I’d like to start this issue with a big thank you to the
organizers of the annual gas engine and tractor show in Portland,
Ind., who, as usual, did a superb job of ensuring that the whole
week went smoothly. And also, thank you to the folks who introduced
themselves and told me how much they enjoyed my articles -it’s
nice to be appreciated!
I had my doubts about producing anything for this issue of
GEM since I hadn’t prepared an article before I left
for the 2003 Portland show and accompanying family holiday. That
left me just five days after my return to England to get over
jetlag, deal with three weeks of paper in the office and get my
life back to normal. I did manage to read the ATIS Stationary
Engine Mailing List mail, which came within the first day or
two upon my return. Today, I had another look at some of the
conversations beyond ‘didn’t we have a great time at
Portland?’ and found a discussion that may interest
water-cooled engine owners.
Since many of the European List contributors were
traveling, this was largely an American-Australian topic, proving
perhaps that some things are the same the world over. This started
with an Australian’s question:
I have several large engines that I run every so often. What can
I put in the water tank to stop or slow down rust? I don’t want
to refill the tanks all the time.
Easy to do. Toss some plain tea bags in next time you run the
engine. This will help seal the water hopper because of the tannin
in the tea. Run it for a day, then take the tea bags out and drain
the water. Now you can fill it back up without worry. Just
don’t forget to drain the water in the fall, or you’ll be
welding in the spring.
I use sump oil in my engines, especially my hopper-cooled ones.
With the hopper-cooled engines, I fill them to the top, run the
engine for a while so the oil heats up and soaks into the iron,
then drain it out.
After a day’s rallying with my tank-cooled engines, I top
the tanks with about 3 inches of oil, and when the water drains it
takes the oil with it, coating everything. It’s a little messy,
but cheap, and you only have to do it once.
I like to run an antifreeze mix in my water hoppers. This is how
I treated an Associated engine last summer:
1. I drained all the water out, removing as much gunk as I
could.
2. I sandblasted the inside of the hopper.
3. I filled the hopper with water and tossed in a big tea
bag.
4. I filled the gas tank and ran the engine until it stopped. I
ran it fast so it would get hot.
5. I removed the tea bag and drained the hopper.
6. I put a 40 percent antifreeze mix in the hopper.
How to ‘cure’ the water hoppers was a hot topic a while
back, and that’s where I got the idea to use tea. Someone
suggested using oak leaves since they also have a lot of tannin in
them.
I just checked the Associated hopper and there’s still no
visible rust. I like this method because it smells nice when
I’m curing it.
I keep water in my hoppers all the time. They’re stored in a
garage, so I never have to drain them. I use a mixture of water and
oil. It inhibits rust, and when you drain them, it leaves a coat of
oil on the inside. It doesn’t harm the cooling capabilities,
either.
I usually fill the hoppers about 3/4 full with water, and I
squirt a little oil into the water. When the water gets hot or
boils, the oil mixes. As the water level decreases from
evaporation, the oil attaches to the sides of the hopper. I feel
that water alone in the hopper allows rust to form even below the
water level. I use the same oil in the water that I use in the
drippers – 20W50 – because that’s what I use in my truck. The
only problem is that it leaves an oily scum on my ravioli cans when
cooking!
Obviously the tea and oil suggestions weren’t
exactly what was required, so the Australian clarified his
question.
I have a half dozen large tank-cooled engines with some holding
up to 40 gallons of water. I have noticed a small amount of rust
forming in the water tanks.
My son and I run the engines every few weeks, so it takes a lot
of time and water to drain and refill each time. Is there some
compound or chemical that would allow me to leave them full? The
hopper-cooled engines are no problem, since we refill them as
needed.
Try putting soluble oil in the tanks. It makes a bit of a stain,
but it won’t rust them. It may look ugly, but it seems to keep
the water oily enough. Make sure you don’t pay too much for it
though, some places have quoted me ridiculous prices.
A big reason I use TSP-PF (sodium metasilicate) is that it’s
cheap. Anything made for scrubbing bricks and concrete pretty much
has to be cheap. It’s available at paint and hardware
stores.
I put TSP-PF in the cooling tank of my Lister diesel clone. It
prevents rust and also precipitates hard water minerals before they
can form hard scale on the hot surfaces of the jacket. The
precipitate does settle as a fine white mud in the bottom of the
tank, but rinses out easily with a hose. Sodium silicate is a
common additive to commercial antifreeze and coolant products for
the same reasons. Real TSP (trisodium phosphate) will work much the
same. It’s banned here, but is also found in commercial coolant
products.
If I don’t use the silicate (I forgot it when I went to
Portland this time), the cooling water drains out quite rusty even
after only a day or two. If I add several ounces to the tank (a
small paper cup full in my 25-30 gallon tank), it drains out
rust-free after months. Of course, it takes a few drain/refill
cycles to get out existing loose rust.
So there you have a variety of solutions for the
prevention of rust in hoppers and cooling tanks. But as usual with
the mailing list, one subject leads to another, and this one was no
exception.
Did you know that some of the N-type hopper-cooled Ronaldson
Tippets ran oil in their hoppers?
Oil in a cooling hopper won’t work well for cooling. It
doesn’t boil until it’s extremely hot. Evaporation is
minimal. It only radiates heat from the limited surface area of the
hopper and from the top of the liquid oil with convection air
carrying away the heat. The thermal gradient must be very large to
carry off the heat generated by a running engine that way. A good
oil coat in the top of a hopper full of water won’t hurt
anything, nor will oil emulsified with the water. The water will
still boil and carry away large amounts of heat at a constant
temperature.
Here’s my take on this question. Heat can travel by three
means. Conduction: Heat touches something and transmits its
vibration. Radiation: Heat travels by light waves, mainly infra-red
unless you run your engine really hard and it’s hot enough to
emit visible light. Convection: The heated substance is a liquid or
gas and gravity moves the heated and expanded gas away from the
heat source.
A dry hopper won’t conduct much since the cylinder barely
touches it. Convection doesn’t work well in a dry hopper since
the air doesn’t circulate well. But, if you fill the hopper
with oil or water, convection will move heat from the cylinder to
the hopper. The hopper has much more surface area to both radiate
and convect heat. Oil can do this nicely.
If the engine is working hard, and if the rate of heat flow from
the outside hopper surface is less than the rate of flow from the
cylinder to the liquid – be it water or oil – the liquid’s heat
will increase and the boiling point may be reached. When that
happens, the evaporating (boiling) liquid will carry away heat as
it evaporates, and you’ll see a need to add more liquid from
time to time. Depending on the liquid, this may occur at varying
temperatures.
When we used alcohol/water mix for antifreeze in our
automobiles, we lost the alcohol pretty quickly if we overheated
the engine. So, the liquid in the hopper helps cooling by
convection. If you touch it, and burn your hand, you have
experienced conduction.
But is convection enough for a working engine? A running
Fairbanks-Morse 1-1/2 HP will boil out water. Put a load on it, and
I suspect oil would not be enough. I could see convection cooling
working – but enough?
I think that the oil would be enough for a working engine. Among
the advantages of oil or water in the hopper is that it helps keep
the heat around the cylinder even. It prevents a hot spot or, at
least, helps lessen it.
The oil cooking in the hopper must really stink if the thing is
working hard, and I suppose it could cook down after a while,
couldn’t it? If you have oil in the hopper and the engine is
running under a load, keep an eye on the piston. If the cylinder
and piston get so hot that the lubricating oil on the piston starts
to break down, you are in big trouble. We want to run the engine as
hot as we can but still have effective lubrication.
Luckily, those wrestling with this concept were put out
of their misery by further explanation behind the oil in the
engine’s hopper.
These engines were used at brick manufacturers. The oil in the
hoppers was only there to heat up the engine and was then
transferred to the kilns to fire the bricks.
Temperatures are dropping, and winter isn’t far
away, so don’t put off draining the water out of your engines
and doing whatever you need to prepare them for the cold weather.
Do it now and save yourself a lot of problems in the
spring.
Now I can go back to sorting out photographs and Web
pages post-Portland. We spend six months of the year preparing for
Portland, an intense week there and six months savoring the
memories.
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
