Why is the engine noise that has just been repaired loud?

The sound of a Cummins engine that has just been overhauled is like a tractor, usually because the valve is damaged, and the sound changes with the engine speed. It is suggested that the owner can check the valve clearance to see if it is seriously worn. The sound of the engine like a tractor can also be caused by the following reasons:

1. The sound from the intake and exhaust valves of the engine coincides with the larger the throttle, the higher the engine speed, and the higher the frequency of the sound.

2. The sound of the timing chain. The reason may be that the viscosity of the oil is problematic, and it is enough to replace the oil with a suitable viscosity, and the timing chain is too long, and the fault of the chain tensioner causes the sound of the timing chain.

3. The sound of large and small tiles from inside the engine. The reason may be that there is too much sludge inside the engine, and the oil pump is damaged, resulting in poor lubrication. The fourth kind. The engine knocks the cylinder, the quality of gasoline is too poor, the anti-knock performance is not good, causing knocking, and the carbon deposit in the combustion chamber of the engine is serious, which causes the knocking.

4. Since most new cars are injected with fully synthetic engine oil for the first time, and abrasives are added at the same time, the viscosity is low and the quality is good. Replace the engine oil with poor quality after the first maintenance. The high viscosity will cause additional friction when the engine is running at high speed, so the engine noise may also become louder.