A modern car engine is a collection of advanced parts and systems that provide the force to propel your car down the road. New technologies and materials may haver made engines more complicated, but the core ideas behind the function of your engine have not really changed over the years. Let’s break down the parts of the typical car engine and how each functions.
Most common engines have 4, 6, or 8 pistons which move up and down in the cylinders. On the upper side of the piston is what is called the combustion chamber where the fuel and air mix before ignited. On the other side is the crankcase which is full of oil. Pistons have rings which serve to keep the oil out of the combustion chamber and the fuel and air out of the oil. Pistons are made from lightweight aluminum alloy and are designed to float in the cylinder without contacting the cylinder walls. They float on a thin layer of oil which is below the rings. If the rings fail, oil can leak into the combustion chamber and you will see grey smoke coming from the exhaust. If the rings wear or you lose oil to the engine, the pistons can score the cylinder walls damaging the engine and requiring a rebuild.
The crankshaft is connected to the pistons via a connecting rod. As the piston moves up and down in the cylinder it rotates the crankshaft and converts the straight-line motion into rotary motion.
The valvetrain consists of valves, rocker arms, pushrods, lifters, and the cam shaft. The valvetrain’s only job is that of regulating how much air and fuel is let in and out of the engine at the proper time. The timing is controlled by the camshaft which is synchronized to the crankshaft by a chain or belt.
Now that we have a basic overview of the major parts that are involved in the internal combustion portion of an internal combustion engine, let’s see some common problems people can encounter and what you can do to keep everything running smoothly.
If your car exhausts grayish white smoke and it does not stop in the first few minutes after start-up, you might have worn piston rings. When piston rings are worn, they allow the fuel and air to enter into the oil and dilute it. This dilution reduces the oil’s ability to lubricate your engine and can cause premature wear. If the rings wear out, they can allow oil from the crankcase to enter the combustion chambers. If the smoke goes away after start-up look to the valvetrain section. If your car only exhausts grayish/white smoke at start-up you may have leaking valve seals. Valve seals keep oil from above the valve from leaking into the combustion chamber. When they wear, they can allow oil to seep into the combustion chamber and collect there until your start the engine again. You generally do not get oil leaking past the valve seals while the engine is running since the seals expand with the heat of the engine and plug the leak.
If you’re hearing a loud knocking noise from the engine, you may have worn crankshaft bearings. This is usually a costly repair and involves removing the crankshaft and either machining the surface where the bearings ride, or replacing the entire crankshaft. Proper maintenance can prevent this type of problem—high quality oil replaced at the suggested intervals for your car, and always maintaining the oil level between oil changes.
If you have any doubts about the condition of your car or its engine, we at King Brothers are more than ready to help you out and get your vehicle in tip top condition. If you’re hearing any strange sounds or knocking, lack of acceleration, or even weird smells from your air conditioning—basically any kind of odd behavior from your car—you just have to call us and we’ll sort it out. Preventative maintenance and tune ups will ensure that you aren’t paying out the nose for complete engine rebuilds or replacements later on.
Our highly-skilled auto mechanics will be more than happy to give your car a full run-through. Give us a call at 313-534-8090 (Redford) or 734-744-8557 (Livonia), or feel free to request for a quote here.