What is the valve clearance for Weichai P10?
2 Answers
For the Weichai P10 engine, the intake valve clearance is 0.35-0.40mm, and the exhaust valve clearance is 0.45-0.50mm. Relevant information about valves is as follows: 1. Function: Valves are specifically responsible for introducing air into the engine and expelling exhaust gases after combustion. Structurally, they are divided into intake valves and exhaust valves. The intake valve draws air into the engine to mix with fuel for combustion, while the exhaust valve expels the burned gases and dissipates heat. 2. Composition: A valve consists of a valve head and a stem. The valve head operates at 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 save on heat-resistant alloys, sometimes the exhaust valve head is made of heat-resistant alloy, and the stem is made of chromium steel, with the two parts welded together. Valve head shapes include flat-top, spherical-top, and tulip-top. Flat-top valves are commonly used due to their simple structure, ease of manufacturing, small heat absorption area, light weight, and suitability for both intake and exhaust valves. Spherical-top valves are suitable for exhaust valves, offering high strength, low exhaust resistance, and effective exhaust gas removal, but they have a large heat-absorbing area, greater mass and inertia, and complex manufacturing. Tulip-top valves have a streamlined shape that reduces intake resistance, but their large heat-absorbing area makes them suitable only for intake valves.
I remember when adjusting the valve clearance of the Weichai P10 engine, it is generally recommended that the intake clearance be around 0.30mm and the exhaust clearance around 0.35mm. However, the actual values should be checked in the official manual, as there may be slight variations for different years or models of the engine, such as older versions or high-load variants. Once, when I helped a friend repair his car, I found that if the clearance is too large, the engine would make noise and have weak acceleration; if it's too small, it could lead to valve burning or power loss. The adjustment method involves first turning off and cooling the engine, then measuring and calibrating with a feeler gauge. Typically, it should be checked every 50,000 kilometers. To be safe, it's better not to do it yourself—take it to a 4S shop and let professional technicians handle it to avoid engine damage from improper operation. Overall, it's about maintaining the correct range: intake between 0.25-0.35mm and exhaust between 0.30-0.40mm. Regular maintenance can extend the engine's lifespan.
