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What should the compression reading be on an aircraft engine?

What should the compression reading be on an aircraft engine?

According to TCM, a cylinder with a compression reading of 50/80 might well be absolutely airworthy, provided the cylinder meets certain other requirements.Another widely accepted OWT is that an engine with compressions in the low 60s is a “tired engine” that will not put out its full rated horsepower. This is just plain wrong.

What was the TCM bulletin for engine compression in 2003?

In March 2003, TCM issued SB03-3 to supersede M84-15. The new Service Bulletin greatly liberalized the criteria for valve leakage. It told mechanics not to reject a cylinder based on any single compression test, but to fly the airplane for at least 45 minutes and redo the test.

Why do I have low compression in all cylinders?

If you have low compression in all cylinders, this is often the culprit. Also, your compression leak may not be in the pistons or head gasket but in the valves. Exhaust valves and air intake valves at the top of the cylinder can also get overheated, and leak gas or the valve seals can become too worn to seal the gas in properly.

Can a blown head gasket cause low compression?

If two cylinders next to each other both have low pressure, a blown head gasket is a likely culprit. If you discover you do have low compression, the only solution is to replace the leaking part whether it’s the piston, piston ring, camshaft, head gasket or valves.

According to TCM, a cylinder with a compression reading of 50/80 might well be absolutely airworthy, provided the cylinder meets certain other requirements.Another widely accepted OWT is that an engine with compressions in the low 60s is a “tired engine” that will not put out its full rated horsepower. This is just plain wrong.

In March 2003, TCM issued SB03-3 to supersede M84-15. The new Service Bulletin greatly liberalized the criteria for valve leakage. It told mechanics not to reject a cylinder based on any single compression test, but to fly the airplane for at least 45 minutes and redo the test.

If you have low compression in all cylinders, this is often the culprit. Also, your compression leak may not be in the pistons or head gasket but in the valves. Exhaust valves and air intake valves at the top of the cylinder can also get overheated, and leak gas or the valve seals can become too worn to seal the gas in properly.

If two cylinders next to each other both have low pressure, a blown head gasket is a likely culprit. If you discover you do have low compression, the only solution is to replace the leaking part whether it’s the piston, piston ring, camshaft, head gasket or valves.

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Ruth Doyle