Many interesting topics were covered this month by the
world-wide members of the internet Stationary Engine Mailing List
and one which was brought to my attention as a suitable subject for
the GEM article discussed ‘snobbery’ at engine shows. The
attitude of some show organisers and exhibitors inspire some lively
discussion, but as last month’s article was on the subject of
shows, I decided to save that for next month and pass on some
brief, but interesting, information about oils for
lubrication.
Strangely, this thread started life when someone asked the
off-topic question of how he could get rid of gophers on his
property, and one suggestion offered the use of a Maytag exhaust
inserted into the offending hole, with the addition of various
substances to the running mixture of the engine. This then
developed into querying which additives can safely be used with
stationary engines.
Before I go and try this I want to make sure. … If I empty the
oiler on one of my engines and put castor oil in there it’s not
gonna seize the piston or burn up the cylinder? I bought some
castor oil last time this was brought up but never did try it
because I wasn’t sure if I’d screw anything up.
Nope. It’ll run great. The worst that can happen to you with
castor oil is stuck rings, but that happens primarily with long
running under very hot conditions. Castor oil has better
anti-friction properties than the old straight mineral oils, and
excellent antis cuffing properties under high bearing loads. Lots
of oils for racing two-stroke motorcycle engines are still based on
castor oil.
You shouldn’t mix mineral and vegetable oil together, as the
vegetable oil goes into lumps and can block oil-ways.
There are special flushing oils required to change from one to
the other, and unless you are racing there is not a lot of point in
using vegetable oil in the first place.
All true enough, but there’s not really a lot of point in
any of this stuff that we do, is there? With a drip oiled piston, I
believe that simply emptying out the oiler and changing over will
work okay either way.
Intriguing statement . . . Why would racing make a
difference?
Because vegetable oils had better performance at high
temperatures than mineral oils. Fully synthetic oils may have
reduced the gap, but you tend to find most air-cooled engines such
as bikes on vegetable oil, while cars, etc. tend to use ‘normal
oils.’
Castrol used to have an information leaflet on the subject, and
I remember our little cafe-racer group in the 1960s having all
sorts of problems with cleaning out vegetable oil after use. Not
many solvents will touch it.
Mixing them is a big no-no and has grenaded more than a few
bikes. I buy Blendzall and run it really lean in my gas for the
desired effect… no ill effects so far. Drip oiler is still used
as normal.
I think the point of using it is to stimulate an old Pavlovian
adrenal response.
It’s probably worth discriminating between castor oil and
vegetable oil as much as we can; there are differences.
Castor oil is indeed a vegetable oil, but as far as I know
it’s unique in containing a fatty acid (ricinoleic acid) with
hydroxyl groups on the chains. They’re somewhat polar and cause
castor oil to cling more strongly to metals than hydrocarbon or
normal fatty oils.
As I know it, Castor oil is a ‘boundary lubricant’ and
holds on under pressure better than the old mineral oils. This was
pertinent in the early days but, now the modern oils with all the
different additives are far superior to straight castor oil; there
is no point in using it. If you like the smell, drip some on the
hot exhaust!!
Castor oil doesn’t dissolve in petroleum solvents, by the
way, but citrus oil or turpentine works fine if you need a thinner
or solvent for some reason.
A short and sweet article this month, but for those for whom
the faint aroma of castor oil drifting over the show ground brings
back happy memories of racing days, it seems it’s possible to
achieve without doing any damage to antique engines.
This coming month should be very interesting engine-wise here in
the UK. We have our biggest national rally in 3 weeks, which has,
so far, escaped from the threat of Foot and Mouth disease which has
seen many rallies cancelled this summer. Hopefully, this rally will
be a taster for the Portland, Indiana show, as there will be a
meeting of English, American and Dutch members of the mailing list,
showing English, Danish, American and Czech engines. There will
also be an exciting addition to our personal engine collection, a
night-time show to celebrate the summer solstice and a city centre
show to mark the opening of a new Space and Science centre,
celebrating technology of the past and present. I’ll keep you
informed!