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View Full Version : Why put manual in gear while parking ?


NothingMan
05-22-2000, 04:42 PM
I love my manual transmission. If I can help it, I will never drive another automatic again.
There is one thing that troubles me though. Whenever someone else drives my car (whether its the lube guy who pulls the car around, or the tire guy who pulls the car around, or a friend who parks the car when I have had a bit too much) they always put it in first gear before they turn the engine off.
Ummmmmmmmm, I have never done that. In fact, when the aforesaid do leave the car in gear, it bucks like a stallion when I try to start it without the clutch in.
So my question is : why do others do that ? Also, is it better for the transmission to leave it in gear ? Can anyone shed some light on this ?

Thanks . . .

NM

notquitekarpov
05-22-2000, 04:50 PM
Certainly the putting the car in gear BEFORE you switch off is a new one on me but one good reason is for an extra level of protection on top of the hand brake. There have been cases of children and even animals left in cars "for only a minute" releasing the hand brake and rolling away into disaster!

One use I have found is when it is VERY cold the hand brake can freeze on - whereas being in gear holds the car just as well without any such risk.

Of course you have to remember to take it out of gear before you start up again or you look really uncool!

Diver
05-22-2000, 04:51 PM
So it won't roll away if your parking brake fails.
I leave mine in reverse.

NothingMan
05-22-2000, 04:55 PM
Let me re-phrase one thing :
I am not certain that the others who drive the car actually put in into gear before parking, I only know it is in gear when I go to start it next.
I made an assuption, perhaps a wrong one.

The point is : why leave the car in gear when it is off and parked ?

BobT
05-22-2000, 04:58 PM
I was taught always to put the car in gear after you parked and set the brake for the same reasons as mentioned above.

LouisB
05-22-2000, 05:42 PM
Putting a standard shift into 1st or reverse after parking is second nature to me---and to others who learned to drive with stick shifts. It serves the same purpose as putting an automatic into park. Engaging the clutch before starting is also second nature. If you propose to stay with stick shifts, I strongly encourage you to develop those two habits.

UncaStuart
05-22-2000, 06:32 PM
Implicit in the replies--but which may need to be made explicit--is that the car engine with the ignition turned off will act as a compressor. If the hand brake were not set firmly, but if the transmission were in gear so that movement of the wheels would translate into movement of the crankshaft, the compression of air in the cylinders would prevent the car from moving farther than it took to build up enough back pressure. All bets are off if it is a diesel-powered car, however.

handy
05-22-2000, 06:49 PM
I do that, its better than using the hand brake. Also, most modern cars you have to push in the clutch to start them...

Vestal Blue
05-22-2000, 07:08 PM
Uncastuart: Great reply!

It works for diesels as well. In fact, better, as they have much higher compression than comparable gasoline engines.

As for my vehicles, I apply the parking brake first, and then put it in gear. This allows the safety-net of it being in gear, without loading up the gear train.

I always push in the clutch prior to starting.

voltaire
05-22-2000, 07:19 PM
In fact, when the aforesaid do leave the car in gear, it bucks like a stallion when I try to start it without the clutch in.


Regardless of your habit of not leaving the transmission in gear, you should ALWAYS have the clutch in when you are starting the car. Not doing so leaves open the possibility of accidents and mishaps. So why not do it? Same thing goes for leaving it in gear in the first place, it's an extra precaution that doesn't cause any extra wear and may just some day save your ass. I've seen cars roll away by themselves in parking lots too often not to do it.

BTW, my car doesn't give me a choice, you must have the clutch in for the ignition to work. But even if it didn't force me, I would still do it.

Strider
05-22-2000, 07:47 PM
I thought my family was the only one to do this. My GF does not put her car in gear when she parks, two of my friends do not, and when I take my baby to get an oil change or something like that, the service men never leave it in gear. My baby is a 1985 Honda Prelude with 290+ thousand miles on it and for all 290+ thousand miles that car has been parked in gear and the ONLY piece of equipment to ever be replaced on that was was the clutch and the water pump. So I would have to say that parking it in gear does not do any kind of damage to the car, or if it does, it is very slight.

That said, I just want to point out that I am the only person I know who does this, and I am the only person I know who has a functional e-brake. Everyone I know who parks using the e-brake has a worn out e-brake. My GF has has to replace her e-brake once already and her car only has 75K on it. Another benefit to parking in gear...

-N

Coldfire
05-22-2000, 07:54 PM
Handy said:

I do that, its better than using the hand brake. Also, most modern cars you have to push in the clutch to start them...


Really? None of the (predominantly European) cars I have driven ever required a pressed down clutch in order to start. Is this an American thing?

I always use first gear and the handbrake, unless it is freezing. Then I only use first gear.

RonaldBarnhardt
05-22-2000, 08:11 PM
I was taught to leave the car in second gear if you're pointing uphill and reverse if you're pointed downhill in addition to setting the parking brake.

Most newer cars require you to engage the clutch before the vehicle will start. I guess too many folks got squished against the garage wall while waving goodbye to their SO in the morning as they started their car in first gear.

brad_d
05-22-2000, 08:26 PM
I was taught to leave the car in second gear if you're pointing uphill and reverse if you're pointed downhill in addition to setting the parking brake.


I've heard that, too, and my question has always been: Why 2nd gear rather than 1st?

I set the parking brake on my truck, and leave it in 1st (pointing uphill or on level) or Reverse (pointing downhill).

Actually, when I think about it, it's not clear to me that distinguishing forward and reverse gears for this purpose matters.

Or, if it does, might conventional wisdom have it backwards? If your car is rolling forwards, would having the engine turning forwards or backwards be a better compression brake? Or does it matter?

Coldfire
05-22-2000, 08:51 PM
It doesn't matter, for the reasons UncaStuart pointed out: which direction the pistons will be forced is irrelevant. The (lack of) compression will still keep the car in place.

gEEk
05-22-2000, 09:36 PM
I was taught to leave the car in second gear if you're pointing uphill and reverse if you're pointed downhill in addition to setting the parking brake.


Actually, I think this is backwards.

I would think that you would want to be in a forward gear if pointed downhill and reverse if pointed uphill. This way, if the parking brake fails and the car begins to roll, the engine will be trying to turn in the "correct" direction.

I think that the reason for this is because of the timing belt/chain that drives the camshaft/valves. Tension is very important here and turning the engine in reverse would remove the preload from the belt. Next time you tried to start the car, the belt/chain would be slightly slack and would suffer a significant jolt when first cranked. This could weaken or even break the timing chain or belt and result in major engine damage (if the engine happened to be of the interference type, i.e. most older Hondas).

Just a semi-informed WAG.

gEEk

AWB
05-22-2000, 10:01 PM
RonaldBarnhardt:
I was taught to leave the car in second gear if you're pointing uphill and reverse if you're pointed downhill in addition to setting the parking brake.

gEEk: Actually, I think this is backwards.
I would think that you would want to be in a forward gear if pointed downhill and reverse if pointed uphill. This way, if the parking brake fails and the car begins to roll, the engine will be trying to turn in the "correct" direction.

Actually, gEEk, Ron was right. If your car is parked pointing downhill, you want to be in reverse because the engine will be torqued in the direction opposite of its natural direction. This is what provides the extra "braking".

There's also the issue of turning the front wheels when parallel parking on a hill. If pointed downhill, always turn toward the curb or shoulder, whether left or right parallel parking. But if you're pointed uphill, turn toward the shoulder if there's no raised curb, but away from the curb if it's raised.

brad_d
05-22-2000, 11:16 PM
AWB:
Actually, gEEk, Ron was right. If your car is parked pointing downhill, you want to be in reverse because the engine will be torqued in the direction opposite of its natural direction. This is what provides the extra "braking".


Well, I've been thinking about this a bit since I last posted, and it seems to me that it shouldn't matter - at least to first order.

If, as the car rolls away after parking brake failure, the engine is being turned in the "correct" direction, then the cylinder(s) on the compression stroke will be the source of the braking - the piston will be moving up, and both valves will be closed.

Actually, you might get some help from the vacuum being pulled in any cylinders on the power stroke. Both valves are closed, and the piston is moving down. The force you get won't be as great in this one, though, so it's probably not enough to worry about. (I can explain my thinking here, to let people critique it, if anybody wants.)

If the engine is being turned "backwards", you have the situations reversed: the power stroke, done backwards, will be the same as the compression stroke done forwards. Piston moving up in the cylinder, and both valves closed. Same with the (I think negligible) backwards compression stroke.

Does this sound reasonable?

The only difference that I can see is the the timing of the valves tends not to be symmetric about TDC and BDC, which would cause some differences depending on which way you're turning. No matter what, though, the valves are closed for much of the compression and power strokes, so the differences are probably minor - the only differences are details at the ends.

Given that the engine is, in principle, being stopped by this, it won't reach the end of a stroke to find out, right? :)

gEEk's comments about the timing belt/chain make sense, and there might be something to it. I'm not enough of a mechanic to be able to tell right off.

Spiny Norman
05-23-2000, 01:20 AM
While geting my truck driver's license in the Army, we were instructed (well, ordered) NEVER to park a diesel truck in gear. When I asked why, I was told that since a diesel engine is in effect a closed system - it doesn't rely on any electrical components for its operation - a brake failure might make the truck roll, activating the (mechanical) fuel pump, starting the engine and making the unmanned truck roll like a juggernaut through the barracks.

I guess it's theoretically possible (and it was pretty enjoyable to imagine, back then), but has anyone heard of this ever happening IRL? I know it's not feasible on a modern diesel (the fuel valve is electromagnetic, for one thing), but some of these trucks were from the Korean War era.

gEEk
05-23-2000, 07:48 AM
AWB said:

Actually, gEEk, Ron was right. If your car is parked pointing downhill, you want to be in reverse because the engine will be torqued in the direction opposite of its natural direction. This is what provides the extra "braking".


I'm at a loss as to why turning the engine in the opposite direction would result in any additional braking force. Assuming the only braking torque results from compression, the air inside the cylinder does not care what direction the engine is turning.

I've turned engines by hand both forward and backward and haven't noticed a difference in effort required. In both cases you can feel the resistance increase as one of the pistons moves up in it's compression stroke.

I'm gonna stay by my original contention that if it matters at all, the only logical preference would be to ensure that the engine will only turn in the normal direction.

Spiny Norman said:

While geting my truck driver's license in the Army, we were instructed (well, ordered) NEVER to park a diesel truck in gear. When I asked why, I was told that since a diesel engine is in effect a closed system - it doesn't rely on any electrical components for its operation - a brake failure might make the truck roll, activating the (mechanical) fuel pump, starting the engine and making the unmanned truck roll like a juggernaut through the barracks.


I can definitely see this happening on older diesels without complex controls. Especially when warm, the engine would not need the help of the glow plugs to ignite the air/fuel mixture. Assuming that merely turning the engine would cause the fuel injectors to fire (quite possible in an older, mechanical setup), I think it is possible that the engine would start.

Heck, I've counted on the ability of an engine to start by rolling the car many times. The ability to start the car when the battery is dead is one of the (many) reasons I prefer manuals to automatics.

Coldfire
05-23-2000, 07:55 AM
Older diesels need to be "warmed up" before you can start them. Some models today even require a waiting period of up to 10 seconds with the ignition on "ON" before switching to "START". I reckon this is to heat up some sort of (pre-) ignition. Usually, there is a symbol visible in the form of a dashbaord light that looks somewhat like the wire inside a light bulb. I remember older cars (70's diesels) that had to be warmed up like this for over a minute.

So I think it's fair to say that a Korean War army truck will not start automatically. A diesel may not need spark plugs, but it does need an initial spark to get going.

Diver
05-23-2000, 10:30 AM
Coldfire said "A diesel may not need spark plugs, but it does need an initial spark to get going."

That would be a glowplug. Looks sort of like a sparkplug with a resistance coil instead of a spark gap.
A diesel will start without it however. It does make it much easier to start and reduces the already very high load on the battery/starter motor due to the higher compression of a diesel.

Responding to some other comments, it never occurred to me that anyone would start a car with a manual transmission without pushing the clutch down.
Maybe people today aren't all that familiar with manual transmissions due to the popularity of the automatic.

handy
05-23-2000, 11:46 AM
'Really? None of the (predominantly European) cars I have driven ever required a pressed down clutch
in order to start. Is this an American thing? '

Yep, its a USA safety feature......

handy
05-23-2000, 11:50 AM
BTW, I have seen a few rolling with the hand brake on but never one in gear. [on a steep slope it might roll a little bit].

Una Persson
05-23-2000, 01:05 PM
BTW, I have seen a few rolling with the hand brake on but never one in gear. [on a steep slope it might roll a little bit].

I have, when the hill was steep enough and compression low enough. My 1979 Honda Civic could not hold itself on a steep hill by the engine resistance alone - it would start "humping" down the hill. I think it only had 7.5:1 compression when new, and it had nerly 400,000 miles on it when the body broke (that's right - the engine ran great, but the body physically broke in two from rust and wear such that you could no longer open or shut the doors).

Tedster
06-14-2000, 08:24 AM
I never use my "parking" brake, it's just become habit to leave it in first gear. This is especially important in cold, wet sub-freezing weather (for obvious reasons) and when parking for long term-- several weeks or more.

Mousseduck
06-14-2000, 09:00 AM
This is a little off the original subject, but still related to manuals. I was taught to put a car in neutral and start it that way, with my foot off the clutch. Anyone else do it that way? I also park in gear, with the handbrake.

Gatsby
06-14-2000, 09:25 AM
Mousseduck,

I've always started in neutral as well. For the hell of it, I just pulled out my owner's manual and this is in fact the way Subaru recommends starting my ('88) vehicle.

I'm sure by now they have made it necessary to engage the clutch as a safety feature, at least on US imports.

The way I see it, the less you have the clutch engaged, the longer it will last.

Coldfire
06-14-2000, 09:35 AM
True, Gatsby, although the wear on the clutch from being engaged whilst starting would be negligable when compared to the wear of a gear change or, worse, acceleration from 0 in first gear.

Mousseduck
06-14-2000, 09:43 AM
Coldfire

I think that may be true, but it must depend on how you drive. I start in neutral because I would never accelerate with the clutch fully engaged, whether changing gears or from a standstill. I always lift the clutch up to the point where the car wants to move forward (like autos do)before I accelerate because it is better for the clutch. So I think starting a car with the clutch in (especially with an old car that usually needs a bit of acceleration to even think about starting) would be quite damaging.

Sorry about the hijack, Nothingman.

Gatsby
06-14-2000, 10:26 AM
I agree with you, Coldfire, it probably doesn't make a whole helluva lot of difference either way. My point was that starting the car with the clutch in is not the only "correct" way as posted above.

handy
06-14-2000, 04:09 PM
One of the things I learned in driving school in high school was how to use the hand brake as a backup brake when you are driving down the street. It's something you almost never see in films where someone is going real fast down some slope cause they can't use the pedal. Idiots.

justwannano
06-14-2000, 04:28 PM
Dad said that the hand brake on the old cars would sometimes pop off.

It was a safety thing.

It is probably a habit thing now days.

I know that I sometimes feel undressed if I don't leave mine in gear. Sort of a ritual I go through.

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