Do you guys have a switch on your clutch pedal ?

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Button
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Do you guys have a switch on your clutch pedal ?

Post by Button » 30 Nov 2019 10:07

I am curious if you guys have a switch on your clutch pedal as some type of starting safety switch? I did a bunch of searching on the site and it seems that there was on odd box that sat on the firewall that was used to switch which points to use on a dual points dizzy for emissions purposes, and maybe that was hooked to a clutch switch? The info I found was not conclusive though. High level my car does not have a switch on the clutch and starts and runs fine but I was curious if this is safety feature I should be considering adding.

Thanks

Chris

Button
Posts: 169
Joined: 25 Jun 2014 14:13
Location: Thousand Oaks, CA..

Re: Do you guys have a switch on your clutch pedal ?

Post by Button » 30 Nov 2019 10:26

Looking at the wiring diagram I am assuming the part labeled CARB SW is the odd emissions thing on the firewall. Where on the car is the NEUTRAL SW (Neutral switch?) that is just before that in the wiring diagram. Would that have been on the transmission?
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icehouse
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Re: Do you guys have a switch on your clutch pedal ?

Post by icehouse » 30 Nov 2019 18:50

Yeah some 510s have them. My coupe doesn’t. Must have been a emission thing. It doesn’t have the brake pressure switch either.
"People don't like it when shit doesn't match their rule of thumb." Sam

datzenmike
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Re: Do you guys have a switch on your clutch pedal ?

Post by datzenmike » 01 Dec 2019 09:43

The dual points are about 5 degrees out of phase so if both are connected the last one to open is the retarded set and if only the first one is connected it's advanced over the late opening by the 5 degrees. Ignition timing is set only on the 'advanced' set. Since emissions are very much affected by a later ignition timing the retard set are used at idle and maybe the first couple of gears? Certainly 4th is at the correct ignition timing for best highway performance and economy. By a series of switches this can be accomplished.

These thing were changed over the years and modified by the car maker but generally the clutch and neutral switch in the transmission connects through the throttle closed/open position switch. This turns off the idle fuel when driving but mainly it removes this fuel from going out the exhaust pipe on deceleration when it's not needed. If you are shifting, the clutch switch and idle position switch connect the solenoid as would coasting in neutral. This would only apply to carbs with an idle cut solenoid.

In addition there is a transmission switch (top gear) that passes through a full throttle position switch that disconnects the retarded set of points for better performance. Looking at it another way the ignition is retarded at part throttle positions in the lower gears

The 521 had an additional temperature switch in the cab. I don't know if the cars got this but it only allowed retarded running above 50F


Myself???? I would just disconnect the advance/retard relay and run full advance. This way you are assured of proper advance at all times regardless of switches adjusted properly or working at all.


I don't think there was a clutch interlock switch for accidental starting in gear. Talk about the auto makers saving us from ourselves... just like the warning buzzer for the key in the ignition or seat belt reminder. If you need those you shouldn't be driving. There was one in my '70 Dart but I disconnected it. This way I could move the car off the road safely with the starter if needed. Or if stalled on the RR tracks. (this never happened) Christ on crutches our new Ram pickup at work won't go into gear with any door ajar.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

Button
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Re: Do you guys have a switch on your clutch pedal ?

Post by Button » 01 Dec 2019 14:40

Wow what a write up Mike - I really appreciate it, that makes sense. It's good to know the original intent, and I also hijacked some of that wiring.

Backing up a bit, I am just getting the car going and I realized the other day that the voltage gauge wasn't going up as I gave it throttle. I did some tests and discovered that the alternator wasn't charging. I did some research and realized since that since I have custom gauges, and no longer have the battery/alternator warning light on the dash it the alternator wasn't get excited. Apparently some load is needed to excite the alternator to start charging. So now I am adding a charge light and am going to hijack some of the unused wiring from the harness since it's already run. I know there is a dedicated wire for this (white with red strip I believe) but It's not easy to access. While looking at the wiring diagram to assess all this I realized I didn't have the neutral and clutch switch and got curious about them. Thank you all for your help.

datzenmike
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Re: Do you guys have a switch on your clutch pedal ?

Post by datzenmike » 02 Dec 2019 20:06

Yes, the charge light needs to work. It provides a very small current to get the magnetism going then it's self generating. Sometimes there is enough residual magnetism in the stator? that if you rev the engine up it will start charging by itself
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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