Hello everyone and welcome in this video
we're going to be learning how V8 engines work
starting off simple and then diving into the details of the 3D printed Chevy Camaro lS3 V8
engine seen here so starting with the very obvious
V8 engines get their name from having a cylinder block in the shape of a V in this case at 90 degrees and
from having eight cylinders in this case the numbering starts at the front most piston on the right
and then works its way back 1, 2, 3, 4, 5, 6, 7, and 8.
This engine operates under the same basic principles as any other gasoline four-stroke engine
focusing on just a single cylinder first the piston pulls in air and fuel as it moves downward
then it compresses that air and fuel as the piston moves upward next a spark plug fires
igniting the air fuel mixture and forcing the piston downward and
finally the piston pushes out the exhaust gasses on its way back up before the cycle repeats itself now in a V8 engine
this cycle is happening in eight different cylinders at different times
instead of multiple cylinders firing at the same time you want them to be spread out so that power delivery is smooth for
this Chevy V8
the firing order is 1, 8, 7, 2, 6, 5, 4, 3
with eight cylinders
there is a cylinder firing for every 90 degrees of the crankshaft rotating
which means that at any point in time there are two cylinders on the power stroke a
four-cylinder engine would only have one cylinder firing at a time meaning the power delivery wouldn't be as smooth
so now let's look at the valve train to see how air flows in and out of the engine
the intake air comes from the top of the engine and into the sides of the cylinder head
the exhaust flows to the sides of the engine
exiting the exhaust valves from the cylinder head looking at the cylinder head removed from the engine you can see that
there is a single intake valve and a single exhaust valve though it's also common to see engines with two intake valves and two exhaust
valves in this case the larger valve is the intake valve and the smaller valve is the exhaust valve
the pushrod valvetrain gets its name from the metal push rods
which activate the rocker arms which open up the valves the camshaft
located in the center of the V of the engine block has lobes on it
which pushed the push rods up opening the appropriate valves here
you can see a simple
demonstration of the push rod being used to open up the intake valve
it presses against the rocker arm seen in red forcing the intake valve open the camshaft
which operates the valves is geared to the crankshaftm
which is what ultimately all the Pistons are trying to rotate for every two rotations of the crankshaft the
camshaft rotates once if we remove the oil pan from the engine we can see the operation of the crankshaft the
crankshaft is the yellow shaft and there are added weights to it for balancing the engine the connecting rods are in brown which connect the
crankshaft to the Pistons what's cool about V8
engines is that the two pistons across from one another are actually paired to the same crankshaft bearing so moving on to those large yellow
counterbalance weights
looking at the first pair of cylinders
you'll notice that as one piston reaches the very top the counterbalance is directly across from it
balancing out the force as it rotates another 90 degrees it now counters the other Pistons force
rotating another 90 degrees the first piston has reached the bottom and the weights counter that downward force with an upward force and then
finally another 90 degrees later the second piston reaches the bottom
where its downward force is once again countered with an upward force.
This is actually balancing out a rocking moment caused by the Pistons movement in full swing
though the whole engine may look complicated from a balancing standpoint
it actually is extremely smooth running with no first or second order
vibrations and only a first-order moment that is countered out through the crankshaft design
all of this is to say that the engine runs very smoothly now this particular V8
is what is called a crossplane V8
which means each connection point on the crankshaft is
offset 90 degrees meaning the pistons operate in two planes or a cross plane the alternative is a flat plane crank
shaft where the pistons are simply offset 180 degrees meaning they all operate in a single or flat plane
the advantages of this engine style include its large
displacement which often correlates with generating lots of power while in a generally compact and very rigid form they have very little vibration
however compared to some engines
they have a relatively higher center of gravity and are complex
since they require two separate cylinder heads rather than just one like an inline engine generally speaking although
they are compact in form they are still quite heavy compared to smaller style engines though of course while producing more power
if you found this helpful
I have included links to other videos you may enjoy
also a huge shout out to Erik Harrell for lending me the 3D printed V8 engine.
I will include links to his work in the video description as always feel free to leave any questions or comments below and
thanks for watching.