Engine Cooling Systems

There's a number of ways to implement a cooling system. This is the page where I will eventually pull this information together in one place. Always remember hot water and steam are dangerous, this information is for educational purposes only, never mess with any of this stuff.

Hopper/condenser

Above is a picture of a Chinese Horizontal, connected to a cast iron steam radiator out of an old house. You can buy these for so much a fin at salvage places, and recyclers of vintage building materials. There's a place in Seattle that charges about $8 a fin for the plain Jane units, the more ornate they are, the more per fin you pay. You simply unbolt the top of the cast iron hopper; make a plate with a pipe fitting in the top, bolt it in place, and connect it to a condenser as shown. lots of other things can be used for the condenser. If you dare to be different, I would imagine one of those aluminum street light poles would work for a condenser.

Hopper systems have advantages and disadvantages. Hopper cooling systems remove the heat via steam.  As an open system the steam rises into the air carrying off the excess heat. Open systems call for water to be added, there's usually a float or flag that indicates the hopper is low. The engine runs at a constant temp and if the elevation at which you are running is not too high, it will be near ideal for a hard working diesel engine.  Hard water can rapidly deposit scale around the cylinder and impede the transfer of heat to the cooling medium; this can cause severe problems. I have heard of people using light acids to remove rust scale, and others suggest setting up a rain barrel to use as cooling water in an open hopper system. One of our readers reported a major build up of deposits in a few hundred hours of running a open hopper system on hard well water. Butch Philips in Cowiche asked that I build him a hopper cooled gen set, I delivered it to his Elk camp this year, he fired it up at 11F degrees and became concerned about the clouds of vapor coming out of the hopper, In real cold weather, it looks like a cloud generator when you get a good load on it. If you haven't seen this, it's pretty cool.

Some readers have written to inform me that their were numerous hopper cooled closed condenser systems in use on the old work engines. These systems allowed the steam to rise and carry off the heat to a condenser (in the form of steam). The steam then condensed in an area remote from the hopper and the water trickled back down the same tube and back into the hopper. Looking at the old cast iron steam radiators used in houses, one might think a small water cooled diesel and one of these finned steam radiators could be put together to form a very effective heating and cooling system. In addition, one would only need to run one pipe (or high temp hose) to the steam radiator. of course it would be wise to assure that this pipe was slanted upwards to the condenser with no low spots in the middle, and that a proper relief valve was added. You'd also want this valve to be able to vent in a safe direction. What you'd be doing is capping the hopper with a plate, and running a single hose or pipe to the condenser. In effect, you'd be suing your engine as a no/low pressure boiler.

I remember being in Ralph Akana's shop one visit; Ralph was born in Kauai and is one of the best wood workers and craftsman I've ever met. He lives in Northern California where fly fishing is good.

Above is one of my prized possessions; and an example of his skill; this net is all hand tied and the wood was bent in a piece of pipe laid across his stove. At the time Ralph was showing me his method of bending wood; I didn't fully understand what was happening. Ralph would cut long pieces of wood and put them in a long piece of pipe with pipe threads on each end. He added a certain amount of water and put the last cap on. One end was laid across his very hot shop stove, with the slightest of inclines going upwards to the other end. What he had created was a closed steam condensing circuit. Steam would form, run up towards the far end, condense and run back towards the stove. The process would make the wood very pliable, Ralph would pull the wood from the pipe and force it into a jig to cure.

You can use the same principle to cool your engine, leave out the wood, and make sure you have a large enough surface to condense the volume of steam you expect to create. It's always a good idea to engineer in a relief valve for safety. This is something Ralph did not do because he understood he had far more condensing surface than required for his application, and he limited the amount of water.

If you have a generous amount of surface area, you will not build pressure, the steam will hit the condenser and immediately condense on the cooler surfaces. Considering this, you could come up with some very interesting condensers that should work fine. And as long as your condenser is higher than your hopper, and the connecting tube between the two moves upwards with no dips. If it's vapor tight, you'll have no reason to add water. Add some rust preventative, but add antifreeze only after you study the effects of what it will do to the boiling point of your coolant, additives will modify the boiling point, which is the operating temp of your engine. If you are wondering how you calculate the operating temp of your coolant mixture, and  elevation, put some in a pan, place it on the stove and put a thermometer in it! this will be your operating temp.  

Thermal siphon cooling systems (no water pump)

Above is a thermal cooled setup showing a cast iron 'hot water' radiator. You can quickly identify a hot water radiator from a steam unit by looking for the upper and lower fittings, steam (condenser units) have only the lower connections. This system works well with a thermostat just like that found in an automotive system.

Several readers have asked about thermal cooling  systems, do they really work well ? If it is so good, why was there a need to put water pumps on engines? Some engine designs move water through jackets on the horizontal for a number of cylinders, This basic design relies on the coolant moving a little faster to carry away excess heat at high power output. You need to look at each engine design to see if it will cool properly without the pump.

Thermal siphon systems usually operate in a loop where hot water is allowed to rise from the highest point in the engine's cooling circuit upwards to a high point in the cooling tank or radiator. There's another connection made at the lower end of the tank or radiator that allows the heavier (cooler water) to push it's way to the lowest part of the engine's cooling system. Naturally, this push is going to displace the lighter and hotter water that will be forced to move upwards thru the engine forcing circulation. It is critical that all connections between the engine and tank or radiator move upwards, with no dips or low spots that could allow for a 'deadhead' to impede the movement of the water.

There's a post on an old engine site I was reading that discussed the installation of a gate valve on the lower cooling connection on the engine. The author explained that when the engine is connected to an open tank, this valve was often closed to allow the system to operate as a hopper cooling system. If the operator wished, he could then open this valve to enable thermal cooling between the tank and the engine. Some operators actually tuned the cooling circuit to match the conditions and the type of work the engine was doing...leaving the valve closed operated in hopper mode, opening it, allowed the engine to run in thermal circulation mode which may have allowed the engine to run 10 or more degrees cooler depending on tank capacity and work being done.

If you make use of a car radiator for thermal siphon systems, make sure it's one with the pluming on the top and bottom versus the cross flow type.

As of 5/2003, I have found that old House style cast iron 'hot water' radiators are excellent for the Lister 6/1. I would imagine they would do well on a converted Chinese Horizontal as well. They are truly amazing, the hotter they get, the better they thermal, they can really pump some heat into the air, or your room. Some of the old ideas are still best today, the only down side is they weigh a bunch.  On the 6/1s, I install a thermostat on the top connection, this allows for a far quicker warm up, it reduces emissions, and reduces wear on the engine. Studies have proven that maintaining an engine at the proper operating condition can greatly improve fuel economy. This is the single biggest gain you can achieve; one engines that are in good condition, with properly adjusted valves, and timing.

Contributions to this page:

(http://www.utterpower.com/cooling.htm) with interest. I have something to add on the subject of deposits:

In closing, both hopper cooling and thermal siphon cooling works on Listeroids and Chinese horizontals, hopper cooled Chinese engines can be quickly and cheaply converted to a closed system of your choice. Remember if the water pump is not there, it can't fail when you need the engine most.  Input from Alan above gives us additional reasons to consider a closed system, and if we don't have it, I think his advice and methods are very important, those deposits building up on the liner can greatly increase temps in the lube oil, combustion chamber, and may lead to a lube oil break down, and a complete failure. 

utterpower cooling manifolds

All the best

George B.   

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