[0:00] If there's one light on your car's 
instrument panel you should never, ever ignore,
[0:05] it's this one:
[0:06] the oil pressure warning light.
[0:08] It usually looks like a little oiling can.
[0:11] And if that light comes on while you're driving,
[0:14] that means you should pull over and 
shut off the engine as soon as you can possibly do so safely
[0:19] and then call a tow truck.
[0:21] And I'm not kidding.
[0:23] If that light comes on,
[0:24] your engine may be mere minutes away from self-destruction.
[0:29] And so continuing to drive is a very risky choice to make.
[0:33] Now, if you're wondering why exactly the engine 
could destroy itself when that light comes on,
[0:39] that's the point of this video.
[0:41] Today we're going to explore the mechanical basics of the internal combustion engine,
[0:46] with a particular focus on its lubrication system 
and why it's required to keep the engine alive.
[0:53] There's a lot of stuff going on inside one of these contraptions, 
and by the time we're done here
[0:57] there's a good chance you'll think it's a miracle we've managed to make these things as reliable as they usually are.
[1:04] Now, if you're a gearhead or even just gearhead-adjacent,
[1:08] there's probably not much you're going to learn here.
[1:10] But if you don't really know that much 
about engines and how they work,
[1:14] and really how they keep themselves working,
[1:17] well I think you'll find this video to be quite informative.
[1:21] Before we really dive in, though,
[1:22] there's something you should know about the rest of the lights on your car's instrument cluster.
[1:27] And that's something is the rest of them!
[1:30] Because they all mean very important things
and are designed to help you.
[1:35] They're even color coded to convey their urgency and meaning.
[1:39] Red lights are bad and need your attention now
[1:43] because they indicate an unsafe condition 
where something is majorly wrong.
[1:48] Yellow lights are warnings which can vary in severity
[1:51] but probably don't need your immediate attention.
[1:55] And other colors are usually reserved for simple information,
[1:58] like the blue light that warns you your high beams are on
[2:01] so please shut them off unless you're in the middle of the country — that's not for use with other cars around!
[2:06] Or the white or green status 
indicators for the cruise control system.
[2:11] If you want to know just what exactly all those lights mean,
[2:14] your car will have an owner's manual somewhere
[2:17] and there's going to be a handy little section which explains each and every one of them and why they might light up.
[2:23] I'd highly encourage looking at that section of the manual
[2:26] and committing those details to memory.
[2:29] But anyway, this is a video about the engine and how it works.
[2:32] So let's dig into it.
[2:34] First, though, if you'll indulge me,
[2:36] here's a brief overview of how electric cars work:
[2:39] [two toots of the drill]
[2:41] But bigger.
[2:42] And now let's take a look at this Renault-Nissan MR-18DE,
[2:46] the engine which powers the venerable Nissan Cube.
[2:50] Let me just, uh, take it apart real quick.
[2:59] Okay,
[3:01] this is the engine block.
[3:03] It's really nothing more than an intricately cast 
and machined hunk of metal,
[3:08] but it's the heart of the engine and contains the cylinders.
[3:11] In this case, there are four of them,
[3:13] and they're all arranged in a straight line,
[3:15] which makes this an inline four cylinder engine.
[3:18] Probably the most common type of engine out there in cars.
[3:22] Not all four cylinder engines are alike, of course;
[3:25] these cylinders come in many different sizes, 
so some are more powerful than others,
[3:29] and they're not always arranged in a line.
[3:32] We'll talk more about that later, though.
[3:34] Oh also sometimes there aren't cylinders at all!
[3:36] But that's mainly a Mazda thing they only sometimes do
[3:40] because rotary engines are equal parts cool and terrible.
[3:44] But they're committed to them!
[3:46] Sometimes - for special occasions.
[3:48] Anyway, the cylinders are each a combustion chamber.
[3:52] The idea is to fill these cylinders with a mixture of air and fuel,
[3:55] and then ignite that mixture so it...
[3:58] expands very rapidly.
[4:01] I would say that mixture explodes,
[4:03] but it's not technically an explosion.
[4:06] What's really happening is that the carbon dioxide
[4:08] and water vapor that are produced in the combustion process
[4:11] have a much larger volume 
than the fuel and air did before it ignited,
[4:16] and that rapid expansion of hot gases 
inside the combustion chamber
[4:20] can be harnessed and turned into mechanical work.
[4:23] And to do that we use pistons.
[4:26] Each cylinder gets a piston just like this inserted from the bottom,
[4:30] and these pistons are able to 
slide up and down inside the cylinders.
[4:35] During a combustion event, as the mixture of hot gases inside the cylinder rapidly expands
[4:41] these pistons are forced downward into the engine block.
[4:44] And that's how we convert the chemical 
energy in the fuel into mechanical energy.
[4:50] Now, the goal of this engine is to spin the wheels of a car.
[4:54] So ultimately the engine produces rotational movement.
[4:57] And since the pistons move up and down inside the cylinders,
[5:01] we're going to need a mechanism to translate 
their up and down motion into a spinning motion.
[5:07] If you noticed the weird stick thing 
with a ring on the end that each piston has,
[5:11] well, this is the connecting rod 
and it's there to connect the pistons
[5:16] to this thing.
[5:17] This is the crankshaft, and it is the thing that spins.
[5:22] The tachometer, the gauge which tells you engine RPM,
[5:25] is telling you how quickly this literal thing 
is spinning inside the engine block.
[5:31] Now we're going to look at this closely 
in a moment to see how the pistons make it spin.
[5:36] But first I want to point out that the crankshaft 
sticks out from the block on both sides.
[5:41] That is how we actually make this spinning crankshaft
[5:44] do useful things for us.
[5:47] Bolted to one side of it
[5:48] is this large rusty wheel with teeth on its edges.
[5:52] This is what's known as a flexplate.
[5:54] The teeth on its circumference are there 
for the electric starter motor to engage with,
[6:00] and turn the crankshaft 
inside the engine in order to start it from a stop.
[6:04] But the rest of this connects the engine to the transmission
[6:08] so that once the engine is running
[6:10] the spinning crankshaft can spin the wheels of the car.
[6:14] Technical note: if you were expecting me to call this a flywheel,
[6:18] well, this is not a flywheel.
[6:20] It's a flexplate.
[6:22] What's the difference?
[6:23] Well, flywheels are used with manual transmissions,
[6:27] while flexplates are used with automatic transmissions.
[6:31] In a car with an automatic,
which is what this engine was taken from,
[6:35] the flexplate gets fastened 
to the transmission's torque converter,
[6:38] and the engine and transmission 
are permanently coupled together.
[6:42] But flywheels are completely different.
[6:45] They're used with manual transmissions
[6:47] and are not really fastened to the transmission at all,
[6:51] since in a stick shift the engine and transmission 
are mated with a clutch under the driver's control.
[6:58] The clutch sort of presses up against the flywheel
[7:01] when engaged to connect the transmission to the engine,
[7:05] and it moves away from the flywheel when disengaged to separate them.
[7:09] And because of this, flywheels have a smooth surface
[7:12] on the outer side which the clutch pushes against.
[7:16] It's also quite a lot thicker and heavier than a flexplate
[7:19] to give the crankshaft more rotational momentum:
[7:22] helpful when getting the car moving from a stop.
[7:25] This Nissan Cube has a manual transmission,
[7:28] so its engine has a flywheel 
attached to the crankshaft and not a flexplate,
[7:32] but everything else is identical.
[7:35] Now, while moving the car is the main thing the spinning crankshaft has to do,
[7:40] it also has to do things like generate electricity to keep the car's battery charged.
[7:45] And that needs to happen whether the wheels are moving or not.
[7:48] Which is why the other end of the crankshaft 
also sticks out from the engine block.
[7:53] But on this side, all we have attached to it is the small pulley.
[7:58] This is the crank pulley
[8:00] and it provides power for engine accessories such as the alternator,
[8:03] air conditioning compressor and water pump via a drive belt.
[8:08] The pulley simply bolts on to the end of the crankshaft here...
[8:12] with this large bolt.
[8:14] Oh, and like in many engines,
[8:16] that pulley has some rubber like material in there
[8:19] to allow it to function as a harmonic balancer.
[8:22] But that's not important right now.
[8:24] What is important right now
[8:25] is how the uppy downy pistons actually make 
the spinny spinny crankshaft spin in the first place.
[8:31] To explain, I want you to focus on these very shiny
[8:34] and perfectly circular surfaces you can find on the crankshaft.
[8:38] These are bearings,
[8:40] just plain bearings.
[8:42] which is a dad joke because 
they are literally called plain bearings.
[8:46] [voiceover]
Oooookay editor me popping in
[8:49] with some notes on terminology.
[8:51] I made the mistake when writing this script
[8:53] of letting a technical definition supersede
[8:56] the common language most people use.
[8:59] These are indeed plain bearings,
[9:01] but they belong to a subset of 
plain bearing known as journal bearings.
[9:06] And the circular, shiny things we're looking at on the crankshaft
[9:08] are usually referred to as the journals.
[9:12] But here's the thing.
[9:14] Journal is simply another word for shaft.
[9:18] All these things are is a polished, circular shaft
[9:21] which spins inside of a stationary circle,
[9:24] which wraps around and holds on to the shaft.
[9:26] Once put together, it's really just two concentric circles
[9:30] where one spins and the other doesn't.
[9:32] And both the spinning journal and its stationary
[9:36] holder are a bearing surface,
[9:38] which is what I wanted to highlight in this video.
[9:41] The interface between those two bearing surfaces
[9:44] is what really matters to the point here.
[9:46] And from either one's individual perspective,
[9:50] the other part is what's spinning.
[9:51] And so that's why I ultimately chose to refer to these as bearings.
[9:56] But I understand a lot of people will be very annoyed by that choice.
[9:59] And so... sorry about that.
[10:02] They consist of that smooth,
[10:04] shiny part in the center of the crankshaft
[10:06] and a thin bushing which surrounds it.
[10:09] You can see half of the bushings here in the block.
[10:12] [voiceover]
Oh, hi. Me again.
[10:13] See, this right here explains the problem.
[10:15] This is literally the bearing.
[10:17] This is the bearing surface.
[10:19] But technically it is a bushing.
[10:21] However, when people rebuild engines,
[10:23] they're going to refer to these things
[10:25] as the bearing because it's the bearing surface.
[10:28] And hopefully that helps explain why I had such decision
[10:31] paralysis around the terminology here.
[10:33] Five of the bearings are all arranged in a straight line.
[10:37] These are the main bearings
[10:38] which hold the crankshaft in the block and keep it centered,
[10:42] but the remaining four are wildly offset from the rest.
[10:48] These eccentric bearings are what the pistons attach to.
[10:52] The big round part at the bottom of the connecting rod
[10:55] can be split in half by loosening these fasteners.
[10:58] And then you can attach the piston and its bushings
[11:01] to its respective bearing.
[11:04] Now, I want to point out as I very loosely attach this,
[11:08] that the mating surfaces here are both metal.
[11:13] This is literally metal on metal contact,
[11:16] and these components slide against each other as they spin around,
[11:21] which feels problematic, doesn't it?
[11:24] Keep that in mind as we continue.
[11:26] If you're wondering why the 
crankshaft has these weird lobe things,
[11:31] well, remember, this is the thing that spins.
[11:34] And since the bearings that the pistons 
attach to are wildly offset from the center,
[11:40] you need counterweights to keep it balanced.
[11:42] And that's what these are.
[11:45] This is roughly how fast the 
crankshaft spins when the engine is at idle!
[11:50] And at redline, it can be spinning ten times as fast.
[11:54] So you really want this thing
[11:56] as perfectly balanced as you can possibly get it
[11:59] to reduce vibration which could tear the engine apart.
[12:02] And you can even see marks 
where small amounts of material were drilled
[12:06] out of the counterweights after casting to make fine adjustments to balance.
[12:11] But anyway, back to the pistons.
[12:13] Once assembled, the pistons function
[12:16] very much like your feet when pedaling a bicycle.
[12:19] In fact, if you look at the crankshaft closely,
[12:21] you'll see that on each end of it
[12:23] is basically the exact same 
mechanism as the crank arm of a bike.
[12:28] And here's what it looks like with 
all the pistons attached and the crankshaft turning.
[12:33] There are several things wrong with this demonstration.
[12:37] For instance, this is upside down.
[12:39] But you'll notice that as the crankshaft rotates,
[12:42] the four pistons move up and down into pairs.
[12:45] When the outer two are at the bottom,
[12:47] the inner two are at the top and Nissan Versa,
[12:50] and they go round and round like a very strange Ferris wheel.
[12:54] I mean, there is a lot of iron in there.
[12:57] and here's what that looks like with the pistons and crankshaft inside the block
[13:01] and the starter motor turning the crankshaft.
[13:04] The block constrains the lateral movement of the pistons
[13:07] which means the piston needs to be able to pivot back
[13:10] and forth with respect to its connecting rod
[13:13] as it flies around the crankshaft below.
[13:16] That's why the connecting rod
[13:18] is attached to the piston with what's called a wrist pin 
(or gudgeon pin if you're British).
[13:23] That allows the top of the piston to sort of wiggle back and forth with respect to its connecting rod.
[13:28] And that's how the piston can stay on 
a perfectly vertical track inside the block,
[13:33] while its connecting rod is flailing all around below.
[13:37] Here's a fun fact!
[13:39] While editing this video,
[13:40] I discovered that I accidentally deleted this section from the script.
[13:44] So here's me putting it back!
[13:46] When we are talking about an engine's size,
[13:49] we're not actually talking about 
how large the cylinders in the block are.
[13:54] At least not entirely.
[13:57] We measure an engine's size by its displacement,
[14:00] and that is defined by how much volume the pistons displace
[14:05] as they move up and down inside the cylinders.
[14:08] The pistons can only move down so far,
[14:11] which only opens up so much space.
[14:14] And in this engine, each piston moves
[14:16] through a volume of 450cm³.
[14:20] There are four of them, of course, and added together,
[14:23] that means the pistons displace a total volume
[14:26] of 1800cm³, or 1.8 liters.
[14:31] And that is why this is a 1.8l engine.
[14:35] However, we could increase this engine's displacement
[14:39] without making the cylinders any bigger at all.
[14:42] All we'd need to do is increase the stroke of the pistons
[14:46] so that they travel farther down before they start 
heading back up, and boom, more displacement!
[14:53] But that's much easier said than done, because to actually make that happen,
[14:57] we'd need an entirely different and much larger crankshaft,
[15:02] which will require redesigning the block.
[15:05] And the power delivery characteristics of a piston engine can vary dramatically when the pistons have a longer stroke,
[15:12] so it might not be desirable for all applications.
[15:16] This is all very complicated,
[15:18] but an engine's displacement presents a hard limit
[15:22] to how much power it can theoretically produce,
[15:24] and this is why, purportedly,
[15:27] there is no replacement for displacement.
[15:30] Then again, my daily driver has an engine displacement of null,
[15:35] and yet it can still do 0 to 60 in well under five seconds.
[15:39] So I'm not sure how true that is these days.
[15:41] But anyway, let's move on.
[15:43] And at this point, we've looked at nearly everything 
which lives inside the engine block.
[15:48] But now you might have noticed a bit of a problem.
[15:52] I said that the cylinders are combustion chambers
[15:55] and expanding gases pushed the pistons down.
[15:59] But, uh, right now
[16:00] those gases don't have anything to push against.
[16:03] This is just a weird series of cups
[16:05] where the bottom can move up and down for some reason.
[16:09] To actually turn all these into combustion chambers,
[16:12] we need to seal it up.
[16:14] And that's done with the cylinder head.
[16:16] But also the piston rings.
[16:19] Before we even talk about sealing the top of the chamber,
[16:22] we also need a seal between the pistons themselves and the walls of the cylinders.
[16:27] The pistons are actually slightly smaller
[16:29] than the cylinders and can flop around in there a little bit.
[16:32] So each one has not one, not two,
[16:35] but two piston rings and a third oil control ring, 
which is a kind of piston ring,
[16:40] but it doesn't have the same job.
[16:42] The two piston rings near the top, known as compression rings, are simply metal rings with a bit of spring tension in them
[16:50] which causes them to expand and fill 
the gap between the piston and the cylinder walls.
[16:56] There are two of them because
in order to put the ring on the piston,
[16:59] it needs a gap, and that gap means the seal isn't so good.
[17:04] So, well, we just throw a second one on there,
[17:06] and ideally you'll position the gaps on opposite side -
[17:10] Well, that one broke!
[17:11] [through laughter]
on opposite sides of the piston when putting the thing together.
[17:15] So with the pistons now 
sufficiently sealed against the cylinders,
[17:19] we have to seal the top of this thing 
so that we have an actual combustion chamber.
[17:24] And that's what this guy is for.
[17:27] This is the cylinder head
[17:29] and it gets bolted to the top of the block and, with the help of the head gasket,
[17:33] actually seals the cylinders up 
so they can become combustion chambers.
[17:38] But this does far more than just that.
[17:41] This is also what allows fresh air and fuel into the cylinders,
[17:45] what expels exhaust from the cylinders,
[17:47] and what ignites the air/fuel mixture.
[17:52] Well, the spark plug is what does that for each cylinder.
[17:55] But the spark plugs live in the cylinder head.
[17:56] You can, see 'em poking out just there.
[17:59] To actually let air and fuel into, 
as well as exhaust out of, the combustion chambers,
[18:05] the cylinder head contains valves.
[18:07] Like most modern engines there are four valves per cylinder, 
two each for intake and exhaust.
[18:13] You really only need one of each,
[18:15] but geometry makes it so you can have more total area
[18:18] if you have two smaller valves rather than one big one,
[18:22] and that allows the engine to breathe more easily.
[18:25] From this side, the valves look like little circles,
[18:28] but what they actually look like is golf tees.
[18:32] And I'm totally serious.
[18:33] They're basically just large golf tees.
[18:36] I'd remove one to show you, but you see,
[18:38] they're held shut with extremely powerful springs
[18:41] and I do not have the guts to remove them for you.
[18:45] So I bought these ones!
[18:47] All that each of these little valves is really doing
[18:50] is plugging a hole in the cylinder head.
[18:53] On the sides of the cylinder head are the intake and exhaust ports.
[18:57] These are where air and fuel goes into the engine on one side
[19:01] and exhaust comes out of it on the other.
[19:03] Look into those ports and you can see the backsides of the valves and the holes that they're plugging.
[19:10] To keep that hole plugged up and the combustion chamber sealed,
[19:13] a spring being held by this retaining mechanism
[19:16] is constantly pulling up on the 
valve stem and keeping it firmly in its seat.
[19:22] But if something pushes down hard enough to overcome the force of the spring,
[19:26] the valves will poke out from where they sit
[19:29] and suddenly the hole isn't plugged any longer.
[19:32] There is now a pathway for air to make its way through this port and into the cylinder.
[19:37] We now have all the ingredients 
to make a series of combustion chambers
[19:42] that we can move gases into and out of under our control.
[19:46] But what actually opens and closes the valves?
[19:51] Well, these things,
[19:53] but, more on them in a moment.
[19:56] Now, we need to discuss the four stroke engine cycle.
[20:00] Virtually every engine out there 
which isn't a very big diesel engine
[20:04] or a very small weed whacker engine,
[20:05] or in a very old car is a four stroke engine,
[20:09] which means that when looking at a single cylinder,
[20:12] the piston actually travels up and down
[20:15] two complete times per combustion event.
[20:18] First, it travels down during the intake stroke,
[20:21] where the intake valve is open and fresh air 
and fuel is brought into the cylinder.
[20:27] Then the valves will close and the piston travels back up
[20:30] during the compression stroke, which squeezes 
that air and fuel into a tiny little space.
[20:36] When the piston is at the top,
[20:37] the spark plug fires
[20:39] which ignites that mixture and forces the piston down during the power stroke,
[20:43] which is the only stroke that actually produces motive power.
[20:47] And finally, the piston moves back up again
[20:49] with the exhaust valve open during the exhaust stroke,
[20:53] where the piston will push the exhaust gases out of the cylinder.
[20:57] And then that repeats.
[20:58] That's intake, compression, power, and exhaust.
[21:02] And for a helpful way to remember that,
[21:03] which I'm sure many of you out there really want me to say...
[21:07] suck squeeze bang blow.
[21:10] To make that sequence actually happen though,
[21:12] the valves need to open and close in time 
with the movement of the pistons in the block.
[21:18] And to make that happen, we use rotating camshafts like this.
[21:24] These fellas are held captive with 
this bracket and spin above the valves.
[21:29] When the pointy bit on each one of these cams, 
known as the lobe, lines up with the top of the valve,
[21:35] it will press down on its respective valve and open it.
[21:40] Here's what that looks like.
[21:42] I want to point out yet again that this is metal on metal contact,
[21:46] but you may notice in this footage that some kind of dark
[21:49] liquid appears to be oozing out of various places
[21:52] and getting all over the cams.
[21:55] That's engine oil.
[21:57] Where is it coming from?
[21:59] The oil pump.
[22:00] But hold on, we're not there yet.
[22:02] First, I want to point out that the sequence 
in which the valves are opened
[22:06] is programed by the physical shape of these things,
[22:09] and that, along with the crankshaft design, dictates
[22:12] the engine's firing order.
[22:15] This engine doesn't fire the cylinders in sequence.
[22:18] In fact, it skips around a bit with a firing order of 1 - 3 - 4 - 2
[22:24] And if I slowly rotate the camshaft,
[22:27] you'll see that the lobes stick out in that same order
[22:31] because they have to open the valves in that order.
[22:35] This engine could have been designed
[22:37] with a simple 1 - 2 - 3 - 4 firing order,
[22:40] but that would require a different crankshaft
[22:43] where pistons one and three are at the top,
[22:46] while two and four are at the bottom.
[22:48] And when you do that with an inline four cylinder,
[22:51] it tends to be even more of a vibrating mess than it already is.
[22:55] Which is why the pistons are paired like this
[22:57] and the firing order skips around a bit.
[23:00] It's just a better balance.
[23:02] But now we have a bit of a timing problem.
[23:05] We need to make absolutely sure that those valves are opening
[23:09] when they should be in relation 
to the pistons moving inside the engine block.
[23:15] One way to do that would be to mechanically interlock 
the camshafts with the crankshaft,
[23:21] which is exactly what this and any engine does,
[23:24] but it's a little more complicated than you might imagine at first.
[23:28] Recall this is a four stroke engine,
[23:30] which means the pistons travel up and down twice for every time a valve opens.
[23:36] But since the camshafts only make one rotation to open their valve,
[23:42] that means we need the camshafts to be spinning 
at exactly half the rate of the crankshaft.
[23:50] We need to do that so the crankshaft makes two rotations for every one rotation of the camshaft.
[23:56] Luckily, that's easy to do with our old friend gears.
[24:01] You may have noticed a couple of gears
[24:02] on the end of the crankshaft away from the flex plate.
[24:06] This smaller gear will drive 
the camshafts with the help of a chain.
[24:11] That's this guy, the timing chain,
[24:14] and it lives underneath this cover on the side of the engine.
[24:17] Its job is to transmit motion from the crankshaft at the bottom
[24:22] all the way up to the camshafts at the top.
[24:25] Now the chain is going to keep 
them mechanically locked together,
[24:29] but importantly, the crankshaft's 
gear has exactly half as many teeth
[24:35] as the gears which drive the camshafts.
[24:38] There are 23 teeth on the crankshaft gear
[24:40] and 46 on both of these camshaft gears,
[24:44] and that ratio will ensure it always takes 
exactly two rotations of the crankshaft
[24:49] for the camshaft to make a single rotation.
[24:52] And so long as this chain doesn't break,
[24:55] they will remain perfectly locked together
[24:57] such that the valves always open at the same time
[25:00] in relation to the pistons inside the engine block.
[25:04] Of course, we can actually 
fiddle with that while the engine is running,
[25:08] and that's why this gear is so thick.
[25:10] But we are not getting into that today!
[25:13] At this point, I've covered all the 
mechanical basics of this engine.
[25:17] And while this is a very common design,
[25:20] it's by no means universal.
[25:22] For one thing, lots of engines have more than
[25:25] or even less than four cylinders.
[25:28] Three cylinder engines have snuck their way into lots of cars 
these days, and many people haven't seemed to notice.
[25:33] And of course, there's all those V6es and V8s
[25:37] V engines are interesting
[25:39] because they add a second bank of cylinders, 
but both banks of pistons share a single crankshaft.
[25:47] This makes them only marginally larger 
than their inline counterparts,
[25:51] while doubling the number of cylinders,
and thus the power it can produce.
[25:56] But more cylinders means 
a thirstier engine which costs more to operate,
[26:00] which is why the old four banger is so dang common.
[26:04] It's good enough.
[26:06] but even within inline fours, there's a ton of variation.
[26:10] This engine has separate camshafts 
for the intake valves and the exhaust valves,
[26:15] and where these live is above the cylinder head.
[26:19] And that makes this a dual overhead cam engine.
[26:23] If you've ever seen DOHC on an engine cover
[26:25] or like on the side of an old car as a badge,
[26:28] that is literally referring to these two cams
[26:32] and where they are in relation to the rest of the engine.
[26:35] Some engines only use one camshaft,
[26:39] but it will have more lobes on it, so it can actuate 
both the intake and the exhaust valves.
[26:44] And that would be a single overhead cam engine,
[26:47] SOHC.
[26:49] But the camshaft isn't always over the heads.
[26:51] Sometimes it lives in the block.
[26:54] Many of those engines will use push rods,
[26:57] basically metal sticks which ride on the cams,
[27:00] and then they stick up into the head so that as the cams
[27:04] rotate and the lobe pushes up on the stick,
[27:06] the push rod will actuate itself against a rocker arm,
[27:09] which then pushes down on the valves.
[27:12] Those engines aren't that common these days because putting the cams over the heads has a lot of advantages.
[27:18] Oh, and not every engine will use a timing chain.
[27:23] For some reason we decided 
to start using timing belts made of rubber.
[27:29] Okay, the reason was
[27:31] that it made engines a little quieter
[27:33] and it's not completely without merit.
[27:34] But don't get me started on Ford's wet timing belt situation.
[27:39] Just an utterly terrible idea
they should be shamed for forever!
[27:44] Regardless, engines with timing belts 
need regular replacement of that belt,
[27:49] because many engines are what's called an interference engine,
[27:53] where the valves will actually occupy 
the same physical space in the cylinder when they are open
[27:58] that the pistons do when they're at the top.
[28:01] So long as the engine is in time,
[28:03] this doesn't matter because the pistons 
won't be near the valves when they're open.
[28:07] But if the timing belt were to break
[28:10] and the cams stop turning with a valve open 
and sticking down into the cylinder,
[28:15] then as the crankshaft keeps on rotating, 
its respective piston will slam into that stuck valve
[28:21] and cause lots of very expensive damage.
[28:25] You don't want that, so you have to change 
the timing belt before it might break.
[28:31] Timing chains are much, much 
less likely to break, but they can fail.
[28:37] Usually, though, it's not catastrophic.
[28:39] Instead, they simply start to stretch out a bit due to the links wearing down,
[28:44] which makes valve timing sloppy, 
but not necessarily bad enough to be a problem.
[28:50] Though if it does get bad enough to where the chain skips a tooth,
[28:54] replacing a timing chain is a lot more involved than a belt,
[28:58] so there is that to consider.
[29:02] Right, and some pushrod engines don't use a belt or a chain.
[29:05] If the camshaft is close enough to the crankshaft,
[29:08] you can simply use interlocking gears.
[29:11] But again, pushrod engines in cars 
are pretty much a relic of the past,
[29:15] with some notable exceptions.
[29:17] Oh, and also there's flathead engines where 
the valves aren't even in the heads.
[29:21] But those are very old designs, 
and this rabbit hole is very, very deep.
[29:25] And eventually you just have to stop.
[29:27] Speaking of stop...
[29:28] At this point, you're probably wondering
[29:30] how any of this relates to the intro
[29:32] and the thing about that little red light
with a picture of an oiling can.
[29:36] Well, everything we've been talking about is made of metal.
[29:41] There's metal on metal contact everywhere inside this engine,
[29:45] and those bits of metal spin really, really fast.
[29:50] Or in the case of the pistons,
[29:52] those bits of metal slide against each other really, really fast.
[29:55] And that's going to cause a lot of damage 
unless you have lots and lots of lubrication.
[30:03] And that is what engine oil is for.
[30:06] Hanging off the bottom of the 
engine block is what's called the oil pan.
[30:10] And this is effectively just a big bucket
[30:12] which holds several quarts of motor oil.
[30:16] Well, this engine has a weird design
[30:18] and the block is split into two pieces.
[30:21] So it doesn't really have an oil pan per se,
[30:23] but the gist is the same.
[30:26] This bottom half of the block alongside a plate,
[30:29] which is the closest thing to an oil pan this engine has,
[30:32] holds just about four liters of oil.
[30:35] Apparently its precise oil capacity is four and 3/8 of a US quart.
[30:41] And sitting below the crankshaft inside the oil pan
[30:46] is this thing: the oil pump.
[30:48] every engine which isn't a tiny little thing for like a lawnmower,
[30:52] has an oil pump and in this one it's driven 
by the crankshaft via a second chain.
[30:58] So long as the crankshaft is spinning, the oil pump will be too.
[31:02] And what this does is suck engine oil 
out of this pan with this pickup tube,
[31:07] force it through a filter to catch any contaminants,
[31:09] and from there, the oil gets sent through many,
[31:12] many tiny little holes and passageways throughout the engine.
[31:17] Look closely at practically any part of an engine which moves,
[31:20] and somewhere along the mating surface, you're going to find a hole which eventually leads back to the oil pump.
[31:28] There are so many holes because when an engine is running,
[31:31] oil is getting forcefully sprayed all over the dang place.
[31:34] in fact, if you were wondering 
what some of these other holes in the head gasket were for,
[31:40] well, some of these deliver oil under pressure 
from the block and into the cylinder head
[31:45] so that it can lubricate the bearings of the camshafts
[31:48] as well as the cam lobes as they slide along the valves.
[31:51] That's why there's oil oozing out of different places in this footage.
[31:55] Some of the other holes in this head gasket
[31:57] allow that oil to return to the oil pan with the help of gravity,
[32:01] though other holes are for engine coolant,
[32:03] which we won't be talking about today.
[32:06] Regardless, let's take a close 
look at the block and crankshaft bearings
[32:10] because they reveal how this works the best.
[32:13] This port with an orange O-ring on it
is where oil is fed from the pump.
[32:18] Once it finds its way in the block,
[32:20] the oil flows through a series of tubes,
[32:23] and you can sort of make out the shape of these tubes
[32:26] and how it tees off here in both directions
[32:28] by looking at the casting of the block.
[32:32] If we look at the main bearing surfaces in the block,
[32:35] we'll see that there's a hole in each one of its bushings.
[32:38] If I remove the bushing, we'll find another larger hole behind it.
[32:43] The oil pump forces a steady stream of oil through those holes whenever the crankshaft is spinning,
[32:49] and that creates a fluid bearing.
[32:52] Once there's oil pressure, the metal surfaces 
aren't actually touching each other.
[32:57] Instead, they glide past each other with a thin film of oil between them.
[33:02] That's how the bearings allow the engine to spin smoothly
[33:05] despite the fact that they're literally just two pieces of metal.
[33:09] But you'll notice that there's a channel 
or groove cut into the bushing here.
[33:14] that is there to create a pathway for engine oil 
to make its way around the bearing
[33:19] and into the crankshaft itself.
[33:22] Notice that the bearing also has a hole.
[33:25] That hole will move around as the engine spins,
[33:28] but it will always be above that groove
[33:30] and so will always be fed oil from the block.
[33:34] And here we can actually see where the hole leads:
[33:37] another hole on another bearing; the bearing 
that the connecting rod attaches to.
[33:42] This is so that those bearings also get lots of lubrication
[33:46] and we get that fluid bearing effect
which keeps the metals from touching.
[33:50] Which by the way in case it's not clear
[33:52] oil is only under pressure inside 
all those passageways and ports and stuff.
[33:58] There's a whole bunch more of them too which I haven't covered
[34:00] inside the cylinder head to keep the camshafts lubricated
[34:03] as well as the moving parts of the valves.
[34:06] But once the oil makes its way out of whatever
[34:08] confined space it used to be in,
[34:10] it will just sort of ooze out.
[34:12] And then it's got to get back to the bottom of the engine
[34:15] so the oil pump can suck it up again.
[34:18] So there is also a series of pathways throughout the engine
[34:21] that will simply return any pooling oil to the bottom via gravity.
[34:25] And that's why internal combustion engines 
need to be close to upright to operate.
[34:31] If I were to turn this engine upside down and try and operate it,
[34:34] or frankly, even on its side like it is now,
[34:37] oil would be pooling in places it shouldn't 
go and the oil pump won't be able to get it.
[34:41] And so the lubrication system just...
[34:44] wouldn't work.
[34:46] And that's bad because everything 
inside this engine moves stupidly fast.
[34:53] If for whatever reason, the engine were to lose oil pressure,
[34:57] then suddenly you have a very big problem.
[35:00] That nice fluid bearing effect you get which keeps the metal parts from actually touching each other
[35:05] will go away and now... metal parts 
are rubbing against each other very quickly,
[35:12] and that's going to produce a lot of friction,
[35:14] which will produce a lot of heat.
[35:16] And before long the engine will seize,
[35:19] meaning parts get fuzed together 
and it can no longer spin at all.
[35:24] It is possible to get a seized engine unstuck,
[35:28] but it will definitely be damaged in some way
[35:30] and will likely have a greatly shortened lifespan.
[35:33] So you never, ever, ever, ever want to run an engine
[35:37] without knowing that there is sufficient 
oil pressure to keep that from happening.
[35:42] And that is what that light is for.
[35:45] It's connected to a pressure switch
which in its resting state is closed.
[35:50] In other words, when there is no oil pressure,
[35:53] that switch completes a circuit which lights up that light.
[35:57] This is what the pressure switch looks like.
[35:59] It's an unassuming little thing.
[36:01] Once the engine is turning,
[36:03] the oil pump will start forcing oil into all those passageways.
[36:07] And this port on the side is tapped off of those passages.
[36:11] So sufficient oil pressure will open this 
pressure switch and extinguish the warning light.
[36:17] This design allows you to check that the pressure switch is actually functional,
[36:21] because if you simply turn the key without cranking the engine,
[36:25] you should see the oil pressure light.
[36:27] There's no oil pressure yet because the engine isn't running!
[36:30] But when you start the engine,
[36:32] that light should go out almost immediately.
[36:35] And if it doesn't, there's a problem.
[36:38] That problem isn't necessarily with the engine, of course.
[36:42] It could simply be a bad pressure switch.
[36:45] But that's a really risky assumption to make
[36:48] because if that light and the switch is working as it should,
[36:52] then if the light comes on, you are
[36:55] then running your engine without oil pressure, which will kill it.
[37:00] Oh, and fun fact eagle-eyed viewers 
of the catalytic converter video
[37:04] may have noticed that this car had a bad pressure switch,
[37:07] but it failed open.
[37:09] The oil pressure light was never coming on
[37:11] even without the engine running.
[37:13] Here's me turning the key and that light is nowhere to be seen.
[37:18] This meant the car could never warn me that I've lost oil pressure,
[37:22] which isn't as bad as actually losing oil pressure, 
of course, but it's still quite bad.
[37:27] Luckily, I happened to buy this entire engine for making videos
[37:30] and it had its own oil pressure switch on there,
[37:33] so I just swapped them over.
[37:34] And now that light is actually doing its job.
[37:37] Quick side note,
[37:38] a lot of older cars didn't have an oil pressure warning light
[37:41] and instead had an oil pressure gauge,
[37:44] but that's mostly gone, 
much to the chagrin of John Davis of MotorWeek.
[37:49] Some new vehicles still have oil pressure gauges,
[37:52] but they're mainly found in big trucks
[37:54] because getting to see an engine oil pressure readout makes some people feel big and manly and important.
[38:01] But I mean, most people don't really care
[38:05] how much oil pressure an engine 
is producing at any given moment.
[38:08] And without knowledge of how much is actually correct,
[38:11] a gauge isn't that useful anyway,
[38:13] and that's why a simple pressure switch 
and warning light which indicates
[38:17] "oil pressure is below a safe threshold," is frankly better.
[38:22] Yeah, I said it.
[38:24] Gearheads like to call these idiot lights
[38:26] because we used to expect people to know 
they should be checking the gauges frequently.
[38:31] In fact, some cars in the past had a little yellow warning light
[38:34] which literally said "check gauges."
[38:37] But while I too lament the loss 
of drivers being expected to know
[38:41] a little more about how their cars work than they seem to now,
[38:44] I think it's fair to say a warning light is all that's really needed,
[38:48] but you do need to know what that warning light means.
[38:52] On that note, why might you actually lose oil pressure?
[38:57] Well, it's very rare for it to suddenly just happen.
[39:02] I hope I haven't made it sound like this is something
[39:04] you need to be extremely vigilant about all the time,
[39:06] though you probably should watch the oil pressure 
light closely after you get an oil change,
[39:12] and I'll explain that further in a moment.
[39:14] If you're just driving around on a normal day, though,
[39:17] it's extremely unlikely
that your engine will suddenly lose oil pressure.
[39:22] That would really only happen 
if the oil pump were to somehow fail.
[39:26] And given that it's literally the most lubricated part
in the whole engine
[39:30] since it sits in oil and pumps it around,
[39:33] that's quite rare.
[39:35] It does happen, but it's extremely rare.
[39:38] However, if your engine burns oil,
[39:41] which it shouldn't, but it tends to start happening
[39:44] when an engine gets very old and worn out.
[39:47] Or if it wasn't designed very well,
[39:50] well then the amount of oil inside 
your engine slowly drops as you use your car.
[39:57] There's quite a good deal of margin for error,
[39:59] so losing a quart of oil between 
oil changes is not likely to cause a problem.
[40:04] But if your engine burns through a lot of oil,
[40:08] then eventually the oil level can get low enough
[40:11] that the oil pump starts to have trouble 
sucking any up through the intake tube.
[40:16] If this is happening, the oil pressure 
light will likely come on and off, seemingly at random.
[40:22] That is not as bad as not having 
any oil pressure at all, but it's still quite bad.
[40:28] The bearings inside the engine 
aren't always getting good oil flow,
[40:32] and they're going to start wearing 
out a lot faster than they should.
[40:36] So you probably need to add some oil to your engine 
if that light is coming on intermittently.
[40:42] But the most common reason you might one day lose 
oil pressure is when somebody makes a booboo.
[40:49] For example, you went in to get an oil change
[40:52] and the technician forgot to actually fill the engine
[40:54] with new oil after they drained the old oil out.
[40:57] Or maybe they forgot to put the drain plug back.
[41:00] Or perhaps they didn't tighten it enough
[41:01] and it backed itself out as you were driving
[41:04] and your car puked all of its oil onto the ground.
[41:07] To be clear, 
I don't want to make it sound like that happens all the time.
[41:10] But seriously, after you get an oil change,
[41:13] pay attention to that light for a while.
[41:16] You really want to make sure it goes out quickly 
once the engine turns over and stays out.
[41:22] But speaking of oil changes,
[41:23] this car is due for one, so let's do it!
[41:26] Why not?
[41:27] In fact, I have no idea whether it's actually due for one.
[41:30] But that's kind of why I'm doing it.
[41:33] Changing your own oil is actually quite easy,
[41:36] but I don't really recommend it because it's messy,
[41:40] you have to deal with the old oil
[41:42] (and yes, parts stores will take 
used oil for free, but it's still annoying),
[41:46] And, it honestly hardly saves any money.
[41:49] But why don't I show you the process?
[41:52] Actually, first, if you don't know why you have to change the oil
[41:56] every some thousand miles or so, well, here's why:
[42:00] The oil gets really hot
[42:02] and the piston rings aren't perfect.
[42:05] Remember, there's a whole bunch of explosions going on in here!
[42:09] Several every second, just at idle!
[42:12] And the intense pressure inside the cylinders means
[42:15] some combustion byproducts are going to end up getting past the piston rings
[42:20] and into the crankcase where they'll mix 
with the engine oil and start to contaminate it.
[42:26] That will eventually start to chemically break it down.
[42:29] And if that's not bad enough,
[42:31] the oil which clings to the cylinder walls gets extremely hot,
[42:35] which also causes chemical breakdown.
[42:37] Over time, this causes the oil to lose its lubricative properties,
[42:42] and that means your engine can start to wear.
[42:45] And if you're really overdue for an oil change,
[42:48] little bits of stuff can precipitate out
[42:50] of old engine oil and stick to things.
[42:53] That's engine sludge.
[42:55] And if it gets bad enough, it can start breaking things
[42:58] by plugging up those tiny oil passageways.
[43:01] So you gotta change your oil regularly to keep that from happening and to keep the engine healthy.
[43:08] I'm deliberately not commenting on how often 
you should do that because nobody agrees.
[43:13] But my basic advice is consult your owner's manual and maybe do it a little more often than it says you should.
[43:21] But I've got one of those 
electric cars and it doesn't need oil changes.
[43:25] How about that?
[43:26] But this one does.
[43:28] So first I'll get it up in the air a little bit.
[43:31] You don't need a lift to do this.
[43:33] If all you want to do is your own oil changes,
[43:35] you can purchase these ramps 
and drive the front of your car onto them,
[43:39] and that'll give you enough room to work with.
[43:42] There's two things you need access to from the bottom:
[43:45] the drain plug and the oil filter.
[43:47] Though in some cars the oil filter is somewhere else
[43:50] or possibly behind a cover of some sort.
[43:53] You'll also need something to catch 
the used oil with, like this purpose made drain pan.
[43:58] And then of course, you'll need new oil and a replacement filter.
[44:02] Here's a five quart bottle of the cheapest oil I found in the store,
[44:06] because this car is not worth getting fancy over,
[44:08] and here's a replacement filter which fits the car.
[44:12] Speaking of the oil,
[44:13] your car's engine is going to call for a specific oil viscosity,
[44:17] which some people refer to as its weight.
[44:20] The Society of Automotive Engineers came up with a way to define motor oil viscosity
[44:25] using a simple numbering scheme, and bigger numbers are more viscous.
[44:29] This car needs 5W-30 motor oil.
[44:33] And the cool thing about that
[44:34] is that this oil has two different viscosity grades.
[44:38] When the oil is cold, it has 
the same viscosity as a five weight oil.
[44:43] That's the 5W, and the W is for winter.
[44:47] But when the oil is hot
[44:49] it has the viscosity of a 30 weight oil.
[44:53] Now any oil loses viscosity and gets thinner as it gets hotter.
[44:57] And this is no different.
[44:58] But as the engine warms up, additives in this formulation
[45:02] slow down that thinning process.
[45:05] And that's how when it's hot, it has the same viscosity
[45:08] as an unmodified 30 weight oil.
[45:11] This is actually a really neat thing we figured out how to do.
[45:14] And it means the engine has 
an easier time starting when it's cold,
[45:18] but still has the same protection 
as a 30 weight oil once it's warmed up.
[45:23] Right. And the breakdown of those additives over time
[45:26] as the oil gets contaminated with combustion byproducts and whatnot, lowers the oil's viscosity grade.
[45:32] And that's yet another reason you need to change it periodically.
[45:36] So to do that, I'll start by draining the old oil from the engine.
[45:40] But first I'm going to remove the filler cap up top,
[45:43] which will allow that oil to leave the engine more quickly
[45:46] by breaking the vacuum and letting air into the top of the engine.
[45:50] Then I'll put the drain pan below the drain plug of the engine,
[45:54] but I'm going to position it off-center.
[45:56] You'll see why shortly.
[45:58] Quick note, the transmission will also have a drain plug,
[46:02] so make sure you know how to tell the engine and transmission apart before you drain the wrong thing.
[46:07] Next, I'll use a wrench to crack the drain plug loose.
[46:11] The engine is warmed up,
by the way, to make the oil flow more easily.
[46:14] with a gloved hand I'll then remove the plug.
[46:18] If you keep pressing in on it while you back it out,
[46:21] you can usually keep it from dripping any oil at all 
until you feel the threads start to click,
[46:26] and then you can simply yoink it out 
quickly and hopefully not get any on your hands.
[46:31] And now that it's flowing out of there,
[46:33] you can see why I didn't center the drain pan.
[46:36] As the old oil flows out, we'll deal with the oil filter.
[46:40] This style of oil filter has built in threads 
and simply screws onto a fitting on the engine block.
[46:47] Or in the case of this car,
[46:49] whatever you call this part,
which isn't really the block, but kind of is.
[46:53] Anyway, these should only be put on hand tight,
[46:57] which means they should come off easily,
[47:00] but should is carrying a lot of weight there.
[47:03] And that's why I have this oil filter wrench.
[47:07] Once it starts coming loose, keep in mind
[47:09] this thing is filled with oil and will be gross.
[47:12] Many drain pans like this one have a spot
[47:15] molded into them to put the used filter and let it drain out.
[47:18] And now I'll take the new filter and with my gloved hand,
[47:22] I'll smear just a little bit of the old oil onto the gasket
[47:26] before screwing it onto the engine.
[47:28] And again, this should only go on hand tight.
[47:33] By the way, these claim to last long enough to only change the filter every other oil change.
[47:38] But these are like five bucks,
so you might as well just change it.
[47:41] Its job is to trap
things like metal shavings and keep them in the filter
[47:45] before they plug up all those little parts and stuff,
[47:48] which would be very bad.
[47:49] So I don't think it's worth risking it.
[47:51] Just replace it.
[47:53] By this point, the engine is probably almost done 
draining the old oil out of itself.
[47:58] But if for some reason it's still flowing, let it flow.
[48:02] Once it's down to barely a trickle, 
though you can put the drain plug back.
[48:07] Ideally, you'd replace this crush washer which seals that hole,
[48:11] but I did not get a replacement, so I will be reusing the old one
[48:15] Once I've started threading the plug by hand,
[48:18] I'll then reach for an impact wrench.
[48:20] Except I'm joking.
[48:21] Don't ever use power tools for this.
[48:24] If you screw up the threads on the oil pan,
[48:26] this oil change went from an easy job to a very bad day.
[48:30] So only use hand tools when dealing with drain plugs.
[48:35] I even looked up the torque spec for this guy.
[48:37] It's 34.3 Newton meters or 25 pound feet.
[48:42] And I used this old torque wrench which I have 
no idea whether it's well calibrated or not at this point,
[48:46] but hey.
[48:47] It's the thought that counts.
[48:48] [click]
[48:50] And now we're done down here.
[48:52] But we're very much not done done 
because the engine no longer has any oil in it!
[48:58] Well, it probably has about half a quart stuck in there 
based on how much of a mess
[49:01] this one made when getting some of this footage,
[49:04] but it's definitely not enough for it to run without damage.
[49:07] If I were to start it now, that would be very bad.
[49:10] Oh, fun fact, did you know engines are dishwasher safe?
[49:13] The dishwasher would not agree, but, uh,
[49:16] it did clean it.
[49:18] Anyway,
[49:19] now we have to put new oil into the engine,
[49:21] which is done via the filler cap.
[49:24] This is literally just a big hole that leads into the timing cover.
[49:28] Look, you can even see the timing chain a little bit.
[49:31] Pour new oil into here and it will fall down into the oil pan...
[49:35] or whatever this is- let's just call it the oil sump.
[49:39] However, this car will not need this entire bottle of oil.
[49:43] In fact, it would be overfilled if I put the whole thing in
[49:46] and an engine with too much oil is also a problem.
[49:51] So I'll put most of it in there,
[49:53] but then I'll have to check how much oil is inside using the dipstick.
[49:57] Which is literally just a stick in a tube.
[50:00] And that tube leads to the engine's oil sump.
[50:03] The stick has markings on the end,
[50:05] and once you've cleaned it using a rag or paper towel or whatever,
[50:08] you'll stick it down into the tube 
all the way and then pull it back out.
[50:13] The tip of the stick should have poked down into the oil,
[50:16] and you'll be able to see the oil level when you pull it out.
[50:19] If you're not seeing any oil towards the markings,
[50:22] you're probably still about a quart shy 
and you'll need to add a good deal more.
[50:27] Just keep adding a little bit at a time, though, 
and repeat the oil level check process,
[50:31] and eventually you'll start to see the oil in the range.
[50:34] I'm going to shoot for just below the full mark,
[50:37] which will account for any oil
[50:39] which might be sticking to the timing chain and junk.
[50:42] And once it's full,
[50:44] well that's an oil change.
[50:46] It's really quite straightforward.
[50:48] Now all that's left to do besides dealing 
with the used oil and filter, of course,
[50:53] is to put the oil cap back on and start the engine.
[50:56] But now a note on prefilling the oil filter.
[51:01] Some people insist that you should fill the oil filter
[51:04] with clean oil before putting it on to the engine.
[51:07] The theory is that this oil filter 
is currently filled with air and not oil,
[51:12] and so when I start the engine,
[51:14] there will be a brief moment 
where the engine is running without oil pressure.
[51:19] But personally, I think this is a very silly thing to obsess over.
[51:24] Why?
[51:25] Well, because not only is the oil filter filled with air right now,
[51:27] but so is every single one of the passageways inside the engine.
[51:31] So forgive me for not thinking
[51:33] filling this with oil is going to make a huge difference.
[51:37] Granted, this engine has a tiny little filter 
and some engines have much bigger ones.
[51:41] But why don't we take a look at how quickly
[51:43] that oil pressure light goes out once I start the engine?
[51:47] Okay.
[51:47] I just changed the oil.
[51:48] Let's crank it up.
[51:50] [engine starts]
[51:54] Yeah.
[51:55] What, one second?
[51:58] One extra second.
[51:59] It's not a big deal.
[52:01] I mean, you go ahead and fill these things with oil if you want to,
[52:04] but I feel like doing that is just creating 
another mess which isn't doing much if anything at all.
[52:10] The film of old oil that's sticking to the bearings, etc.
[52:13] is going to be enough to prevent damage in the 2 or 3 seconds
[52:17] it takes the oil pump to fill even a really big oil filter.
[52:21] Regardless, now that the engine is running, it's prudent to check the oil filter and drain plug for any signs of leaks.
[52:29] And assuming there are none,
[52:31] you're done!
[52:32] We've looked at a great deal of stuff today,
[52:34] but we've just been looking at 
the basic mechanical parts of the engine.
[52:39] Yeah, there are a whole lot of spinny bits in there,
[52:42] and they all need lots of lube to keep on spinning,
[52:45] but they don't start spinning unless 
a whole lot of other stuff happens.
[52:50] For instance, we need to deliver 
fuel to the combustion chambers,
[52:54] and we need to ignite that fuel with a spark plug.
[52:58] We use a computer to do those things,
[53:00] and we've been doing that for decades now.
[53:02] But the computer needs to know
[53:05] precisely where each part of this engine is,
[53:08] so it can tell when it should do those things.
[53:12] In the next video on 
engine management tech, we'll be looking closely at,
[53:17] well, that part, the management part,
[53:20] because while this is a very intricate
and fascinating piece of machinery,
[53:24] it is literally useless without the digital system
[53:28] which controls the spark plugs, the fuel injectors
[53:31] and even the intake valve timing.
[53:34] I'll be covering all of that in the next video in this series,
[53:37] so stay tuned.
[53:40] ♫ load-bearingly smooth jazz ♫
[53:43] [whirring sound is increasing in speed]
[53:45] [schwoop]
[53:46] [banging]
[53:47] [comically metallic crash]
[53:48] It's fine!
[53:50] It's fine.
[53:51] Nothing happened.
[53:52] It just fell off the table.
[53:54] It's fine.
[53:56] This is the crank pulley and it provides power for the engine accessories.
[54:02] That's not working.
[54:04] and it provides power for engine accessories such as the alternator,
[54:08] the air conditioning compressor...
[54:12] I thought you would behave a little better.
[54:13] You didn't. You didn't.
[54:16] [oh no here we go again]
[54:20] [the sounds weren't as funny this time]
[54:23] It's fine.
[54:24] Nothing happened.
[54:26] It's fine.
[54:28] So now I guess I need to start plotting my atonement for the bearing/journal decision.
[54:33] Does one plot an atonement?
[54:35] Well that's not important right now.
[54:36] What is important is that you imagine the animated character Doug Funnie writing in his bearing.
[54:43] For some of you, that hurt.