What dohc does

This explosion forces the piston back down the cylinder, moving the crankshaft and ultimately the vehicle. The piston moves back up the cylinder due to the firing of other cylinders and the exhaust valve opens up and the burned fuel and air is pushed into the exhaust port. The 4 stroke cycle starts over again and continues so long as the vehicle is running.

All of these strokes are happening very fast, and the speed is referred to as RPM or rotations per minute. The higher the RPM, the faster the engine is operating and rotating the crankshaft.

At high RPMs, the 4 stroke cycle can occur hundreds of times a second. The camshaft is what opens and closes the intake and exhaust valves to suck in air and force it out during this process. Overhead valve or pushrod engines are typically found in older vehicles or larger engines.

The camshaft is installed inside the engine block and is operated through lifters, pushrods, and rocker arms. It is difficult to precisely control valve timing at higher RPM and is better suited for V8 or larger engines. They are lower cost and offer high torque at lower RPM.

Single overhead cam or overhead cam engines have a single camshaft installed in the cylinder head. DOHC is a synonym for dual overhead cam, and this means you have two cams operating the exhaust and intake valves. The engine has one header but with two cam rods. The camshafts are often tied together by a short chain but sometimes, the timing belt wrap around both gears.

Dual camshafts do often produce more horsepower, and it is therefore often equipped in newer cars. Older cars had not the same need for performance, and therefore, they were fine with a single camshaft. Because of the number of valves per cylinder — a dual camshaft engine will often have better fuel efficiency than a single camshaft engine.

More performance can actually often lead to lower fuel efficiency. This is because of the much more efficient engine when you let it breathe properly. The downside of the DOHC engine is that you have many more valves, camshafts, and parts that can break down. A single camshaft requires far fewer parts for the engine to function properly. If you are looking for a reliable engine without too much performance, SOHC is probably the right choice for you!

Because the DOHC engine also gives greater performance, you will often find these much smoother without misfires. This is because of the efficiency and easiness to control valve timings. That depends on what you are looking for. DOHC is better for performance because you will get more horsepower with it.

SOHC is better for reliability. A SOHC engine contains much lesser parts, which will make it more reliable. DOHC engine is much more efficient, and you will get more power output from the engine. A DOHC engine will therefore also have better fuel consumption because of the efficiency.

The SOHC engine is a good engine type, but it depends on what you are looking for. If you are looking for a reliable engine, the SOHC is a good engine for you. If you are looking for performance and good fuel consumption, DOHC is a better choice. Having four valves per cylinder allows the engine to pump enough air to run and make useful power at these higher speeds.

Another interesting thing that some car makers do is have a separate intake runner for each of the two intake cylinders. One of the intake runners is wide and short for maximum airflow, the other is a tuned intake runner. When the intake valve is open on the engine, air is being sucked into the engine, so the air in the intake runner is moving rapidly toward the cylinder.

When the intake valve closes suddenly, this air slams to a stop and stacks up on itself, forming an area of high pressure. This high-pressure wave makes its way up the intake runner away from the cylinder. When it reaches the end of the intake runner, where the runner connects to the intake manifold, the pressure wave bounces back down the intake runner. If the intake runner is just the right length, that pressure wave will arrive back at the intake valve just as it opens for the next cycle.

This extra pressure helps cram more air-fuel mix into the cylinder -- effectively acting like a turbocharger. A DOHC engine is a dual overhead camshaft engine, or an engine with two camshafts.

What is the advantage of a DOHC engine? The biggest advantages of a DOHC engine are increased power and increased speed. This type of engine can particularly increase your vehicle's engine power at high speeds. What are dual overhead camshafts? A dual overhead camshaft is an engine that features two camshafts per bank of the cylinder head.