Definition
A shop tool used by aircraft maintenance technicians to measure the force required to compress a valve spring to a specified length. The tester verifies that each spring still produces the manufacturer's required pressure at both the valve-open and valve-closed positions, confirming the spring is within service limits.
Plain English
A device that checks whether a valve spring from an engine is still strong enough to do its job. It squeezes the spring to a set length and shows how many pounds of force that took.
Context Anchor
Seen during aircraft engine inspection, overhaul, or cylinder maintenance when valve springs are removed and checked.
Why Pilots Care
Weak or incorrect valve springs can cause valve float, improper timing, or engine damage in flight.
Intuition Check
A valve spring tester does not test the whole valve system in a running engine. It tests the spring itself by measuring its force at a set compressed length.
Example Sentence 1
During the cylinder overhaul, the mechanic placed each valve spring in the valve spring tester and rejected any that failed to meet the minimum pressure listed in the engine manual.
Example Sentence 2
During the engine inspection the valve spring tester showed that two springs had lost the required pressure.