Dual Mass Flywheels - advice please.

jimricho · Guru

Dual Mass Flywheels - advice please.

ibbo · Guru

Hey Jim,thats got'em thinking,a bit of a curly one.Daveo will probably have a few clues.Sorry I can't help you.Bloody hot here at Karuah.Cheers.Ibbo.

dave06 · Guru

I would replace the whole setup as a "one piece" I.E. thrust bearing, spigot bearing, clutch plate and pressure plate, unless it is showing "hot spots" or "out of alignment, showing by the hot spots then I can see no reason to replace it

this would have to be decided at the time of appraisal, simply no other way to do it,

if excessive wear is present I would go original as I'm a bit suspicious of after market ones, I cannot see any reason why it would show signs of failure at such low mileage

certainly if you are going to hang onto the vehicle for the foreseeable future

jimricho · Guru

Thanks Davo for your input. It sounds like the voice of experience here and I appreciate that.

regards,

Jim

PS Ibbo, bloody hot here in Charlestown too, but the Southerly Buster has just arrived as I type this.

DeBe · Guru

Hi Jim is DualMassFlywheels Mitsubishis way of describing what was known as twin disc clutches that were used in Valiant chargers & Volvo trucks?? If so I had a volvo truck with twin clutch plates & one floating thin flywheel wich was burnt out. Sent the flywheels & clutch assy to a Clutch & brake rebuild center in Adelaide & then refitted it. Daryl

jimricho · Guru

DeBe wrote:

Hi Jim is DualMassFlywheels Mitsubishis way of describing what was known as twin disc clutches that were used in Valiant chargers & Volvo trucks?? If so I had a volvo truck with twin clutch plates & one floating thin flywheel wich was burnt out. Sent the flywheels & clutch assy to a Clutch & brake rebuild center in Adelaide & then refitted it. Daryl

Hi Daryl, prior to this issue arising I had never heard of a Dual Mass Flywheel so my knowledge is limited to a web search on the subject. The term Dual Mass Flywheel is a generic one and not specific to any make of vehicle or OEM manufacturer.

The following websites contain more info....

http://www.europeancarweb.com/tech/0701_ec_flywheels/index.html

http://moodle.student.cnwl.ac.uk/moodledata_shared/cdx%20etextbook/dswmedia/trans/clutchMan/clutches/dualmassflywheels.html

Jim

justcruisin01 · Guru

Hi Jimricho , I,ve heard something of these but no detail ,
I hope to be talking to my mate here in the next couple of days , he is the top bloke in town & I;ll ckeck it out .

I.m sure these are different to the twin plate clutches ,1971 falcon GT & HO,s had these .

I had a 1971 XY 351 cub in ,4 speed , traction lock diff ,twin 9inch clutch plates .This was a ford reps demo car , 1 of only 10 built , it was no 2 .
A bugger of a clutch system for trying to back trailers /vans etc.
You had to do it quickly or the heat build would reduce all clearance mahing it hard to change gears , it was ok on the road .Replaced the clutch several times .

The 302 cub in v8 used a single 11 inch plate ,some fitted this to the 351 but it could not handle the extra grunt .

See what i can find out .

-- Edited by justcruisin01 on Saturday 23rd of January 2010 08:27:24 PM

DeBe · Guru

Thanks for that Jim, After reading those articles it looks like a very expensive flywheel whose main benifits are smooth running & a potential to burn out if engine torque exceeds a preset level when towing. Personaly i think i will stick to vehicles with conventional flywheels, mutch cheeper to repair !!!! Daryl

dave06 · Guru

no worries Jim I could explain exactly what the fly wheel construction is and what it entails but I have backed away from going in to much detail in the techies area because of animosity

suffice to say I have a fair bit of trained mechanical knowledge that makes me very conversant with the application of which you speak! although now I have been "promoted" to jockeying a desk I still hang on to the knowledge and keep up with modern vehicles

jimricho · Guru

Thanks again Dave, that's why I have "taken on board" your comments. This is well outside my area of expertise (I use the word loosely). I agree with your not going into much detail as that is available on links quoted earlier in the thread.

dave06 · Guru

Jim you're a top bloke and I don't want you to go into this expense with your eyes closed, this has been annoying the crap out of me here, and at the risk of anarchy in the ranks and a possible law suit I will have my say!

what we do is to replace the DMF flywheels with the SDF simply because of the failure rate of the DMF and the subsequent high cost associated with them

the failure rate is a lot higher we have found when towing is involved, the DMF's fail because they are designed to slip internally and placing all the strain on a set of springs and rubber mounts, the replacement cost of the DMF unit itself is around the $1200, if you go non genuine the internal springs and rubbers are not up to spec and have a faster failure rate

we install a standard off the shelf SMF from a similar model at a far less cost and have had no problems with them after that, these can even be reconditioned units

any good mechanical workshop familiar with this model will be able to do it,

this is my opinion only, I will not be entering into any debate with anyone regarding anything I have placed on here, I am responsible for only my input,

I will not be saying who "WE" are!

jimricho · Guru

dave06 wrote:

Jim you're a top bloke and I don't want you to go into this expense with your eyes closed, this has been annoying the crap out of me here, and at the risk of anarchy in the ranks and a possible law suit I will have my say!

Mate, telling me I'm a top bloke won't stop me suing you for everything if I can find the slightest possible excuse. wink

Seriously, I really appreciate your input and that of everyone to this thread. This is an example of the forum working at its very best.

dave06 · Guru

OH!!! Nice!!!

justcruisin01 · Guru

G/Day Jim, took a little longer than expected but I just had a chat to my mate on the flywheel set up .These are in many vehicles today ,even commodors.

dual mass ,,yes they are very expensive & prone to fail at some time.

the design is two peice ,inner bolted to crankshaft,

outer is mounted on another spigot bearing to certre it as well as a series of springs to make it flexible .

this is to soak up vibrations & noises like any other damper system [not the one in the camp oven ]

you may have seen things like steel blocks clamped on leaf springs , extended weights on crossmembers,exhausts syst.gear boxes & diffs ,twin tube tail shafts in rubber mount etc.

This is all part of stopping noise & vibration. The dual mass can not be machined ,it is replacement only.

How ever some can be converted to single peice flywheel, but this may lead to noise & vibrations, bit of an unknown as to whether this will happen or not .

How old is the mitsy ? some time back they extended the warrenty to 5yrs general & 10yr on drive line, worth checking.

A noisey thrust bearing is a concern as to the cause at that kls. The clutch is operated in one of two ways,

A mechanical system ,,ei Cable or hydraulic.

Generaly two things will cause this,

[A],, if it is cable it needs to have the clutch clearance checked & adjusted if ness, at service time ,

[B] hydraulic can have a adjustable clutch slave cylinder, this needs the same check at service,

in the case of either of these systems if the adjustment is wrong the thrust bearing will be running all the time,thus it is wearing out.

[C] this is the old operator problem of resting the foot on the clutch peddle while driving, this inturn will keep the

bearing running all the time.

Hope this has shed some light on the design & operation of the dual mass verses single mass systems.

jimricho · Guru

Firstly, a big thanks to everyone who contributed to this topic, especially Jim (justcruisin) and Dave for going out of your way on my behalf. Since posting this topic all the independent advice has pointed towards "retro-fitting" a single mass ("common or garden variety") flywheel, as confirmed by your input. This is especially so when considering that about a third of all "mileage" is towing and the remainder is mostly around town running involving a lot of stop/starts and gear changing.

I have had a second opinion on the source of the noise and this has positively confirmed the clutch bearing as the culprit. The condition of the rest of the clutch assembly and the flywheel is unknown until the gearbox is dropped out (or whatever they do) and inspected. The vehicle was purchased in 2003 so it's well out of warranty but as I intend to keep it for some time yet I have made the "executive decision" to replace the whole clutch set-up including the flywheel (SMF type) and this will be done next week. Hopefully by doing this I won't have to revisit this issue again during the life of the vehicle.

That after-market SMF flywheel replacements are readily available for the Pajero may convey some sort of message about the original DMF unit?

I "take on board" the comments made about clutch usage and will monitor this in future.

Thanks again,

Jim

edit...bloody typo, why can't the keyboard read my mind?

-- Edited by jimricho on Friday 29th of January 2010 05:27:22 AM