Technical - Oil and Lubrication

Oil Types

(Information provided by David Holyoake of Stewart Engineering - The Sunbeam Specialist)

Engine & Gearbox:

A good quality Mineral monograde oil (we recommend Morris Lubricants 'Elite' range of monograde oils. These are specially formulated for classic type vehicles), SAE 50 in the summer and SAE 40 in the winter (Note: SAE is just a classification. The 50 refers to its viscosity).

I definitely do NOT recommend the use of multigrade oils! (read Sunbeam data sheet no.15 for the reasons why).

What we have found is that these days so few owners use their 'Beams in the depths of winter, that SAE 50 is generally acceptable all year round. It's now all Stewart Engineering sell!

Rear drive:

SAE 140. The actual type of oil recommended is AG140. This is a non or very mild EP gear oil to API Classification GL 1 or 2. This oil is highly resistant to oxidation and foaming and remains in good condition for long periods. The oil NOT to use is standard EP type gear oils as these often contain a lot of sulphurous products which will corrode yellow metals very quickly, they will cause the worm wheel to disintegrate!

Front forks:

Fork oils come in various viscosity grades and are classified by a system known as 'Weights', i.e., 5, 10, 15, 20 WT, etc. The type of oil is a 'High VI Suspension fluid', and for use in a Sunbeam we recommend 15WT. Some other manufacturers class this as a 'Medium' WT.



Sump Capacity
S7 > 3 Pints
S8 > 3.5 Pints
Stewart Finned > 3.5 Pints
Stewart Spacer > 1 extra Pint
Gearbox Capacity
2 Pints
Rear Drive Capacity 0.5 Pints
Front Forks Capacity S8 > 3/8 Pint (213cc)

Engine Oil Circulation