Automotive Vibration Analyzers – Part 1 of 5

Automotive Vibration Analyzers – Part 1 of 5


in this video I’m going to review the six different automotive vibration analyzers that I’m aware of that are out there that are still available and the advantages and disadvantages of each and this will be a five part series we’re going to start with the least expensive options and move up and then show you how each of these vibration analyzers for automotive vibrations and and every truck vibrations are used and so just to give you a quick review as far as the history of vibration analyzers right here on the workbench we have what’s called a resonant Reed tachometer and this Reed tachometer is very old I’ve searched the internet and I have found one place that still sells them it’s a precision instrument that will show you the vibe the vibration frequencies that it is exposed to and it can be helpful in automotive vibrations however this tool costs around eight hundred dollars and I will demonstrate this tool how to use this tool here in a moment along with its advantages and disadvantages the least expensive tool that is available and not exactly the easiest one to use is the Briggs & Stratton sairam etre and I’m going to demonstrate how to use that tool also that tool you can find for less than $30 and it can be very helpful for vibration diagnosis but it requires more than one person to go on a test drive and to take readings and measurements and it can be very temperamental and hard to read but I’ll show you I’ll give you an example of that here in just a moment the next vibration analyzer that’s out there historically that I’m aware of are these two boxes here on the end the Box in the rear there the red one it also came in black the the red is the forward version of what’s called an electronic vibration analyzer there was a black version or a black cased one for General Motors and Chrysler and and it’s called the electronic vibration analyzer some people refer to it as version one it is known as the e VA electronic vibration analyzer or Eva and it came out in 1991 and I’ll have a separate video on how to use the two different Eva’s the Box the gray box is in front of us here is the electronic vibration analyzer version two and it came out in 1998 and has a few revisions both of these are still available on eBay I’ve seen them for sale anywhere between 300 and 700 dollars for a kit originally these things cost anywhere from $1,500 to about $2,500 depending on if they came with the timing light for driveline vibration balancing or not the next kit over here was from a company that is no longer in business V tronics Corporation and they were bought out by Bosch automotive salute service solutions and this V tronics mts 4100 and 4000 series scope this one’s a 4000 I bought this one through the rotunda tool program the four thousand in the 4100 analysers for vibration diagnosis and noise they call it NVH noise vibration and harshness diagnosis they were very expensive around four thousand dollars for a complete kit and when I bought this when I was fairly impressed with it but the thing that threw me off other than the extreme price of the initial purchase was that it really didn’t do anything more than the the EVAs did over here it seemed to respond a little more quickly than they did but that’s really not a big deal in vibration diagnosis but what really got to me on this MTX 4000 is that the software will quit working after a certain time period on myung my initial purchase it was two years so after two years you got this notice saying your software is expired call this number to renew it and they want almost three hundred dollars for one more year to use the tool that you’ve already paid up to four thousand dollars for and that was just too much for me it was not worth it and a year or two ago when I tried to renew it just for use in my classes when I called the number nobody seemed to know how to update this MTX 4000 anyway since the the boss company took over me Tronics and through rotunda I got forwarded from one person to another in phone messages and just it never happened I just horrible luck with this MTS 4000 in the 4100 version of it all right the next one that just came out last December is in this particular version is for General Motors this is a oscilloscope diagnostic kit but there’s versions for other manufacturers out there also this one’s specific to GM but this is from Pico Tech Pico technology the Pico scope people and there’s a version for independent shops right over here and basically what’s in this big box right here the black one is the combination of a four-channel Pico scope and if you’re not familiar with Pico scope it’s a saw it’s a pc-based oscilloscope with a USB interface oscilloscope module and you can buy oscilloscopes anywhere from one channel clear up to four channel for automotive use and they have even more channels for non automotive use but the oscilloscope you’re going to need are either a two channel or a four channel oscilloscope for it to work with the Pico NVH diagnostic kit right here and this is a fantastic kit I would say this is the top-of-the-line kit for vibration diagnosis that’s available today and the cost of the combination kit here is equivalent to the old original electronic vibration analyzers the NVH diagnostic kit last time I checked was somewhere around $800 I believe and the Pico scope oscilloscope depending on if you get a four channel or a two channel can be as much as around $1500 and then the software is a free download and they do updates for free unlike the V tronics MTS 4000 there ok well let’s let’s do a demonstration here on the first two vibration analyzers that I mentioned to you what I have is I have a a small will and tire that’s got an electric motor that that drives it and this we’ll entire assembly has a vibration and it is a vibration that we’re going to pick up using the electronic verb sorry the Reed tachometer right here and also the Sairam être from Briggs and Stratton and so let me show you how we’re going to do that the first thing I want to show you is I want to prove to you the rotational speed of this will once it gets rotating so the we put a piece of reflective tape here on the the tire and I’ve got a snap on photo tachometer here and I’m going to just as this will comes around I’m going to turn the photo tachometer on and measure the speed of the wheel and tire assembly when it gets up to full speed it ends up being around thirty two hundred thirty three thirty four hundred rpm and at that point it steadies out as far as its speed and that lets say if we were at 3000 rpm with this tire rotating when we talk about vibration diagnosis we typically measure vibration frequency which is how many shakes per second are occurring in Hertz and so this read tachometer here on the scale has Hertz Shaun across the the front of it so we go anywhere from ten Hertz over here on the left to 20 Hertz on the upper row and then it starts at 20 at the bottom row and goes all the way over to 80 at at the far right hand side so this tool can measure anywhere from 10 to 80 Hertz in vibrations and once again as far as frequency is concerned for vibration diagnosis we’re talking about the number of shakes per second and so at 3,000 revolutions per minute if we divide that by the 60 seconds on this tire assembly 3000 divided by 60 is 50 so we should read 50 Hertz on the read tachometer and also on the sairam etre but i’m going to turn this electric motor on that’ll drive the wheel and tire assembly now and it’s it’s going to be noisy but I’m going to get the photo tach up here to show you what speed we’re at so here we go on that for 2,800 2,900 3,000 3,100 3,200 it’s kind of stabilizing 3,300 all right so our 3,300 rpm I can feel the table shaking it’s not a real bad vibration but 3,300 rpm would be 55 Hertz on the scale here so we’re gonna expect the reads in this area right here to start shaking and so I’m going to hold this right back here and I’m going to zoom in and you can see right here see that one read that’s jumping up and down that is at 57 Hertz 57 Hertz so we must be at about 3400 rpm let me double check 34 45 now let’s watch this read tachometer as I turn off the power to the motor and we’re gonna see this set of reor this read start to move its way down the scale as we turn off the power so here we go and you can see it moving down there is a 30 25 20 now the upper row 16 for 12 so this tool the the read tachometer is it’s a precision tool and it can measure and and does measure vibration frequencies by having the little pieces of metal vibrate up and down according to their natural frequency they’re there and you take that frequency that you read off of the read tachometer and try to match that to the rotational speed of some parts or of the parts on the car you’ve got things that spin the same speed as tires things that same spin the same speed as engine related components and if it’s rear-wheel drive or four-wheel drive the propeller shafts we have items that spin at those speeds and so this tool has to be held against something solid when you’re using it it does work it is expensive and hard to find but they are out there and if you see one you’ve got yourself it or if you come across one you got yourself a nice a vibration analyzer now this next tool I’m going to show you in this section of the video is the reed tack Arab sorry the Briggs & Stratton sairam etre it’s actually made by a German company t re y SI t made in germany trace it I’m not sure if I’m mispronouncing that but what we have here is a window in the top with a dial that represent represents rpm so shakes per minute is what this will be showing us or on the Briggs and Stratton engines I understand without a tachometer they could put this on the engine and set the idle speed at the bottom here we have shakes per second in Hertz so the top is shakes per minute at the bottom is shakes per second now we already know that this tire and will Assembly spins around 3400 rpm or about 54 Hertz well the the sairam etre here has this piece of wire see this yellow tip right there this piece of wire as we rotate the dial let me rotate it here notice the piece of wire extends and as it extends it changes what frequency it corresponds to now this wire will vibrate at what what it’s referred to as its natural frequency and so as we extend this wire really long as long as it’ll go that corresponds to 14 Hertz which is just about the tire speed of most vehicles on the freeway 10 12 14 Hertz as we bring it in the frequency increases so here’s 20 Hertz 25 Hertz 30 35 40 50 and 60 and so and it goes clear up to clear up to 800 Hertz clear inside here well what we’re going to do is I’m going to place this sairam etre back here and let me turn the motor sideways you can see it a little better here I’m going to place this sairam etre right here on this metal frame and then I’m going to start extending the wire out and what this tool will do is that wire will shake really hard when we’re when it picks up a vibration that matches the length of that wire if it doesn’t pick up any vibrations if it doesn’t shake at all and obviously if there’s no vibrations on the vehicle then it’s not going to do anything but if you have a vibration on the vehicle if you extend this wire out very slowly and pull it back in very slowly go through the range there you’ll find a point where it’ll vibrate quite severely it’ll this this yellow end here will shake back and forth almost a full inch when we get to a certain point and how far it shakes back and forth is relative to how severe the vibration is okay so let me turn on the electric motor I’m going to zoom in here so you can watch the the wire and let’s see if we can get it to vibrate so I’m going to crank it out to around the 50 Hertz mark and notice right now it’s the wires just sitting still but if I rotate the dial and make the wire get a little bit shorter or longer so right right there you see how that wires wiggling back and forth when it shakes like that that means the frequency that’s displayed on the dial itself down here the frequency displayed on the dial is the frequency of the vibration which you need to know for matching it to the rotational parts on a car now notice if I shorten it a little bit oh it got a little bit wider right there it’s really shaking a lot let me put my hand behind it maybe you see it better maybe not if I make it too short it quits vibrating then I can take it back up through the range of the vibration there there’s shaking really bad and if I make it too long it quits vibrating also so there’s a sweet spot there where it actually is telling us that is the frequency of your vibration right there and it’s telling me here that it’s about 58 Hertz oh by the way if we look at the reed tachometer on the bench here you’ll notice it also has a reed shaken at 58 Hertz so they’re both corresponding with each other and will show us what frequency we are feeling as we drive a vibrating vehicle down the road now let me shut the power off all of these tools excuse me for bumping the camera there all of these tools the electronic ones that I showed you at the start of the video and these non electronic ones can help you to determine the frequency of the vibration but for most technicians it’s not very helpful to just know the frequency of the vibration you’ve also got to know how to match this that frequency to the rotating parts on the car so that you can avoid making mistakes like balancing tires when it’s a driveline vibration or replacing you joints when the drive lines out of balance or or vice versa there’s all kinds of things that I’m going to shoot different videos on to show you as far as vibration diagnosis is concerned both of these tools that I’ve showed you today an expensive one an inexpensive one they’re very difficult to use for most people most technicians because you’ve got to not only go on a road test but you’ve got to be able to hold this against something solid in the car like the window or a seat frame or something which is going to require a second person to do it safely and dial in and find the frequency that you need another problem with this Sairam être is it only goes down to 14 Hertz a lot of tire speed vibrations especially for trucks are slower than 14 Hertz so this will never read tire speed vibrations on taller tires the read tachometer only goes down to 10 Hertz over here so it won’t read anything lower than 10 which some big tall tires on trucks certainly go below 10 but these other tools the Pico scope the other tools that I’ve shown you here they will go lower than that and like I said I’m going to take you through how to use each one of those show you the advantages and disadvantages of each and then end up with what I believe is the package out there the picoscope package that’s available and show you how to use that and how that can save you time and money avoiding misdiagnosis and replacing parts that were just simply not needed so as I said this is the first of a five part series on vibration diagnosis as far as tools are concerned the next one I will show you how to use the electronic vibration analyzer


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