Team-BHP - Emergency driving

Great thread Sudev: Now I gotta practise to change gears without clutch. What I have done in previous cases was slot in third start / push start jump and drive..until destination and most of my cars being diesel, it worked!!

Superb: I tried upshift as well as downshift as mentioned and it works :thumbs up both with my antiquated MM540-KMT90 as well as Fiat Punto MJD.

Now my silly question: What is the long term damage if i dont use the clutch at all, apart from starts? Will the synchroniser go for a toss? or can i continue doing it? I'm just loving it guys - Sudev, DKG, please give more tips like these :I Rule:

Quote:

Originally Posted by headers (Post 2360515)

Will the synchroniser go for a toss?

I personally feel they are bound to as when you attempt to shift into a gear the synchroniser cones or plates actually rub against a part of the gear to either brake it or speed it up to match the driven gear speed. Now with the clutch engaged the synchroniser not only has to work on the mass of the input gear but the crank/flywheel.pistons, cams, valves the whole engine too not to mention the effect of vacuum. You will wear the synchronisers in no time

^^

What he means is though syncrhoniser is strong enough, dont keep doing it again and again - you have a clutch - which can take better loads and is designed to do the job - Only in case of EMERGENCY, use this technique and the synchroniser will help you do the job gracefully!!

Correct ?

^^^
Hi,
Actually the synchroniser is not strong enough. The synchroniser can only speed match an unloaded input shaft. If the input shaft is not free, speed matching will have to be done by the driver, using the throttle. And he has to have enough skill to push the gear lever at just the right time.

Doing it absolutely perfectly everytime is not possible (at least for us mere mortals). Even if you can't hear the grating, or feel the jerk, you have accelerated wear.

Like most emergency routines, it has to be practised before you actually need it.

Regards
Sutripta

Professori special thanks for that last line. Just what I was trying to convey with my inept language skills.

Practice this once or few times. It would be a lesson well learnt with minimal cost or damage to vehicle.

I wanted to check this out, But I don't know why but every time i tried slotting the gear without the clutch I unconsciously stepped on the clutch. Then I consciously kept my leg away from the clutch pedal. This time I got the gear stick out of second gear but could not get myself to slot the third gear. I was pressing the clutch again. Its become almost automatic to press the clutch with a gear shift.
The witty part is tried this 3-4 times and I have given up now. wondering how people are doing it.
Guys, Got any tips ?? just so that I can try this out once.

A probably harsh question: Is it even worth trying it out?

How many times does a clutch actually fail under normal wear and tear that 'trying' this routine is being advised? Trying this even once runs the risk of ruining my gearbox. On the other hand, if I am not riding the clutch it will last me a good 60k or more and will usually show signs of wear.

No disrespect meant to OP and others who have contributed various technical bits, but I feel the risk far outweighs any benefits.

Quote:

Originally Posted by figo_mba (Post 2362174)

Guys, Got any tips ?? just so that I can try this out once.

Read the post by sudev and DKG - They clearly explain how to do the same. I tried and suceeded, not in 1 but 2 different breed of vehicles :D

Quote:

Originally Posted by honeybee (Post 2362345)

A probably harsh question: Is it even worth trying it out?
..but I feel the risk far outweighs any benefits.

Hi Honey, this thread aint for you.

On a serious note, it is good to learn such tricks only to understand the vehicle better as well as not get stranded in case of EMERGENCY!!!

Cheers

@figo_mba : That is why I suggest that you try this out and not have to learn things when situation is bad.
To shift up : Carefully slot to neutral. To do this it help to lift foot off the accelerator so that there is least power transmission through the gears. Then wait for a half a second and then push the gear towards the next slot. Bear gentle pressure the gear will slot in when the RPM's of both gears (engine side and transmission side) are matching.

What do you do if the gear does not slot?? Let the car roll on and remain in neutral and rev the engine once. Then try slotting the gear with gentle pressure - do not force it in. As soon as engine RPM's come down and match the transmission side the gear will slot.

The last is what we do when we are trying to down shift. Rev the engine so that engine RPM's match the lower gear. (Sorry Proffessori for such unscientific preaching - but lower gear only in terms of gear number and not gear ratios).

This is a related question, but can one avoid this situation if we have some approximate knowledge of clutch life left and replace the clutch as preventive maintenance. That brings to the next question, is there a list of life of clutch in various vehicles or can we get one with some collective wisdom here? I changed my "2WD" Peugeot engine commander jeep's clutch when I procured it, and driven 20k kms on-road 95% of the time. I don't know how many more kms I have left on my clutch life.

Quote:

Originally Posted by sae90 (Post 2363056)

You will know your clutch is wearing out if you accelerate and the engine rises in rpm and vehicle moves a few seconds later.

BTW, this is an EMERGENCY DRIVING TECHNIQUE!!