This Cummins Crankshaft Was Almost Scrap Metal...

hello everyone and welcome back to the gmz online YouTube channel in today's video we're taking you through the entire process of grinding this 240 pound L10 Cummins crankshaft and you're going to want to stick around because the cleaning guy messed something up on this one going through figuring out my specs figuring out what bearings I can get figuring out if the bearings come in metric under sizes or inch under sizes because that does make a slight difference getting the diamond set up here because I need to address the proper radius on the wheel that we're going to grind with foreign now the bad part is is over the years I have acquired one more wheel then we have slots for in the cabinet here so I have to roll this one out lean it over out of the way a little bit pops it Loose off the taper a lot of wheel for an old man to lift a lot of responsibility for the cleaning guy we'll get that on there just exactly the right torque we've brought the diamond out we've traversed it across the wheel there and now I need to bring it down so it's almost touching the stone if you put a piece of paper between the diamond and the wheel and I bring that down and kind of keep feeling with the paper there there it is so it's just almost touching the wheel but not quite get down before I fall down about one and three quarter wide yeah we've got a a radius gauge here to compare I'm going to mount the dresser on there the dresser was not anticipating that movie actually make sure we have enough distance between the dresser and the wheel and I have cut this pencil to the distance that I use for my gauge I thought pencil be more accurate than a tape measure good old number two so now when I bring this power this in I know it will stop before I hit the diamond because I have made sure with my pencil gauge so I brought it in and I'm going to feed in until I'm almost up against the wheel I can see a little air gap between here yet and see my diamond will cut a radius on there trying to figure out how I want to do this because I'd really like to have some coolant on that but it's a messy trying to do this with coolant so I think I'm going to do it without okay let's fire the wheel up see what happens oh foreign it's a little easier on the motor okay when you start a big wheel like that help it get momentum yeah help it get momentum up without drawing so much current for so long gives a little time to cool the windings [Music] okay there I'm just barely up against the side of the wheel [Music] now I'm going to go in until I just touch the base of the wheel okay I can hear it I just touched off on the face [Music] so now just like the other side I want to address that radius so I'm going to flip this little knob down here and that allows my diamond to rotate this direction right there I am I just touched off on the side there we have it wheel should have proper radius for both doing the rods and the mains on that crank we need to get the Chuck suggested and mount the crankshaft and that's going to take a little bit of time too yep it really wasn't that bad yet it had one I think it was this one back here that was it's it's quite grooved yeah real rough it just feels like a file when I run my fingernail across that it hadn't spun the bearing or taken it completely out but uh it was definitely time that it needed some attention and they didn't even know that was a problem with it because they were planning on just doing an in-frame overhaul and after they got into it realized that it was maybe worse than they thought it was dial indicator on here and we'll see if we can maybe tell how how warped this crank might be hopefully it's pretty close being right on and it does appear to be very close I don't know if we've even got two thousands there under two thousandths run out there so I won't need to do anything towards straightening this crank it'll grind okay just fine I don't think I could get any straighter than that if I tried all righty but yeah that that journal is really rough it's not worn that much but it's sure rough huh you think it got dirt or something through it or ice looking at the engine I think there was a lot of dirt went through that from somewhere because all of the bearings are scratched real real bad yeah how do you feel about all those Math teachers who told you you wouldn't have a calculator in your pocket every day well I was one of those nerds in high school that had the pocket protector and the calculator strapped on my belt so oh boy so before we move these Chucks out always like to spray them down with a little bit of lubrication loosen them up here and I guess before I start here Ridge should check the zero on the other axis so check here make sure my gauge is zeroed checking this direction I'm right on checking over here I could stand to adjust that just a little bit each little Mark on that would be a half thousandth okay so now I have the Chuck centered this Direction with the machine but now in this direction we need to move it out for the stroke length of the crank looking back at our specs here our stroke link is supposed to be 5.354 there's a machinist rule here to get us close so that that reads off the stroke so that reads off half stroke this reads stroke length Okay this scale here is stroke length that gets Us close and I also need to adjust the counterweights shine me a little bit light [Music] I don't know exactly where this is going to come out I'm just going to take a guess I'm going to run them out to number nine on the scale uh we'll be able to around the time lapse we'll be able to tell that once we get the cranky in there so we know our stroke length is three or excuse me 5.354 cut that in half for half the stroke length makes 2.677 75 77 so now this gauge here has to be set to that length so I'll set it up here in the fixture my micrometer out here 2.677 I'm going to transfer that measurement over here to the Chucks there we are on that one so once again we got the checks close using the scale on here and then at that point we get out the micrometer and set up the dial indicator here to transfer our measurement so we know our stroke length is exactly right now I'm going to go ahead and lock these down and they can still be fine adjusted a little bit even when I have them locked down but it just makes them a whole lot easier to move and a lot less wear on the slides in those Chucks if you loosen them up to make the big adjustments okay we're not too bad there need to open that one up a bit so now let's try rotating this but I'm not sure how far off I am on balance and as you can see it's still heavy so it's heavy because it's off center because you're going to be doing the rod journals right so there are counterweights under here that I can't see because our glass is so I'm going to go on up to 10. and let's see what that feels like then do you know how heavy the weights actually are no I I don't know what the wait sorry in here uh evident evidently enough to counteract the crankshaft and if you get even bigger cranks in here we have other weights that you actually bolt on back here on the back side of the okay Chuck slides to counteract the weight yeah see now I've went too far it's the other one that's the other way awful close I think we'll stop right there if you look at that there are none of those Rod journals that are on Center we can't grind any of those so we're gonna move the crankshaft into this position right here lock it in place foreign so now when I roll this down and lock it in place again if you'll notice on the Chucks here I have a jaw directly underneath because I'm going to loosen the crankshaft in here so now that crankshaft is loosened in both Chucks it's just sitting there there's nothing locking in place if I get this v-block out here set that in here then I rotate that crank in the Chucks just a little bit until this v-block there there I brought it into the V I can feel the feeler gauge where into the V on both sides so now I snug the crank down now when I rotate that crank these two journals here should be on Center I can't quite go all the way around my wheels on the way back there so by offsetting the Chuck's half of the stroke length of the crank you now are spinning on Center on those two Center on these two Rod journals they are in the center line of the of the machine yeah and then to do the other ones you'll be able to rotate the Chucks rotate the truck Chuck's 120 degrees and I can catch the next two journals another 120 degrees and we'll catch the last the last two yeah in fact I'm probably going to start grinding on this one here I'll rotate around the grind on it first always want to do your worst Journal first make sure it's going to clean up the way you think it is should we go eat lunch let's eat lunch come back later okay okay so we're back from lunch now and if you remember before lunch there we had got the crank mounted in the machine and rough indexed in I want to start with this journal obviously that journal is not on the center line of the crankshaft grinder I have to loosen both our Chucks here and Index this thing uh let's see that'd be 240 degrees from where we were there so we've indexed crank around to where the journal that we're getting ready to start grinding on is on the center line of the crank machine itself but we need to actually dial it in so I'm going to put my little dial indicator on here you can see we are way way off so I'm going to start position B and get that relatively close and I'm going to go to position d 180 degrees you see where almost a full turn of the dial off so I'm going to split that difference with the fine adjustment here on the Chucks and now I'm going to see where we're at okay from d [Music] to B I'm almost exactly right on my index is pretty close to being on but this check now from let's go from position C we're out on a needle I'm going to go to position a [Music] we're what uh four thousandths off on the stroke length so to match even though I set up the machine to what the crank was per the spec it doesn't match what this crank was ground the last time so we're going to try to bring that in so that means I need to bring cranks this direction about two thousandths of an inch put my stroke length gauge on and I'm going to come up two thousandths of an inch [Music] there's C and there's a we're pretty much right where we need to be now let's just for fun spin this thing all the way around and what you're looking at there is how far out around that journal is just for fun let's move over to the companion cylinder see we're on number five here number two would be the companion cylinder and that journal is not worn as much it might be to our advantage to actually be doing our uh checking on that one see what happens there yeah we're quite a bit different on that one so let's see if that is in the index Direction so there's d [Music] to B yeah our index is off just a little bit which is not uncommon on crankshafts you see that all the time but now let's see what our stroke length shows us so I'm gonna go position C [Music] so we're about ten and a half on the needle there go to a 11 and a half so we could uh we could go back just a little bit on that adjustment I made earlier okay I think we've got this dialed in as close as we can possibly be because what you're seeing there as far as needle movement is the wear on the journal itself yeah but now I want to show you something big heavy crankshaft how could that thing possibly ever move I mean it's got to be super super strong in that engine but watch that needle all I got to do is pull back and forth on that crank and I'm tweaking it almost two thousandths of an inch there that's what is frustrating when you grind a crank and you get one that is literally like graining a wet noodle it just goes all over the place you got a lot of experience with that I don't want to talk about that so anyway Once Upon a Time an old guy uh uh that was pretty well known in our area as being the guy to go to for grinding crankshafts he actually uh had a machine set up in our shop at one point in time before we bought our own machine and ground cranks for us and he used to put a little bolt just a a bolt with a threaded nut on there in between the journals that you were not working on at that moment foreign and not tighten this up super tight because you're going to tweak the crank but just enough to hold that in place on and put it in on every one of the journals where we're not grinding that you can possibly put a bolt in there like that and that helps keep the crank from flexing while you're grinding gives it just a little bit of rigidity and I'm not tightening this tight I'm just putting that in there snugging it up enough so it doesn't fall out yeah I don't want those falling out while we're working but I don't want them overly tight either didn't change anything on the crank probably I can still Flex that crank but it does give me just a little more rigidity between each one of those journals and one of the last things I'm going to do when we're grinding say a light passenger car crank I just leave the slides on the Chuck's snug tight but with this heavy crank I'm going to go ahead and lock these bolts down because I don't want a chance of anything moving around on me and with the added weight of a crank this size it could move and again on this crank being heavier Duty I got out the heavier steady rest to help compensate for all that we want to make sure again with my trusty little pencil gauge here that I have plenty of room between the journal and the wheel so I can actually come in just a little bit here and now I know that when I bring when I feed the wheel in it's not going to crash because I have checked it with my gauge yep foreign and I want to dress it with the diamond on the machine itself I'll feed it down just a little bit till I hear it there it is just touched and give it just a teeny tiny bit more slow this down so we can get a real nice dress on the Wheel back the other direction and I believe we are ready to start grinding but before we do that I have not set up my Arnold gauge so let's do that okay there's a scale on here [Music] assuming we're going to take 10 off I'm just gonna roughly start that out just a little bit below 10. you can really see how around that crank is let's put a little coolant on and I'm going to start feeding in until I start grinding usually you can hear a difference in the sound of the coolant when you get real real close to the crankshaft [Music] we just touched the crank I can here see a couple little Sparks I'm going to set my wheel down here for about ten thousandths of an inch [Music] kind of give me an indication as we go in [Music] now you can see already there we've only taken what three or four thousandths off the crank if even that much and how much closer we are to being around at this point so with that I'm going to set this back on five it doesn't necessarily have any meaning because I haven't actually miked anything yet but it gives me in my mind somewhere to work from so now I'm going to back the wheel off move the gauge back and I'm going to get out the mic and I'm going to see where we are at [Music] we are at 3.1 oh six four I'm going to write that down 3.106 3 let me check again 3.106 yeah I'm only actually going to go with 3.1063 the bearings for this are actually in metric sizes rather than inch sizes so when we convert our red Journal diameter to metric go under 0.25 millimeter and then I'm going to go a couple of 10 000 smaller than the high side I like to keep the cranks on the high side of spec but I need to be inside the high side anyway our finished size is 3.1007 3.1007 minus three point one zero six three we've got just over five and a half the lower five and a half thousands to go which is close to where I thought we were right off the gauges here turn on a little coolant here come back into that five where we were [Music] and I'll go ahead and adjust it that half thousands [Music] but now I'm going to sweep over and kiss the uh the side of this journal with this Stone [Music] there I'm up against the uh left side of that journal so there on the right hand side of the journal haven't drowned anything yet I'm gonna go ahead and sweep over there [Music] okay so you're just feeding in real slow yeah the button moves too the button moves two ten thousands of course the wheel I can move whatever I want but when you get down close to the end it's best to use the uh button there so you can feed two ten thousandths of an inch at a time okay I'm gonna check my measurements again that's showing I should have about two thousandths to go okay 2.1 O2 [Music] we got to an attempt to go this is good okay so if we adjust this for two and a ten wasn't it [Music] I've got quite a bit over on that side this sweep over to the other side and get it a little closer so I'm going to go clear over till I bump right there [Music] and then we'll grind it down to within about one on the steady rest there you're tightening it up because well not necessary I mean you're not tightening it up a lot but you're just keeping it I'm keeping steady pressure against it because as you grind that steady rest actually is getting looser yeah as material goes away as the journal goes away I have to keep feeding and steady rest in just a little bit more at a time to keep that same steady pressure under the crank yeah because people always look at it and they're like he's not even turning the knobs well they see me it's just kind of a habit I just kind of let my hands slip on the knob yeah to keep pressure against it but I'm not really you can see I'm not really turning the knob I'm just okay so this side over here where I can measure that's my problem is I'd like to measure on that side of the steady rest but the radius gets in the way there so I'm gonna have to do all my measuring from this side so I'm going to go ahead and move the wheel over to the right hand side of the crank continuing to measure on this side where I can and bring it to final size and then I'll come back to this side and get final size so again I'm going to go over till I bump the until I kiss the cheek of that Journal [Music] yeah I'm just right there [Music] and you can see that needle ever so slightly waving that might be one ten thousandths of an inch if even that much I wish it would run perfectly true but I crank this size things Flex we've done everything we can to reduce that as much as possible [Music] okay I'm gonna quit right there my wheel is not quite as wide as that journal so we have ground about three quarters of the width of that journal but now I'm gonna have to sweep back to the other side kiss off there and that was not good with about a thou to go we ended up with chatter on the journal being this close to finish size there was no salvaging it at .25 millimeter undersize forcing us to move forward taking all of the rod journals to the next undersize of 0.5 millimeter well when I got up against the side and it was doing that thing they've ground all those flat spots I can't believe it did that we try to avoid mistakes but they do happen and we have no problem showing that with our audience the customer in this case was already on the fence about grinding this crank or getting a new crank and since we screwed up and had to take the rod journals to the next undersize we're going to offer the customer that they can pay for this crank if they decide to use it or if they decide to go with a new crank there will be no charge for this one [Music] yeah right in the middle 90 and a strong six so you're a couple tenths under what we were shooting for but you're still six tenths within yeah we're still still within I I mean our range of where we need to be is here I wanted to be right here but in reality I ended right here but I'm still above the middle on that range okay we ready to try another one yep [Music] our index is off ever so slightly how's that look let's see let's go with that I don't see that's as good as it gets for a slightly worn Journal right yep so basically the index is off from the companion cylinder but I mean it's so minuscule that it will not be measurable on when the Piston comes to the top I don't think you'd even be able to measure the slight amount this is off but if it was off a ton then it would mean that one you know this one was hit in top dead center before they companion that's supposed to be at the same time right just to give some context yeah it's what the index means it's far enough off that you have to correct for it when you're grinding the crank to be able to make the crank grind and clean up but it's such a small amount that by the time the crank puts the Piston at top dead center it would not even be measurable yeah foreign [Music] [Music] [Music] foreign did you get same spot yes came out same spot on that one so now we can uh roll this around the index and uh two more grain the next two journals okay so now I'm going to rotate the crankshaft 120 degrees come back against our stops here [Music] [Applause] does that make you nervous everything about this makes me freaking nervous now let's see how close we are on the index of this one pretty darn close yeah we're a couple thousandths out that is incredibly close I wouldn't need to but I'm gonna bring that in so we match what the crank was when it was new we're pretty much just down to what the amount of wear has at that point now you'll also notice that I'm always rotating the crank this direction I did catch myself doing it the other way a little earlier you may have seen that on the video but guys should always rotate the crank this direction when you're making adjustments here because if you would accidentally be too close to the wheel and you bring the crank around this way and it bumps the wheel all it does is Bump the wheel and leaves yourself a bruise on the crank where it ground a little extra all you got to do is go inside and change your underwear right but you go the other way and you're too close and with the direction the wheel is spinning it will actually pull the crankshaft into the wheel and that's when things could get really really ugly and you might need to change more than just your underwear because as you can see right now when that swings around those counterweights would hit the wheel yeah if I wasn't in the right position [Music] [Music] [Music] foreign [Music] yeah so it goes a lot quicker once you get the first one dialed in basically yeah once you get that first one dialed in and kind of figure out your plan things start moving along a lot quicker it's pretty much like everything in the shop you spend way more time with all your setup then you do the actual Machining right b120 yeah so we're off a little bit there on the stroke length uh again from the factory my machine should bring it right back into the same stroke we didn't change anything there foreign [Music] [Music] with that I think we're done with the rods feel better I feel better 3.90 and a strong six tenths that's about where all of them came out sweet now what do you do well now we gotta break everything down and move the Chucks back to Center Line and we'll be ready to grain the mains you take all those out for yeah we'll leave those out for grain and Maines I'm probably gonna put two steady rests under the crank to do the mains so those won't be required did we do all them I hope so it didn't look that bad before it just scuffed up right now it looks the same just not scuffed up it was shiny before and it's shiny now well I just rotated the crank so that one of the jaws of the Chuck oh right is directly underneath the crank okay and when I rotate it 90 degrees out this way it brought me a little bit farther away from the graining wheel there all at Mouse too is a little bit more clearance so when I'm lifting this big heavy crank out of there I don't accidentally bump the wheel and break it okay right because you have to take it out to I have just yeah I have to take it back out and bring the stroke back to Center it's not cracked no it has a nice ring to it I wonder how many people [Applause] [Music] I wonder how many people get that I don't know and then we'll get in here bring the counterweights back [Music] did you always have the air drill to do that uh we figured that out pretty quick that was a lot of work running them back and forth with the t-handle yeah and now we need to get those exactly on Center this fixture has been zeroed in so that we know it's dead center so I need to come up there again I need one more Revolution here okay ah bouncing side to side okay there we go and that gets Us close but now we need to put the actually put the crankshaft in and then we'll indicate off the crankshaft itself okay we'll go ahead and tighten the crank in the Chuck's now now I'll get my indicator back in here and we will indicate off of the seal surfaces so when the crank is installed it should run true to the seal surfaces so there's no problem with leakage and hopefully uh well if we're true to the steel surface here the timing gear should run through if we're true to the seal surface back here and the flywheel goes on that same surface the flywheel should run true just like before I'm going to check from B position to a or to D position so we're right on the four here I go back to B and we're about three and a half so I'm going to split the difference on that back to B awful close pretty good now let's come in here to the a position and if I bring it back to that same number we should be awful close to being on Center yeah I'm going to call that good enough for right now let's go get this side dialed in you said he might do a speedy sleeve yeah he was talking about uh wanting a speedy sleeve I wouldn't personally I wouldn't put one on the back end I think that's plenty good yet no reason to put a speedy sleeve on there but that definitely has a bit of a low spot in there just all sudden it dips into the spot huh well it runs pretty dang true for the rest of it yeah the rest of the way around it runs through and then you come to that one spot and it acts weird I mean we're less than a quarter of thousandths off center there and and I think that is it's just the fact that back into that is not completely round that is one of the constant struggles of our pull the lever there pull it how much just like that just enough to make it move I was going to say that's one of the constant struggles of our job is we're always working off okay stop we're always working off of something that's either worn out or something that the last guy potentially machined wrong or yeah we're not working with brand new here we're we have to make the best out of what we've got I think we got that about as close as that one's going to be too now go ahead and pull the engage the lever there so it keeps the crank turning okay okay so you can see how we're running here pretty darn close let's move over to the actual main Journal surface I'll catch up on the edge here where hopefully it's not worn we've got uh three quarters of a thousands run out compared to the existing seal surface and then of course here where it's worn there's no telling what we'll have there not too bad yeah absolutely actually almost better there than where where I thought the surface was not worn so now on the back end of the crank we're pretty darn close there now let's go down to the main bearing surface see what it does same way with it it has that same kind of funny dip in it now let's see how warped this crank is we'll get in the middle here that is really good I was going to say honestly all of that looked pretty good yeah that looks really good I was afraid we'd have maybe two or three show up yeah at this point but no you couldn't ask for that to be any better and probably what we're reading there is the where on the journal so anyway I'm gonna go ahead and set up I think two steady rests in here start grinding and see if we can make Mains come out okay so I'm gonna start out with all my steady rests loose so you're just changing the Arnold gauge so it'll read yeah just changing it from our raw Journal diameter to our main Journal diameter [Music] on the journal there because we're not going to have any water on there any coolant on there for lubrication so now I'm going to go over to the other Journal yeah there we are grinding running nice and steady yeah take that to five right yeah and I'm gonna sweep over find the radius of the crank just touching that radius may go the other way there's that one so I'm going to go back to the first side right on zero daddy as can be four four eight zero two or three four four eight zero three where I want to be [Applause] so these two journals are done you're now supporting the crank there there there and there because you've got these right right so there's plenty of support on the mains to keep it running straight and we're ready to come in on this rear main not a lot of room on each side of the wheel makes me a little nervous but we'll get it figured out and we've put some color on there to make a little bit better better visual for you [Music] set grinding already yeah that's already grinding okay now that's taking it off I mean it goes way so fast you can hardly see it but there's a few little scratches left in there and let's see how much we've taken off at that point uh about two thousands [Music] [Music] today a new day it's a new day today is a new day we spent a good deal all time yesterday grinding this crank took much longer than normal since we had two or since we were filming it at the same time so anyway we're ready to polish it now in essence we are going to polish the journals in the opposite direction of what they were Ground you may not realize that just looking at this but the grinding wheel ground the journals and pushed all the Burrs in this direction pushed them around that way when we get ready to polish we're going to put our belt on here and the belt is running and even though the crankshaft is turning this direction the belt is running the opposite direction fast enough that it will pull all those burrs break a lot of them off smooth it out and any that is left are laid over this direction so when this is in the engine running the Burrs are not digging into the bearings and we're and we're when you're saying Burrs we're talking microscopic we're talking microscopic Birds we're not talking it's not like you could put your finger on here and it dig into your finger no you can't feel it you can't see it it's microscopic but the bearing material can feel that yeah the bearing knows so anyway I guess we're ready to get started here yep the bearings are smarter than we are yeah there you go I'm gonna put on my dust mask because this does make a little bit of abrasive dust and and the iron metal dust thank you so he went down onto the snout there so you can polish this yes surface and this surface yes even though that one that one's probably gonna need a speedy sleeve on it wear sleeve put back on it but regardless we need to clean uh get the rust and everything off of it so it'll be clean when he does get ready to put one on this one back here there's a little bit of wear on there but I wouldn't put a sleeve on it I think it'll be better just the way it is then do you ever Chuck inside yes with these Jaws I can't but I do have a different set of Jaws on here that you can Chuck from the okay inside out with that we have a freshly grounded polished L10 Cummins crankshaft at .25 millimeter under on the mains and .5 millimeter under on the rods be sure to drop a comment like And subscribe and we'll see you in the next one thanks for watching

Channel: Jim's Automotive Machine Shop, Inc.

Views: 580,447

Keywords: Engines, Engine Machine Shop, Machine Shop, Engine Shop, Machining, Automotive Machine Shop, Automotive, Cars, Trucks, Tractors, Gas, Diesel, Performance, rebuild, high performance, internal combustion engine, pistons, cylinder heads, jim’s, jim's automotive, jamsi, jamsi online, Blueprinting, rebuilding, engine building, connecting rods, engine block, boring, valve job, engine rebuilding, jim's automotive machine shop, Cummins, Crankshaft, L10, Heavy Duty, Heavy Duty Diesel, Diesel Truck, Semi

Id: FuVPx9kC2Yk

Length: 51min 37sec (3097 seconds)

Published: Sun Dec 04 2022