About Engine Oil

Oil does the engine lubrication but also helps with cleaning. It picks up lots of nasty things from your engine and also absorbs any petrol that slides past the rings plus with time, moisture from the atmosphere. This isn’t a problem because when you drive the car, those contaminates are burnt off with the engine at temperature and any particles cleaned through the oil filter. That’s why it needs to be changed regularly and when it is run, it needs to get up to a healthy temperature so that any contaminates (like absorbed petrol and moisture) are burnt off. That is why the Club Tuning Runs are aimed at a spirited drive not a slow cruise. The mechanicals in your MG need to get up to temp and be run there for a goodly period.

Ideally the oil (not water) temperature needs to get up around the 95°C+ for the oil to work at an optimal level. Even in the race car I have trouble getting up there (yes I run an oil temp gauge), and I even have a thermostat on the oil cooler. Matt has taken the oil cooler off his race B to get more oil temp and with the engine coming out of Myf again, I will be doing similar. A road car would be much worse. Modern oils may be good for a modern engine, but you need to have a good quality oil designed for our old engines. The water and oil temp do not correlate.

Since road cars don’t see the temperatures that a race engine does, regular oil changes are necessary to maintain good and ongoing engine health. I know it seems like a waste if you don’t drive the MG much but ’use it or lose it’. Actually, the oil in the race car gets changed after only a couple of meetings. Probably only 2 hours of running time. It’s all about maintenance.

Steve Jones

On The Marque December 2020