How to Adjust Valves for a 4-Cylinder Engine?
2 Answers
Rotate the first cylinder to the compression top dead center (align the mark on the crankshaft pulley or flywheel with the 0 scale or the pointer in the timing gear housing). Adjust the exhaust valves of cylinders 1, 2, and 3. Then rotate 360° and adjust the exhaust valve of cylinder 2, the intake valve of cylinder 3, and both intake and exhaust valves of cylinder 4.
I recently taught myself how to adjust the valves while repairing my old four-cylinder car, and it was quite interesting. The basic process is: first, let the engine warm up by running it for about five minutes before shutting it off, as the metal expansion ensures more accurate clearance. Then, remove the valve cover, being careful not to let dust fall inside. Each cylinder has four to eight valves, depending on your car model, and you need to adjust them in the firing order, usually starting from cylinder one and turning counterclockwise. Use a feeler gauge to measure the clearance—standard values are typically between 0.15 to 0.25 millimeters, which you can check in the manual. When adjusting, loosen the fixing screw, insert the feeler gauge and pull it out gently, then tighten the screw until there’s slight resistance before locking it. Don’t forget to measure each valve twice to ensure accuracy, as too little clearance can cause the valve to stick, while too much can lead to noisy operation. With just a set of wrenches and a feeler gauge, you can do it yourself. After finishing, reinstall the cover and start the engine to listen—if it runs smoothly, you’ve succeeded. Regular checks can prevent premature engine wear and extend its lifespan, but beginners should take it slow and not rush.
