DMF or SOLID?.

[felixx]

Chatting with a mechanic to day about the DMF's in the Vectra.He said that a lot of vehicles which have them as standard,are changing to solid flywheels,not just because of the inherent problems with DMF's,but also because,being direct,the low down torque is much more effective,and the clutch efficient.Are there really any positive benefits to having a solid set up or is it just all talk?. FELIXX.

[mozzer99]

I can't see how removing the springs in the flywheel (which is effectively what you are doing by removing the DMF) which move 20mm or so would have any effect on the torque.
If the solid flywheel is lighter -the flywheel is accelerated faster and the engine will rev freer. Tickover is harsher on a petrol - I'd guess that on diesel it would rock about badly if a lighter version was fitted.

As far as I can see DMF's were used to smooth out the power pulses at low revs and so protect the gearbox from shock and make a smoother drive. In order to do that without a DMF (on a diesel) it would require a very heavy flywheel to such an extent it would be harder to turn over and it would react to gear change revs adjustments very slowly?

Benefits of a solid flywheel are purely down to cost and life expectancy IMHO. A clutch change and DMF at up to £1,000 is serious money, especially if it is every 50-80k miles? If you intend to keep the car it may prevent you needing another DMF(+clutch) during it's lifetime - therby saving considerable money.

I'm unsure of the effect on the life of the gearbox - but it can't be good can it?

As an aside - On Toyotas which began fitting DMF's in the early 90's it was normal practice to weld them up when they failed (and have then rebalanced if you were keen). Just a thought for a cheap solid flywheel conversion? If you spot welded the DMF up at equal distances and length of weld you could do on the car and not greatly effect the balance?

Just my thoughts having built race engines with lightened flywheels some time ago! (when diesels were strictly for buses)

[bembo449]

we've done quite a few LUK flywheel convo's at clutch replacement , particulaly on mondeos ! i did one on a 2.2 SRi i got and never thought about welding it up ! worth considering though aslong as its done proper and wont cause problems done the line

[Mopar Man]

LUK told me in about a months time there will be a solid flywheel conversion on the market. About time

[dh.dti]

i have been discussing with some vx owners on another site about having a solid fly made up

[bembo449]

LUK have been slow in getting some flywheel convo's to the market AND they still dont make one for the 2.0 mondeos tdci ! ( fords biggest seller i'd reckon )

[delberto]

my dmf has been going for ages.....and clutch is now slipping so gotta get mine done before it fails. soild conversion being slow off the blocks makes sense as luk make and sell lots of DMFs as OE and replacement parts. good idea about welding up the old DMF though- but doubt many garages will be keen on saving us money either.
please update this when the solid one comes out as I'd love to think it'll work fine..
;-)

[GazVXLINE170]

When you go for a solid flywheel you need some form of 'throttle dampening'. This effectively works to cancel out/reduce the torque spikes as much as possible. Fitting a DMF does the same thing but as you have a mechanical device and not electronic doing it then there is scope for wear. Personally I don't think the DMF is as much of an issue - if we are talking reliability wise then I would say they aren't unreliable but just need to be treated properly.

Gazza4