Making sure your engine has proper compression is vital for its health. You can rely on one of two methods to test this, but they aren't quite equal.

The Compression Testing Machine is a fully digital testing system that offers high precision control and accuracy. It allows automated computer control of test techniques to provide ease of operation.

The Box Compression Machine is a completely digital testing system with high precision control and accuracy. It enables automated computer control of testing techniques to provide ease of operation.

A hand holding a compression tester that's attached to an engine cylinder. - Aleksandr Kondratov/Getty Images A healthy engine is a precision piece of machinery. When its tolerances are within spec, ...