DO NOT replace a flywheel housing without doing this! - Don't Get This Wrong

All right guys in today's video I wanted to talk about really an overlooked underrated part of your engine that can cause significant issues in your driveline if it's not done correctly and this is something I came across later on in my career because the type of equipment I worked on up until I became a fleet manager at a trucking company I didn't run across this too often but in heavy duty trucks and stuff it does seem to be a common cause of having to remove your flywheel housing and put a new one on or you removed it for another reason and you're putting it back on but ultimately if you think about the flywheel housing itself it is just bolted on to the back of your block so when you put the flywheel housing on even if it does have some guide studs or pins dowels whatever you want to call them that help it guide it on there once you tighten the bolts here that hold that flywheel housing on there is enough play or available movement in this housing to throw it off whether it's up too high down too low off to the left off to the right so when you're looking at the flywheel housing you've got to imagine all the stuff that's attached to this housing going backwards along the length right you've got a manual transmission you've got a clutch automatic transmissions you've got torque converters you've got the transmission itself bolted onto this flywheel housing behind the transmission you've got u-joints drive lines all the way to the pinion at the differential and if this thing isn't true in a straight geometric you know line then everything that's behind it is going to be slightly skewed so instead of going straight back you're coming at an angle and it might not seem like much but a few thousandths of an inch off over spec on this measurement of whether this flywheel housing is straight on this block or not can have a very big impact when you look seven eight feet down to the actual diff or you know i'm exaggerating a little bit there but you get the point it's going to be exponentially bigger the further back you go so how do you know if the flywheel housing is on there straight different oems will have you do different ways of doing this measurement but one of the key terminologies that you might look for is going to be concentricity how round something is which is just a fancy way of saying is this thing on there straight so the way that we do that is we will take a dial indicator and this dial indicator's magnetic base is on the actual flywheel or flex plate all right one of the things that i'm always laughing about with my students is that they always insist that they put that dial indicator right here in the middle of the flywheel house right in the middle because there's like what's supposed to be measuring all the way around the housing it's got to be centered no it doesn't if i put the magnet where i have it off here to the side and then i put my dial indicator tip down here i'm still going to be the same distance as i travel all the way around and what i'm looking for is differences in that distance from one point to the next point so i'll walk you through the way cummins wants you to do it once you get your dial indicator installed and you got the lip of your dial indicator on the inside surface of the flywheel housing right here then they want you to take four measurements typically what you would do is put this thing at 12 o'clock because it makes it easier and you would zero it so you would have to rotate the engine until the dial indicator tip was at 12 o'clock that is where you zero it your first measurement therefore zero all right then you would rotate it to um you're supposed to do take measurements at three six and nine but since the engine is supposed to be rotating this direction your first measurement should be at nine o'clock so we'll rotate it to nine o'clock take a measurement rotate it to six o'clock take a measurement rotate it to three o'clock take a measurement you add those measurements together to get your total indicated runout most of the specifications you're going to see like for example in the cummins manual are going to relate the maximum allowable tir total indicated runout to the diameter of the flywheel housing so you may have to take a tape measure and measure the inside diameter in this housing to figure out which of the measurements in your table has the spec that you're looking for this little guy right here based on the measurement of just a little over 16 inches has a spec of 16 000.016 so if i took measurements at 12 9 6 and 3 and my total measurement was 19 thousandths i am basically three thousandths out of spec now i got to look at kind of where my measurements were and see if the problem is in my vertical or my horizontal and then change that other manufacturers like international may just have you watch the dial indicator go all the way around monitoring where the high point and the low point was and then the difference between the two is your tir so different oems might have different ways of doing this different specs one of the things i like about my little training aid engines here are that i know for a fact that when they made these they disconnected these flywheel housings and shifted them to get them to fit on these frames that they set up so almost all of these are out of spec so it gives my students something to look at that not necessarily going to be what they expect it to be which is good but it gives them an idea of what a bad one would look like so you did the measurement and you're out of spec what do you do next well typically you just loosen the mounting bolts you tweak it slightly based off your measurements of which direction you think you need to go and just kind of loosen the bolts maybe you give it a nudge a little rubber mallet kind of pop it a little bit to one side and then snug the bolts up i wouldn't torque them at this point because you might still need to do some adjusting but kind of snug them up run the measurement again and then once you get in spec then you torque down these bolts that way now you've got true alignment of the flywheel housing and everything looks good the dial indicator is a great way to do this um cummins makes a rotational tool i made another video about so technically on this one if if my ocd made me put this in the middle i could do that and i could still rotate this guy um on my internationals that i have we put a half inch drive uh socket on the back of these and welded them on so they could take a breaker bar and rotate their engines so they have to kind of do it like this to still be able to rotate the engine the other thing is to make sure that you have a good solid dial indicator you know i'm tapping mine it's not moving you don't want to mount a dial indicator in a way that it it moves instead of being moved with the needle and if you didn't have this secured properly didn't have it tightened down that could cause some serious issues the other thing you want to make sure of when you're using a dial indicator is to stay as true and perpendicular with the thing you're measuring as possible so if i wanted to put it on my hand i wouldn't want my dial indicator pointed like this i would want it on there so now as i'm rotating it's reading straight all the way around whereas at an angle i may not get that depending on the thrust of it so kind of hard to explain but you want as true as you can possibly get sometimes that's not possible mine has a very slight angle to it right now because the magnet as deep as this is it's not very deep so i had to kind of twist in and down to get it to line up in there so i hope this helps a little bit with something that maybe a lot of you didn't know again my more senior mechanics out there that watch these videos have probably seen this and experienced it in their career a funny story is that when i first took over as a fleet manager we had a transmission that the mounting bolts had backed out of and the transmission had fell back a little bit and the vibration cracked the flywheel housing and so we put a new flywheel housing on it and then the next day i come into work and i see that that truck is still sitting in the bay and i asked them i'm like why is that truck still here we got the new housing and put everything on yesterday right and my technician says no we actually need you to call uh international and have them send the guy over that can do the measurement for us and make sure it's right so at the time i thought what measurement is he talking about is this some complicated mystery measurement that only the dealership has the tools to do is it something that i'm going to have to do every time we do this how expensive is it how much are they going to charge me all those fleet manager things popped into my head so i was very curious when the technician from the dealership got there i literally followed him underneath that truck to watch to see what it was he was doing and it was this i was hot i got on my guys's case i said are you guys incapable of putting a dial indicator on a flywheel and rotating an engine and writing down measurements like why the hell are we paying someone to come from a different shop and do this for us and it was just a lack of understanding and a lack of doing exactly what i did which is what are they doing getting underneath there looking and going well ---- i can do that right so that's kind of the issue that uh i have with this and why i kind of stress this to my students is this is the simple kind of job that you need to be able to do and not expect it to be farmed out to someone from a dealership that apparently knows how to read a dial indicator better than you do right so um this is something that if you wanted more information about it please like subscribe comment let me know what your questions are i'll do my best to answer them uh also consider becoming a channel member my garage cats and garage owners get first access to answer questions they get first access to request video topics and the it's the best way to communicate with me is through the channel membership program so please check that out and thank you for watching thank you for making charlie's garage a success bye