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  #1  
Old 06-15-2003, 02:51 PM
minor7flat5 minor7flat5 is offline
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Anything bad happen if I disable my clutch switch?

Other than the fact that I'll be able to drive my stalled car off the railroad tracks using my starter motor ...

Here's the problem: The clutch switch in my '95 Saturn has gone bad. Unless I stomp on the clutch (or manually press the switch with my thumb) several times, the ignition will not work. I looked at the switch and saw that, while the switch looks kind of odd and hard to get out, I can easily pull off the wires attached to it.

For the next few days, I suppose I'll go around starting my car by shorting the wires from the clutch switch by hand.

What's to keep me from permanently connecting them together?
Is the clutch switch simply a momentary switch in series with the keyswitch, or is there something more profound at work, such as the clutch switch providing data to the computer?
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  #2  
Old 06-15-2003, 02:59 PM
Q.E.D. Q.E.D. is offline
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Re: Anything bad happen if I disable my clutch switch?

Quote:
Originally posted by minor7flat5
What's to keep me from permanently connecting them together?
Is the clutch switch simply a momentary switch in series with the keyswitch, or is there something more profound at work, such as the clutch switch providing data to the computer?
No, go right ahead and disable it if you need to. It's just a simple momentary-contact switch, and its sole purpose is to prevent you from trying to start the car with the gear engaged. Just be extra-careful to make damn sure you're in neutral when starting your car near the edge of a cliff.
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  #3  
Old 06-15-2003, 04:10 PM
Gary T Gary T is offline
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What Q.E.D. said.

The clutch starting switch is just another example of trying to "idiot-proof" things. Handy perhaps for those who don't like to think much about what they're doing, frustrating for those who like to have all options open to them.
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Old 06-15-2003, 04:11 PM
Gary T Gary T is offline
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Interesting observation--as far as I have seen, all Asian and American cars have these switches, (at least some) European cars do not.
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  #5  
Old 06-15-2003, 08:26 PM
minor7flat5 minor7flat5 is offline
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I think I'll give it a go.

I've always been a bit peeved that they put such a silly thing in new cars to idiot-proof them. A clutch switch and a "time-to-shift" light. Great.

Ahhh for the good old days of cranking the car without hitting the clutch and feeling the car lurch forward as we called ourselves idiots under our breath.

So, I'll be able to do two things: get off the RR tracks with a stalled car (as mentioned before) and start the car by reaching in the window and turning the key. I like it.
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  #6  
Old 06-15-2003, 08:47 PM
NinetyWt NinetyWt is offline
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I did this a couple of weeks ago, in my '90 Civic.

It's definitely easier to start the car. However, I learned (to my huge dissapointment) that the clutch is in trouble. Now I'm going to have to put a clutch in it. *sigh* But I don't think I'm going to reconnect the switch.
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  #7  
Old 06-15-2003, 08:54 PM
Princhester Princhester is offline
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For the record, Australian cars don't have them either, at least not in any manual car I have driven.
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  #8  
Old 06-15-2003, 09:02 PM
Q.E.D. Q.E.D. is offline
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The clutch cable in my car broke once. The only way I could get home was to force-shift it while driving and shut the engine off to stop, so it wouldn't stall, then use the starter to get the car moving again. It was an interesting ride home, I'll tell you. I won't say what kind of car it was, but if I'd gotten rear-ended, it might have exploded.
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  #9  
Old 06-15-2003, 09:28 PM
Tuckerfan Tuckerfan is offline
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Quote:
Originally posted by Q.E.D.
The clutch cable in my car broke once. The only way I could get home was to force-shift it while driving and shut the engine off to stop, so it wouldn't stall, then use the starter to get the car moving again. It was an interesting ride home, I'll tell you. I won't say what kind of car it was, but if I'd gotten rear-ended, it might have exploded.
A Pinto, perhaps? I had a Chevette that my brother had disabled the clutch switch, and I drove the car for a couple of years without a problem (other than it was a Chevette, of course).
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  #10  
Old 06-15-2003, 09:37 PM
stypticus stypticus is offline
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My parents drove their Volkswagen Beetle for a month with no clutch, Q.E.D., just as you say.

My dear old dad disconnected the clutch switch on his Valiant as soon as he found out it had one.

minor7flat5, my dear old dad told me to depress the clutch when starting regardless of gear. First, it's a good habit. Second, it decreases wear and tear on the starter motor, which doesn't have to crank as much weight around to start the engine.

You wouldn't want the car to leap forward when you're leaning through the window, would you?
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  #11  
Old 06-15-2003, 09:47 PM
bubba jr bubba jr is offline
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One thing that has always bothered me is that by pushing
in your clutch to start the car you are actually putting a
HUGE amount of stress on the thrust bearing of your
crankshaft(NO oil pressure). I've always disconnected them,
snap a cable/blow a cylinder and you can still get going.
Not to mention it helps putting a nonrunning(something
I seem to have TOO many of) cars on a trailer.
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  #12  
Old 06-15-2003, 09:56 PM
Q.E.D. Q.E.D. is offline
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Quote:
Originally posted by bubba jr
One thing that has always bothered me is that by pushing
in your clutch to start the car you are actually putting a
HUGE amount of stress on the thrust bearing of your
crankshaft(NO oil pressure).
Say what? Where did you hear this from? The clutch has noththng whatever to do with either your crackshaft or your oil pressure. The entire clutch mechanism is housed within the transmission and only the clutchplate makes contact with the flywheel face when the pedal isn't depressed. There's no mechanical connection between the clutch and the engine other than that.
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  #13  
Old 06-15-2003, 10:14 PM
Booker57 Booker57 is offline
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An engine has no oil pressure till it is running at a certin speed. If you have a gauge you can watch the pressure build right after starting.

As for putting stress on the crankshaft thrust bearing, I don't think that there is that much end play and once up to speed it has the oil film to protect it. I could be wrong.
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  #14  
Old 06-15-2003, 10:31 PM
Princhester Princhester is offline
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[press release issued by motor industry today]
Mr Joe Bloggs of the American Motor Industry said earlier today that although crankshafts produced by the industry sometimes cracked, this was due to driver abuse and lack of maintenance.

Mr Bloggs said while the use of the term "crackshaft" by Mr. Q.E.D. of Elizabeth N.J. earlier today might be thought by him to be great craic, ultimately it was nothing but a cheap wisecrank on his part.[/press release issued by motor industry today]
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  #15  
Old 06-15-2003, 10:36 PM
Q.E.D. Q.E.D. is offline
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You know that was an awful wordy way to point out a typo.
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  #16  
Old 06-16-2003, 12:17 AM
Gary T Gary T is offline
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bubba jr: One thing that has always bothered me is that by pushing in your clutch to start the car you are actually putting a HUGE amount of stress on the thrust bearing of your crankshaft (NO oil pressure).

Q.E.D.: Say what? Where did you hear this from? The clutch has noththng whatever to do with either your crackshaft or your oil pressure. The entire clutch mechanism is housed within the transmission and only the clutchplate makes contact with the flywheel face when the pedal isn't depressed. There's no mechanical connection between the clutch and the engine other than that.

When the clutch pedal is depressed, pressure is applied to the release (throwout) bearing, which touches and applies pressure to the pressure plate assembly, which is bolted to and applies pressure to the flywheel, which is bolted to and applies pressure to the crankshaft. In other words, bubba jr is correct in saying that depressing the clutch applies pressure to the crankshaft, and that this pressure is borne by the thrust bearing. I don't know that it's a huge amount of pressure, but however much it is, it's not really a problem--that's essentially what the thrust bearing is for.

And yes, this occurs during start-up, when there is no oil pressure (it's not that the clutch is related to engine oil pressure, it's that the described event is occurring before oil pressure has built up). But there is greater stress on the rod and main bearings during start-up, again before oil pressure builds. Residual oil film on the various bearings handles the loads.

The above is part of the reason that a great deal of engine wear occurs while starting, especially if the engine is cold. But unless you can operate your car without ever shutting the engine off, it's something that has to be accepted.
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  #17  
Old 06-16-2003, 02:25 AM
Princhester Princhester is offline
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There's a very very groovy maintenance manual for VW's that I used to own which was great fun. Someone will no doubt be along in a minute with the name of it. The hippy author (who in my opinion gave very good advice) recommended that you start the 'dub, then sit in the driver's seat rolling your smoke, and by the time you'd done so and lit up and had a few drags, the engine would be in fit and fully lubricated state ready to drive off with a minimum of engine wear.

My 25th anniversary edition of the book had appendices by other guest author/mechanics, the original author having died (lung cancer gained while waiting for his car to warm up perhaps?). One of the other guest authors "corrected" the original author thusly: while your engine is cold, it is wearing faster due to lack of lubrication etc. So you need to warm it up as fast as possible. If you just leave it idling, it will warm up only slowly because it is not under load, so it is best (he said) to place the engine under as much strain as possible as soon as you start it, to warm it up faster! That was his reasoning. I shit you not.

I seem to remember that he even said that his driveway was extremely long and steep, and he made sure he started the car and then drove up the driveway immediately so as to "minimise wear".
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  #18  
Old 06-16-2003, 03:13 AM
capnfutile capnfutile is offline
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Dat book is...

That was " How to Keep Your Volkswagen Alive - A Manual Of Step-by-Step Procedures for the Compleat Idiot" by John Muir. An American classic, first edition December 1969 and still in print. I have three copies. I also bought the one for my Subaru, and they've done Honda, Nissan, Toyota, etc. Essential for ownership of an air-cooled VW, and fun reading no matter what car you own.

Every technical writer should be forced to read this book. Especially the Chinese ones who write assembly manuals.

capn
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  #19  
Old 06-16-2003, 06:01 AM
Princhester Princhester is offline
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Thanks capn, that's the one.
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  #20  
Old 06-16-2003, 07:59 AM
Gary T Gary T is offline
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I would definitely advise against placing the engine under as much strain as possible when it's cold. That's a recipe for throwing a rod. Muir's manual was pretty good overall, but on that point the guest author is wrong. Trust me.

With modern fuel injected cars that run well during warm-up, the standard advice is to not let it sit and warm up, but start driving right away--gently--to reach normal operating temperature sooner.
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  #21  
Old 06-16-2003, 10:49 AM
MajorTom MajorTom is offline
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The only disadvantage to permanently shorting the wires is if you have cruise control. The system will alway's "think" the clutch is disengaged and prevent cc from operating. The solution would be to either replace the switch or install a momentary pushbutton somewhere handy.
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  #22  
Old 06-16-2003, 07:14 PM
minor7flat5 minor7flat5 is offline
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Ahhhh.... That's much better.

Just went out, popped off the wire harness, poked in a U-shaped piece of 14-gauge copper wire out of my toolbox, wrapped it in black tape and stuffed it out of sight.

How pleasing. The car starts right up.
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  #23  
Old 06-16-2003, 11:08 PM
Omar Omar is offline
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Quote:
Originally posted by MajorTom
The only disadvantage to permanently shorting the wires is if you have cruise control. The system will alway's "think" the clutch is disengaged and prevent cc from operating. The solution would be to either replace the switch or install a momentary pushbutton somewhere handy.
The truth to that statement depends on the type of car. For example, on my 91 Honda Accord, there are 2 seperate and independent switches. One for cruise control, and the other being the neutral safety switch.
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