 | Home > Puma (Tdci) > Anyone fitted a dual mass flywheel to tdci |
 
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17240   
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It would certainly be interesting to hear feedback when someone does a DMF conversion.
My instincts are to distrust DMFs since (a) I don't understand why they're necessary (there is no reason why it is impossible to design a decent conventional clutch for the job, even if LR has forgotten how), and (b) the DMF and clutch fitted to the TD5 is such a dog, performs so badly, and is so expensive to replace. I am personally convinced that it was the dismal performance of the TD5 DMF and clutch the caused LR to switch back to a conventional set-up for the TDCi; shame that the result is worse than the problem it was intended to solve! I cannot accept that it was a cost consideration, since the cost of implementing the change from the Transit's DMF to the production set-up would have been considerable and is likely to outweigh any unit pricing savings. I had always intended to convert my TD5 Disco2 to a solid flywheel/sprung clutch setup because I am fed up with the DMF wearing out, but I have to admit that the Puma Clutch Experience has cured me of this. When I get round to it, it will get DMF number 3 (it's now at approx 200,000 miles). It frustrated me at 120,000 miles to have to remove a perfectly sound clutch driven plate costing pennies to replace a worn out DMF costing hundreds. At least a TDCi driven plate every 50k miles is cheaper in the long run than a DMF every 100k miles. |
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4th Sep 2014 10:49am |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558 
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cant see the cost of setting up a solid flywheel for defender was much as there was one already done for the transit solid conversion
we only ever fit a solid conversion as a last resort or owner wont pay for dmf |
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4th Sep 2014 11:11am |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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I know the solid flywheels have a clutch plate with springs . but the dmf flywheel you can move with 1 finger you cant move the clutch plate springs like that , dmf are much softer if that makes sense
and as I see it the puma engine had a dmf when it came out in the transit first , was it designed to have a dmf ? Last edited by munch90 on 4th Sep 2014 11:20am. Edited 1 time in total |
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4th Sep 2014 11:17am |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610 
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I haven't had any clutch issues to date from my 08 90XS, have no drivetrain or rattle issues.......
Despite the question being asked and 'theorised' answers, what are the distinct advantages if any over a soild with a DMF, and why would anyone wish to go this route if they aren't experiencing any issues with the original setup please? If you go through life with your head in the sand....all people will see is an ar5e!! Treat every day as if it is your last....one day you will be right!! |
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4th Sep 2014 11:19am |
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| ZeDefender Member Since: 15 Sep 2011 Location: Munich Posts: 4731  
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If it ain't broke, don't fix it
 Tell someone you love them today because life is short.
But shout it at them in German because life is also terrifying and confusing... |
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4th Sep 2014 11:21am |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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I know what you mean , if you got 75,000 - 100,000 then yes may be worth leaving it alone
but the question was asked first (by me) due to amount of low mileage gearbox problems posted on the forum , so would be worth fitting one if you only got 20,000 30,000 or less from a gearbox |
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4th Sep 2014 11:24am |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610
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In any event if the vehicle is a 'keeper' the clutch will eventually need doing sometime. I'm trying to gauge which at that juncture would be best. Dependant on mileage I suppose I have really answered my own question perhaps?
Noworries4x4 does phenominal mileages wonder what his take on this would be? If you go through life with your head in the sand....all people will see is an ar5e!! Treat every day as if it is your last....one day you will be right!! |
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4th Sep 2014 11:31am |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17240
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The only reason for a DMF that I can comprehend is if the engine is so rough running torsionally that the a more complicated damping setup is needed than can be accomodated in the driven plate, ie the geometry of the springs required makes them too large or too numerous to fit in the driven plate.
DMFs have only become necessary with the advent of the modern, light, high-revving diesel engine, which is by its nature not torsionally smooth (by which I mean that the revs fluctuate, and the crankshaft is constantly experiencing an angular acceleration and deceleration). Historically diesel engines were fitted with big heavy flywheels and as a result ran smoothly but were slow revving, low revving, and not responsive. To allow the responsiveness the mass of the flywheel has to reduced to petrol engine levels, whcih means the flywheel no longer has the inertia to smooth the torsional vibrations. The 'solution' to this is to make the flywheel in two parts. One part is rigidly attached to the crankshaft, provides the rotational inertia necessary to keept the engine running, but does relatively little to damp the torsional vibrations. The other part is (when the clutch is in) rigidly attached to the gearbox input shaft in angular terms and is intended to damp torsional vibrations in the transmission, in effect it is a transmission flywheel. The two are joined by springs which are intended to prevent the worst of the vibration from the engine reaching the sprung part of the flywheel. Conceptually it isn't a bad idea, but the main failing is the scope for wear and slop in the flywheel, which inevitably results if unpleasant drivability issues such as jutch judder, etc. From the owner's perspective, the downside is that the the flywheel is expensive to replace. With a traditional, hard sprung dirven plate and solid flywheel, it was very rare to have damper spring problems since the clutch plate was generally worn out before the springs failed. With the DMF setup, or the Pumas solid flywheel but soft-sprung driven plate setup (since softer prongs are needed for the high speed diesel engine characteristics) the springs wear much quicker, and tend to take on a permanent set. This means that on a TD5 you generally need to replace the flywheel long before the clutch, and also means that the TDCi driven plate fails long before it wears out. Ultimately this is the price we pay for a diesel engine which drives like a petrol engine. |
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4th Sep 2014 5:32pm |
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| K9F Member Since: 12 Nov 2009 Location: Bournemouth Posts: 9610
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Great write up Blackwolf.
 If you go through life with your head in the sand....all people will see is an ar5e!!
Treat every day as if it is your last....one day you will be right!! |
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4th Sep 2014 5:41pm |
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| munch90 Member Since: 26 Oct 2013 Location: guildford Posts: 3558
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works in much the same way as the mass damper on freelander props (rubber mounted metal ring ) and as said its to help even out rotataional vibrations and I think that mainly all diesels now are direct injection has a lot to do with it there are some petrol engines that have them as well (mainly jap stuff ) |
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4th Sep 2014 5:52pm |
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| MK Member Since: 28 Aug 2008 Location: Santiago Posts: 2396  
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Nowadays small dieel engines develop big torque and beacuse of their overall size there is no room to fit a proper clutch with a massive flyheel.
Cheap solution: Single mass Flywheel and a disc with sh11ty springs to adsorb angular variations at idle. less cheap: mercedes, toyota, nissan, mitsu, some ford, etc. In general, all vehicles fitted with light duty diesel engines are prone to fail in their clutch. Puma 110" SW ............................................................. Earth first. Other planets later |
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6th Sep 2014 1:51pm |
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| blackwolf Member Since: 03 Nov 2009 Location: South West England Posts: 17240
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Space isn't the reason for a small flywheel - there's enough room in the Defender driveline for a flywheel at least four times the mass of that fitted.
If you fitted a heavy flywheel to a modern, light, high-revving diesel, then several undesirable things will happen: 1) it will take ages to rev up, 2) it will take ages to slow down, 3) there's a good chance that at high engine speeds the flywheel may disintegrate and kill you. That aside, it would be smooth. Undrivable, but smooth. More cylinders would help. A straight-eight, provided the angular arrangement of the crankshaft was optimised, would be much smoother than a four. |
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6th Sep 2014 3:33pm |
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| MK Member Since: 28 Aug 2008 Location: Santiago Posts: 2396
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Think you are right on that. Anyways, most brands (of similar design) go for the DMF. All japs trucks we use for geology work never suffer of clutch problems until several 100k miles of abuse. On the other hand a medium size mining company with a fleet of Pumas they need to replace clutches every 50kkm or less. Before with the TD5īs was not that bad. Good enough for me to say the LR design is bad/cheap. Puma 110" SW
............................................................. Earth first. Other planets later |
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6th Sep 2014 3:45pm |
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| roel Member Since: 08 Aug 2009 Location: Lelystad Posts: 2039  
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My 90 td5 has now about 90k Miles old and slips ones and a while if I use my powerbox on the road. So is probably on the end off it's life.
So I have to replace probably the DMF too.  Roel
1984 90 2.5 na Diesel - RR V8 (1994-2001) 1997 Camel Trophy Discovery 300TDI (2001-2009) 2005 G4 Discovery III 4.4 V8 (2008-2018) It's gone but it still hurts. 2003 90 Td5 (2009-now) |
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7th Sep 2014 7:34am |
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