What you have is probably normal. The attached diagram shows the different crankcase ventilation systems applied to the 140 and I expect that yours is probably like part #3 on the diagram. Some early cars just had an inverted U tube attached to the side of the engine. So, your crankcase is ventilated; however, it lacks the positive ventilation associated with the later PCV systems.
The smell of oil vapour from the engine is probably normal for a car without PCV system. It will be made worse if you have ring blow by.
With some parts switching, fiddling and modification you can convert to a PCV system which has two benefits
- forced air flow through the engine will help to reduce the build up of moisture and other contaminants in the engine oil
- directing the crankcase air flow into the intake manifold where it is ultimately burnt in the cylinders reduces the unpleasant oil vapour smells.
The later PCV equipped cars had two different PCV systems distinguished by the air flow direction. Some (earlier cars) had air flow into the filler cap and out the oil separator / flame trap and into the intake manifold. Later B20s (Djet for sure) had air flow into the oil separator / flame trap and out the oil filler cap and into the intake manifold. Depending on the application they use a PCV valve or a restricting nipple so don't go mixing and matching the designs. If you want to add PCV to reduce the smell pick a design and use the parts numbers from the parts manual to get the correct matching parts.
Ron K's web site has a hall of shame showing creative incorrect PCV systems along with the correct PCV systems
https://www.sw-em.com/pcv_diagrams_and_notes.htm