Popular Post Adam001 Posted October 5, 2021 Popular Post Share Posted October 5, 2021 (edited) Thought I would do a little mini-write up on my experience of dealing with Vibrations, and may continue it if interesting. So, like lots of other people I did lots of work to my 110 over COVID, a lot of the focus being on sealing, closures, insulation, damping etc to the point that when the windows and vents are closed I can actually say I have a quiet truck (Well it's all relative right?!)!!! One thing that was driving me nuts was a very obvious vibration between 35 and 39mph, independent of clutch, load or gear. Did the obvious. Looked for play in bearings, pinions, UJs, lost wheel weights etc. And while I found a little slack in my rear propshaft slider nothing seemed particularly wrong. So naturally leaning towards being a bit of a nerd I looked for a more scientific approach, it's the modern age right!? Found a youtube video about an app.... Was a little dubious, especially using it on a vehicle with the refinement development level of a lawnmower, but the reviews seemed pretty good and in general I was more curious than anything so got it. Setting the app up is very easy, I have a M57 engine, TD5 R380, disco 2 LT230 1.211 and standard sized tyres, so had to put those in manually, which is easy using the unlisted vehicle option. Plumb in the figures: Then you just hit start and go for a drive, go and find that vibration and hit record You then get a live screen and any trouble areas shine up red as you drive, it uses all the ratios and speeds to work out what everything is, simple and clever. Once you are happy you have a good record you stop and save the recording, you then get the report, this was my first go from a 17 second recording: Pretty sure of itself that it's a second order driveshaft speed related vibration (2 shakes per revolution of those parts) and a full report: When you click the button 'How do i fix this Vibration?' you get some great guidance Then you have to engage your brain and follow the logical steps, my car is standard ride height and all mounts are good so ruled those out. I was already thinking at this point about that rear propshaft slider, but that would only give me a first order vibration (Which a first order vibration was just showing on the report), however that seemed like a good place to start anyway, getting a bit aggressive with the UJs and putting a DTI showed one of the UJs had play, not a huge amount but enough to determine it was bad and needed solving. Did the same on the front shaft and no apparent issues in the UJs or slider, so went and replaced the rear shaft. Took it for another test drive and ran another report, but the vibration was still there so didn't add much extra value, values were a little less, but definitely not solved. At this point I was really hoping it wasn't differential related so took off the front propshaft to inspect further. Top UJ was very very stiff, no play but definitely no good, wrap on the yokes didn't reseat so 2 new GKN UJs. Installed, took it for a drive, no different but checking the UJs both had play in them now! hmm, maybe the prop is just rubbish or suspect UJs, hate doing UJs and trying to grease between the lobes so got a wide angle propshaft, wanted one for ease of maintenance anyway. Took it up to about 10mph, million times worse. what?! So knowing I've ruled it all out and fixed the known issues, looked at the next suggestion, phasing, new propshaft was in-line with the markings suggesting that's correct and old prop was out of phase. So after lots of googling I learnt of the non-paralleled element of the front flanges so thought about re-phasing it, but refused to as that would then just unbalance the shaft, so checked my old propshaft, that was out of phase but actually the wrong way, the short end was 1 spline clockwise whereas google suggested 2 splines anti-clockwise, so re-clocked it.... But then decided that's also a bit mute as the UJs are suspect and who knows what balance it was at. So went to Gwyn lewis and got one of their lovely shafts: As you can see, correctly phased and balanced in that condition, fitted to the vehicle and went for several drives at different speeds: Solved Was an interesting experiment I must admit and I do think it's a great use of technology. I think I would recommend it as it certainly reduces problem solving time, but obviously only if the problems are not obvious, in my case I wouldn't have considered the phasing aspect and that's something new about defenders I've now learnt. It's now telling me I have a potentially out of round tyre/wheel and some basic engine vibrations, I think I can tell but they are not significant. But I may continue down the rabbit hole out of interest. For now I'm happy this particular vibration is solved before a long Scotland run! Adam Edited October 5, 2021 by Adam001 5 4 Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 5, 2021 Share Posted October 5, 2021 That's a very interesting post, thank you! Quote Link to comment Share on other sites More sharing options...
Gazzar Posted October 5, 2021 Share Posted October 5, 2021 Agreed! Quote Link to comment Share on other sites More sharing options...
elbekko Posted October 5, 2021 Share Posted October 5, 2021 (edited) Oh, now that is interesting! I'll have to have a play with that next time I'm out in the P38. Edit: Err, except for the €99 price tag... Edited October 5, 2021 by elbekko Quote Link to comment Share on other sites More sharing options...
Adam001 Posted October 5, 2021 Author Share Posted October 5, 2021 Yeah it's not cheap and the cost really did hold me back for a while. But without it I do wonder if I might have made the mistake and replaced my front diff as the backlash is quite large. Quote Link to comment Share on other sites More sharing options...
Maverik Posted October 5, 2021 Share Posted October 5, 2021 For the super interested - An paper on Vibration measurement and analysis - there's a bit in it regarding the use of acoustic measurements - the conclusion seems to support acoustic as a good way to do it, but evidently is not been massively researched. A review of vibration and acoustic measurement methods for the detection of defects in rolling element bearings A review of vibration and acoustic measurement methods for the detection of defects in rolling element bearings - ScienceDirect Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted October 5, 2021 Share Posted October 5, 2021 That's awesome! Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 5, 2021 Share Posted October 5, 2021 I expect worth every penny, if it stops you having to shotgun parts at a problem. Quote Link to comment Share on other sites More sharing options...
Lightning Posted October 7, 2021 Share Posted October 7, 2021 Great piece of kit, l am very impressed with that. l assume it wasn't available when Land Rover were building Defenders, either that or it was never used Quote Link to comment Share on other sites More sharing options...
Maverik Posted October 7, 2021 Share Posted October 7, 2021 I'd love to give this a go... but I'm worried it would pull up so many transmission issues it would melt my wallet and drive me insane trying to solve the problems 2 Quote Link to comment Share on other sites More sharing options...
Mo Murphy Posted October 7, 2021 Share Posted October 7, 2021 7 hours ago, Maverik said: I'd love to give this a go... but I'm worried it would pull up so many transmission issues it would melt my wallet and drive me insane trying to solve the problems Me too ! Mo Quote Link to comment Share on other sites More sharing options...
Adam001 Posted October 8, 2021 Author Share Posted October 8, 2021 21 hours ago, Maverik said: I'd love to give this a go... but I'm worried it would pull up so many transmission issues it would melt my wallet and drive me insane trying to solve the problems Watch this space 🤣🤣🤣 1 1 Quote Link to comment Share on other sites More sharing options...
uninformed Posted October 15, 2021 Share Posted October 15, 2021 Here is some added reading: https://www.aulro.com/afvb/projects-and-tutorials/278232-how-make-defender-quieter.html 1 Quote Link to comment Share on other sites More sharing options...
Troll Hunter Posted October 16, 2021 Share Posted October 16, 2021 ^^^^ That is a brilliant thread from aulro.com. Thanks for posting the link. Perhaps this could be linked in the Tech archive since it's far more comprehensive than anything else I've read on LR noise suppression. Of course, it's given me a load more work in my rebuild! Mike Quote Link to comment Share on other sites More sharing options...
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