Is a Major Overhaul Necessary for Insufficient Cylinder Pressure?
1 Answers
Whether a major overhaul is necessary for insufficient cylinder pressure can be divided into the following two scenarios: 1. Fault in the valve train: This leads to insufficient cylinder pressure, and in this case, a major overhaul is not required. 2. Piston ring wear: When piston rings are worn, valve seals are not tight, cylinder gasket seals are not tight, or the cylinder itself is worn, a major overhaul is necessary. Below are the reasons for insufficient cylinder pressure: 1. Severe piston ring wear leading to reduced sealing effectiveness: There are three piston rings—two compression rings and one oil ring. The compression rings prevent the fuel-air mixture from entering the crankcase, while the oil ring primarily serves a lubrication function, reducing wear on the cylinder walls and piston rings. 2. Abnormal wear such as scoring or unevenness on the cylinder walls: Carbon deposits or other foreign particles enter the cylinder and scrape the cylinder walls during piston movement, causing scoring. 3. Poor sealing of the valve seats or spark plug seats: Excessive torque during spark plug installation can damage the threads. Carbon buildup can cause poor sealing of the valve seats, as carbon deposits adhere to the valves, preventing them from closing properly against the valve seats, resulting in insufficient cylinder pressure and gas leakage.
