Greetings from sunny England to the readers of GEM. As
I write it’s August, and as we’ve had several days of hot
sunny weather the media is full of hysteria about ‘record
temperatures,’ ‘global warming’ and ‘drought.’
Actually, in the UK it only takes three consecutive days of any
particular kind of weather to bring the nation almost to a grinding
halt. How the rest of the world manages to cope with their various
extreme conditions doesn’t seem to register!
In the world of engine restorations, the answer is to ask the
advice of friends on the Stationary Engine Mailing List
who may have encountered similar problems. In this case, a query
came from someone in the Australian state of Victoria in the bottom
right hand corner of the country (I know – I looked it up!), which
is in its seventh year of drought.
And so on to the discussion that attracted my attention this
month on the Stationary Engine Mailing List. As ever, the
following comments reflect a variety of opinions that surfaced
during this discussion.
Currently, we have largely voluntary water restrictions in and
around Melbourne. As such, filling engine cooling tanks, while not
banned, is a bit of a waste. My Southern Cross P has a 110-liter
tank on it. The water in the top is usually hot enough to steam,
but the water in the bottom never gets hot. I’m considering
putting a much smaller 40-liter tank on it. The engine uses an
endothermic cooling system -i.e., it’s not pumped – the water
siphons when it gets hot enough. I know the top pipe will have to
be level with, or slightly above, the head inlet pipe so that water
will always cover the combustion space. Usually, I have the lower
pipe lower than the engine outlet – this is the bit that I’m
not sure matters. To use the smaller tank I have to build up its
height so its top pipe matches the engine top pipe. This means that
the water from the bottom outlet will have to flow horizontally
rather than downwards – will this matter? I think probably not as
the system depends on heat not gravity but I do not want to find
out the hard way. Anyone have any thoughts on this?
Sure! 110 liters is an awful lot. You could go to quarts instead
of liters, because they’re considerably smaller.
If you only have metric water available, you could put a
secondary tank inside the original. The original would only be to
maintain the original look. The secondary will be nearly the same
height, but smaller cross section. A large pipe might work well for
the secondary.
I’ve seen a picture of a similar setup, in which a smaller
tank is inside the main tank and is used for situations where the
engine won’t heat up properly. It cannot be seen from the side
so all the public sees is a standard tank. It’s not a good
thing to have an engine running too cold, either.
How about applying the ‘brick in the toilet tank’
principle? Put some bulky vertical object in the large tank to fill
much of its space without changing the level of the water.
The question of pipe angles was a subject of
surprisingly conflicting opinions.
As long as the water in the tank is at a higher level than the
head, the pipe to it can be horizontal. As for the bottom pipe,
horizontal will work, too. The main thing is to not let any part of
the water jacket run dry.
Horizontal will work. It can even angle uphill, as you will have
pressure from the head of water above the outlet of the tank.
In my opinion, the top pipe should slope up at least slightly.
Doesn’t matter much for the bottom pipe. If the top pipe slopes
down at any point or has a high point in it, air or steam could
collect and stop thermo-siphoning completely. I think it’s poor
design in a thermo-siphon system to use a thermostat or valve in
the top pipe, and for the same reason. If the valve’s not
opened, or the thermostat sticks, steam will push the water out of
the head through the bottom pipe. The empty head will heat up and
possibly crack. With the flow restriction in the bottom pipe and an
open top pipe sloping upward, it’s no problem if you forget to
open the valve restricting coolant flow.
As long as there’s water in the tank above the opening of
the top pipe steam bubbles will escape up the pipe to the tank, the
jacket will stay full of water and you’re effectively running
with hopper cooling.
It won’t thermo-siphon unless that tank is full and the top
of the water in the tank is above the highest part of the cylinder.
The bottom pipe is easy. The top pipe should run up at a slight
angle (preferable, but not imperative). The hot water wants to be
on top and only needs a little help to float up through this
system.
How about four cinder blocks or a 12-volt bilge pump? I can cook
the heck out of them in my Reid tank in the blistering sun, and
they keep ticking. With a bilge you don’t have to fill it up
all the way.
This response was from another Australian, hence the
references to unfamiliar engine marques!
Although on an entirely different bent, my McDonald C Type is
hopper-cooled as is my Rose berry 3C. I had the tank made for the
Rose berry as per the factory instructions, which in retrospect
were for the engine running under load.
As I was trying to curb costs, I reasoned that the one tank
would also be more than sufficient for the McDonald and therefore I
could share it between them. The tank maker thought I was wrong,
and as it turned out he was right and 1 have since had new tanks
made for each engine.
The problem was that the engines ran way too cold, which was a
disaster for the McDonald. Being a diesel it usually runs at just
above an idle, and even running a grinder there was never a long
enough running time or big enough load to get the engines warm
enough with the huge tank.
I see many Roseberrys running a 20-liter drum with a great head
of steam at rallies. Good for boiling lunch and letting the
onlookers think they are steam engines, but way too close to being
too hot for my liking. I have also seen a couple of false tanks
(one inside the other), and these work well while maintaining the
right look.
The original question in this discussion was asked as
someone was preparing to take his engines to a show, and some of
the responses came in a little late for that show, but not too late
for lessons to be learned.
You turned out to be exactly right about having a slight upward
slope to the pipe. I had it horizontal – fortunately, I use clear
pipe and can always see if the water is moving. About an hour in
the pipe emptied of water and filled with steam and air, and from
then on I had to loosen the hose clamp at the engine end every 15
minutes or so and let the steam and air escape. Wish I had read
your advice before the show.
I think I’ll go make the tank an inch higher and run the
engine for a bit and see how much difference it makes.
I bet even a very slight up-slope in the top pipe will help a
lot. Expecting air or steam to move ‘up’ with a horizontal
pipe is like expecting water to drain off of a flat roof. Great
idea using a clear pipe to test it.
That’s all for now. I’m off to water the garden
before a hosepipe ban is announced. Not to mention that’s a
chore that usually guarantees rain within 24 hours!
‘As long as the water in the tank is at a higher level than
the head, the pipe to it can be horizontal. As for the bottom pipe,
horizontal will work, too. The main thing is to not let any part of
the water jacket run dry.’
‘I bet even a very slight up-slope in the top pipe will help
a lot. Expecting air or steam to move ‘up’ with a
horizontal pipe is like expecting water to drain off of a flat
roof. Great idea using a clear pipe to test it.’
Engine enthusiast Helen French lives in Leicester,
England. Contact her via e-mail at: Helen@insulate.co.uk You can
join the Stationary Engine List on the Internet at:
www.atis.net
