Crankcase Evacuation System

A crankcase evac kit helps the engine to release pressure built up in higher horsepower applications. While engine valve cover breathers release pressure, crankcase evacuation systems add additional suction to help pull the pressure out faster and more efficiently by connecting to the header collectors through a hose and fitting. The existing exhaust gas from the engine through the headers creates low pressure, which draws crankcase pressure from the valve covers through the hose and specially-designed collector fitting. This reduces oil leaks and increases horsepower from reducing build-up crankcase pressure.

Though the instructions can vary depending on the crankcase evacuation system, in general, the directions are similar to installing a crankcase evacuation system. When researching exhaust style systems, if your vehicle doesn't have mufflers, confirm it will be compatible. Typically, a crankcase evacuation system with mufflers is required as backpressure is needed for it to work properly. The first step is installing the specific breathers from the kit into the valve covers. Next is to drill a hole on the top surface of each header collector. Usually, this involves the removal of the headers to gain clearance. The specialty fitting is then welded at a 45-degree angle into the hole, which helps to create the scavenging effect the exhaust uses to help draw crankcase pressure from the engine. Next, the headers are reinstalled (if removed) and the check valves are threaded into the fittings with thread sealant. The check valves prevent exhaust gasses from flowing back into the engine through the valve covers. The hoses are then connected to both the intake side of the check valves and the valve cover breathers, with care not to let the hoses touch the hot exhaust and headers. The crankcase evacuation system installation is then complete. When installing a crankcase vacuum pump setup, the install is similar on the valve cover side. However, a crankcase evacuation pump is added to the front of the motor and is driven by a belt off the engine crankshaft with the help of a pulley and mandrel. A breather tank is required and installed as well, to collect oil vapor being vacuumed along with the crankcase pressure.

A JEGS expert is ready to answer your questions and help you find the crankcase evacuation system that you require for your specific application (such as a SBC, BBC, SBF, BBF, SBM, BBM, or other engine).