What is a crankshaft? Let’s take a deep dive.

All right guys, in today's video we are going to talk about the crankshaft. What is a crankshaft? What are the parts of the crankshaft? What the crankshaft does? What are some of the key things we want to look for? So let's get started and take a closer look at this guy. All right, so when we're looking at a crankshaft you're going to notice that you have these guys right here. These are called journals and you have connecting rod journals and main journals and you can tell the difference between the two by looking along the length of the crankshaft. So you can see how this journal is lined up with this journal and that journal right here is lined up with this journal and so forth. All these journals that are traveling in a straight line through the center of the crank are your main journals and it's these journals that sit in the engine block and have a cap or a bed plate that bolts around them and holds them into the engine so these are like the support journals it's what holds the crank in the engine these outside ones that are a little bit smaller you can see you got one here then you got one way out here then you got one here and then you got one way out there they're offset from the center right those are your connecting rod journals so your connecting rod is attached to your piston and your connecting rod attaches to these journals with a cap that holds them in place and whenever the piston gets pushed down by combustion that is going to push on this and that's what makes the crankshaft rotate so the entire purpose of this entire assembly right here is to basically take the the linear motion of the piston going up and down and turn it into rotary motion that rotary motion then gets transferred into the transmission the drive line into the wheel ends so without this you don't rotate right your engine's pistons are just going up and down this is what converts it to rotary motion all right so you got your main journals your connecting rod journals and then we have the front and end of the crank which we would call the snout usually and the snouts up here on the front and up here in the very front we can see that it's got a little hole in it that's going to be a threaded end where you usually put a retaining bolt for like a vibration damper or something like that and then right past the main journal on the front here is where you have a sealing surface so a front seal from like the front cover of the engine would be going around this guy or around this portion up here probably this guy's little chain uh groove or gear groove looking thing that is going to be for like a timing chain or a timing belt or it's going to be what attaches your crank to your camshaft to get them to time correctly all right so that's the front of the crank the the seal surface and the timing chain pulley or gear if we come down here to the other end we got the back side of the crankshaft and you can see it has a sealing surface as well right here where our rear main seal would go and then you have the bolt holes in the back of it where your flywheel or flex plate would mount so this is where the power gets transferred from whatever's mounted here to your transmission all right next thing we have is the big pieces that are in the middle of these and these are called crankshaft throws crankshaft throws are basically there to help with a couple of things they're part of the support structure but they are cut in a way that it doesn't interfere with the pistons and they are balanced, right? A crankshaft has to be balanced for the engine that it's in. If you go and change massive things about your pistons, your cylinders and connecting rods and things like that, and you change weights, it has to be balanced, right? Otherwise you're going to have a really bad vibrating engine, which means that that's another reason why your flywheel that you put on has to be balanced for that engine, right? So it has to be balanced. And sometimes they will balance these by cutting out sections. So some of these cranks, you'll look and you'll see little holes cut into them. That's because they took weight off of them to balance them. So that is the crankshaft as a whole. So again, the rear of the crank where the flywheel mounts, the crankshaft throws, your main bearing surfaces, your rear sealing surface, your connecting rod journals, and the front of your crank, the snout where the damper would go the sealing surface and the gear for a chain or a belt or something like that on the front all right so uh in the next video what i will do is i will break down kind of what the measurements are right how do we measure this how do we inspect it to make sure it's serviceable because this is a brand new crank and you're not going to see a crank that looks like this that's been in a car for any significant amount of mileage but when you get them cleaned up and stuff there are some measurements that you would want to do to make sure that crank is still serviceable can it be put back in the engine does it need to be ground a lot of stuff that comes up with this guy right so that's going to be in the next video look forward to that one we'll measure these we'll talk about the measurements and stuff and please like and subscribe consider becoming a channel member becoming a channel member is one of the ways i get funds to buy things to make videos about so the more money i make on this channel the more videos i'm going to be able to create so if you like this video please like and subscribe but more importantly consider becoming a channel member thank you