If all those engine goodies don’t result in cylinder pressure, performance is sure to disappoint, and there’s more to the story than you think. From the June 2004 issue of Car Craft magazine.

The purpose of your engine is to compress fuel and air and then ignite it, creating heat energy that then makes mechanical motion. If your engine can't compress the air and fuel properly, the ...

Compression test kits do just what they say: measure the ability of each cylinder of your engine to combust the fuel/air mixture without losing any of the resulting energy.

Mityvac’s compression tester is unique in this list for including an air-hold adapter that you can use to effect valve seal repairs without having to remove the engine’s cylinder head.

on the compression tester's gauge. Make sure to count the number of engine revolutions it takes to reach max pressure and repeat the test for each cylinder, cranking the engine the same number of ...

A compression test reveals the condition of your engine's valves, its valve seats, ... TIP For a cylinder below 100 psi, pour 1 teaspoon of engine oil into the plug hole and retest.

This reduces compression in the cylinders and you don't get as big a bang for your buck, so your vehicle loses power. Piston rings can be replaced, but it's an expensive job.

And uniformity is key: having two adjacent cylinders that differ in compression by 40 psi should be a red flag. Our 325Ci had an even 180 psi across all cylinders. So we crossed this one off the list.

Compression ratio is the difference between the total volume of the cylinder and combustion chamber at BDC and their volume at TDC. If you have 1,000 cc of space at BDC and 100 cc at TDC, the ...

Compression test kits do just what they say: measure the ability of each cylinder of your engine to combust the fuel/air mixture without losing any of the resulting energy. While they're not as ...