Cylinder numbering in an engine can vary depending on the specific engine layout and manufacturer. However, in most common engines with a standard inline configuration, the cylinder numbering is as follows:

- Cylinder 1 is typically located on the side of the engine closest to the front, or the frontmost cylinder in a transverse (sideways) engine.
- Cylinder 2 is usually the next cylinder in line, moving towards the back of the engine.
- Cylinder 3 follows after Cylinder 2, continuing towards the engine's rear.
- Cylinder 4 is typically the rearmost cylinder in an inline engine, farthest from the front.

It's important to note that this numbering scheme may not apply to all engines, especially those with different configurations such as V-shaped or horizontally opposed engines. In such cases, the cylinder numbering may be different. Consult your specific vehicle's service manual or consult a professional mechanic for accurate cylinder numbering information.