C5 clutch dual mass or single plate?

[falling-out-with-my-car]

People rant on about how good they are as tow cars but believe me stick on a four wheeled car transporter trailer at 26 feet long and 8 ft wide with a double axle and your stomach will be in your boots whilst the trailer is empty.the tyre pressures for these hired trailers is 56psi. However single axles are fine because they allow the suspension to behave more naturally.

[elma]

I've only ever towed a mini trailer on a Xantia. Majority of my towing has been in pickups, barely notice the trailer in one of those.

[falling-out-with-my-car]

I've recovered two GS's from the borders of scotland a BX with a BX my Xantia estate with dads hatchback. Its OK on new clutch now. And my 2cv with the S2 Xantia both of which have been trailered to borne for either restoration or engine rebuild. I wonder how Barry is these days . The C5 came with a witter tow bar so I'll bear your comments in mind. Thanks.

[Paul-R]

...stick on a four wheeled car transporter trailer at 26 feet long and 8 ft wide with a double axle and your stomach will be in your boots whilst the trailer is empty...

Ah, memories. And fully loaded as well...

Many years ago when I used to go rallying I was returning home up the M5 after an event in Stroud. My rally car (a Vauxhall Chevette) was on the trailer (a 4 wheel commercial one that the company used to collect cars on). The tow car was an MGB Roadster (not even the GT) and I suppose that I must have gone just a touch too fast for the conditions when I suddenly found the trailer trying to overtake the tow car. I turned into the swerve and then was treated to a lurid eight-wheel drift from the left hand lane all the way across to the central crash barriers.

Luckily the motorway was almost deserted and fortunately at that point the skid stopped and I was able to drive out of it and return to the left hand lane at a slightly slower speed. Needless to say the experience had a remarkable effect on the adrenaline levels of the two occupants!

[jsp]

Someone on here enquired about the cost of a replacement solid flywheel and found it was more expensive.

well unable to find a replacement conversion kit to a Single mass flywheel for my 2007 138BHP MK2 C5 Exclusive Hatchback.

I emailed Valeo customer services on Sunday. giving all the necessary information from the reg document Model: variant: reg number:

They replied yesterday, They have a Single Mass Conversion Kit for the 138BHP 2.0l Hdi and the part number is 835069

I looked it up online and the price is £249.00 for the 4 piece kit.

This beats a replacement dual mass flywheel kit including the flywheel by £200.00 then of course we are looking at labour or about £300.00

so current single mass clutch changes for older single mass clutch cars at around £500.00 all in is about right at most garages.

unless of course you plan to do the job yourself.

it is slightly more comforting that Valeo have admitted over time that the dual mass flywheel is a failure to consumers with them failing at around 50-60K.

and have designed the 4p Valeo SMF conversion kit.

I will be giving them a chance especially as I like to be able to tow large four wheeled car transporter trailers.

Been in one of my old neighbours car for 1.5years now this KIT4P. 835068/069 is for all 2.0l HDI PSA cars. It has been fitted under his 05 407sw (basically same engine gearbox and undercarriage and still satisfied everyday. DMF are still in beginning stage and some of the DMF materials arent good as before. DMF is for comfort driving basically. Some HDi engines have both DMF or SMF fitted on the same model car e.g. Berlingo

[white exec]

Is there any evidence that, pre-DMF, transmissions were being damaged by modern DI diesel engines ?
Or that manufacturers reduced the strength/mass of their transmissions following the introduction of DMFs (so opening up the risk of damage should an SMF kit be fitted) ?

[jsp]

LUK SMF conversion kit was too light as I expected so. more Tq. so more problems. Valeo kit4P is same weight as standard dmf. I never had seen any damage on the old HDIs. Even my dealer says. It's just for comfort driving.

[GiveMeABreak]

Is there any evidence that, pre-DMF, transmissions were being damaged by modern DI diesel engines ?
Or that manufacturers reduced the strength/mass of their transmissions following the introduction of DMFs (so opening up the risk of damage should an SMF kit be fitted) ?

I think JSP is over generalising the issue with regard to 'comfort'. It's the torsional stress that is the issue and striving to make more fuel efficient engines whilst reducing emissions brings challenges.

Down speeding and downsizing will inevitably increase the excitation of torsional vibrations from the combustion engines. High dynamic fluctuations with high mean torque will create problems associated with Noise, vibration and harshness (NVH) and durability of engine and drivetrain components. This creates a need for improved technology for reduction of torsional vibrations.

2.0 HDi engines are not all the same and the Kit4Ps are different as indicated by Valeos own brochure, where there aren't kits for all models, as has already been covered. But I think it is agreed that NVH is the issue and I simply cannot see how any single flywheel conversion is going to do as good a job as a DMF. Any increase in torsional stress has to be bad for the transmission components - but each of us will have to make that choice.

I know you like the detail Chris, so the following theses contain a lot of technical info, but also are an interesting read, even covering TMFs - yes triple mass flywheels amongst other devices!
These are masters theses in applied mathematics from the University of Gothenburg, Sweden, but focus on the various flywheel models.

http://publications.lib.chalmers.se/rec ... 220654.pdf
http://publications.lib.chalmers.se/rec ... 238131.pdf

[white exec]

Marc,

Thanks for those. Surprisingly, they actually look reasonably readable, with the exception of the author's surname!

I have some personal interest in DMFs, our Totota D4D having eaten two of them, along with their unsprung clutch plates. First DMF lasted 60k km, its internal circumferential springs broke up, and it shredded the clutch plate. The second (an 'improved' Toyota version) lasted just 20k km, and did similar.

With both DMFs, clutch control was never good: on steep hill starts, revs had to abnormally high in order not to suddenly stall the engine (which isn't funny, or good for anything on a diesel), which in turn can scorch the resin-based clutch plate. Reverse hill starts were even worse, due to the high reverse gear ratio. Reverse hill starts still remain difficult on many modern cars.

After two DMF failures (about €600 a go in genuine parts), I decided to go SMF 4P. Valeo could not supply 'for political reasons' (I think they were OEM suppliers to Toyota, so could not produce a rival kit themselves), so I went ADL-Blueprint. This kit was easily fitted, and for the first time delivered proper clutch control for the RAV4. It has been on the car for 128k km now, and is as good as when it was fitted. Vibration is very slightly more than previous DMFs when new, but less than when these DMFs had aged. There have been no issues with the drivetrain. The 4P clutch plate does include greater capacity springing, compared to a conventional one.

Before fitting the SMF 4P kit, I did check that Toyota hadn't downsized any of their D4D engine or drivetrain components when they moved to DMF. I couldn't find any evidence that they had, as replacement parts before and after seemed to have remain unchanged. Huge numbers of Toyota D4D vehicles seem to have had SMF kits fitted, notably Avensis taxis, worldwide. What is bit depressing is that DMFs are now classed as 'service replacement parts', and not expected to last the life of the vehicle, not covered in many cases by the owner's expectations of warranty.

[GiveMeABreak]

Absolutely right Chris, the DMF given it's operating nature is classed as a service item - nobody really heard of replacing solid flywheels before the DMF switch. I would imagine this would be more of an issue for your D4D and similar vehicles. I guess it will come down to long term tests to determine any detrimental effects on the transmission components and whether there will be any reliable information on attrition to those components with the solid conversions.

[mark2256]

The dual mass flywheel had actually sieze solid on my C5 and when driving it I could feel a nasty vibration through the pedels. After I replace the flywheel and clutch the vibration had gone so I would always go with dual mass.

[jsp]

Marc,

Thanks for those. Surprisingly, they actually look reasonably readable, with the exception of the author's surname!

I have some personal interest in DMFs, our Totota D4D having eaten two of them, along with their unsprung clutch plates. First DMF lasted 60k km, its internal circumferential springs broke up, and it shredded the clutch plate. The second (an 'improved' Toyota version) lasted just 20k km, and did similar.

With both DMFs, clutch control was never good: on steep hill starts, revs had to abnormally high in order not to suddenly stall the engine (which isn't funny, or good for anything on a diesel), which in turn can scorch the resin-based clutch plate. Reverse hill starts were even worse, due to the high reverse gear ratio. Reverse hill starts still remain difficult on many modern cars.

After two DMF failures (about €600 a go in genuine parts), I decided to go SMF 4P. Valeo could not supply 'for political reasons' (I think they were OEM suppliers to Toyota, so could not produce a rival kit themselves), so I went ADL-Blueprint. This kit was easily fitted, and for the first time delivered proper clutch control for the RAV4. It has been on the car for 128k km now, and is as good as when it was fitted. Vibration is very slightly more than previous DMFs when new, but less than when these DMFs had aged. There have been no issues with the drivetrain. The 4P clutch plate does include greater capacity springing, compared to a conventional one.

Before fitting the SMF 4P kit, I did check that Toyota hadn't downsized any of their D4D engine or drivetrain components when they moved to DMF. I couldn't find any evidence that they had, as replacement parts before and after seemed to have remain unchanged. Huge numbers of Toyota D4D vehicles seem to have had SMF kits fitted, notably Avensis taxis, worldwide. What is bit depressing is that DMFs are now classed as 'service replacement parts', and not expected to last the life of the vehicle, not covered in many cases by the owner's expectations of warranty.

I think this is fully down how you drive it. 2 years almost now and 35k mls put on the smf kit and car drives smooth now. Only very low rpms should be avoided. juddery clutch is only at very low rpm.

[white exec]

Agree with that. If you treat the clutch roughly (and a lot of drivets do) then you can expect problems. Also, nothing shocks a sprung DMF flywheel more that stalling a diesel fitted with it. Ironically, because of less good clutch control (internal backlash, as the DMF ages) stalling, especially at low revs, becomes increasingly likely.

When we go electric, all this nonsense . . .

[jsp]

Then a fire would start due battery puncture see Tesla.

[Stickyfinger]

I will look forward to 2 million volt lithium fuelled firebombs going off in underground car parks soon then