Dual Mass Flywheel - Design & Operation

Let AutoMate set the story straight about Dual Mass Flywheels.
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[@1961UK]

I have been driving cars for 40yrs and have never had a clutch break up or the gearbox failing due to a single mass flywheel. The company's that are producing DMF's are making a killing financially due to the DMF's failing accross the globe on modern cars. Its all about money nothing to do with ''engine harmonics'' . DMF's are so damn expensive considering there designed to fail at low mileage.

[@novi0974]

.... same goes for the clutch pulley on modern alternators ..

[@1961UK]

@@novi0974 I agree had change a couple of those due to lock up.

[@goaway6786]

#welditup

[@SH3RIFF187]

Everyone needs to make some cash somewhere. The service and parts departments in a dealership are it’s bread and butter to an extent.

[@agt155]

Cars 40yrs ago had piss all torque compared to modern Diesels - that is why DMF's are required.

[@borhanosmanvolmerk3029]

We have been manufacturing single mass flywheel and clutch kit since 2010 in Turkey. You know single mass flywheel is more economical and more comfortable than dual mass flywheel. We export to many countries over of the World. VOLMERK FLYWHEEL

[@CyclicCollective]

My Nissan X-Trail T31 2.5 petrol runs a single mass flywheel, don't know what brand but the improvement is massive. Occasionally if moving away up a steep hill it pays to change to second gear slightly later than the DMF would allow or the SMF will allow a slight oscillation from the drive, otherwise everything is improved.

[@RGV2300]

I remember the time when a clutch repair man recommended me to weld the DMF. The result: it felt exactly the same as before, driving was comfy.

[@Rick-tm3vs]

Outstanding video

[@CyclicCollective]

Good presentation. These might be good in some situations but I drove 230,000km on DMF Nissan X-Trail 2.5 petrol and the clutch was terrible. It tended to shudder on take up and also made a terrible sound if blipping the throttle on down-shift. The DMF was bad but overall the car was still pretty good and I replaced it with another car the same, after a head on collision write off, that already had a solid flywheel/clutch replacement. The improvement is miraculous: smooth take off's and smooth double clutch down-shists but the engine does oscillate if accelerating under high torque at low revs so I use a lower gear in these situations which are very rare. The cabin noise is supposed to be higher but I don't perceive any difference but the power certainly feels more direct and the car feels sporty. Exedy do solid fly wheel conversions for many cars so if you do need a new clutch I would say consider ditching the DMF system. As for Diesels, I don't drive diesel cars but the Kenworth 18 speed and Volvo 14 speed prime movers I have driven have solid clutches and they are necessary for down-shifting.

[@nagec1]

Oh..of kors it isf vw,the pioneer of dual mass fl. failier.

[@Mrfarmboy553]

Is it possible for there to be separation in the DMF? I have a 04 Jetta TDI manual that shudders when I let the clutch out from a dead stop in first gear. There seems to be lots of clutch left though as it engages early. All other gears shift normally.

[@caseyrevoir]

The surface of the flywheel meeting the clutch disc is probably warped, and or pressure plate. This can really get a shudder/wobble in everything resembling a shopping cart caster on a joyride. (This same shudder thing happens with solid flywheels) The pulse of the momentum let's everything 'slop' back and forth, getting a Tacoma Bride collapse thing going on.

[@danssv8]

I got a dual mass flywheel in my 2008 Mitsubishi pajero and unknowingly thought it was my clutch plate that slipped at 280 000 kilometres. To my surprise it was the dual mass flywheel that was buggered and not the clutch. Also I thought it was the main crankshaft seal that was leaking and no it was graphite grease black grease that actually came out of the two part flywheel at the centre between the two part flywheel. Nothing wrong with clutch kit or main seal on engine. Further inspection I could rotate the flywheel without the engine turning , now had to replace the flywheel as well and not just the clutch kit. I'll go back to single mass flywheel so I don't have to worry about changing another flywheel lol. What was the engineer thinking???. Old cars drove just fine with a one solid cast flywheel and the don't pack up like a stupid dual mass that's made to break. My advice is go the old school single mass lol.

[@danssv8]

Moral of the story dual mass flywheel (dmf) is a two part flywheel that will break on you it's just a matter of time , mine broke at 280 000 kilometres on a 2008 Mitsubishi pajero. I'm going back to the old school stuff where they were made to last and now going back to a single mass flywheel (smf) . The 2009 models came with a single mass flywheel , that's the way to go .

[@caseyrevoir]

In slow revving diesels pickups the gear noise from a solid flywheel decreases MPG's by causing a lower gear to be chosen to eliminate the noise with a higher RPM. 2,500 RPM can be approaching redline in some applications.

[@firstlast2268]

Yup old 7.3s F series

[@86angrybees]

@@firstlast2268 get rid of the limiter and put heavy springs in that sucker and you got a powerhouse. Screaming at 3 grand

[@justjoe5373]

Is that with automatic transmission? With manual the rule is drive the car in the lowest RPM without the engine choking so if you can drive it 3rd gear low RPM or 2nd gear med-high RPM you choose the 3rd. Also I've never had any experiences with trucks, only your "normal" everyday cars

[@fierakuitali9313]

I have some bearing noise . When I press and release the clutch come out this noise. Can this bearing cause other issue or can drive it

[@eugeneoreilly9356]

It's the clutch release bearing.Clutch kits come with new bearing.Never replace these two components individually,only as a set.

[@eugeneoreilly9356]

Those damping springs have a nasty habit of breaking.

[@agt155]

You have the choice of damper springs in the flywheel (DMF) or damper springs in the clutch plate (SMF).

[@1961UK]

Dual mass flywheel is a weak link waiting to give up.

[@982678249]

It's good and bad thing. DMF's are designed to be "weak link" that takes the hit from engine vibrations. If you replace DMF with SMF, you may notice lot more vibrations when driving and on worst cases premature wear on i.e. transmission parts. I've understood that on diesels DMF's also allow of use lighter parts, because it absorbs lot of vibrational forces, so transmission won't need to be built so "touhg" as with SMF. Just use good amount of RPM's with DMF too so it will last a bit longer, but eventually it will give up...

[@caseyrevoir]

Cool, I can shade tree that weak link much easier than splaying the internals of my transmission across three work benches.

[@exothermal.sprocket]

DMF are like the "cush drive" on the back of a motorcycle. On a motorcycle wheel, the rear sprocket (on chain drive) connects to the wheel hub with fingers that engage with rubber pucks. The torque transmitted from the transmission to the rear sprocket comes in pulses (due to engine firing intervals) which are absorbed by the rubber pucks, so the rear wheel isn't getting the harsh pulses from the engine firing. DMF are essentially a cush drive for transmissions.

[@kallepunkken]

1:51: Not sure if im looking a at wizard with wizard eyes or a robot with robot eyes

[@aliqadri4672]

What is engine harmonic ..??

[@CyclicCollective]

It feel like a wobble in the engine best felt when hill starting on a steepish hill after shifting to 2nd; this can be prevented by changing later under such loads I.e at 2500rpm for a petrol instead of about 2200rpm.

[@exothermal.sprocket]

Harmonics are simply "vibrations", for example, a guitar string moving back and forth very quickly producing sound. With an engine, the combustion pulses in the cylinders coupled with the firing interval of a given engine configuration produces torque pulses through the crankshaft and that pulsation (back and forth, or "harmonic") is transmitted through the flywheel and transmission shafts.

[@goaway6786]

In other words all transmission components can be lighter- cheaper to make- and you can be charged thousands when, not if but when, your flywheel fails. Double win for auto industry. More profits on sale of vehicle and mega bucks for repairs. #welditup!

[@michaeljohnston243]

You ain’t kidding! I just had to shell out $3200 usd on a clutch replacement on a POS jeep renegade! The DMF alone was almost half the price, then all the associated other clutch components. People say labor is the expensive part but it was honestly the smallest portion of the bill.

[@thelloyd87]

There’s no replacement for displacement

[@exothermal.sprocket]

Forced induction increases displacement without increasing cylinder volume.

[@indioloco]

party wheels until the wheels fall off

[@CyclicCollective]

From reading other comment it seems DMFs "may" be good in some diesels but Nissan used them in petrol engines and in some cases made things a lot worse. Please evaluate each case on it's merits and talk to an independent mechanic.

[@AmritGrewal31]

Why not just have a slightly heavier flywheel hence getting rid of the parasitic losses and failures. I'll tell you why! This is why: 💵

[@exothermal.sprocket]

Heavier mass of a SMF may slow the engine response from gear to gear. You can dampen engine torque pulses with increased flywheel inertia, but it also slows the engine RPM response when you remove your foot from the throttle (changing gears, RPM takes longer to fall). Also any extra rotating weight will be mass that combustion has to overcome to accelerate your vehicle.

[@alexhickey5633]

These dam things are always more shuddery than their single mass counterparts. Maybe if manufacturers took the extra effort to actually balance an engine they wouldnt need these

[@fawzisdudah8511]

Needs more thought and work on the video

[@la3ar214]

Poor video.