Flywheels

What is a flywheel?

A flywheel is a heavy metal disc that helps to balance and smooth out the rotation of the engines crankshaft. The heavy nature of this metal disc also helps to keep the engine running when the accelerator is released. The flywheel is also instrumental in starting the engine. The starter motor connects to the teeth of the flywheel to initiate the starting process.

There are two types of flywheel. These are:

• Dual mass flywheel (also known as twin mass flywheel)

• Single mass flywheel (also known as solid mass flywheel)

What comes with a flywheel?

Flywheels are sometimes sold as part of a clutch kit however if ordering the flywheel on its own the only parts that are sometimes included are the flywheel bolts. These are also known as a flywheel screw set.

The parts notes will say if the flywheel bolts (screw set) is included. It is good practice to change the flywheel bolts at the same time as these are stretch bolts which are fitted to the required torque setting to prevent over tightening and damage while fitting.

How do I choose the correct flywheel?

Replacing the flywheel is often a time consuming task and an expensive one too. It is crucial that the flywheel is the correct one so as not to loose time or incur additional cost. If you can obtain the original manufacturer (OE) part number and compare it to the replacement part then that is one of the best ways to get the correct one.

If you are not able to obtain the OE part number here are some factors to help you choose the correct part:

• Number of gears (i.e. 5 speed or 6 speed etc)

• Manual or semi or fully automatic

• Transmission type / transmission code

• Dual or single mass flywheel

• Brand of the original clutch or flywheel. Sometimes the brand of the flywheel needs to match the brand of the clutch

• Vehicle manufacture date (this is not the date the vehicle was registered but the date it was made

• Engine number sequence (up to or after as specific number/letter

• VIN (chassis number) sequence (up to or after as specific number/letter

What brand of flywheel should I choose?

There are not many aftermarket makers of flywheels so choice is limited. LuK, Sachs, and Valeo manufacture flywheels for the original car makers so these are classed as premium brands. There are a small number of aftermarket brands such as Borg and Beck, Febi and National that offer long warranties which show they have confidence in their flywheels. The choice is often down to availability and budget which is sometimes trumped by manufacturer compatibility restrictions.

How can I tell my flywheel needs replacing?

If you are not sure if your flywheel is faulty then we would always recommend that you have your vehicle inspected by a qualified mechanic to receive an accurate diagnosis. Some of the symptoms of a failing flywheel are:

• ifficulty changing gear

• Vibration while using the clutch

• Clutch makes a clattering sound

• Burning smell from underneath the vehicle

• Clutch slipping

• Clutch not fully engaging

• Engine vibrates - Flywheel not balanced