Dual Mass Flywheel

[Oldone]

Hi all
Recently my 2.4 1992 Surf manual developed a sharp loud rattle at intermittent intervals. After looking all around the vehicle I decided the fault was in the transmission. The clutch was working well but did click occasionally when reversing. This was the only clue to the loud rattle. When the gearbox was out the flywheel was discovered to be a “Dual Mass Flywheel”.
A new one me. The flywheel has a sprung centre with springs acting as a shock absorber. I my case three of the springs had failed allowing the flywheel to move against the one remaining spring making a sharp rattle.
The cost of a new Toyota dual mass flywheel is something like £490 + VAT + the clutch kit.
One of Milners solid replacement flywheel has been fitted together with a clutch kit.
Has anyone else had similar experiences and how do the Milner replacement parts work long term.
Oldone

[exmee46]

Found this on the web ...

What is the DMF's function? It is designed to isolate torsional crankshaft spikes created by diesel engines with high compression ratios. By separating the mass of the flywheel between the diesel engines and the transmission, torsional spikes can be isolated, eliminating potential damage to the transmission gear teeth.

Engine-side flywheel damper springs The damper springs that are visible on the engine side of DMF are designed to dampen heavy torsional spikes that occur when the diesel engine's torsional frequency matches the torsional frequency of the transmission. When torsional frequencies match (have the same amplitude), severe damage can occur to the transmission if not isolated. DMF's isolate the torsional frequency match between the engine and transmission to an r.p.m. range below the operating range of the engine (usually between 200-400 r.p.m.). These damper springs only work hard when the engine passes through 200-400 r.p.m. at vehicle start up and shut down.


Kev

[NiftyNev]

These damper springs only work hard when the engine passes through 200-400 r.p.m. at vehicle start up and shut down.
Kev

My thoughts on this if you have a manual.No idea what effect it has on autos.If a Dual Mass Flywheel has been replaced with a Solid Flywheel then starting and shutting down engine should be done with gear box in neutral and clutch in.As far as I can see this would isolate the gearing in the box from the effects of the Tortional Spikes.This is how I always start and stop an engine anyway.Anyone else have any thoughts on this?

Neville

[exmee46]

My thoughts on this if you have a manual.No idea what effect it has on autos.If a Dual Mass Flywheel has been replaced with a Solid Flywheel then starting and shutting down engine should be done with gear box in neutral and clutch in.As far as I can see this would isolate the gearing in the box from the effects of the Tortional Spikes.This is how I always start and stop an engine anyway.Anyone else have any thoughts on this?

Neville

I guess its not an issue with an auto because the torque convertor provides the isolation between the crankshaft and the geartrain. Replacing the DMF with a (cheaper) solid flywheel seems quite a regular thing - but I agree that starting and stopping the engine with the clutch disgenaged would protect the gearbox. I read elsewhere though that some clutches with DM flywheels do not bother with the normal clutch shock absorbing springs on the driven plate (the DMF springs effectively do the same thing) so if you only replace the flywheel and dont replace the clutch plate with a sprung version you will run the risk of subjecting the gearbox to shocks when you let the cltch in firmly.

Kev

[NiftyNev]

so if you only replace the flywheel and dont replace the clutch plate with a sprung version you will run the risk of subjecting the gearbox to shocks when you let the cltch in firmly.
Kev

I would think that something would break very quickly without springs in one or the other.

Neville

[Oldone]

I would think that something would break very quickly without springs in one or the other.

Neville

Gday Nev
A new clutch assembly and clutch plate were fitted together with the solid flywheel. I now hear more noise from the gearbox when at rest and out of gear. The noise stops when the clutch pedal is depressed
Don

[Bikenuts]

Gday Nev
A new clutch assembly and clutch plate were fitted together with the solid flywheel. I now hear more noise from the gearbox when at rest and out of gear. The noise stops when the clutch pedal is depressed
Don

I had my DMF replaced with a solid one in Feb, I've noticed no change in the 10K miles I've done since.

Matt

[Oldone]

Dual Mass Flywheel

I had my DMF replaced with a solid one in Feb, I've noticed no change in the 10K miles I've done since.

Matt

Thank you Matt
I must admit when you make a major change to the manufacturers spec
sometimes trouble results. Pictures of the sprung flywheel are attached so everyone can see what we are talking about.
Don

[Morr]

Gday Nev
A new clutch assembly and clutch plate were fitted together with the solid flywheel. I now hear more noise from the gearbox when at rest and out of gear. The noise stops when the clutch pedal is depressed
Don

Sounds like a worn thrust bearing, when the clutch assembly was replaced was it a 3 piece assembly ?
Clutches are often supplied in 1 piece (friction disc) 2 piece (friction disc & pressure plate) or 3 piece (disc, plate & bearing) kits.

If the thrust bearing was not replaced, it may not be happy with what is presumably a different pressure plate (due to different clutch assy for different flywheel) to that which it originally worked with.

[Oldone]

Dual Mass flywheel

Sounds like a worn thrust bearing, when the clutch assembly was replaced was it a 3 piece assembly ?
Clutches are often supplied in 1 piece (friction disc) 2 piece (friction disc & pressure plate) or 3 piece (disc, plate & bearing) kits.

If the thrust bearing was not replaced, it may not be happy with what is presumably a different pressure plate (due to different clutch assy for different flywheel) to that which it originally worked with.

Hello Morr
The thrust race was not replaced. It was inspected and felt OK. However its a sealed for life unit and may well be dry.The new clutch takes very little foot pressure to go down so the bearing has less load. Fingers crossed for now, pulling the box out again this month is daunting for an old man like me.
Thank you for your interest.
Don

[Morr]

Hello Morr
The thrust race was not replaced. It was inspected and felt OK. However its a sealed for life unit and may well be dry.The new clutch takes very little foot pressure to go down so the bearing has less load. Fingers crossed for now, pulling the box out again this month is daunting for an old man like me.
Thank you for your interest.
Don

As long as the noise does not get appreciably louder you should be OK. If it starts to get louder it could be increased wear within the bearing or the bearing starting to wear the fingers of the pressure plate, obviously not good. But if it stays constant it should hopefully be ok, I've know many cars to run for years with noisy thrust bearings.

[goodjazz]

Can you not weld the duel mass flywheel so it acts just like a solid Flywheel. Then Balance it after.

[mud skipper]

Hello Morr
The thrust race was not replaced. It was inspected and felt OK. However its a sealed for life unit and may well be dry.The new clutch takes very little foot pressure to go down so the bearing has less load. Fingers crossed for now, pulling the box out again this month is daunting for an old man like me.
Thank you for your interest.
Don

IF YOU ARE PULLING THE BOX OFF AGAIN opps i'm shouting sorry
check the crank end spigott bearing if surf's have them, its in the end of the crank where the g/box spline mates up.
good luck

[Oldone]

Can you not weld the duel mass flywheel so it acts just like a solid Flywheel. Then Balance it after.

Thanks for you interest goodjazz.
The flywheel is made of many small parts. While it might be possible to weld things up solid. and fit a clutch plate with springs.However should the welding fail removing and replacing the gearbox is heavy work. At sixty eight my ambition to work on vehicles is much less than it was a few years ago.
Oldone

[Oldone]

IF YOU ARE PULLING THE BOX OFF AGAIN opps i'm shouting sorry
check the crank end spigott bearing if surf's have them, its in the end of the crank where the g/box spline mates up.
good luck

Hi john.sally
When the gearbox was out. the opportunity to clean and inspect was taken.
The Surf is a very well made piece of kit. In hindsight I should have changed the thrust bearing but it looked and felt good for a few more thousand miles.
Don