In the test, you blow air past the partly open exhaust valve and outward through the port. Normally you have built a device to hold the exhaust valve(s) at the desired lift (just as not all real ...

All engines allow some exhaust gases, unburned fuel and ... which is a source of varying air pressure, the PCV valve maintains the optimal level of vacuum in the crankcase to extract the products ...

A backfiring car is more than a noisy annoyance, it can mean problems with your engine. Here's what can cause engine ...