What is the purpose of a cranking compression test?
A compression test reveals the condition of your engine’s valves, its valve seats, and piston rings and whether these parts are wearing evenly. Healthy engines should have compression over 100 psi per cylinder, with no more than 10 percent variation between the highest and lowest readings.
What is the normal compression for a gasoline engine?
about 140-160 pounds per square inch
Since the gasoline engine has a spark plug, only moderate compression is enough, requiring about 140-160 pounds per square inch (PSI). Depending on their size and application, some engines may require a higher compression such as 220 PSI.
What kind of engine did the Pontiac Bonneville have?
Engine options remained unchanged from the 1964 model year, with a389 cu in (6.4 L), 333 hp unit being standard, equipped with a Carter AFB 4-barrel carburetor. A 421 cu in (6.9 L) engine was an optional upgrade. Both engines had choices of Tri-Power multi-carburetion setups and higher compression ratios.
When to do compression test on GM 3.8L?
Testing the compression of each cylinder or a specific engine cylinder is becoming a standard test when troubleshooting hard to diagnose misfire conditions on the GM 3.8L V6 equipped cars and mini-vans.
How do you test the compression of a car?
When everything is all set up, have your helper crank the engine while you eye-ball the compression gauge (tester). Once the needle stops climbing, have your helper stop cranking the engine. Write the compression value down on a piece of paper. Repeat steps 1 thru’ 6 on the remaining 5 cylinders.
When did the Pontiac Bonneville Brougham option come out?
Beginning in 1964, a Bonneville Brougham option package was available that included an even more luxurious interior trim level with front and rear seats featuring center armrests, upgraded door panels and a standard Cordova (vinyl) roof with “Brougham” nameplates.