The importance of changing the oil cannot be over-emphasized. This engine, designed in the 1930's, does not have a true oil filter as we see them on modern cars, and while the air cleaner is relatively efficient, the design of the crankcase ventilation system is such that un-filtered air is drawn into the crankcase constantly. Changing the oil is the only way of getting the micro-grit, combustion products, and engine wear products out of the oil, so do it at the suggest intervals, or your engine's doom is assured.
You will need:
- A bit less than 3 litres of oil (discussion of oil)
- An oil change gasket kit (comprising of 2 round paper gaskets, 6 small copper washers and one larger copper washer)
- Something to drain the old oil into (find something that will fit under the engine and has a mesh to stop you from losing important nuts and bolts, you can buy oil drainers from your local motor factors)
- Something to clean the oil filter in
- Some petrol or kerosine to clean the oil filter with
Some people prefer to drain the oil when the engine is hot and the oil drains quicker. Others prefer to do it when everything is cold and nicer to work on. They can then use the extra time that it takes for the oil to drain to do other stuff, like setting the valves.
Locate the sump plate. It is the round plate about 4 inches in diameter at the very bottom and center of the engine. There are two types of sump plate, some have a central bolt which can be undone to drain the oil, others need the whole sump plate to be removed. Whichever type you have remove the plate and filter, not just the drain plug.
Place whatever you've decided to use to catch the oil under the engine and, depending on what type of sump plate you have either undo the center bolt or loosen the nuts around the outside of the plate until the oil starts pouring out. Leave the nut nearest to you till last, that way when the plate seperates from the engine the oil is directed away from you rather than all up your arm.
When the oil has drained as much as it will by itself remove the sump plate completely along with the oil strainer that sits above it inside the case and the two paper gaskets. Leave the oil drain pan underneath the engine as it will continue to drain for a while.
Thouroughly clean the sump plate and oil strainer with petrol or kerosine. Dry them thoroughly,then put them back on the engine with the new gaskets from your oil change kit so that there is a gasket sandwiched between the case and the oil strainer and another between the oil strainer and the sump plate. Make sure you put the center bolt back in the sump plate. Use the new washers from your oil change kit.Take care tightening the nuts back up, (0.7mkg), they're only small. Check them again after a few miles driving in case the gaskets have compressed.
Put in the oil, 2.5 litres should fill it to the mark, leaving a little bit left over to change the oil in your oil bath air filter.