Bulletin Today, March 26, 1982
by Roberto C. Bernardo
Noisy Engine. There are major sources of engine noise. The fuel combustion is one. This is commonly referred to as fuel knock or knocking. This noise is attributable to the fuel injection equipment. It is usually precipitated by improper injection timing, bad spray formation by the nozzles, and other malfunction in the fuel injection equipment.
Other noise may come from the engine piston or internal running parts that produce chattering and clattering noise.
Another is the continuous or gear noise, usually associated with timing gear train, alternator and water pump and are attributable to the worn-down condition of their bearings.
Low temperature knocking which shows up upon starting the cold engine but disappears as the engine wams up, must not be confused with ordinary knocking; this is normal in diesel engines. Engine noise changes as the engine warms up to normal operating temperature. This is due to thermal expansion- running clearances change in magnitude.
The development of the skill identifying the type of noise and its possible source could be very advantageous to the diesel users from the point of view savings and time.
Its identification could tell the user what kind of repair or servicing is required by their unit. If it is knocking or fuel knock that was observed, it would be a job for a diesel fuel injection equipment mechanic or service shop. If it is clattering or chattering noise, as the case may be , then it's a job for the regular or ordinary engine mechanic.
To be able to develop required skill to identify the normal noise from abnormal one- habitual listening to running engine is the secret.
Here's a simple way to do it: First, eliminate the source of outside noise by removing the fan belt temporarily. This will subdue the