Prolong Clutch Life - Don't Use It When Shifting Gears

[DARISC]

This will also extend the life of your synchro rings as well. Think I'm nuts? Not so- and I'm sure a lot of you older guys out there know it.

When I was a poor Navy Seaman at the Hunter's Point shipyard in S.F., the clutch on my 54 Austin Healey 100 4 suddenly wouldn't come back out after being depressed, the day I was driving back home, so I looped a a leather belt around it and drove it from San Francisco to San Diego, using the clutch only when I was forced to a complete stop, pulling it back out using the belt to get going again.

Not using the clutch except when starting from a dead stop, and of course while stopped, works with any manual trans I've ever driven, from a 49 Chevy w/3 on the tree, RX7 twin turbo, 99 Vette 6spd and my current 82 SC coupe with the much maligned 915 trans (which I happen to enjoy very much).

Of course this demands a good familiarity w/your gear box, and ya gotta pay attention to what you're doing. It's not for competitive driving, and a missed shift can be disastrous, but properly executed, with aural attenton to your engine revs, it's smooth as butter.

I don't drive this way normally, but it's a good thing to know how to do in certain cases such as my Healey incident. It's also amusing to tell a passenger friend to watch your motionless left foot as you go up & down through the gears, seamlessly, smoothly and without a hint of grind, crunch or lurch.

Yeah, it's kind of an ego thing too.

[widebody911]

Works with my VW bus, too, and I've driven trucks in this fashion as well. I've also driven a few trucks with a split rear-end, which doesn't even have a clutch.

However, the cost of a clutch disk < synchros; the chances of getting a shift right with the clutch > chances of rev-matching the engine and trans correctly.

[BrokeMyCar]

I did it when my old miata lost the slave-cylinder on the Bay Bridge. Stopping was interesting... it would stall so I would turn the car off as I appraoched a light. I found I could start it in 1st or 2nd with a little bit of gas, and then match RPMs for shifting on the higher gears.

Alas, that was the last time anything interesting happened to the miata. Way too reliable, so I had to give it to my father.

Babak

[Wayne 962]

Originally posted by DARISC
This will also extend the life of your synchro rings as well. Think I'm nuts? Not so- and I'm sure a lot of you older guys out there know it.

The Porsche gearbox has a slip synchro design that uses friction surfaces to match the speed of the gears within the transmission (connected to the wheels) to the speed of the engine. If you shift the car at exactly the correct RPM for the speed that you are traveling, then you indeed experience no wear.

However, I do not know anyone that can do this in real life. If you shift without putting in the clutch, then you are using the friction of the synchro rings of the transmission to mesh and align the two speeds together (assuming you're not "perfect" in your shifting). This will inevitably cause your synchro rings to wear out sooner.

When you push in the clutch, you disconnect the engine from the transmission. This allows you to shift gears as the internal components of the transmission slow down or speed up to match the speed of the car. If the engine is still connected, you are fighting the momentum / power of the engine when you engage the gear (all assuming that the shift is not "perfectly aligned"). In this manner, you will definitely increase wear on the synchros in your transmission.

The simple way of thinking about it is that you need friction to align the speed of the engine with the speed of the car. By not using the clutch, you are then using the internal components of the transmission to accomplish this task instead (the synchros), and will thus increase wear on the synchros. One of the principles behind this design is that the clutch is meant to be the wear part of the assembly - not the synchros. It's far, far cheaper to replace a clutch, than it is to replace synchros in your transmission.

Of course, if you can shift perfectly 100% of the time and match the speed of the car with the engine, then there will be almost no wear. But again, I don't know anyone who can shift like this 100% of the time.

This is how it is for the Porsche 911 transmissions - I know that other cars have different synchro designs that may or may not be more amicable to clutch-less shifting.

-Wayne

[DARISC]

Wayne, you're absolutely right, and as I say, I don't normally shift w/o clutch. That's because, as you say, one can't be 100% all the time, and oh yeah, I'd rather replace a clutch than rebuild a trans! When you're ON though, the lever changes the gears w/absolutely NO resistance from the synchros helping.

I posted this kinda for the fun of it, having read numerous questions about heel & toeing & double clutching. I take a certain pride in having learned to drive with a stick and pride in getting a lotta miles out of a clutch while driving hard but not abusively (went 74k miles on my 99 Vette 6 speed, which I drove like the muscle car that it is, rather than a refined driving machine like my SC).

I've only had my SC (my first Porsche) for about 8 months, and I didn't have the confidence to even try it with the 915 until this morning on the way to work. How sweet it was! (however I'll refrain from doing it except to show off, for all the reasons Wayne states).

[bkreigsr]

I had to drive home from an autox in Md to south NJ with no clutch. (stupid plastic cable-end retainer). only had to get out and push from stop once.
Waynes right, the trans took a beating from which it never really recovered.
Bill K

[williecoyote]

I had a very good friend who drove his MG Midget from Raleigh, N.C. to Palm Springs, Ca. (Poor college student) He lost the clutch in Albuquerque, N.M. He finished the trip shifting without the clutch. He said that he would slow down, and try to keep rolling at red lights. Whenever he had to stop, he killed the ignition. Then shift into first, and start the engine when the light turned green.
I don't know what it did to the transmission, but he did make it to Palm Springs.

[RT930turbo]

It is fun to see peoples reactions when you shift with no clutch, also pretty common thing to do in a big truck with a non synchro, strait cut gear box. A few formula cars I have driven have had strait cut boxes in them, and all you do is lift off the gas for a split second to break the torque, and slide into the next gear. Tons of fun!

[evill]

I would just do as Porsche says here

Ed (hope it's OK to borrow this pic)

[Bill Verburg]

prolong clutch life

I believe that you are addressing a problem that doesn't exist

[Wayne 962]

Originally posted by RT930turbo
It is fun to see peoples reactions when you shift with no clutch, also pretty common thing to do in a big truck with a non synchro, strait cut gear box. A few formula cars I have driven have had strait cut boxes in them, and all you do is lift off the gas for a split second to break the torque, and slide into the next gear. Tons of fun!

Yup - straight cut, should be no problem and minimum wear. Tough to shift if you don't know the exact points though...

-Wayne

[Jeff Alton]

I shift all the time on the street with out the clutch, just for fun to see if can match the revs perfectly. I consider it practise at being smooth on the track. But, I agree with Bill, you may be trying to fix a non-problem.

Cheers

[Motorhead-45]

"Prolong Clutch Life - Don't Use It When Shifting Gears "

Prolong the life of my $300.00 clutch at the probable expense of trashing my $3000.00+ transmission? Huh!? I'd rather change a clutch than rebuild a transmission...just finished doing both due to previous owner's hamfisted driving technique. FYI the first clutch lasted over 70k miles.

And yes I've driven many commercial and military vehicles that survive quite well with the no-clutch technique. I'd venture to guess that the hardware inside these transmissions is a good bit more robust then our Porsche parts.....probably less expensive than the Porsche parts also!

[Gasman59]

MY first car (VW Bug) lost the clutch cable. I drove it home with no problems. As to stopping, I matched the engine "power" to speed, basically unloading the trans, popped it out of gear into neutral and stopped.
Engine off, first gear, crank and away we go!
Same for up-shifts, matching, (unloading the trans), produced smooth shifting.

I have a friend who owns and drives a dump truck. He never clutches other then stopping and starting.
The shifts are as smooth as silk.
Ron

[masraum]

Yeah, as others have said. A great bit of knowledge/skill to have in case something happens to your clutch. I think I put about 50-75 miles on my old 911 driving without the clutch when the slave cyl went out and the clutch broke, but I don't think that you are saving yourself any money by shifting without the clutch when everything is working correctly. I can do it in my miata, I've done it in my old '65 Impala, etc... But doing it regularly is just asking for expensive trouble.

[tsuter]

"Prolong Clutch Life - Don't Use It When Shifting Gears "


Prolong brain cells.....don't use while driving.....

[NY65912]

Yep, I've been driving without clutching for years. I drove 5200 gal fuel oil trucks (Mack DM R models.) Only used the clutch from a standing start or when stopping. Down shifting is possible as long as you have a good year to match up the input and output speeds........but I've always did it on my trucks.

It's an understanding of matching the input shaft speed with the output shaft speed...either up or down.

You develope a "feel" for the gear box and then it's like second nature. None of my trucks ever needed near the amounts of clutch adjustments or for that matter clutches. I drove delivering oil thru the streets of Brooklyn, PLENTY of shifting, never a problem.

Drove my VW's for years like this as well. I've been a little leary of trying it out on the P cars. But I think I shall give it a go. Mind you, we are talking about slow deliberate shifting.

[Gunter]

I think this falls under the category of: How many raisins can you stuff up your nose?

You can also prolong the life of your brake pads if you only use the emergency hand brake.