What is the valve adjustment mnemonic for a 6-cylinder engine?
2 Answers
The firing order is 1-5-3-6-2-4. When piston No.1 reaches top dead center (TDC), you can adjust the intake and exhaust valves of cylinder No.1, the exhaust valves of cylinders No.3 and No.5, and the intake valves of cylinders No.2 and No.4. After rotating the crankshaft one full turn, when piston No.6 reaches TDC, you can adjust the intake and exhaust valves of cylinder No.6, the intake valves of cylinders No.3 and No.5, and the exhaust valves of cylinders No.2 and No.4. Below is an introduction to valve knowledge: Composition: A valve consists of a valve head and stem. The valve head operates at extremely high temperatures (intake valve: 570~670K, exhaust valve: 1050~1200K) and withstands gas pressure, valve spring force, and inertial forces from transmission components. With poor lubrication and cooling conditions, valves must possess sufficient strength, stiffness, heat resistance, and wear resistance. Intake valves are typically made of alloy steel (chromium steel, nickel-chromium steel), while exhaust valves use heat-resistant alloys (silicon-chromium steel). To conserve heat-resistant alloys, some exhaust valves feature a heat-resistant alloy head welded to a chromium steel stem. Current Status: To improve intake and exhaust efficiency, modern engines commonly employ multi-valve technology. The most prevalent configuration is four valves per cylinder (though some designs use 3 or 5 valves per cylinder with the same principle, such as Audi A6 engines), totaling 16 valves for a 4-cylinder engine.
I remember when repairing cars before, the 6-cylinder valve adjustment mnemonic was '1-4-2-3-6-5', which refers to the adjustment sequence: first adjust the valves of cylinder 1, then cylinder 4, followed by cylinder 2 and 3, and finally cylinder 6 and 5. It's quite straightforward to operate—just wait until the engine is completely cooled, then use a wrench to tighten the screws and measure the clearance with a feeler gauge, aiming for about 0.2 to 0.3 mm. The key to the mnemonic is to prevent messing up the sequence, which could lead to uneven valve clearances and affect the engine's power output. If unsure, it's best to check the car's manual or ask a mechanic. After trying it a few times, my engine sound became smoother, and fuel consumption dropped a bit. But don't stress too much—take it slow to avoid damaging valve springs or other parts. With proper maintenance, the car runs more steadily on long trips and has fewer strange noises.
