How reliable is the dual-mass flywheel?

The flywheel, without any exaggeration, can be called the most versatile device. It not only compensates for the unevenness of the crankshaft rotation and transfers torque from the engine to the gearbox, but also untwists the crankshaft during start-up. Smoothing of torque pulsations occurs due to periodic short-term accumulation and subsequent release of kinetic energy. The energy reserve occurs during the working stroke of the piston, and the flow rate in other strokes. At the same time, the more cylinders (and, consequently, the more total running time), the more uniform the torque of this engine, and hence the mass of the flywheel can be smaller.

According to their design, flywheels are of several types. The most common - continuous - is a massive cast-iron disc with a diameter of 30-40 mm with a steel gear notched on its outer side, which ensures, with the help of a starter, cranking the crankshaft during start-up. There is also a two-mass flywheel and lightened. The use of a two-mass flywheel, which includes two disks, allowed to get rid of the installation in the driven clutch disk of the damping device. A lightweight flywheel is usually used when tuning an engine. The reduction of the moment of inertia occurs due to the displacement of the main mass of the flywheel closer to the edges of the disk, as a result of which its mass (up to 1.5 kg) decreases, the dynamic characteristics improve, and the engine power increases (up to 5%).

How is the two-mass flywheel arranged?

This flywheel consists not of one, but of two bodies. The first of them connects directly to the crankshaft and is also the starter's crown. The second housing is the basis for mounting the clutch assembly. Both bodies are connected together by means of sliding bearings (radial and thrust), having an intermediate damping system. The connection device allows them to move relative to each other in the axial direction. From the inside, the dual-mass flywheel is filled with grease, which ensures efficient and proper operation of the spring packs. Packages, in turn, are separated by special plastic separators, which prevent their blockage.

The two-mass flywheel operates in a stepwise manner. Soft springs of the first stage are responsible for starting and stopping the engine. The stiffer springs of the second stage provide dampening of the torsional vibrations during normal driving.

This design is made for more reliable vibration damping, noise reduction, synchronizer wear reduction, engine transmission protection from overloads, gear shifting convenience. At the same time, there is an increased wear of the spring-damper system, usually resulting in a breakdown of the arc spring - the main element of the dual-mass flywheel.

When do I need to change the two-mass flywheel?

Uneven engine operation, vibration and noise at idle speed can cause abnormal operation of the ignition system, plunger pairs, throttle, and other devices and assemblies, including a sign that the two-mass flywheel is faulty. Symptoms that clearly indicate that it's time to replace it are as follows:

• Formation on the surface of cracks;
• Loss of lubricant in the clutch housing;
• It can not be turned in either direction.

Repair of a two-mass flywheel in handicraft conditions is practically impossible, and therefore it usually changes entirely. Although, in some cases, the bulkhead and repair of the flywheel can be cheaper than buying a new one (the minimum price is about $ 500). Another option may be to replace it with an ordinary all-metal - analogous to a two-mass one.

According to experts, for a longer and more reliable operation of the two-mass flywheel it is necessary to observe the elementary rules of operation, namely: for diesel engines designed to work with high torque, do not allow prolonged low-speed operation, and also squeeze the clutch pedal before muffling the engine .