Dual Mass Flywheels

-westy-

-westy-

-westy-

Soldato
Joined
7 Nov 2002
Posts
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Location
Snorbans, UK
Hello,

At the risk of sounding a bit thick, what exactly are Dual Mass Flywheels, and how do they differ from a normal flywheel? I know what a flywheel does, I'm just a bit curious about a 'dual mass' one, and what purpose it serves.

Thanks :)
 
The flywheel is effectively a weight which is fastened to the end of the crankshaft of the engine. The power from the pistons tends to be created in ?pulses? and the weight of the flywheel smoothes out these pulses by providing inertia to the rotating engine. As well as providing a weight the flywheel has a gear around its circumference on which the starter motor operates and is a convenient means of attaching the clutch which provides a variable connection to the transmission.

Modern diesel engines generate high torque and as a result they need extra smoothing out or ?damping?. To help with this process a DMF (Dual Mass Flywheel) is fitted. This is effectively two flywheels that transmit the drive through a number of springs which cushion the drive to the transmission
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First return from Google after entering "Dual Mass Flywheel" ;)
 
It's primary purpose appears to be going wrong and costing the owner a fortune to replace.
 
Lopéz said:
It's primary purpose appears to be going wrong and costing the owner a fortune to replace.
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Lol £665 for mine and a clutch this week for the vectra indeed their main job is to make life as difficult and expensive as possible
 
It's essentially a mechanical filter that smooths out rapid speed fluctuations in the crankshaft to reduce drive train noise and vibration. Two flywheels sit one on top of the other, one is bolted directly to the crankshaft and the second is loosely coupled to the first and driven via large springs.
 
So does the Mondeo at 58k, touch wood.

Is there a key to maximising their life? Smoothness and mechanical sympathy is always one of my priorities when driving really, so I'm hoping that helps :p
 
Howard said:
So does the Mondeo at 58k, touch wood.

Is there a key to maximising their life? Smoothness and mechanical sympathy is always one of my priorities when driving really, so I'm hoping that helps :p
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In the diesels the killer is people driving at too low an engine speed. Because they smooth out a lot of the juddering you might get by labouring the engine, a lot of people don't bother changing down at times which knackers the dmf
 
You can get solid flywheel replacement kits from valeo and a couple of other sources which are much cheaper but I here rumblings that the extra 'shock' into the transmission can wear out the gearboxes at a much quicker rate.
 
monkey_boy said:
Awesome smugness but, don't petrol engines have DMFs too? I thought they just weren't as vulnerable because petrols don't have the same level of torque.
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Smugness has sod all to do with it. It just amazes me that people don't use google for such simple questions.

And yes,some petrols have them also. :)
 
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