I'd like to start with a big "Thank You" this month. Thank you to the organizers of the Portland show who, as usual, did a superb job of ensuring that the whole week went smoothly. And also, thank you to the folks who came up and introduced themselves and said how much they enjoyed these articles - it's nice to be appreciated!
I had my doubts as to whether I'd manage to produce anything for this issue of GEM, as I wasn't organized enough to prepare an article before we left for the 2003 Portland show and accompanying family holiday, which left just five days after our return in which to get over jetlag, deal with three-weeks-worth of paper in the office and generally get our lives back to normality. I did manage to read the mail which had come in to the ATIS Stationary Engine Mailing List within the first day or two, but that was definitely reading without absorbing! However, today I had another look at some of the conversations beyond "didn't we have a GREAT time at Portland?" and found a discussion which will be of interest to the owners of water-cooled engines. As many of the European contributors to the List were traveling, this was largely an American - Australian topic, which just goes to prove that some things are the same the world over!

* I have several large engines which 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. Get yourself some plain old tea bags and toss them in next time you
run the engine. This will help seal the water hopper with tannin. After you run it for a day, take the tea bags out and drain the water. Now you can fill her back up and be fine for a long time. Just do not forget to drain the water in the fall, or you will be welding in the spring!

* I just use good old sump oil in my engines, especially my hopper cooled ones. With the hopper cooled engines I just fill them right up to the top, run the engine for a while so the oil heats up and soaks in to the iron then drain it out.
With my tank cooled engines, after a day's rallying, I fill the top of the tanks up with about 3 inches of oil, and when the water drains it takes the oil with it and coats everything. It's a little messy but cheap and you only have to do it once.

* I keep water in my hoppers all the time. I keep the engines in a garage and never have to drain them.
I use a mixture of water and oil in my hoppers. It inhibits rust and when you have to 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, then I squirt a little oil on to the water.
When the water gets hot or boils, the oil mixes to some extent. When the water evaporates, and the water level decreases, the oil will attach itself 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 as the oil 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!

* When I was at the Streaky Bay Engine Museum in South Australia last year, they also ran the engines for public display with oil in the hoppers.
With over 300 engines in store and a mixture of air and water cooled engines they cycle through the ones for running. In order to reduce the time and effort to prepare these for operation with only a small number of volunteers to operate the engines, they leave the ones 'on duty' with a Shell oil in the hopper. There reasoning was that with the generally short running times (abut 4 hours max) and low speeds (not under load) the oil was satisfactory.
The oil could stay in the hoppers not needing to be drained, didn't evaporate and stopped rust in the hopper. Another advantage was that it could be recycled and used in other engines as they came in to the roster and the one going out was left with a coat of oil in the hopper.
It seemed to work for them.

* I like to run anti freeze mix in my water hoppers. This is how I treated an Associated last summer:
1. Drained all the water out and got as much of the gunk out that I could.
2. Sandblasted the inside of the hopper.
3. Filled the hopper with water all the way to the top, and tossed in one of those big tea bags for making iced tea.
4. Filled the gas tank and ran the engine till it stopped. I ran it fast, so it would get good and hot.
5. Removed the tea bag and drained the hopper.
6. Put a 40 percent anti freeze mix in the hopper.


There was a discussion about how to 'Cure' the water hoppers a while back and that is where I got the idea on using the tea from. Someone suggested using oak leaves, since they also have a lot of tannin in them.
I just checked the Associated hopper; still no visible rust to be seen. I like this method, as it smells nice when I am curing it.

Obviously the tea and oil suggestions weren't exactly what was required, so the Australian originator of this discussion clarified his question.

* I have half a dozen large tank cooled engines some hold up to 40 gallons of
water. I have noticed a small amount of rust starting in the water tanks.
My son and I run the engines off and on every few week; it takes a lot of time and water to drain and refill each time so I thought there must be some compound or chemical that would allow me to leave them full.
The hopper cooled engines are no problem as we refill them as needed.

* It is called, strangely enough, "Corrosion Inhibitor", and is readily available from any auto parts/accessories store.

* I know about rust inhibitor but the trouble is too many engines! The rust inhibitor costs around AS$6.00 x 20 engines = AS$120.00.
It means a lot of tins to save all the coolant if I move the engines to rallies, then carrying the tins and refilling the engines. I was hoping there would be some easier way of slowing rust.

* Try putting soluble in the tanks. It makes a bit of an oil stain but it won't rust.

* I think that means Soluble Oil. That's the white goo that I use as well. Looks ugly but seems to keep the water oily enough. Don't pay too much for it though. I pay about AS$14 for 4 liters. Other places have quoted ridiculous prices.

* Soluble Oil is the way to go. It will protect what we have left of our aging water jackets, pumps, pipes etc


* A couple of folks I know keep a water-antifreeze mix in the hoppers all the time. Seems to work well.

* A BIG reason I use TSP-PF is that it's cheap. Anything made for scrubbing bricks and concrete pretty much has to be. It's available from paint stores, hardware stores, Lowes, Home Depot...
I put "TSP-PF" (sodium metasilicate) in the cooling tank of my Lister diesel clone. It prevents rust and also precipitates hard water minerals as a fine milky suspension before it can form hard scale on the hot surfaces of the jacket, (it 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/coolant products for the same reasons. Real TSP (trisodium phosphate) will work much the same. It's banned here, unfortunately. It's 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 noticeably 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 was no exception!

* Did you know that some of the N type Hopper cooled Ronaldson Tippets were run
with oil in their hoppers?

* I've got to ask about this! I can see oil as an agent in a closed system or a radiator
type of system - it will transfer heat or move it, but in a hopper?
Water I'd bet is used because of the cooling effect of evaporation - it takes a lot of heat energy to boil the water, so that heat energy is lost as the water boils and evaporates, but how does oil do that? I used to have a nifty wine cooling flask - you soaked it in water, then filled it with wine and as the water evaporated, it helped keep the wine cool at the table. Or leave ether, etc. on a surface and as it evaporates, the surface loses its heat
energy and thus feels cooler.
I'm curious! How can oil, a substance you aren't going to lose to evaporation, going
to be an effective cooling agent in a hopper?

* Oil in a cooling hopper won't work well for the reasons you mentioned. It doesn't boil until something over 700 degrees F. Evaporation below that's pretty minimal. It can only
radiate heat from the limited surface area of the hopper and the top of the liquid oil, with of course convecting air carrying away additional heat. The thermal gradient will have to be very large to carry off the heat generated by a running engine that way. A good coating of oil 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 energy at a constant temperature.
That's the way my IHC M's run for years. Everything in the hopper's gotten thoroughly coated with oil leaked from the oiler, and won't rust!

* Here's my take on this question.
Heat can travel by three means:

Conduction (when it touches something and transmits its vibration to it)

Radiation (when it travels by means of light waves, mainly infra-red unless you run your engine REALLY hard and get it hot enough to emit visible light)


Convection (similar to conduction, but the heated substance is a liquid or gas and gravity is present to move the heated and thus expanded liquid gas away from the heat source)
So, a dry hopper will not do much conduction since the cylinder doesn't touch much. Convection doesn't work well in the dry hopper either as the air in there can heat, but doesn't move well since there is no opening near the bottom for cold air to enter. But, if you fill the hopper with either oil or water, convection will move heat from the cylinder to the hopper. The hopper has MUCH MORE surface to both radiate and convect heat. Oil can do this task nicely.
But if the engine is working hard, and if the rate of heat flow from the outside surface of the hopper is less than the rate of flow from the cylinder to the liquid, be it water or oil, the heat of the liquid will increase and the boiling point of the liquid may be reached. When that happens, the evaporating (boiling) liquid will carry away heat as it evaporates and you will see a need to add more liquid from time to time. Depending on the liquid, this may occur at varying temperatures. Back when we used alcohol/water mix for antifreeze in our automobiles, we would lose the alcohol pretty quickly if we overheated the engine.
So the liquid in the hopper helps cooling by moving, via convection, heat from the cylinder to the hopper surface where it radiates or convects away from the engine. If you touch it, and burn your hand, you have experienced conduction.

* But is it ENOUGH for a working engine? I mean, gee, a running FM 1.5 hp will boil out water. Put a load on it, oil I suspect would not be enough. I could see convection cooling working - but enough?

* No, I think you will need to monitor and add water if you work it. As you note, the FM will (if they are throttle governed) boil out water. The idling hit and miss runs much cooler due to the pumping action of cool air into the cylinder between power strokes.


* I would think that the oil would be enough for a working engine. One of the
biggest advantages of having oil or water in the hopper is that it helps keep the heat around the cylinder more 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. Really, 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 of the reasoning behind the oil in the hopper engines.

* These engines were used at brick manufacturers; the oil in the hoppers was only there to heat up and was then transferred to the kilns to fire the bricks.

I've been doing these articles for long enough now that you've probably got a good idea of what I'm going to say next, but nevertheless, I'll say it again, especially given the subject matter this month. Temperatures are dropping and winter isn't far away so don't put off draining water out of your engines and doing whatever you need to do to prepare them for the cold weather. Do it NOW and save yourself a lot of problems in the spring!
That's it, lecture over. Now I can go back to sorting out photographs and webpages post-Portland. We spend 6 months of the year preparing for Portland, an intense week there and 6 months savoring the memories!

stationary-engine@atis.net

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