Why do we have different types of oil?

performance over the last 30 years.
Generally the type of oil to use is influenced by the temperature and the operating conditions that are subjected on that particular engine.

Generally there has been no drastic change in the making of vehicles other than improvements that have been done over the last 30 years.
Vehicles that were made in 1960 generally had a temperature range of 100 degrees celcius.
We are talking of your Rambler, Chevrolet, Ford, Zephyr 6 and those made in 1970’s, the Datsun 1100, 1200, 1300cc had a temperature range of 150 degrees celcius and those in 1990’s about 200 degrees celcius and the thereafter over 350 degrees celcius for the latest cars.

What this then means is that the type of oil has to change to cater for the increase in temperature.
There is need then to look at the both diesel and petrol engines to appreciate this change.
Diesel engines could be broken into three main classes in terms of speed of rotation.

This is normally in inverse proportion to the axle to the engine. Hence those of high speed, medium speed and low speed and these ranges can be made as follows, those that are below 350 revs per minute are known as low speed, those that are from 350-1000rpm medium speed and those above 100 rpm high speed.

In case of petrol engines, these are literally broken into commercial and passenger cars operating under vary different conditions such as extensive stop-start city driving or the highway.
In this case vehicles require oil that give the engine protection hence operating efficiently with little or minor service requirements.

The type of oil should allow ease of starting, guards against wear and tear of cams, tappets, pistons, and bearings.
In addition the oil has to reduce sludge occurrence under both cold and hot, low load conditions, high-speed conditions of operations. By analysing this it is obvious that there is a need for a multigrade oil that

improves viscous drag being proving easy starting, rapid oil circulation from cold.
It also improves fuel economy at the same time keeping adequate viscosity to protect against wear and tear under fully warmed up/high speed driving conditions.
Then for high-speed diesel engines such as construction equipment, industrial stationery application, commercial and road haulage invariably apply a lubrication system in which the crankcase oil lubricates both the bearings and the cylinders.

The type of oil should be able to work under conditions that promote oxidation and thermal breakdown of the oil which normally leads to oil contaminants such as soot and combustion products.
Corrosive products are sometimes found in the oil creating both from oxidation weal acids, which corrode bearings from contamination of strong acids emanating from combustion of the sulphur compounds in the diesel fuel.

Lets met again next week for more Obel tit bits and keep up your comments.