Maximising the service Life of dual mass flywheels
Sachs Recommend the following steps to maximise the service life of Dual Mass Flywheels.
The Dual Mass Flywheel (DMF) is designed to dampen engine vibrations within certain pre-determined
ranges for each vehicle type. DMFs are required on modern engines in order to cope with the increased
vibrational characteristics generated by these new engines. Conventional torsion dampers, which are
traditionally incorporated into the driven plate, cannot cope with these increased demands.
On modern engine designs peak torque levels are achieved at lower engine revs. This assists with
reducing fuel consumption and vehicle emissions, but also increases the vibrations generated by the
engine. These vibrations must be isolated from the vehicle transmission in order to prevent noise and
potential damage.
Anything altering these vibrational frequencies and forcing the DMF to operate outside of its design
parameters, may damage the flywheel and shorten its service life. It is therefore vital that the relevant
vehicle systems are checked for correct function and operation BEFORE a new DMF is installed. Some
commonly identified problems are listed below. These faults are more likely to occur in vehicles with high
mileage. The faults detailed below can in themselves be responsible for vibration and noise during the
operation of the vehicle. It should not be assumed that the noise and vibration are being caused by a
defective DMF. It should be noted that a clutch using a traditional torsion damper set up can also be
affected by these issues.
Engine
1. Consider engine fault or flash codes
2. Consider engine camshaft wear
3. Consider the correct operation of fuel injectors and associated wiring harnesses
4. Consider excessive crankshaft end float or lift
5. Consider crankshaft damper damage and operation
6. Consider the function and correct operation of EGR valves
7. Consider the function and correct operation of swirl valves and actuators
8. Consider the condition of turbo boost hoses and pipes
9. Chip tuning and other performance enhancements carried out on vehicles fitted with
DMF can alter the engines vibrational characteristics. This may damage the DMF and shorten
its service life
Gearbox
10. Consider wear on the gearbox input shaft and associated bearings
General
11. Confirm DMF is correct for application by engine code
12. Do not allow vehicle to idle for long periods to run air conditioning or heating
13. Consider battery condition and cold cranking performance
14. Consider the Operation of Torque Limiting Valves and Frequency Modulators
15. Consider the Condition of Hydraulic systems and cleanliness of hydraulic fluid
16. Avoid incorrect driving techniques, such as pulling away in high gear with low engine revs,
frequent stalling of the engine or driving in a gear that is too high
17. Make sure that the correct tooling is used to install the clutch and DMF. Using the
recommended specialist tools will ensure that the units are installed without causing
damage to the components. Always use the correct tightening torque and tightening sequence
18. Do not use high pressure cleaners, steam jets, cleaning sprays or compressed air when
cleaning the DMF. Cleaning of the DMF contact surfaces should be carried out using a clean
oil free cloth and a suitable solvent.
If vehicle systems are performing correctly this will ensure a prolonged service life for the
Dual Mass Flywheel.
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