The Functions of a Motor

By: Larry Martin

1966 Dodge 426 Hemi

The Basics

There is: The block The crankshaft The pushrods The pistons The heads The intake manifold The carburetor

The exhaust manifold The distributor The timing chain The harmonic balancer The camshaft The lifter rods

A Basic Motor Block

The Block

The block is the main structure of a motor. It acts as a casing for the internal components. The bore of the block and height of the deck is where most of the power is determined. The bore is the cylinder in which the piston moves up and down through. If this is correct, the motor will run very strong, well, and efficiently.

Small Block Steel Crankshaft

The Crankshaft

The crankshaft is the “rotating” part of the motor. It moves around and around to move the connecting rods and pistons to produce power. The crankshaft can be turned or in other words shortened to de-stroke the motor to produce more rpm (rounds per minute), which in the end will result in a massive power gain. If the crankshaft is bent the motor will not turn over and will be locked up.

Set of Pushrods

The Pushrods

Another name for the pushrods are the “connecting rods”. They are connected to the pistons to push them up towards the head to produce compression. Just like the crankshaft you can shorten these and produce massive power and gain more torque. If the connecting rods are bent the motor will still run just not as well and you will lose a lot of power.

Set of Pistons

The Pistons

The pistons is what makes your motors compression. The piston has to be strong because of the combustion that is ignited to push the piston down in order to complete another round. There are very many types of piston but all are made of the same type of material, aluminum. There are flat-top, dome, and relief pistons. Flat-top are exactly what they say the top is flat. Dome pistons have a lower middle spot that creates more compression. Relief pistons are the pistons with what looks like hammer hit it at an angle. This also results in more compression.

Motor Heads

The Heads

These are where most people screw up and ruin everything. The heads are the most crucial part of the motor. They create compression, supply the cylinder with fuel, and also let the compression out of the cylinder. If the head is warped or cracked it will cause the motor to lose compression therefore it will not run correctly.

Intake Manifold

The Intake Manifold

The intake manifold is located on top of the heads. It allows the fuel from the carburetor be evenly distributed between cylinders through the heads. The intake manifold is subject to leak and cause the motor to lose vacuum Water also runs through the intake manifold then through the heads and if there is a leak it will mix with the gas and foul out the spark plugs.

A Carburetor

The Carburetor

The carburetor is what supplies the motor with fuel and controls how fast the motor is running. If you have too small of a carburetor the motor will not run right and will not have any power at all. If the carburetor is too big it will flood the motor out until it picks up enough rpm to catch up to the amount of fuel supplied. There is also many types of carburetors and some are illegal to run on the road.

An Exhaust Mnifold

The Exhaust Manifold

The exhaust manifold is where the exhaustion from the combustion chamber is let out into. This helps give the motor some back pressure so the heads don't crack or bust from being hot and the very cold quickly. It also makes the vehicle quiet... but if you install a set of headers, it will change the sound of the motor completely. There are many types and sizes of exhaust manifolds and headers.

A Distributor and Coil

The Distributor and Coil

The distributor and coil is what ignites the fuel in the combustion chamber in order to keep the motor running. It sends electrical currents through special wires and to the spark plugs. If the distributor or coil goes bad the motor will still crank over easy but will not fire in order to start. The voltage from the coil is very high and will surprise you if it bits you. It puts out around 44,000 volts for an average, but for race cars and high performance motors you can get around 80,000volts.

A Timing Chain Set and Timing Gear Set

The Timing Chain

The timing chain connects the crankshaft with the camshaft so that the turn at the same exact time. This allows the motor to have timing and so that the camshaft will lobe on the correct valve at the right time. There are many types of timing chains, but for racing applications you can get timing gears which are louder but more efficient on timing.

A Harmonic Balancer

The Harmonic Balancer

The harmonic balancer is what keeps the motor from rattling your brains out when the motor cranks rpm's. It balances the motor in order to keep it upright and floating. If the motor is not balanced correctly it will result in a bent or warped crankshaft.

A Camshaft

The Camshaft

The camshaft is the heartbeat of the motor. It determines the sound, horsepower, and torque of the motor. The lobe separation and lift is very important along with the duration. The bigger the lift the more horsepower and noise you will have. The bigger the duration the easier it will be on gas and it might have some change in torque also. Dodge has the highest lift to ever be put in a motor and it also makes the most horsepower, torque, and speed than any other make in the world.

Set of Lifting Rods

The Lifting Rods

The lifting rods connect the camshaft with the valves to open them. When the valve opens, the fuel is either put in or let out of the combustion chamber. The lifting rods allow the valves to open and do that. If the valve opens too far and hits the top of the piston, then there will be some catastrophic failure occur. These can be shortened or lengthened to create a custom lift.