What is the purpose of a crankcase breather system?

A crankcase ventilation system removes unwanted gases from the crankcase of an internal combustion engine. The system usually consists of a tube, a one-way valve and a vacuum source (such as the intake manifold).

Why do engines need positive crankcase ventilation?

Positive Crankcase Ventilation is a system that was developed to remove harmful vapors from the engine and to prevent those vapors from being expelled into the atmosphere. The PCV system does this by using manifold vacuum to draw vapors from the crankcase into the intake manifold.

What causes excessive crankcase pressure?

Powerful spikes in crankcase pressure are a classic sign of a blown head gasket, or a cracked engine block. Leaking exhaust valve seals will also contribute to spikes in crankcase pressure, which are particularly noticeable because the valves are just below the oil filler cap.

How do you check a crankcase?

Not only can you measure crankcase pressure with a vacuum gauge or manometer, you can also use an accurate pressure transducer such as a Pico WPS500 to measure crankcase pressure with a scope.

How do you get rid of crankcase pressure?

This usually happens when the engine is under load or at high rpm, which is when pressure builds up quickly and needs to be relieved the most. The extreme solution to prevent all of this is to install a vacuum pump that continuously draws the pressure out of the crankcase.

How do you release crankcase pressure?

A dry-sump oil system or a pulley-driven vacuum pump can evacuate crankcase pressure so effectively that it can create a vacuum. The vacuum is typically regulated to run at -5 to -20inHg on most applications. The negative crankcase pressures (a.k.a. vacuum) further improve ring seal.

What causes positive crankcase pressure?

Boosted Crankcase Pressure The intake manifold is under pressure during most running conditions when an engine is turbocharged. The gas and oil bypassing the rings are still present, and the pressure generated by the turbocharger can increase crankcase pressures. That’s when a more advanced PCV system is required.

Why does a crankcase breather work on a motorcycle?

This layout featured a crankshaft seal to prevent oil from entering the engine and getting into the primary side and vise-versa since it was basically breathing from the engine and camshaft. This type of breathing system works for stock applications and should be left alone if you have a “stock” motorcycle.

How does a crankcase breathing system work on a stag?

If the pressure in the pipe goes above atmospheric the one way valve opens and dumps the pressure to the front of the throttle disc so the gasses are drawn into the engine rather than creating a stink.

Can a crankcase breather give you a headache?

The crankcase breather system is often neglected and overseen although it has a major role in the proper functioning of your engine. Because of this, various symptoms and problems may appear over time which can give drivers a big headache, especially with used cars.

What kind of ventilation does a crankcase have?

Most modern engines use a Positive Crankcase Ventilation (PCV) system. The system is fairly simple: A filtered air source serves as an inlet. A hose connected to the air intake tube.