Fellow stick shifters, I have a mechanical advantage related question for you all! I have a 2006 Toyota Corolla with a 5 speed transmission. I learned a while ago that I could start the car when rolling down a hill (or if I have a strong enough assistant) if my battery is dead or weak. When I was reviewing the technique, I read some comments saying that I should use 2nd gear or higher instead of 1st gear when I go to pop the clutch and start the engine. Why is that? What is the logic behind choosing a higher gear?
Thanks!
learned a while ago that I could start the car when rolling down a hill (or if I have a strong enough assistant) if my battery is dead or weak.
Dead batteries won't make the engine run by push starting it. Modern cars need power to fire the spark plugs. It can be done with a weak battery if the alternator is still good, though. Popping the clutch into gear while rolling forces the engine to turn, only instead of the engine turning the transmission, the transmission is spinning the engine. The car itself becomes the starter. There's a physical connection between the manual transmission and engine, as opposed to the automatic's fluid-filled torque converter. You couldn't push start an automatic, as a result.
I would assume there's slightly less rolling resistance in 2nd gear than in 1st gear. You can get slightly less torque in exchange for a little more speed and still have enough mechanical advantage to push-start the engine. There's a combination of speed and torque that must be enough to start the engine, and higher gears mean less torque is supplied in exchange for speed.
It's similar to a running standard Transmission at idle, not going anywhere. If you put the transmission in the highest gear possible, you won't really go anywhere and you'll start burning up the clutch.
I read some comments saying that I should use 2nd gear or higher instead of 1st gear when I go to pop the clutch and start the engine. Why is that?
The gear reduction just makes it easier to overcome the pressure in the cylinders
I’ve always learned it as push starting in second gear. I don’t really know why. That’s just how I was taught. My guess is that it balances ease of pushing the car, with the power needed to crank the engine.
