An engine needs fuel, air and spark to make it run. The piston is what takes this explosion and sends that energy down through the connecting rod and spins the crankshaft. It sounds complicated and technical. It kind of is.
But a piston is a neat thing and does a neat job. This job is so neat in fact, that your engine won’t work without them.
If you read through this article, you’ll be throwing out compression, skirt, and valve relief jargon like a pro. And if you aren’t impressing people with your intelligence then what’re you doing?
What’s a Piston?
A piston is made out of a metal compound and is forged into the shape of a cylinder. It slides up and down inside your engine block. Your engine oil coats the cylinder walls and allows it to travel up and down smoothly.
The top of the piston comes in a lot of different shapes and sizes. The top of the piston, or the ‘piston crown’, is what takes the combustion and absorbs the explosion, sending the piston back down the cylinder bore.
That’s why the piston has to be made strong. It has to endure thousands of explosions while your car just sits at a red light.
How does a Piston work?
Well the fuel and air is combusted, whether it be in a petrol car engine, or a diesel engine, the piston travels down. But how does a piston make an engine work?
Suck, squeeze, bang, blow. The piston travels down, inhaling air and fuel into the combustion chamber through the opening of the intake valve. It then travels up, squeezing the air/fuel mixture. The spark plug or compression creates the bang, sending the piston back down. The piston then travels up, blowing the exhaust gas out of the chamber via the exhaust valve.
How does a Piston make an engine work?
The piston is travelling up and down, it’s very interesting, I’m aware. But how does it make the wheels spin?
It’s connected to the connecting rod, with a wrist pin. The wrist pin allows the rod to rotate without shearing. The piston rings protect the oil from seeping into the combustion chamber while it’s lubricating the internal components.
This connecting rod is bolted to the crankshaft and it spins the crankshaft. The crankshaft connects to the transmission and voila! You have rotational force communicated to the wheels.
Murphy’s Law, “what can go wrong – will go wrong”
Your engine’s piston can fail in a number of ways.
Mainly, your piston rings can start to fail. This allows oil to sneak into the chamber and be burnt up. That leads to excessive oil consumption.
Chattering from the engine usually means that the wrist pin has failed or the connecting rod is starting to play on it’s bearings.
If you snap a connecting rod, drop a valve, burn the crown or pre-detonate, it’s pretty much a ‘bye bye’ to your engine.
If you are worried about your engine, or you need some work on your pistons, we can help with that. By connecting you with one of our experienced garages here, you can rest assured knowing you’re getting expert service at the best prices.