Do it yourself
Frequently asked questions about cars and motorcycles
Car tutorial (Do it yourself) Motorcycle tutorial (Do it yourself) Frequently Asked Questions

From theory to practice: the bore/stroke ratio

Model: (Various brands) Various
Part: Engine

In this video we try to understand some things about the bore/stroke ratio: the square, undersquare or oversquare engine. To know what type of engine we have, we need to know the bore, which is the distance between the walls of the cylinder (in mm). The stroke, on the other hand, is the distance between the top dead center and the bottom dead center (also expressed in mm). Bore x stroke = we will know if it is a square, undersquare or oversquare engine. In a square engine, the stroke and bore are equal (let's say 50 and 50). The undersquare engine (also known as "long stroke") will have a longer stroke than bore (let's say 60 stroke and 40 bore), which will have high torque, low rotations and high thermal efficiency, like diesel engines. On the other hand, the oversquare engine is the opposite: it will have a shorter stroke and a larger bore (let's say 60 bore and 40 stroke), so the piston rotation speed will be very high and consequently all mechanical components will be highly stressed.

Posted on 22 May 2024 by ScegliAuto

Video tutorial

Related tutorials

How Piston Rings Work on a 4-Stroke Engine
How Piston Rings Work on a 4-Stroke Engine
(Various brands) Various In this video tutorial, see how piston rings work on a 4-stroke engine. In this case, there are 5 rings: 2 are similar to those on 2-stroke pistons, …
How does a scooter's variator work?
How does a scooter's variator work?
(Various brands) Various In this video we see how the variator of a scooter works, so how to transform the engine RPM into effective thrust. The main components are the movab…
The Crucial Function of the Two Lambda Sensors
The Crucial Function of the Two Lambda Sensors
(Various brands) Various If your vehicle experiences hesitation during acceleration, the issue may be due to the lambda sensor, located on the exhaust before the catalyst, wh…

How to Open the Bonnet of a Renault Megane if the Lever is Broken?

If the lever that unlocks the bonnet of the Renault Megane is broken or not functioning, there is an emergency procedure to unlock the mechanism: remove the right front grille located at the top of the bumper. Once the grille is removed, you can locate the actuator mechanism: by pulling the spring in this position, you can unlock the actuator, allowing you to lift the bonnet and access the components located inside the engine compartment. You can then close the bonnet simply by lowering it.

Watch the video!


by ScegliAuto

More videos