Cylinder Number Designations - Lycoming IO-390-D3B6 Installation And Operation Manual

Cylinder Number Designations

• The propeller is at the front of the engine and the accessories are at the rear of the engine.
• When viewed from the top of the engine, the left side cylinders are 2-4. Cylinder 2 is at the
front of the engine (Figure 9).
• When viewed from the top of the engine, the cylinders on the right are 1-3. Cylinder 1 is at the
front of the engine.
• The firing order of the cylinders is 1-3-2-4.
System Description
Page 6
IO-390-D Series Engine Installation and Operation Manual
Figure 9
Cylinder Number Designation
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March 2020