Why should you check valve train clearances before fully running the engine?

• A. To maximize horsepower
• B. To prevent damage to the valve train components
• C. To reduce emissions
• D. To improve fuel economy

Answer: (B)

Checking valve train clearances before starting the engine ensures the gaps between cam lobes, lifters, pushrods, rocker arms, and valves are correct. If clearance is too tight, parts can bind or contact each other as the engine heats up, potentially preventing valves from sealing properly, bending valves, or damaging cam lobes and lifters. If clearance is too loose, valves may not open or close fully, leading to poor compression, misfires, excessive wear, and noisy operation. Verifying and adjusting to the manufacturer’s spec (usually while cold) helps the valve train operate safely during warm-up and normal running, preventing serious damage. While proper clearances can influence overall performance, the primary purpose here is to prevent damage to valve train components.