What does 342 on the valve tappet represent?
2 Answers
The number 342 on the valve tappet represents thickness. Here are the relevant details: 1. Hydraulic Tappet: The hydraulic tappet maintains constant contact with the camshaft, operating without any clearance. Inside the tappet, hydraulic pressure is used to adjust the clearance. The hydraulic tappet mainly consists of a plunger, a check valve, and a check valve spring. It stores or releases engine oil through the action of the check valve, and by altering the oil pressure within the tappet chamber, the working length of the hydraulic tappet can be adjusted, thereby automatically regulating the valve clearance. 2. Valve Tappet Cleaning Interval: The cleaning interval depends on various factors, such as the vehicle's driving environment, the control method of the fuel-injected engine, and air quality. Generally, cleaning is required every 20,000 to 30,000 kilometers. If the vehicle operates in a heavily polluted environment (mainly referring to inhalable particulate matter), impurities can quickly accumulate on the throttle body. Over time, this can affect the engine's air intake, necessitating cleaning. This phenomenon is most noticeable when starting the vehicle.
I've seen this type of numbering multiple times in engine maintenance. The numbers on valve tappets, such as 342, typically represent the thickness of the shim in micrometers, which is 0.342 millimeters. The valve system requires precise adjustment of the clearance to ensure proper opening and closing of the valves. If the size deviation is too large, it can lead to increased engine noise, unstable power output, and even accelerated wear of components. During maintenance, this number helps in selecting the correct spare parts—you can remove the tappet to measure the existing clearance, then use numbers like 342 to choose a new shim. It's recommended to regularly inspect the valve system, especially in high-mileage vehicles. Checking every 20,000 kilometers can prevent major issues. Ensure cleanliness during operation to avoid dust affecting precision, as these small details directly impact driving smoothness.
