Compression Test on a Piper Aircraft Lycoming Engine - Research Paper Example

Compression Test on a Piper Aircraft Lycoming Engine The limitations for the differential compression check are discussed below:The pressure readings should be nearly equal for all cylinders with at least a difference of 5psi. Pressure differences of 10 to 15 psi require an investigation to be made by resetting the valve in a later check in 10 hours unless in excess of 15 psi.Pressure readings equal to or above 70 psi are satisfactory for the engine. If it is less than 65 psi, then it is an indication of engine wear and checks are to be made at time intervals of 100 hours.

Pressure readings below 60 psi indicate that there is rapid increase of engine wear and this reduction in engine pressure should be accompanied by the removal of cylinder overhaul.Pressure losses exceeding 25% of the applied pressure is an indication of cylinder defection, but this is subject to operating the engine for a time period of at least three munities to enable sealing of rings with oil. However, leakages occurring after recheck compel for correction of pressure readings obtained. This correction can be done by placing a fiber drift on the engine rocker arm located directly over the valve stem and the drift is tapped several times using a hammer in orde to remove any foreign materials between seat and valve face.

When doing this correction, the propeller should be rotated to make sure that the piston does not lie at the Top Dead Centre (TDC) so that the valve does not strike the top of the piston in the engine.The engine should be rotated to ensure reseat of valves in a correct manner before a compression recheck is done. The top spark plug from each cylinder is removed before the compression check is performed. This is done by connecting the pressure regulator and the adapter to cylinder number two and the propeller is turned on to ensure that the piston was at TDC on the compression stroke of the engine.

The pressure gauge was set at 20 psi following AC 43.13 recommendations to make sure that we achieve the TDC.The gauge was turned to 80 psi following the manufacturers and the AC 43.13 recommendations.The first gauge reading was 80 psi and the air gauge reading was 76 psi. The prop was moved back and forth to ensure proper placement during double checking on the readings obtained.Manufacturer’s dataGeneral characteristics of the engineType of engine: A four-cylinder, horizontally air-cooled.

Bore diameter: 5.125 inch (130.18 mm)Engine Stroke: 3.875 inch (98.43 mm)Displacement: 319.8 cubic inch (5.24 liters)Dry weight: 244 lb (111 kilograms)Engine ComponentsValve train: Two overhead valves for every cylinderEngine fuel system: Updraft carburetorFuel type: Minimum grade of 80/87 avgasOil system: Wet sumpCooling system: Air-cooledPerformancePower output: 150 horsepower (112 kW)Compression ratio: 7:1Power-to-weight ratio: 1.63 lb/hp (0.99kW/kg)Serviceability of the 0-320 Lycoming engineThe Lycoming cylinders are serviceable approximately within 950 hours since the overhaul.

This includes the complete assembly of the steel cylinders including valves and pistons. The cylinders can be removed and replaced with nitrited Lycoming cylinder assembly in order to upgrade horsepower to 160.