Why is a crankshaft not straight?

The internal combustion engine really is a remarkable thing. Little explosions take place over and over, firing pistons at remarkable rates to ultimately propel a vehicle forward. The crankshaft is a special engine part, and looks rather strange when not connected to the rest of the engine. So, here’s a common question people ask when first seeing one: Why is a crankshaft not straight?

This article will explain what the crankshaft does in an engine, why it has those parts that jut out in different directions, and what you should do if you think you might need crankshaft refurbishing services in KwaZulu-Natal.

What is a crank (and a shaft)?

A crank is a force mechanism, or a machine that is able to create force. In this case, a crank is a straight arm attached at a right angle to a central shaft that rotates. This rotation forces the arm into motion, essentially converting circular motion into reciprocating motion, or the other way around.

Crankshafts are generally made from steel, and are nestled below the cylinders. The shaft is the central core, or the backbone, of the engine. It has extending sections along the shaft that are positioned at varying degrees. The next section talks about what attaches to the crankshaft, and how the crankshaft makes the motor magic happen under the hood.

How the crankshaft works

Crankshafts feature crank pins, lined up to accommodate the pistons above. The cylinder-based pistons are connected to the crankshaft via connecting rods, or “conrods”. The “big end” of these rods are attached to the crankpins. These rotate along with the crankshaft (but at a wider circumference), allowing for the pistons above to bob up and down from Top Dead Centre to Bottom Dead Centre.

The rotation of the shaft is transferred through the flywheel and to the transmission. Without the unique rotating nature of the crankshaft, force cannot be converted into vehicular motion. It’s one of those essential components that make the whole engine system possible.

One thing that would be difficult to do is to bend a crankshaft, but they can be worn down and damaged in other ways. When this happens, you’ll notice it immediately. Then it’s probably a good idea to call a crankshaft maintenance workshop.

Professional crankshaft repairs in KZN

Eagleharm Engineering is one of Durban’s longest-standing engine maintenance workshops, with over 50 years of engine mechanics experience. Our clients trust us with their valuable engine parts, which we meticulously clean and calibrate to factory specification. If you require your fleet of vehicles to remain in peak condition, planned engine maintenance – including critical crankshaft maintenance – is the way to ensure it.

Connect with Ryan or Todd Harmsworth to arrange a professional engine refurbishment in KwaZulu-Natal.