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Manual trans safety switch?

11K views 15 replies 8 participants last post by  Bryan59EC 
#1 ·
Hi All,

Fixing to plumb my hydraulic clutch (LS3 with Jerico 4 speed), and was wanting your thoughts on whether or not to add in a 100# safety switch that would activate a relay to keep one from starting with the clutch engaged? Although I lived through the '60's, I don't remember if these cars ever had anything like it...

Russ
 
#5 ·
Russ;

I've had a fair amount of people ask this. My response is YES you may remember proper procedure; but we're now 3 generations removed from the heyday of manual gearboxes. If someone else decided to move your car and it lurched forward and hit something or someone...you'd feel pretty awful. And it would definitely cost more than the NSS itself.

I always recommend adding them.
 
#6 ·
By all means add a neutral (clutch) safety switch. People get to working on a problem, reach in and "bump" the starter...car turns into a drone attacking the washer and dryer. Just rewired a guys car that has an auto trans and column shift. Used a relay off the brake switch so that he must press the brake to start.
 
#9 ·
...car turns into a drone attacking the washer and dryer.
Hundreds of Maytags are needlessly attacked every year in their natural habitat. For the cost of a large designer coffee, you can help. No Maytag should have to suffer...Donate today. You will receive a picture of a Maytag, and letters from home, along with missing socks and the occasional pink shirt.

Sorry...something compelled me. :D
 
#7 ·
I haven't always been good about having clutch safety switches. That actually has been a help... Three quick stories: My car stalled in heavy rain in the middle of a busy intersection, waiting to make a left, motor would not start, was able to limp it out of the intersection and off to safety with the starter motor. Another time again in heavy traffic (a downtown construction area), I hit a huge pothole so bad the jarring broke the clutch linkage pivot stud off the block and I had no clutch. Then traffic came to a stop and of-course so did I... Using the starter motor I was able to re-start the car in first a number of times to get myself along in traffic and finally out of there. If I had needed to wait to be towed, it would have been a huge mess. Finally I broke a clutch linkage on a trip where I was returning home but still a couple hundred miles away, it was Sunday p.m. and no parts stores open and I limped home the same way, using the starter motor to get going and shift w/o clutch (glad I practiced that when I first started driving). None of those "saves" would have been possible with the clutch safety switch in there. Naturally you could say none of this was good for the starter, but it handled it in each case.

Then on the other hand, once I just jumped in my car in a parking lot, hit the starter in gear when I thought it was in neutral and hopped my very-lowered car right up and over a parking stop, landing on the headers and squashing a couple of tubes flat. Good one! Wouldn't have happened with the switch, and that incident clearly shows a potential safety issue.

So if I were to be making a recommendation about clutch safety switches, I'd say have one but wire a go-around.
 
#8 ·
All of my cars (not her's or the kid's) have manual trans.
Habit---clutch is depressed before key is turned.
My 79 C-10 had a manual trans before it was 6 years old (my third AT on that car went right in the trash after GM had warrantied 2 of them)
Never did bother with adding a clutch switch or NSS on that one.

But----on both of my ElCaminos with Tremecs, I wired in the NSS on the trans.
Car must be in neutral before it will start
 
#11 ·
Here is a thought

If you are not too interested in keeping your backup lights.

Could use the reverse switch as a sort of 'safety measure'

Ford & GM used a similar method in the early 70s where the car would
not start unless it was in reverse.

Altho they used a linkage driven backdrive and retained the backups.

switch does not necessarily need to be inside the cabin or attached to the trans.
Might be able to come up with something using the Zbar or clutch rod
 
#12 ·
Here is a thought

If you are not too interested in keeping your backup lights.

Could use the reverse switch as a sort of 'safety measure'

Ford & GM used a similar method in the early 70s where the car would
not start unless it was in reverse.

Altho they used a linkage driven backdrive and retained the backups.

switch does not necessarily need to be inside the cabin or attached to the trans.
Might be able to come up with something using the Zbar or clutch rod
Hard to do on a juice clutch. Man, I hadn't even considered b/u lights! A switch for that would be relatively easy. Actually, my car ('63 Rambler American) doesn't even have any b/u lights - yet. Guess I need to rethink this now...

Russ
 
#13 ·
I remember a friend of mine taping a dime down on a contact switch for some reason. Details are a bit fuzzy but it got him home LOL

Historical note:

Borg Warner engineers didn't want the T56 to have a bonafide reverse synchro. One of the OE's balked (probably GM) and a synchro reverse was born. Heres the rub: You could put your camaro into reverse at any speed. There is a reverse lockout switch. If the switch dies, and you NEED reverse; there is a spring-loaded detent called a"crash through." So man up and YANK...it'll find its way into reverse.

To review:
instead of having a Muncie or T10 style reverse, a synchro was added. To avoid the danger of inadvertent reverse engagement, an electrical switch was added, which then required a separate spring loaded detent LOL

Russ:
What about a 12v button on the shift knob? Hold button in for the reverse lights?
 
#16 ·
The idea is to prevent the starter from operating unless certain conditions are met. That in itself is some sort of safety measure.

wired like this----the car cannot turn over (with the key) unless the brake pedal is depressed enough to activate the brake lights.

Now, if you have a vehicle that needs a little persuasion to start and stay running (needing both feet -brake and accelerator-) chances are pretty good
the operator/owner will put the car in neutral before firing up
 

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