Dual-mass flywheels and driveline vibrations | Auto Expert John Cadogan
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- Опубликовано: 15 ноя 2023
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As I have explained to many customers, in decades of technical support... "It is a feature, not a fault".
The correct technical explanation is characteristic of the car.
the radiator leak is a feature yo cool the air-conditioning to sub zero temps 😅
you know some has got this excuse and believes it😅
Lol BatcaveOz, I'm guessing you work for pharma 😂😂
"Those clots and the myocarditis are part of the design, not a fault"
Lol, you can't fix gullable but they can euthanase it by instalments 😮
Customer complaint: car doesn’t stop to well
Cause: characteristic of motor vehicle
Remedy: customer to use factory fitted bumper bar , utilising the car in front ,braking system. Customer to monitor .
A feature is simply a fault that couldn’t be fixed prior to the ship deadline.
Conversion kits that are single mass flywheels typically make driveline vibration far worse, regardless of what the fan boys will tell you. Another great video, thank you John.
I've had dealings with these single mass conversions and have found if the clutch needs replacing, it is not available as a separate unit and is impossible to match up !
Best explanation of kinetic friction and static friction I have ever heard! Keep it up John, love your posts. 😊
Thank you very much.
Kenetic friction is when Barbie gets it on without KYGel. Static Friction occurs when you realise she is your first cousin.
Relative Humidity is the sweat whilst getting it on with your Aunty.
Same deal with a tyre at the traction limit compared to when it has begun to skid.
read my comments.. @@AutoExpertJC
As usual a great presentation from someone who knows what they are talking about and not the usual Jeremy Clarkson type rambling nonsense we're to often subjected to
I'm sure he knows about journalism, especially of the tabloid variety but as you said,anything Clarkson says especially on a technical level should be immediately dismissed.
Spot on.
My introduction to DM flywheels came some years ago when I bought a 2006 Jetta TDI (used, with warranty and about 20K on it) with the auto DSG transmission. After about four months, a noticeable shutter would occur at startup lasting a second or two. This was intermittent at first, but progressively began to occur more frequently and for longer duration. I mentioned it at my next service and when an experienced mechanic test drove it he advised the foreman of the problem. After some discussion with regional VW, they got approval for the repair. It turned out the flywheel and transmission both need replacement. I was given a replacement vehicle for the four days it took to repair mine. I went on to drive the Jetta another 250K with no further repetition of the problem.
After years of riding motorcycles ( and I haven’t stopped yet) without rubber mounts on the engine and box and usually big heavy flywheels, especially on a 500 single, any car feels smooth and vibration free. All the bikes I’ve had have a low frequency shudder but the frame absorbs most and the grips , seat and foot rubbers the rest. If a modern car is too rough then you’d better off stay in bed! Lightweights.
👌😂
try a maxi scoot bro! all that nonesense is all the way at the back insulated through quite a bit of wizardry. once you go past the "yuck, scoot" phase they're amazing, especially for cruising!
Motorcycle rider here, too. And I enjoy big singles..the one I tend to ride more now is an xr600r made street legal (no, not an XL or XR-L).
I do find a buzzy 4 cyl in a car particularly annoying, though. Even if it is counterbalanced, the unpleasant sound remains. I hear it even in stock, quiet cars...it is just a quiet annoying sound, then.
No matter, a transverse 4 in a fwd car just makes sense, and I always have one or two, and just live with them. They just can't sound like a nice v8 or I6. Certain v4's are great, but that configuration is rarely used in cars unfortunately. And with good reason.
“Fruit in the Ute and sell it to the man in the suit” - love it. Great video, so clearly explained I was able to relay the lesson to my 14 yr old daughter
I am a member of Institute of Automotive Engineers (IAME) in NSW. I am a mechanic/machinist, not an engineer, now retired, and have replaced some DMF units, but always with a DMF. Sure they are more expensive, but I was also advised by IAME years ago that vehicle manufacturers are very mindful of costs and if they thought a SMF would do the job, at is cheaper price, they would do so - John intimated the same. Also OE R&D is "somewhat" larger than most after market SMF manufacturers, no matter how good and experienced that after market manufacturer might be. Also even though some commenters to this video have indicated they have not had any problems with SMF conversions, I would suggest talking to gearbox reconditioners and ask them re SMF conversions and the effect that has on 5th gear, or whatever the top overdrive gear might be in a vehicle. At steady throttle, the reduced smoothness of the pulses (torsional vibrations) transmitted via the SMF versus the DMS, does not do the 5th gear any good. Or that is what I was told by gearbox reconditioners and also the IAME. Also it is MY neck if something goes wrong with the gearbox after a SMF conversion. I lose out big time, having to recondition the gearbox and also have to replace the SMF and fit a DMF, all at my expense. So no thanks. If the vehicle is fitted with a DMF I will only refit a DMF, no matter what any SMF manufacturer of other person who has had no problems with a SMF conversion might say. I wear the liability; I will have to wear the cost. Only way I will fit a SMF conversion is if the SMF manufacturer puts in writing that they will wear the cost of any gearbox issues (plus R&R) that arise after their SMF conversion is fitted; also without any weasel wording that allows to get out of it on a technicality - don't think they would do that. So for me, fit DMF if originally fitted and SMF if originally fitted. If a person insists on SMF instead of DMF they need to find some other bunny.
Very interesting perspective. I've put a lot of mileage on SMF conversions and never had a hint of trouble with any of them but it's interesting to hear that as a possible side-effect.
Subaru in particular used DMF's on some "higher end" models to give them a more "luxury" driving feel. And this is the usual reason I see them being used. In the case of Subaru they produced many models using the same engines and transmissions with both SMF's on the "sporty" and "entry level" models, and then DMF's on the higher end "luxury" models. Since the DMF's are difficult to resurface, expensive to replace, and in some cases NLA (no longer available from the manufacturer) they are almost universally replaced with the SMF equivalent. Having worked on all these models now for well over a decade (own a Subaru performance shop with chassis dyno, etc), I can say with absolute conviction that it makes no difference at all in terms of longevity and reliability. It's a luxury driving experience "feature" and nothing more - at least in this specific case and I suspect many others.
When they first became common in the UK DMFs were a disaster as there was a plague of early lifetime failures.
Thanks very much Bob - I can see that being salient for the gearbox, with the torque multiplication in high gears x millions of pulses. Excellent addition to the discussion - I really appreciate you taking the time to lay it out. (Also another excellent reason not to labour the engine in overdrive, and use it only for light loads.)
DMF clutch system usually uses unsprung/solid clutch plate (not all, but most do). SMF clutch system usually uses sprung clutch plate
Just had a DMF and clutch renewed on my T6, Great to understand the forces involved to hopefully make this costly purchase last as long as possible, Thank you John.
Want to keep it longer? When you take off, leave a gap then launch it rather than slipping it. That's what causes all the wear. DCTs are crap at stop start traffic.
@@grantleyhughes my DCT doesn't go too bad. It has a creep function that feels pretty much like a torque converter. Just got to make sure it's a wet clutch.
Oh, how this video made me smile..... Had to replace the clutch in my Transit over here in good old blighty and as the DM flywheel was also worn out I opted for a solid flywheel conversion..... Garage told me that I would notice a considerberly harsher gearchange, they were not kidding, man it sent shudders through the cab each time I strokeed the gearstick! After 6 months 3rd gear had had enough, booked a flight out ot there and was never seen again! I sourced a seconghand gearbox and had that fitted, the penny had not quite dropped yet on it being the solid flywheel that had killed 3rd gear but rather it was the high miles on the original box that was the problem.... Well another 6 months went by before 3rd gear in this box joined the other 3rd gear..... So brand new box, new DM flywheel and clutch fitted and all is now good and as a bonus I no longer grit my teeth when changing gear, which is nice! Love your videos, keep up the good work :)
I also bought a MR Triton GLS with the superselect 2 on your recommendation John, knowing you owned the same car gave me the upmost confidence in my decision. It has been the best vehicle I’ve ever owned.
Thank you John!
There are two main killers of dual-mass flywheels. Firstly driving too slowly in each gear will wear it and secondly letting the clutch slip badly and heat up when the clutch is dying. Some people may not notice that their clutch is slipping either because they have no mechanical feeling or understanding or because the road conditions may be so bad that one is concentrating on the surrounding traffic and cannot hear the engine revving up. I usually spot a slipping clutch when the rev counter moves and the speedo does not...
Whilst we don’t see eye to eye on EVs and Lithium Ion batteries, I love your passion, down to earth explanations and vocabulary, which makes your engineering videos interesting and enjoyable. 👍
I think Clint put it best: "Man's gotta know his limitations". Same with designs by engineers and redesigns by commercial managers. Gearbox oil fitted for life means gearbox oil will deteriorate by 70,000 miles. Then buy new gearbox. DMF = better emmissions, faster acceleration, cheaper gearbox for life. Means DMF will likely fail at 70,000. Then buy new DMF.
The first generation of BMW M5 officially sold in Australia was a great example of the effects of a dual mass flywheel and springs in the clutch plate interacting - and consumer expectations. By the third generation of twin cam six BMW were running some big cams to produce a lot of horsepower from the naturally aspirated engine and the E34 M5 had a very 'lumpy' idle. BMW also specified ATF in the Getrag 290 gearbox. At idle in neutral the layshaft would rattle quite loudly, so loudly it could be clearly heard inside the car. There were a lot of customer complaints about the noise but nothing dealerships could do about it. I owned two of them over the years and always enjoyed those aspects of the character of the car, though clearly it wasn't for everybody even then.
Bummwahahs…Barvarian Money Wasters…Yea. My daughter bought a M5 dfor and the trim is crappier than a poverty kia. Cheap and crappy.
The rest of the vehicle would have extreme difficulty justifying it’s price tag. German rubbish built to Chinese standards.
Well, that was interesting.
I remember seeing springs inside a clutch-plate, and wondering, at the time, why they were there, being pre-internet and lacking in vehicle engineering references, I just let it go. But now, all was revealed, and curiosity, albeit, 3 decades old, has been sated. Many thanks.
Thanks for this explanation John. My 2012 VW Amarok does this occasionally but after 176,000 km it is still on its original clutch and flywheel.
My VRA rescue squad purchased a 2022 auto Triton on my recommendation, which was based on yours and you owning one. And on the same recommendation we upgraded to the model with the Super Select II system. The people of the Tweed Valley purchased many meat tray tickets to get into that ute.
Well done 👍 dude 😉
Definitely one of your "besties" !
Have exactly the same experience with my Outback 2.0 diesel manual. A fantastic car with 225000 k's on now. But even after changing to a new fully DMS+clutchset with 175 k's on after 20 thousand the vibration came back.
I live in the high north of Sweden Lappland has worked at car test engineering and noticed that it is more worse in the summer, cold winter close to not feeling it anymore.
After building it out with 175000 we could see that the middel bearing was on time to wear out.
It is exactly like you explain it in an phenomenal way ! 🧐👍
I would also recommend to leave it, even a second time to an DMS again, have heard from some people which changed to a single one that the drive becomes miserabel after.
Of course am I disappointed that engineers do not develop them more reliable 🤬 but there exists much worse things.
Thank you for that video
1A 5 ⭐️
Most failures of dual mass flywheels occur when the centre bush fails and causes the flywheel to run out of balance,and early VW flywheels used to fail when the damping springs came out the side and jammed against the bellhousing.
Really good explanation of how these work, my only experience was having several friends getting annoyed with theirs. In perspective though they're into performance and once you start getting into the OEM 'do not exceed' regions of power, the DMF was becoming a liability that might decide to discombobulate and gnaw its way through the housing so they switched back to single flywheels. Usually lighter than standard. Just for that extremely violent jolt of acceleration, worse fuel economy and some outrageous clamping force of clutch.
All good weekend fun though hardly civilized on a daily driver basis.
A really clever basic explanation of these. I get people lost in the jargon.
I'd love a follow up video John on lightened flywheels. I'm shortly going to fit one to a tarmac/track car and your kind of explaining makes so much more practical sense that mine. Always learn from you. Thanks for these videos.
"A really clever basic explanation of these."
Might have been: *_two flywheels connected by a spring._*
6 words vs. a 20-minute video.
Everyone's a critic...
@@AutoExpertJC Can't wait to hear my words read back to me in *_Strine._*
Is that how you present it in your videos? :) @@aliendroneservices6621
@@aliendroneservices6621 But that doesn't explain the why. I like how John makes the complex physics understandable.
Very interesting and informative video John. Liked the way you explained things. Although i am chuckling at a couple of your funny terminologies. I had to laugh when you described the gearshift wobble as the queen Elizabeth II wave😅. I think from here on in, whenever i see a manual transmission shifter wobble, I'm gonna be thinking of you describing it as like the queen Elizabeth II wave! Farmers and tradies don't care about gearshift vibrations and whatnot as you said, i totally agree with that. The city people tend to worry more about that sort of stuff because they're after refinement. Thats also true.
WRT the 'refinement', my 20 year old Porsche with DMF and springs in it's clutch, does not judder on take-off, even at low revs, whereas my 2021 Citroen Relay van with DMF (no idea about clutch springs) will judder on take-off if 'normal' revs are used, so I agree with you there.. A good point that I had not thought of.
In the case of the van, and since I don't actually do much town driving, I reasoned that I would rather add a little wear to the clutch than stress the DMF and risk that breaking, and so I use a little hight revs on take-off which eliminates the problem.
As always - a great informative video... Thanks! (and keep up the techy stuff - please )
Clutches don't tend to wear-out these days do they(?). In my last five vehicles, 400k+ km each, I've never experienced a worn-out clutch, which is more than I can say for DMFs. I've just had one replaced under warranty at
If you use a regular clutch properly, you should never have to change it. A few car gurus said this many years ago. Most die from riding the clutch pedal.
You learn something new every day.
Thanks.
But that pushes out something you learned last week...
@@Cheepchipsable Not if you buy more storage :-)
You listen to this then get interrupted by some bimbo advertising the new Google phone. Thankyou John for your service to humanity.
I agree the time to bring this up is the 1st service. My uneducated though was clutch shudder which could have been caused by contamination during assembly or abuse. I would guess at what the dealer would suggest. Very educational on flywheels. Thank you.
Here in Serbia we buy used cars from Germany. And of course all if them are 150-250 000 km odometer reading. And guess what's the life span of clutch and dual mass flywheel.
So we all drive cars with conversion to normal flywheel. Only unlucky ones with V6 engine gotta get original one.
Car is actually worth more with conversion done.
I had a similar experience with a Mazda ute a long time ago. The dealer eventually found that the wrong oil was put in the diff. The limited slip differential clutches were slipping. Correct oil and no problem for next 180,000 km.
That was very, very interesting. Greetings from Prague, CZ where today it is scrotum tighteningly cold
The fridge examplemof the two types of friction was very done well!
My dual mass gave up at ~50k miles so I put in a single mass from Calolina Cluch. Silky smooth shifts for over 150k miles now and without the clatter and odd feel of the dual. No regrets.
Great explanation of how a DMF operates.
Had a 3.0L ZD30 Patrol come in the shop with what felt like an almost 2 cylinder misfire at idle. Car drove fine, couldn't replicate or fault it on the road. Ended up being a broken DMF. It had close to 90º of free play. That 30 odd kgs of unbalanced rotating mass sure made itself known.
Great vid.
My ears or my eyes did not bleed, thanks for the dissertation,stay upright
I have often wondered how they work. great video
The torsional vibrations are caused by the firing pulses so saying the dual mass flywheel is absorbing torsional vibration is functionally the same as saying it absorbs firing pulses.
"froot in tha' ute to sell to a suit" fantastic quote John.
had my smf conversion kit which was around 30-40% cheaper than dmf kit installed on my 20years old A3 2.0 tdi diesel 55k miles ago when the dmf failed and everything is still great car is at 207k miles no issues whatsoever apart from some things you get used to like stiffer clutch pedal other than that smf will outlive the car
Is that a VE or PD TDI? It won't be a common rail, which all diesels have been for over ten years now. VE and to some extent PD engines torque is now where near as pulsing compared to a common rail.
Love your way of telling someone it's a ute not limo
Hi, John. Most cars which have dual mass flywheels have clutch plates without springs. I don’t know specifically about the triton, but in my experience, it’s very rare to have a dual mass flywheel, paired with a clutch plate with springs.
Thank you for that tip. I was unaware.
@@AutoExpertJC I've just done a clutch replacement on my '13 R51 Pathfinder and changed from dual to single mass flywheel. The old clutch friction plate has 4 springs, so may not be 100% true
The correct name for clutch springs is torque springs.
All springs resonate.
The coils supporting a vehicle are typically a bit under 2hz.
The sum total of driveline play may be creating a sweet spot for these angular oscillations.
@markkelc he did say 'most' which covers this.
Great combination of educating me and ROFL moments (e.g fruit in a Ute).
Great stuff J!
Brilliant! Many thanks! ❤from UK.
I swaped mine to a single after the og died. Definitely less elegant but have 10 years strong. The biggest difference was how easy it was to stall, embarrassingly so initially. But you get used to it.
Great post with excellent explanation. I know I'm, going to be doing "Doosh, doosh, doosh" rest of the day.
Great explanation on flywheels, thank you. My mechanic once told me, it's not quite easy to diagnose, as you said, without disassemling the flywheel, but you can observe, whenever you stop the engine and feel a little shaking from the engine after it stops, you know it's hard to describe, that probably is a problem with the flywheel.
Not a problem, a feature. The flywheel will continue to drive the engine for a few rotations, they dont just instantly stop. And engine is balanced for under power, not being powered, so you get a bit of rattle/vibration.
Thx John. Been watching for ages. Just want to give you a 👍👍.
2014 Honda CR-V 2.2 turbo diesel manual. Fantastic combination of power (torque)/acceleration and fuel economy.
Had to change the dual mass flywheel clutch which was very costly. The mechanic had trouble doing the job.
The clutch is light to operate and IMO ideal with the take up, smoothness.
It’s an impressive product.
I’ve read the Uk forums where this engine is “hotted up” and can take it.
The economy averages 5.5 litres per 100 klms (or less) average driving which is 3/4 highway, 1/4 town.
Fantastic vehicle all round, so IMO it’s worth the “dual mass flywheel cost (pain) once every 200,000 klms or more, if you are lucky).
IDK why we think EVs are so good when this one can do 1000 klms a tank from a 2 minute refill.
When EVs now longer have about 5 “issues”, then I might concern one.
(In no particular order)
-range at least 1000 real world klms before recharging
- reasonable parts costs which any ol mechanic can work on (lol…as if THAT will ever happen;)
-takes 2 minutes or less to recharge
-battery will not spontaneously combust
-safety
-insurance costs
-depreciation
-poor residual value
-battery robustness to not degrade its life in a medium level accident.
-end of life battery recycle and easy in vehicle replacement system hopefully in 15 plus years…
None of this is too much to ask for is it????
Yet another top article.
As a consumer I get how this vibration could be annoying given the dosh outlaid.
Maybe an auto would have been more suitable.
Both (manual/auto trannies) have their advantages.
I can agree, they build them with DMF for a reason. I own an '08 Transhit van, 2.4 CRD. Approaching 300,000km, all was nice until the CSC went poopie, half draining the fluid reservoir. Obviously, the box of gears had to come out, not a job I'd lightly recommend the average back yarder for a weekend thrill. With the mileage on it already, I thought 'F' it, I'll put a new clutch in while it's apart. Same company, same quality clutch with solid flywheel, $580, or with DMF $1300. Yeah, under half the price, I chose the solid number. When the DMF came out, it was flogged out quite nicely, sloppy, and crap all through the bellhousing. Once it went back together, it now shudders taking off from rest, along with quite loud neutral gear chatter, none of which existed prior. If I had my time again, I'd pay the other $700 to keep it as designed. Long stroke, slow turning diesel making a bang every half revolution as you said John, transmits that shock wave somewhere.
Word of warning. If you replace a DMF with a SMF in a transit you will eventually damage 3-4 gear. 3rd and 4th are on the layshaft not the main shaft . SMF create a harmonic vibration at idle as there is nothing to dampen it. This “chatter” damages the case hardening on these gears and eventually breaks a tooth. I have rebuilt 100’s of these boxes and it’s always SMF conversions that do the damage. So when a customer wants cheap option l, I say “the money you save will go towards the 2nd box or a rebuild” .90% of the time the boxes are not economically viable to rebuild.
John, I don't know if YT has sense of humour, but I always get a Polestar ad when watching one of your vids.
I’m pickin’ up good vibrations…..
John’s givin’ me good citations….
My misses has a duel clutch in the Genesis. Sweet and smooth, even when getting a thrashing, which is often.
Genesis has just opened a Showroom in Wickham St, Fort. Valley in BrisVagas, and, by invitation, The Child Bride has booked a test drive of a new G90 sedan. $191,000 Shitville MicroPasoes. Faaaaaaark, women. You paid $18,600 under list on the Genesis you flog around in now…..
I’m not made of money. The Childbride is No. 2 for me, my enquiry is, John, could you please put me in touch with Tiffany, your former No.3 ?
My mid life crisis has been ongoing for thirty years now, so long life is something I must have going for me.
Brilliant mate, greetings from England.
Great explanation John, very good description for the layman. It certainly sounds like that is the issue to me.
And yes, I tend to fit single mass flywheels when the dual mass gives up the ghost - dual mass feels a little bett r but generally unless you drive the two back to back the difference is not particularly noticeable.
Good explanation of DMF’s, primary and secondary inertia, torsional acceleration of 4 cylinder diesels (& less so on 6 cylinder diesels), usually DMF’s are used to combat gear rattle, modern low friction gear boxes have a rattle resonance which is excited by torsional acceleration (2EO on a 4 cylinder and 3EO on a 6 cylinder). Also the much higher cylinder pressures make the torsional excitations even worse, in the olden days diesels made 140/150 bar peak pressure and now they are upwards of 180bar…
Gear stick vibration is usually worse with direct mechanical gear shifters, cable shifter systems have much better vibration isolation.
DMF’s hate engine stalling as it puts a massive torsional event into the system and too many of these will kill a DMF, bump starting is not very good for DMF’s either for the same reason.
I’ve been working in R&D on diesel’s in both FWD and RWD/AWD applications for over 20 yrs….and it is usually driven for NVH performance rather than anything else, the calibration guys don’t tend to like them as they have to calibrate the fuelling to prevent stalls etc and calibrate around the DMF resonances, these are particularly bad at very low temps e.g. -25C cold starts where the engine can sit of the DMF resonance at around 300/400rpm and not have enough torque to overcome the cold friction of the engine, and they sound awful in this condition.
Mine (2020 manual glx r) has a similar thing, was interesting to get used too at start. Now seems normal, big trailers tend to make it more noticeable.
Triton was best value for money when i got it and been happy with it. 75000 km now
Usual quality John, great explanation, thank you. Polite but direct and factual.
You killed me this AM with the comment about how they market a utility vee-hickle to yuppie scum. All the fruit to the suits, reminds me of "rich urban bikers" RUBs, or Goldeing riders. Cheers
I would also reccomend fitting the single mass flywheel conversion kit on your car. That is, if you want to destroy your transmission.
And why would you destroy the transmission? Just learn how to operate your car smoothly and sympathetically and everything will last a whole lot longer. As usual it’s the fault of the nut behind the steering wheel
@@highdownmartin Because DMF has designed in play (not just in the springs), and the transmission is designed to work with that play. When you put a fixed flywheel the strain is larger on the transmission. The same as if you install a DMF from a different manufacturer, that has play is different direction compared to the OEM.
A common vibration problem arises with lift kits on 4wd utes. The lift trashes the required geometry of the uni joints. There are fixes but they aren't always successful.
If you aren't doing harder offroad driving leaving it stock avoids the issue. If you have a dmf and it is noisy, get it sorted. Having one let go is really messy!
Lots of MR Tritons do this. Mine did from new as soon as I loaded it. Mitsubishi replaced the complete tail shaft assembly. Problem is totally solved.
The dual mass applications I've worked on had no springs in the clutch disk. I once put a new disk into a dual mass clutch where the springs in the flywheel were absolutely hammered. They didn't do anything any more and the two parts could just slap back and forth. That car drove very well. The only trouble was that if you accelerated and then let off, you could feel that clunk. It was very minor and not a concern on a cheap A to B basic transportation application. After that experience, I would be in favour of converting any dual mass vehicle into a traditional clutch. Let's face it, if your car has a stick, it's not some luxury land yacht where Winston is going to be perturbed by a teeny tiny vibration at low speed.
I have only ever seen DMF on diesel cars in UK, the petrol civic does not have one but the diesel civic does - and the number of cylinders and power output is the same, the difference is that the diesel puts out more torque at lower revs - so the DMF in the diesel is to protect the drivetrain from high torque pulses at lower revs, where the output of the petrol is much smoother.
On v8's: while most v8's are configured to fire at every 90 degrees, that is a function of the choice of rod pin positions on the crank and not a function of the engine itself. These pins are sometimes offset at unusual angles to alter the exhaust note and to change the torque characteristics. Such monkeying around is more common in motorcycle engines, but the autos can do it too. Yes, this makes a bit of a mess of balancing the rotating mass, but there you go.
The guy who wrote you the email, was very chuffed about your excellent reply on the facebook forums.
I had the opposite issue with my golf r manual. The dual mass fly wheel combined with a clutch actuation restrictor (which essentially stops you dumping the clutch) made the gear change horribly slushy. Swapped for a single made the gearbox sound straight cut and very chattery if gear change not smooth, not to mention being much lighter and handling a lot more torque. Perfect 🤩
Whenever I have come across this problem it has been due to engine mounts if it's not the left foot. I suspect that the problem here is also down to the left foot, if you always endeavour to drive like a chauffeur of a Rolls Royce with royalty in the back you wont get the gear shift wobble however bad the design.
2:46 I needed to hear this. My gearbox has always made a fair bit of chatter under load/overrun in 5th. It's been this way at least 14,000 miles. I suppose if anything was breaking it would have broken by now.
My old Nissan Qashqai became undrivable once warm. Used to dread stop-start traffic. Sold to me when cold by a local cop. Learned two things: 1) Avoid DMFs. 2) Don't expect someone to be honest just because they're a cop.
Having owned a manual 5(e34) and 7(e23) series BMW your remarks regarding the gear stick Elizabeth shake was quite amusing. Both had the same motor and same family gearbox but the 5 was fitted with a dual mass flywheel and yep - she shook like ol Lizzy. Was a common 'fix' to fit a single mass flywheel from a previous model 5 or 7 to the e34 when the original flywheel went kaput. As I owned the cars at 15-20 years old warranty was never a concern....
Resonance!
To 'engineer' it out, you have to add a damper. Which is a wear component, and extra one.
My previous car a mk5 mondeo had issues with the dmf due to the fact that Ford don't use balancing shafts and rely on the dmf to dampen the vibration so when you're at idle you can feel the vibration through the car was getting quite annoying so got rid, the car had only done 40000 miles so you would expect a flywheel to last a bit longer and there expensive to replace as the transmission needs to be removed to access the flywheel so labour and parts about £1000 but probably three times this in a dealership
Not being a propeller head I benefitted from your explanation John!
"That's a lot of time between dishes, isn't it?" - somehow makes me think lunch.
JC with the goods again ❤
I am consistent.
Thanks John, I learnt something today.
Anyone that's ridden an old British single and a "modern" Japanese high revving single will know about flywheel inertia and witness how comparatively easy the modern bike is to stall at low r.p.m. trickling.
Thanks, John, for a very interesting and informative video.
I have owned a few vehicle with DM flywheels and although they were torquey enough to pull away from rest, I was led to believe that such a practice reduced the life of the DM flywheel, because it made the QE2 wave more pronounced. Many drivers like to pull away on tickover and then accelerate once the clutch is fully engaged, because it obviously extends the life of the clutch's friction material. I think it may be smoother and more sympathetic to slightly increase the revs from tickover when moving away from rest; it means in my experience less shudder in the powertrain. Now the clutch life is going to be shorter, but it is a lot cheaper to replace a clutch friction disc than it is to replace a DM flywheel. I'd be interested to learn what your opinion is, John.
My thinking exactly (but better worded)
I have recently replaced the DMF in my BT50 with a SMF clutch kit. Absolutely no issues other than the idle speed is a little more noticeable.
From a towing stand point, I think the clutch engagement is a lot more positive, especially with hill starts.
Dunning Kruger suits quite well on these. Should not laugh but can't stop.
Great essay on the flywheel. Can we do the harmonic damper next?
On my 2008 Mazda BT50, the DMF springs decided to shit themselves in the middle of the Simpson Desert. I had a SMF and new clutch installed instead and the only difference that I've found are increased vibrations from stuff that you shouldn't be doing, like 3rd gear, 1100rpm acceleration. The DMF used to hide things like that
The shuddering of the gear stick is a built in feature that dates back at least from land rover s1 just stick an 8 ball on top and watch the ladies eyes water
Obviously it comes down to exactly how the Manufacturers engineers have designed the overall systems in the first place for instance quite a few Subaru models that came with a DMF fitted for NVH more than anything else because Subaru themselves offer a SMF conversion for certain models so one can safely assume the Engineering is not an issue with these models or the Factory themselves would not offer the option of either as replacement parts.
Much as back in the day when Mitsubishi Vans were notorious for balance shaft issues and we modified them by rotating the balance shaft bearings in the block to block the oil feeds to the balance shaft to retain oil pressure and removed the balance shaft and treated the engine to a normal performance engine full engine balance they became a more responsive reliable engine because of that modification when done properly.
A more expensive option manufacturers rarely used as at high volume levels a balance shaft was actually cheaper than basically blueprinting every engine.
Example back in 1971 when a GTHO Phase 3 was $5200.00 new a blueprinted 351 was a factory option at a cost of $200.00 that puts the cost of such work into perspective multiply those figures for say the Last falcon GT at $100,000.00 and figure the cost of blueprinting that engine these days, Balance shafts are cheap fixes as are duel mass flywheels as vehicles were both reliable and long lived previously without them, Think about that.
Nearly 20 minutes and John-Boy hasn’t told us if HIS Tridon does the ‘old shudder’ off the line.
My take on this is with modern diesels having so much torque just off idle, the temptation to ease the clutch out a little too early is there.
My FWD Vito does the same thing when I’m a little early on the clutch engagement with very few revs.
Try giving it a little more RPM, or ease the clutch out a little slower. I believe the shudder will go away.
It’s all got to do with the way you drive.
Try it and let us know how you go. 👍
Mine is an auto, genius: no flywheel...
@@AutoExpertJC A-ha !
I must’ve missed it when you said that.
Hmmm same idea as a harmonic balancer/damper springs in a clutch plate using a tuned resonance via the spring so it doesn't vibrate harshly over most of the rev range. The tradeoff is that it has a vibration out of its tuned range. Maybe call it a sacrifice just as you move off passing through a very transient part of the range so the rest of the range is smooth. The Grumman Tiger plane also had a part of its engine range that you could not operate continuously in probably just for some unhappy potentially damaging resonance. If you watch a washing machine spin cycle, it will have a bit of a shake starting and then spin smoothly before a wobble when it stops. I suggest the same dynamics is in play with the Triton.
Also very handy for isolating transmission from diesel pump torsional noise.
A fluid mass damper can help reduce the oscillation with a lightweight flywheel. I fit them if available when transitioning to a solid. I kinda feel bad for that word now, transitioning used to mean other things...
the dual-mass fw can be also damaged if you let go of the clutch with too low gear for the speed at hand. (did this when i was learning to drive). Smashed the fw quite nicely into goggins mode.
The best advise I've ever given on a forum was "I dunno, ask you mechanic", funny it was a psychology forum.
yep had one go on my SAAB 93 freaking expensive
OMG now i will be driving my manual transmission Dmax with a grin, unable to unsee/unthink of the queen elizabeth's wave each and everytime 😂😂
I thought you explained that very well
Sounds like the old " fault of the model " excuse. I owned a 2008 Ford Ranger with a dual mass flywheel. It developed a bit of a shudder after a few weeks ( I bought it new ), turned out to be the two piece driveshaft. Fixed under warranty and no more problems.
Forums are a _great place_ to get advice.
Question: I was camping at Dingo Piss Creek last night. Woke up this morning and, during the night, someone has popped the bonnet and stolen my battery. Does anyone have the contact details for a nearby battery supplier?
Forum answer: I don't know. I've never owned a car and have never been to your country. I feel like your car won't start because the windscreen wiper fluid has run out. Hope that helps.
Hi John, you should also mention the difference in clutch engagement between ceramic and organic friction plates. Organic friction material is so smooth compared to ceramic. I had a truck driver that used to control the speed of his truck, whilst backing a trailer, by holding some rpm ie 1200 and riding the clutch. Consequently, he burned out two clutches in short order so, I fitted a ceramic clutch which, he complained bitterly about being shit. My advice to him was, learn to drive properly and the problem will go away. NB twin plates clutches aren’t that easy to replace in a twin steer, flatbed truck.
Don’t know which brand of truck you owned, but do you know anything about clutch brakes ?
I know two blokes who have died because of asbestos clutches and brakes….ceramic stuff is brilliant.
Fleet management is a bitch.
Had a class 8 truck with aluminum frame rails and a ceramic clutch is the worst for that.
No slippage with ceramic caused the aluminum frame being more flexible effecting the clutch linkage having no feathering control esp loaded on a hill.
@@dougstubbs9637 I’m a qualified mechanic and I’m familiar which clutch brakes. Doing brake relines and clutch jobs can be a dirty dusty job so, it pays to wash the dust away with a suitable liquid. Components containing asbestos were banned here a long time ago.
Ford DMF had a lot of issues back when I worked in the automotive trade. I hate the feel of DMF as they do change the feel and clutch action vs all the SMF I have driven over the decades. As to the smoothness of driving a SMF car well that all comes down to how good or bad a driver is. For me the reason DMF came in was due to how many people could not drive a manual smoothly and as such they came out with DMF to sort of smooth out all the bad manual drivers and hence get more sales for their cars vs others but as they all went to DMF that advantage went and then people who could drive a manual car well now had a less enjoyable driving experience.
Surprised John didn't use the "learner driver failing to ease off the brakes as the car comes to a standstill" lurch for the static v dynamic friction coefficient example.
My Merc C220 had one.Always felt a slight judder when pulling away on 1st,even after replacement.Rest of the gears were fine.
Just fit a 6 puk button clutch and single mass flywheel after 6months no more complaints 😂