Causes Of Turbo Failure

hi I'm Nick Perkins with calibrated power today on diesel insights we're going to jump into turbo charger failure now everybody has seen that turbo charger that's the wheels hit the cover and thing is exploded grenaded it's in a million pieces it's like an automotive crime scene right you're like well it failed because the nut came off or the shaft snapped not so fast okay we're gonna dive down a little further we're gonna see what is the first symptom of that turbocharger failure and try and isolate things back into one root cause we're gonna go over a couple of those root causes and then tie them back into how you operate your truck how you maintain your truck and how they might impact your turbocharger stay tuned [Music] so in front of me here I have a few turbochargers a couple turbochargers I have an he-351ve this is off a late model Cummins Ram this is off of an early model 0304 Cummins Ram he-351cw the principle is similar okay we have a compressor wheel we have a turbine on the back and the turbine drives the shaft which controls the compressor drives the compressor and compresses air into the motor okay you know how turbochargers work I'm not going to go through the details here what you need to understand as far as turbocharger failure is that there's some really critical parts that control how the turbocharger stays in one piece your turbine your compressor okay you know how those work but in the middle we have bearings right these bearings the axial bearings they control side to side play they basically float in the center section this is the center section and then we have the thrust bearing that's what's in my hand right here and that controls the in and out movement of the of the uh we'll call it the rotating assembly okay this is a 270 degree thrust you can see it doesn't go all the way around that'd be a 360 degree thrust Okay so turbochargers can fail in all sorts of ways usually what happens is they lose balance and they lose balance for one reason or another and the wheels make contact and then you have that catastrophic issue okay so let's talk about some of the reasons why the turbocharger might lose balance well these things are operating at a hundred thousand to two hundred thousand RPM under high load so the balance is really critical now most of them are balanced on high speed machines we have a high speed balancer and house we also have a low speed balancer so balancing the turbocharger you can usually count on a good turbo shop turbocharger is usually balanced before it goes out now to balance one of these typically what's going to happen is the manufacturer of the wheel is going to balance the Wheel by grinding one side of it so similar to like how you'd add weight to a tire you're going to balance a compressor wheel the same way or a turbine wheel you're going to grind part of it so that it comes within balance okay so you take metal off cool yep makes sense well unfortunately during operation there are ways the metal can come off of a compressor wheel or a turbine for instance if you have a poor poor air filter on the truck and you're getting dirt or debris in through the air box now okay I have a good air filter but my previous turbocharger failed and it spit a bunch of parts into the air box and I forgot to check the air box well if it ingests aluminum and it hits the front of these compressor blades it's going to take Material off of the compressor blades and as it takes that material off you're going to lose balance how else I'm going to show you this wheel out of a rock sore now this wheel was oversped interesting you can tell that because if you look at the back of the wheel you can see orange peel and that orange peel is where the aluminum is actually separated and and strained so much that it has changed shape it's deformed and it's orange peeled on the back of the wheel what happens there well you can imagine as material comes off that you know as this inside stretches the outside of the blades the speed is much higher even so the metal might even just fracture right off the outside of that blade as soon as that happens you're already at maximum operating speed of the of the wheel boom very high load on the bearings anytime the wheel is out of balance one more way that that happens you can burn off the blades on a turbine so we say watch your egts right well why Pistons everything okay well turbine two you can burn the tips right off of a turbine by over exhaust gas temp when you're over exhaust gas temp you take that material off the outside of the turbine blades it's very heavy material it's in Canal usually and when that happens the turbine goes out of balance and kind of Cascades from there well what do I mean by Cascades from there the balance and the control of the wheel in this direction so is controlled by these axial bearings these are bronze and they're fed oil inside the center section so they they basically ride on a race you know inside the center section like so if this thing is out of balance you're going to put a load that's higher than natural on these bearings and they're gonna they're gonna break through the oil film and when they break through the oil film they make contact with the inside of the housing and they overheat when they overheat they start to deform and that bronze or brass is going to cover up the oil fill holes and as soon as that happens it's like a light switch you totally lose your control on whichever side went out and then you know let's say it's a turbine side for instance well once you lose these two bearings well I should say a turbine side once you lose this bearing the only thing holding the turbine control bearing wise is going to be the oil seal you can see on this one the oil seal oil control rings are totally gone the whole setup's melted um basically burn the oil seal right out of it and then you totally lose control of where the turbine head is in the center section and it makes contact and as soon as the situation happens where it makes contact boom stall something's going to give you're going to see either the nut come loose or the shaft snap or the turbine head is going to go flying you know people will critique the weld on the turbine Shaft or critique the material that the shaft is made out of nothing on Earth is going to stand the the stopping Force the deceleration force of 150 000 RPM hitting the side of a turbine it's just not going to happen so something's going to give and the thing's going to let go okay so we talked about losing balance how it takes out the bearings in the center there's other ways that you can lose these bearings okay one of the most noteworthy ways is poor oil quality so that can come either with low viscosity and when that happens you get that material transfer you get a lot of heat and basically the bearing disintegrates um in practice as you're driving the vehicle now you can see here I have a couple of a couple of shafts and these are out of stock Lois I'm gonna take this wheel off here just to show you guys something you can see how nice and shiny that shaft is I just wipe that off with a napkin and some brake cleaner this shaft is out of the same style same style turbo charger you can see how it's all discolored you can see the purple and the bluing down by the turbine you're going to get a lot of heat creeping up through that turbine and trying to get into the shaft if oil can't flow freely through that bearing it can't get rid of the Heat and eventually you're going to lose you're gonna have viscosity breakdown on the shaft and then that bearing is going to lock up now you can just see the color on this thing the color of burned oil you know this is a poor oil quality turbine shaft now it probably didn't fail and I didn't see any evidence of crashing any evidence of major bearing failure these things will take a beating but they're not going to last forever when they're not respected not taken care of next thing would be contaminants so you might have good oil but you might have contamination in the oil or in the turbocharger itself usually poor oil quality is seen in the turbocharger first so unless you're getting oil analysis done or you're cutting your oil filters open you're not going to see that you have poor oil quality because you're probably not going to hear an engine knock it's not going to knock the main bearings the rod bearings the cam bearings out first it's going to take out the turbocharger bearings because those are the high speed bearings now when you have debris in there it's kind of interesting because you can see lines on the on the bearings it's not that they got hot or that they got black or that they got blue or anything like that it's just that there's lines and scoring now you get enough scoring on that thing and it's going to take out a few thou and all of a sudden the bearing's not doing what it's supposed to do and has the same effect as having bad oil or being out of balance so those are the ways that the axial bearings can fail poor oil contamination overspeed out of balance let's talk about the thrust group so the thrust group this is a 360 degree thrust basically controls the shaft as it tries to go in and out now there's a lot of in and out loads on this thing anytime you're compressing air or you're having pressure on the turbine it the exhaust is trying to push the turbine out the back the compressor is trying to claw its way out of the front of the cover so the thrust bearing holds that shaft from moving either direction now ideally those two loads are balanced and they're balanced enough that the oil film on this thrust bearing can hold things in place indefinitely if you have imbalance or you have excessive Heat or you have a load that is simply too high for the oil film you're going to pull through the oil film and you're going to start making marks on this thrust bearing this is a great tool for us because they usually don't get sent out the downpipe and they don't you know they usually survive the catastrophe and we can tell okay what kind of shape was the thrust bearing in and where was which side was the wear on so if there's wear on one side it tells the story if there's wear on the other side it tells a story what we usually see is there's an oil feed side and that side goes towards the center section now the turbine's trying to pull its way out right so on these variable geometry trucks like the LOI the LML some of the whole set stuff guys work the veins really really hard to try and get them to spool up and in the scenario where you might have a boost leak or you have some sort of intake issue which is really common on those older trucks is you're working the veins so hard that you're and you got so much Drive pressure on this thing that it's trying to pull against the thrust bearing and you break through that oil film you don't see any wear on the other side but you see a lot of wear on this face and that means that the the thrust group is being pulled you know sorry basically being pulled in the direction of my finger and it's just oh it's just wearing the hell out of that thrust bearing if you see where on the other side that would be like a rag in the intake or surge so if you have that kind of thing that's really going to load that thrust bearing back and forth back and forth and then you're going to kind of see equal load on both sides of the thrust bearing okay so thrust bearing load big deal right well it's not a big deal until it goes catastrophic okay because once that turbine and wheel is able to move back are able to move forward all of a sudden it's out of control and these are extremely tight tolerances in these turbochargers so in order to get a good seal between the wheel and the compressor cover we keep really tight tolerances right ten thou fifteen thousand somewhere around there depending on which side you're on if that wheel can move forward it can make contact with the with the compressor cover or the turbine can make contact if that happens all bets are off right because as soon as you make contact it's going to take Material off of the wheel the wheel is going to go out of balance and the whole thing's a show from there okay so how do we prevent thrust bearing wear well the best way to prevent thrust bearing wear is to respect what the turbo Builder says for Max boost if you can respect that if you can keep the turbocharger out of Surge and I don't mean surge like you let off the throttle and you hear one cough I mean surge like you're under load and you're hearing that flutter sound that's what's really going to beat up thrust bearings um so if you can keep keep Drive pressure and boost within the range that's recommended by the supplier and if you can keep the turbocharger out of surge odds are you can keep the thrust bearing happy now this is of course a 30 000 foot view of Turbo failure there's many other ways that individual specific rpos you know like an lb7 can fail one way specifically a whole set can fail one way specifically each turbo has kind of its own weak points um and we may go into those in a future video If you guys comment or you know post on there let us know what part of this video you thought was particularly interesting but this should give you a good idea of those things to look out for you know really high level stuff and keep your truck in good shape so keep good oil in your truck keep contamination to a minimum watch your exhaust gas temperatures and respect the maximum boost level set forth by the turbo Builder also if you can keep the truck out of any sort of boost leak you're going to protect yourself from over speed you're going to protect yourself from you know beating up the bearings excessively or beating up the thrust group from having to work your variable geometry turbocharger really hard hopefully this has been helpful I'm Nick pregnantz and another diesel insights we'll catch you next time 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Channel: Duramaxtuner

Views: 69,882

Keywords: Turbo, diesel

Id: mA3IXbb_H-4

Length: 13min 52sec (832 seconds)

Published: Thu Oct 13 2022