruise control not disengage upon braking isn't a problem; I just don't know how big the problem really is.

The brakes always win. (Unless they are bad.) All cars have four wheel brakes, but most cars only have 2 wheel drive. And most cars can stop from 60MPH (100 KPH, whatever) in a much shorter distance than they can accelerate to 60 MPH.

The lethal part that he was discussing is that if you were using the hand throttle to hold the engine at, say 4000RPM under load (80 MPH) when you drop the clutch the engine will accelerate past the red line and break something before you have the chance to push the hand throttle back to the idle position. The hand throttle idea works fine on Diesel cars because the fuel injection pump is a governor of sorts, but with gas engines it is a really bad idea.

BTW: I have read many times that the cars sold in the U.S. had those removed by the dealer for liability reasons. So if the car was on Craig's list it was more likely one of those early 80's after-market cruse controls that everyone else here talks about.

[Maddos]

I've installed these aftermarket (Command Cruise) in

manual Nissan Navara

manual Hyundai Lantra

auto Ford Transit

auto Ford F100

auto Ford Festiva

My zeds are the only cars I haven't done it to, only because they're not long distance, boring cruisers.

For about $300 Aus they're pretty good value for money and if setup right are very good.

[mdbrandy]

sounds exactly like the one i had. had a slip on thing that went over the turn signal arm, right?

Yup, I believe it did. If memory serves, I got it at Sears...