Clutch/Neutral Safety Switch

I am currently completing most of the electrical wiring. I would like to include a clutch/neutral safety switch.
Any ideas as to how to add one? To the clutch pedal, a switch on the clutch hardline or on the slave cylinder?
Any specific product in mind?

Thanks
 

Malcolm

Supporter
Have to confess I am not sure to what you are referring when you speak of a clutch/neutral safety switch. What does it switch?

However if you want to fit a switch I would suggest you look at a mechanical switch that is not part of the hdraulic line. A brake light activation switch on a bracket off teh pedal or indeed off the slave cylinder arm(might get a bit hot there) should be cheap and simple to install.

If on the other hand you want a fluid failure switch to monitor the clutch hydraulics then the above is no use to you at all!

Malcolm /ubbthreads/images/graemlins/smile.gif
 
Colin,

Your neutral gate is controlled by the Morse cable, not the shift rod(s). It shouldn't be too difficult to adapt a neutral safety switch to the cable end, at the bottom of the shift lever.
Malcolm,
A neutral safety switch prevents the engine from being started, while a gear is engaged.

Bill
 

Malcolm

Supporter
Thanks Bill. Could not a switch as I described be used so that you could only start the car with your foot on the clutch pedal? I have not heard of manual gear change cars needing such a switch before. Automatics, yes. Tell a lie! When I was involved with Cobra replicas there was this chap who arrived at work so the engine was nicely warmed up. Jumped out to go into his office but was approached by a chap who asked to listen to the engine a bit longer. Owner of the car leant in and flicked the ignition switch. Engine caught immediately and as it was in gear the car drove off on its own. Into a brick wall requiring a complete new body shell. Ooops!

Malcolm
 
Malcolm,

Sure, you could put a neutral safety switch on the clutch pedal, but you'd need a midget to replace it, if it ever died on you! /ubbthreads/images/graemlins/wink.gif
The only drawback to a neutral safety switch on a manual transmission, is if you should lose the clutch slave cylinder.
I had that exact thing occur years ago with a Lotus Elan, during a torrential downpour, and I was able to get home by putting the car in first gear with the engine off, and turning the key. The engine caught, and I flat shifted it, to get home. Stop lights/signs were a challenge,
as I had to shut the engine off, and pray that it started again! /ubbthreads/images/graemlins/shocked.gif With a neutral safety switch, I would have looked like a drowned rat, as walking 5 miles to a phone would have been my only option!

Bill
 
You should be able to install a hydraulic brake light switch in the clutch circuit. I would use it to control a relay - a brake light switch probably won't handle the starter current for the long run. Put in a hidden "bypass" switch for those times where the switch's function would be a problem.
 
If you lose the clutch hdraulics you can still start the car in gear and drive that way, you just have to push the clutch pedal when you do it, chances are at that point the clutch pedal will stay down meaning you only need to push it once but if not just use it like you would when it worked. As for what switch to use, I would just get one from a car that has one and adapt it to the linkage somewhere, I have never seen a hydraulic one before. Just remember that the clutch N.S.S. needs to install at the end of the clutch travel so it is depressed when the pedal is down, unlike a brake switch.
p.s. I live about 30 minutes from Blaine so if you would like some help with the electrical (or anything else) i would love to come and see your car.
 
Thanks Malcolm, Bill, Bob and Eric for all the input. I am looking for something similar to the clutch interlock switch that hangs off the clutch pedal on the older Mustangs and was hoping that some else had already done the adaptation. I will grab one from the salvage yard and see what I can mock up.
Eric send me an email; it would be great to get together and talk.
 

Malcolm

Supporter
You may need offset feet to drive a GTD but you won't need a midget for accessing the clutch pedal switch as GTDs have an access panel over the footwell right above the pedals.

Reading the comments about starting a car in gear reminds me when my mate Neil and I drove from John O Groats to Lands End in my Dax Cobra about 15 years ago. For you US guys that is from the northern tip of Scotland to the southern most tip of England, a mere 863 miles in 17 hours.

As we were driving to John O Groats with about 7 miles to our arrival at the starting point for our little jaunt the clutch springs popped out of the friction plate, not that we knew it at the time. All we knew was lost clutch opreation in the middle of nowhere! We had to start the car in gear as described above for 1000 miles plus of motoring to do our planned run and get home again. Added a bit of spice to the trip. Especially on the orbital motorway around Glasgow in rush hour when we hit a traffic jam and we were in the outside lane. The battery was struggling so when the radiator fans kicked in to cool the engine there was no longer enough juice in the battery to start the car. Solution was for Neil to get out of the car, open the bonnet, turn off the fans manually, I would start the car in first gear and bumble along the outside lane, Neil would lean into the engine bay restart the fans, shut the bonnet and then have to jump into the moving car! Really got some wierd looks for doing that! Haven't seen ourselves on Police Camera Action yet either.

You won't be able to do that in a 40!

Malcolm
 

Lynn Larsen

Lynn Larsen
I have set mine up as Bob described. As a matter of fact, I have fitted two brake switches on my clutch line. One, near the master cylinder completes the circuit for the starter. As suggested, this actualy only allows the energizing of a relay. Granted, all I have to do is lay my foot onto the clutch to achieve this, but if I have to do this much, I feel I will go ahead and depress the cluctch pedal to start the engine.

The second switch is near the slave and is used as an input to the ECU along with a neutral switch off of my shifter linkage. If the clutch is disengaged or the transmission is in neutral, the computer knows that there is no load on the engine and it will supply only enough fuel to idle the engine. The trick to the neutral switch is placing it where the exhaust won't effect it. I built a little box with a micro switch that is activated by a cam bent into 3/16" rod which follows the shift mechanism (I have a Porsche transaxle.)

I made an aligator clip jumper to bypass the system in the shop and when doing any work requiring multiple starts of the engine. It works quite well with the cylindrical female fittings on a standard brake switch.
 

Malcolm

Supporter
If you go for an electrical contact pressure switch in the clutch line, be careful of the type of clutch fluid you use. It was found that over time the silicone based fluids corroded the contacts inside these switches so making them fail. Hence I switched to a mechanicl switch.

Malcolm
 
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