1. Intake Stroke:
* The piston moves downward in the cylinder.
* The intake valve opens, allowing a mixture of air and fuel (from the carburetor or fuel injectors) to be drawn into the cylinder. The downward motion of the piston creates a vacuum, drawing the mixture in.
2. Compression Stroke:
* Both the intake and exhaust valves close.
* The piston moves upward, compressing the air-fuel mixture. This compression increases the temperature and pressure of the mixture, preparing it for ignition.
3. Power Stroke (Combustion Stroke):
* At the top of the compression stroke, the spark plug ignites the compressed air-fuel mixture.
* The rapid expansion of the burning gases forces the piston downward with considerable force. This is the power stroke that drives the crankshaft, ultimately producing the engine's power.
4. Exhaust Stroke:
* The piston moves upward again.
* The exhaust valve opens, pushing the spent exhaust gases out of the cylinder.
This four-stroke cycle repeats for each cylinder, but staggered. The small-block Chevy is a V8, meaning it has eight cylinders arranged in a V-shape (two banks of four cylinders each). A sophisticated crankshaft and camshaft system ensures that the cylinders fire in a specific sequence (firing order) for optimal power and smooth operation. This sequence is carefully timed to balance the engine's forces and minimize vibrations.
Key Components and their Roles:
* Crankshaft: Converts the linear motion of the pistons into rotational motion, which is then transmitted to the transmission and ultimately the wheels.
* Camshaft: A rotating shaft with lobes that operate the intake and exhaust valves through pushrods and rocker arms. The camshaft's timing is critical for proper engine operation.
* Connecting Rods: Connect the pistons to the crankshaft.
* Pistons: Move up and down within the cylinders, driven by the expanding gases during the power stroke.
* Valves (Intake and Exhaust): Control the flow of air-fuel mixture into and exhaust gases out of the cylinders.
* Spark Plugs: Ignite the air-fuel mixture in each cylinder.
* Fuel System: Delivers the fuel to the cylinders (either through a carburetor or fuel injectors).
* Ignition System: Provides the high-voltage spark to ignite the air-fuel mixture.
* Lubrication System: Provides oil to lubricate moving parts, reducing friction and wear.
* Cooling System: Removes heat generated during combustion to prevent engine damage.
The specific design details (such as bore and stroke, valve train design, and other internal components) vary slightly depending on the specific small-block Chevy engine variant (e.g., 265, 283, 307, 350, etc.), but the fundamental four-stroke operation remains the same.
