1

Handbrake is off all this time.

I read/heard that while in complete stop or idle, when car is in neutral, there is RPM around 800 RPM.

  1. Does that mean the flywheel (which is connected to the engine) rotates at 800 revolution per minute while in neutral?

  2. If so, how come it is safe to fully release the clutch while in neutral?

  3. If I fully release the clutch (while in neutral), then the clutch disk (which is connected to the wheels) and the flywheel (which is connected to the engine) will engage together, right?

  4. Why isn't the car moving even though flywheel and clutch disk are engaged (since I fully release the clutch), and there is a rotation of 800 RPM?

Improve this question

3 Answers 3

Reset to default
2
  1. Does that mean the flywheel (which is connected to the engine) rotates at 800 revolution per minute while in neutral?

Yes. The flywheel is directly connected to the engine so it will rotate at exactly the same speed as the engine.

  1. If so, how come it is safe to fully release the clutch while in neutral?

During normal running operation (going down the road), the transmission allows power to be transmitted from the engine to the drive wheels. When in neutral, there is no power transmission. The input shaft (which is connected to the clutch plate [aka: friction disk], which is connected via the pressure plate to the flywheel) is allow to spin freely. The input shaft is not directly connected through gearing in the transmission to the output shaft.

  1. if I fully release the clutch (while in neutral), then the clutch disk (which is connected to the wheels) and the flywheel (which is connected to the engine) will engage together, right?

When the transmission is in neutral, the clutch disk isn't connect to the wheels. But yes, when you release the clutch pedal, the friction disk, pressure plate, and flywheel (in essence) become a single unit and spin together at the same rate. This is regardless of what gear you're in.

  1. Why isn't the car moving even though flywheel and clutch disk are engaged (since I fully release the clutch), and there is a rotation of 800 RPM?

Because when the transmission is in neutral, there's no power being transmitted. Without power transmission, there is no vehicular movement.

What this all boils down to is this ... you have an incomplete understanding of how a transmission works. It doesn't matter if it's a manual or automatic transmission ... if the transmission is in neutral (or even park for an auto), the vehicle isn't going to move via power output of the engine (it can roll if gravity has it's way, no doubt). There's no way for the power to get to the wheels.

Improve this answer
2
  • 1
    The last paragraph : very good, especially gravity...
    – Solar Mike
    Commented Apr 1, 2019 at 20:18
  • Neutral means, No Go!
    – Moab
    Commented Apr 6, 2019 at 0:55
0

Because neutral means none of the gears (1 to 5 or 6 plus reverse) are engaged so no drive to the driving wheels...

Improve this answer
0

At idle in neutral, the engine is rotating at idle speed (which is indeed around 800rpm, but does vary in different cars), and so yes, the flywheel is also rotating at that speed. However, when you are in neutral, the input and output shafts of the gearbox are not connected together - they're only connected when you engage a gear.

This means that you can safely release the clutch, as this causes the clutch disc and gearbox input shaft to rotate at engine speed, but not the output shaft or wheels, as they're not connected.

Improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .