Remove coil wire from distributor cap and ground the wire. Remove the spark plug from number one cylinder. Stick your finger in the spark plug hole. Have an assistant jog the engine over with the key. When you feel and hear compression coming out from the number one cylinder (it will be obvious) tell your assistant to stop. At this point you will continue to move the crankshaft clockwise by hand until the timing marks for TDC are lined up. You now have the TDC firing point for number one cylinder.
No compression could be various things from your piston to your crank start with your piston by doing a compression test
You can determine if you're on the compression or exhaust stroke by observing the position of the piston and the alignment of the crankshaft. When the piston is at the top dead center (TDC) and both valves are closed, it's the compression stroke. Conversely, if the piston is moving down from TDC and the exhaust valve is open, then it's the exhaust stroke. Additionally, you can feel for air pressure at the spark plug hole during the compression stroke.
The piston stroke that prepares the fuel mixture for combustion in a four-stroke cycle is the compression stroke. During this stroke, the piston moves upward in the cylinder, compressing the air-fuel mixture that was drawn in during the intake stroke. This compression increases the temperature and pressure of the mixture, making it more conducive to ignition when the spark plug fires.
You're talking about an engine compression brake, commonly referred to as a Jake Brake.
The four-stroke cycle consists of four distinct strokes: intake, compression, power, and exhaust. During the intake stroke, the piston moves down, drawing in a mixture of air and fuel. In the compression stroke, the piston moves up, compressing this mixture before the spark plug ignites it during the power stroke, which forces the piston down. Finally, in the exhaust stroke, the piston moves back up to expel the burnt gases from the cylinder.
It is the volume of the cylinder/combustion chamber/head gasket/piston volume(dish/dome) when the piston is at the bottom of the stroke divided by the volume when it is at the top of the stroke.
A 4-stroke engine operates through four distinct phases: intake, compression, power, and exhaust. During the intake stroke, the engine draws in an air-fuel mixture as the piston moves down. The piston then compresses this mixture in the compression stroke, followed by ignition during the power stroke, where the burning mixture forces the piston down. Finally, in the exhaust stroke, the piston moves back up to expel the exhaust gases, completing the cycle.
Top dead center (TDC) refers to the position of a piston at the highest point in its cylinder. It can occur at the end of both the compression stroke and the exhaust stroke, depending on the engine cycle. During the compression stroke, the piston moves upward toward TDC, compressing the air-fuel mixture before ignition. Therefore, TDC is not exclusively the compression stroke; it is a position that can be reached at different points in the engine cycle.
The compression ratio of an internal-combustion engine, or an IC engine as it is more commonly called, is the ratio of the volume the highest capacity of the combustion chamber to its lowest capacity. In the IC engine, the piston makes a stroke, resulting in the compression of the air in the combustion chamber - the ratio between the volume of the cylinder and combustion chamber when the piston is at the bottom of its stroke, and the volume of the combustion chamber when the piston is at the top of its stroke, is the compression ratio.
Two strokes have two cycles the piston go through intake/compression and ignition/exhaust where four strokes have four separate piston cycles intake compression ignition and exhaust.
During the compression stroke in an engine, the piston moves upward, compressing the air-fuel mixture in the combustion chamber. This compression increases the pressure and temperature of the gases, making them more volatile and ready for combustion when the spark plug ignites the mixture.
Bad compression is usually worn out piston rings, no compression is usually bad valves - assuming it's a 4-stroke.