Dual mass flywheel: what's it for?

[rwb]

Yes, this old chestnut. The 407 needs a clutch and flywheel and I just can't put the solid conversion idea to bed.

Is it really to protect the engine and gearbox from rough gear changes?

http://www.gsfcarparts.com/022pc0240
A rather eye-watering £490.

[grasmere59]

My 110 has a solid flywheel conversion fitted,it was done just before I bought the car and I've done 20k + miles since some of which has been towing the caravan with no problems at all,the only thing I will say is that I have a very slight vibration around 1500 rpm but as I never drove the car before the solid flywheel was fitted I say if the vibration was there before or not.

[jasper5]

http://www.honestjohn.co.uk/forum/post/?t=61626

http://www.youtube.com/watch?v=YnaXB8q3uzQ

https://www.google.co.uk/search?q=dual+ ... B600%3B629

That's a hefty quote

When I bought the DMF for my 407 the guy at the dealers told me that some models had a solid flywheel option, whether that was true or not I don't know....mine didn't have the option.

[jasper5]

http://www.youtube.com/watch?v=DbvP5EvpUbA

[rwb]

Thanks Jasper.

Conclusion: the purpose of the flywheel is to damp pulses from the power strokes of the engine. Engines with more power strokes (e.g., V8) have lighter flywheels; they naturally run smoother because of the greater frequency of the power strokes at a given engine speed.
As the torque produced on each power stroke increases, more damping is required, and this may be achieved either by a heavier flywheel or by using a dual mass flywheel.

I think that's dealt with that one once and for all

Next question: what causes them to wear and fail?

[jasper5]

Have a read of this....

http://www.techtalk.ie/index.php/why-do ... s-fail/706

[Doggy]

Have you checked the price at Pug, Rich? (Sometimes it's not the most expensive option).

if you use carparts4less with voucher code 'save5' you can get both LUK parts, (DMF + clutch) for £415.13 delivered - not great, but a bit better......

They also do a solid flywheel conversion kit for £318. Personally I wouldn't risk it, at best you risk a bit of roughness like grasmere's at worst a snapped crankshaft. Chances are you're only going to do it once even if you have the 407 as long as it's predecessor. In my book 'saving' £100 on a solid conversion is far too big a risk.

[rwb]

Now that I understand that it's needed to dampen engine pulsing as an alternative to a stupidly heavy solid flywheel, it's a no-brainer to keep the DMF.
I do remember being advised to check with Peugeot... but it's just so counter-intuitive that they could possibly quote anything that isn't utterly absurd.
£564.99 at Mr Clutch, but it's unclear whether that includes a flywheel (probably not).
I think Jasper will probably get first refusal on the job.


For failure reasons I'm gonna say: labouring the engine and rough gear changes.
I claim that you can drive at low revs in a high gear without labouring the engine. For example, I can push the 407 along at 50 in 6th at 1400rpm provided the road is flat or downhill, but if I need to apply power then I must change down in order to avoid labouring the engine.

[Captain Jack]

Rich, 75k seems like an awfully poor mileage for a clutch/flywheel.... Just shows how sh!t things are made these days!

Are you getting worsening symptoms?

[trem1]

Cost me £680 back in July to have a flywheel/clutch kit and rear crankshaft oilseal fitted at a local garage. I priced all the locals and price was between £650 and £1000. Mr Clutch is one to avoid they quote you for basic then the price rockets when your cars in bits

[rwb]

It's this "chatter" only in neutral and much worse when just started. Sunday was quite bad -- which set this off. I think it's still at the "let it develop" stage but I want to be cartain of the right course of action for the inevitable.

There are reports of dmf failures from 35k on the 2.0. It will of course depend a lot on how the car has been used and driven. And given that the dmf is to do, it's silly not to replace the clutch at the same time.

Hoped to get 18 months out of it before this happened but that's just the chance you take buying a car
If I'd had a lower mileage example like CJ then that would have cost me an extra 1k anyway...

[jasper5]

The DMF failed at 44,000 miles on my 2 litre.
I always knew it would fail sooner or later, but was shocked when it failed so early!
Mine had been used for towing, but had only 24,000 miles on when I bought it.

When I dismantled the clutch and flywheel the flywheel wasn't in too bad a state...despite the rattling it had been doing.
There was a vibration from the passenger's footwell as well.

The clutch was in as new condition, but I replaced it anyway...the clutch on the 407 is quite expensive compared to the 406.

[midsmike]

Rich have you done the clutch I could get you a price on my trade

[Captain Jack]

Jasper, so do you reckon you could have gotten more mileage out of your flywheel considering its condition when you got to it and despite the symptoms?

[jasper5]

Jasper, so do you reckon you could have gotten more mileage out of your flywheel considering its condition when you got to it and despite the symptoms?

To be truthful, yes!

The problem I had was that my wife flatly refused to drive it with the rattle and the vibration so it had to be done asap!