Tech – Oil: Additives (Detergents)

Detergents

Purpose:

  • Maintain engine cleanliness by preventing deposits
  • Keeping oil acidity in a safe range.
  • Operation:

    Detergents work on high-temperature surfaces such as the piston rings and the area immediately behind the piston crown. Detergents incorporate bases to neutralize acids created by the engine in operation. Calcium, magnesium or sodium) sulfonates and phenates are frequently employed and are exhausted over time as the oil is used. Adherance to the service interval is critical to main effectiveness.


    Adverse Consequences:

    Deposits in the piston rings can cuase rings to stick (failing to rotate) in their piston grooves causing excessive spot wear on cylinder walls and cause loss of compression. Deposits also prevent the engine from shedding heat effectively, degrading performance and accelerating wear. It’s also possible for deposits to restrict the flow of oil to other parts of the engine. In turn the reduced flow may cause excessive heat in those areas which then can “cook” in aditional deposits.

    As a byproduct of combustion, engine oil increases in acidity. If unchecked, the PH value of the motor oil will become excessively low and corrosive. As oil is circulated through out the engine, the effects can potentially be transported through out the engine.


    Additional Concerns:

    Cheaper oils made form less refined base stocks (group ii) contain a comparetively larger proportion of parafins (wax) which are more prone to depositting. Group iii mineral spirit base stocks as a result of greater refining have proportionately less parafin, and group iv, genuine synthetics, simply avoid parafin by not creating them at all in the manufacturing process.