A Dual Mass Flywheel dampens engine vibrations and prevents them from being transmitted to the passenger compartment via the transmission and shift linkage.
This type of flywheel setup is often found in high-performance and diesel-powered engines.
A dual mass flywheel has two separate flywheels that come with their own damper springs, friction material, and ball bearings, which allow them to move independently.
By allowing some sort of movement to exist between the two flywheels, the damper is able to absorb engine torque peaks and normal vibration, resulting in a smooth drivetrain operation.
In a dual mass flywheel setup, the two flywheels twist out of phase by as much as 60 degrees. This is what allows the system to absorb torsional oscillations.
The entire damper assembly in a dual mass flywheel is completely sealed.
The Flywheel Explained
A flywheel is a heavy plate that helps create inertia. As the crankshaft speeds up while a cylinder fires, internal engine friction causes the crankshaft to slow down while waiting for the cylinder to fire again.
The flywheel provides inertia to help the crankshaft maintain a constant speed.
It also plays a part in absorbing heat due to clutch operation by acting as a heat sink for the clutch friction disc.
Generally, the four major roles of a flywheel include:
- Smooth out or dampen engine power pulses
- Absorb heat from clutch operation
- Create a connection point that permits the starter motor to crank the engine
- Serve as an application surface for the clutch friction disc
Dual Mass vs. Single Mass Flywheel
Aside from the number of flywheels, there are other ways to differentiate a single mass from a dual mass flywheel.
Efficiency
While a single mass flywheel is great for quicker engine revving and frequent gear changes, it’s not as effective as a dual mass flywheel when it comes to reducing noise and vibrations.
In addition, having a dual mass flywheel allows for smoother engine operation, improving overall fuel economy.
Application
As mentioned, large vehicles with diesel engines and a manual transmission usually have a dual mass flywheel setup. There are, however, some petrol cars that also come with dual mass flywheels.
Meanwhile, single mass flywheels are usually found in racing engines and off-road vehicles.
Durability
Both flywheel setups are equally durable, but a single mass flywheel has a bit of an advantage.
A single mass flywheel has a greater thermal and warp resistance than a dual mass flywheel. Also, a single mass flywheel can be resurfaced when needed, so it has a longer service life than its counterpart.
In the case of a dual mass flywheel, its hollow design makes it more susceptible to heat-related warping than a single mass flywheel.
Cost
Given the complex design of a dual mass flywheel, it can be quite expensive to replace. You’ll also need to replace the entire assembly, unlike a single mass flywheel.
Bad Flywheel Symptoms
In the case of a damaged dual mass flywheel, symptoms are often likened to a slipping clutch. Once the torque-limiting friction material connecting the primary and secondary flywheels fail, you’ll need to replace the entire assembly.
Here are some of the other signs of a bad flywheel.
Gear Trouble
A slipping flywheel means the gears are slipping, too. A rapid increase in engine speed without an increase in ground speed when shifting gears is a telltale sign of slippage.
A damaged flywheel can also make it difficult for you to switch gears. If left unaddressed, you might not even get out of the driveway.
Burning Smell
If the flywheel’s friction surface gets contaminated, you might get a whiff of something burning in your vehicle. This can also be caused by excessive friction in the clutch.
Excessive Vibration
Reducing vibrations is one of the main responsibilities of the flywheel, regardless of whether it’s a single or dual mass type.
So if you notice that your vehicle is getting more uncomfortable to drive in due to vibrations felt all over the cabin, it might be time to replace your flywheel.
The flywheel is bound to wear out after some time, resulting in discoloration, hairline cracks, or even smeared metal on its surface.
What Causes a Flywheel to Wear Out?
Aside from age, other factors can cause the flywheel to wear out faster than its intended service life.
Contamination
Oil or grease contamination can significantly reduce a flywheel’s efficiency, as it can cause the flywheel and clutch to slip.
Improper Installation
Misalignment, imbalance, and inadequate torque can negatively impact the flywheel’s performance.
To avoid these issues, it’s best to leave flywheel replacement at the hands of an experienced professional. Flywheel replacement might not be the easiest task for an average DIYer, and doing it poorly can result in more issues down the road.
Overheating
The flywheel can only endure so much. Poor driving practices and car maintenance can accelerate wear on several components, causing the engine to overheat.
When this happens, the flywheel can warp under extreme heat and develop cracks on the surface.
Keep Reading: Related Posts
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.
