Flywheel construction



 For cars with a manual transmission and long mileage, it is quite possible to have clutch problems. This is often due to a worn or damaged flywheel . The operating mileage of a flywheel is in the range of 200 - 300 thousand kilometers. If this happens at significantly lower mileage, the reasons are several: aggressive driving style, other clutch failures or operating conditions.

What is a flywheel?

This is a metal disk with a diameter of 300 to 400 mm. On its periphery there are teeth with which the adhesion of the pressure disk with the starter and the rotation of the crankshaft when starting the engine. The flywheel is mounted to the crankshaft, and on the other side of it is attached the clutch housing with bolts. It accumulates the kinetic energy of the engine and ensures smooth rotation of the crankshaft. The flywheel participates in the work of:

  • Elbow - the connecting rod mechanism ensuring smooth rotation of the crankshaft.
  • The transmission where the flywheel is the clutch master disk .
  • The gearbox, which ensures the transmission of torque from the starter to the crankshaft, where it performs the function of a drive wheel.

The body of the flywheel is made of cast iron. A steel crown was pressed around its periphery. In order to increase the inertial properties, the flywheel is lighter in the middle and heavier on the periphery.

Types of car flywheels

Depending on the design features, they are divided into:

  • Hard flywheel or single-mass - is a cast iron disc with a pressed ring gear, which ensures engagement with the starter when starting the engine. It is mounted to the crankshaft by means of a flange. On the other side, the clutch housing is bolted to it. The flywheel is the leading disk of the clutch.
  • Lightweight flywheel - typical for tuned engines. It is significantly lighter than the standard up to 1.5 times. This helps the engine accelerate faster, which improves the car's dynamics and increases its power by up to 7%. For the production of lightweight flywheels use wear-resistant alloys that can withstand high loads. Its advantages are in the silent, fast and efficient work.
  • Dual mass or damper flywheel - made of two discs with damping springs between them. It has many advantages over the hard flywheel:
    • Eliminates crankshaft vibrations.
    • Protects the transmission from overload.
    • Reduces wear on synchronizing parts.
    • Provides easy and smooth gear shifting.
    • Reduces fuel consumption.

    The disadvantage is the more frequent damage to it, due to the high load. The most common reasons are:

    • Mechanical overloads or incorrect operation of the clutch can lead to abrasion of one of the flywheel discs, which leads to the destruction of internal parts.
    • A damaged axial bearing between the clutch discs leads to overheating of one of the discs and damage to the flywheel.
    • Improperly installed parts can lead to blocking of the flywheel and loss of its damping characteristics.

Why change the flywheel?

During the operation of the car, the teeth of the flywheel ring and its working surface wear out. This most often occurs when driving aggressively, driving with the clutch pedal depressed and sudden starts from a standstill. Vibration, slippage and noise occur during engine operation. This can lead to accidents. The flywheel must be replaced at:

  • Side noise with engine running.
  • At high mileage of the car.
  • With frequent change of parts on the clutch.
  • In case of natural flywheel wear during operation.

Signs of a flywheel malfunction appear when the engine is started and stopped.

Flywheel symptoms and elimination

  • Worn or damaged flywheel teeth are due to:
    • particles entering the housing
    • damaged starter
    • incorrect mounting of the starter to the flywheel
    • worn gear ring as a result of operation

    These faults are rectified by replacing the ring gear, diagnosing and repairing the starter and properly mounting it to the flywheel housing.

  • The beating of the flywheel occurs when the engine is running and:
    • worn or damaged clutch parts
    • clutch slip
    • incorrect installation when replacing coupling parts.

    To eliminate the beating, a diagnosis is made to determine the location of the beating. When beating is minimal, the flywheel can be scraped on a lathe. At higher beats, the flywheel changes. It is mandatory to diagnose and repair the clutch to eliminate the causes of the beating. The clutch is mounted on the flywheel with the prescribed tightening force of the bolts by means of a torque wrench.

  • Damaged working surface of the flywheel is observed in:
    • worn ferro disk or other clutch failure
    • clutch slip
    • high mileage of the car
    • incorrect coupling installation

    If the work surface is damaged, the flywheel must be replaced. It is mandatory to diagnose the clutch and, if necessary, repair it.

  • Flywheel bed breakage to the crankshaft occurs when:
    • high mileage of the car
    • incorrect installation 

    Removal is done by changing the flywheel. Inspection of the crankshaft and, if necessary, its replacement. Remove and install the flywheel to the crankshaft. Tighten the flywheel bolts to the crankshaft with the required force.

  • Broken holes for attaching the clutch housing to the flywheel:
    • in case of incorrect installation
    • if the vehicle has a long run, it is possible to loosen the bolts and wear the holes

    To eliminate this fault, it is necessary to replace the flywheel or, if possible, cut a new thread. Be sure to check the correct installation and balance the flywheel. Balancing the flywheel with the crankshaft and clutch ensures that they work in synchrony and guarantees a long service life.

  • Signs of a worn damping flywheel :
    • squeaking when starting and stopping the engine
    • occurrence of vibrations that disappear at high speeds
    • scraping sound of metal when shifting gears

    If necessary, repair the damper flywheel . Defective springs can be replaced. In the event of a more serious damage, the flywheel must be replaced.

If flywheel needs to be replaced

Flywheel replacement and repair are complex manipulations that are best performed by qualified auto mechanics at a garage. To replace the flywheel it is necessary to remove the gearbox, the clutch and to fix the crankshaft. In addition, clutch and flywheel diagnostics are mandatory. The installation itself must be carried out technologically correctly, observing the instructions of the manufacturer of the respective car. Improper installation can lead to rapid wear of systems and accidents and loss of considerable resources, nerves and time.

Comments

Popular Posts