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Thread: Removing thermostat from water cooled engine.

  1. #166
    Registered User wsimpso1's Avatar
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    Re: Removing thermostat from water cooled engine.

    Are you guys still arguing over this?

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    Re: Removing thermostat from water cooled engine.

    Quote Originally Posted by cheapracer View Post
    You are wrong, of course there's cold air.

    The Earth spins on an axis that, well, wobbles, and the differing angles cause a difference in concentration of the sun which in turn causes what we know as the seasons, so we get hot air in the Summer when the sun's concentration is at it's greatest, and we get COLD AIR in Winter when the sun's rays angle cause them to be less dense.

    Or you could be at he Artic or Antartica where the air is really cold.



    Mind you a simpler way would be to stand in front of an air conditioner, but only if the thermostat is working correctly.
    Cold is what we call "the absence of heat". Darkness is what we call "The absence of light". Evil is what we call "the absence of good". I think this is what Tony is talking about.
    Pops

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  5. #168
    Registered User BBerson's Avatar
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    Re: Removing thermostat from water cooled engine.

    Quote Originally Posted by wsimpso1 View Post
    Are you guys still arguing over this?
    I think this thread is just the free flowing hangar flying thread of the week. Thread du jour. Just try to keep it aviation related.
    I learned a few important things from our experienced experimenters, such as I don't need or want a thermostat in an airplane.

    So next question:
    Do valves actually burn in a watercooled engine? Seems like the engine would blow steam and the owner would shut it off first. But I only work on aircooled engines, so what do I know.

  6. #169
    Registered User Dan Thomas's Avatar
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    Re: Removing thermostat from water cooled engine.

    Quote Originally Posted by N8053H View Post
    But you would need to be an engine builder or one who rebuilds engines to understand this. I am not speaking of a parts replacer. But one who line bores, grinds valves, turns cranks, decks cylinders. But again most do not do this kind of work to understand this.

    Tony
    I have rebuilt engines, ground valves, resized cylinders, and ground crankshafts. I guess that wasn't enough...

    I have to quit this. It's the reason for my periodic absences. Much too easily irritated into trying to correct something that really isn't important. Sorry about my attitude, folks.

  7. #170
    Registered User cheapracer's Avatar
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    Re: Removing thermostat from water cooled engine.

    Quote Originally Posted by Pops View Post
    I think this is what Tony is talking about.
    I'm deeply impressed Pops that you know what he is talking about.
    Quote Originally Posted by BoKu View Post
    The vast majority of engineering failures are the results of failure of imagination rather than failure of calculation.

  8. #171
    Registered User Winginit's Avatar
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    Re: Removing thermostat from water cooled engine.

    Quote Originally Posted by Dana View Post
    It's not the motion of the water that prevents freezing; it's the fact that warm(er) water is continually entering the pipe, replacing the water dripping out of the faucet that has been cooled by the cold pipe. Put another way, the faster moving water is more effective at warming the inside wall of the pipe and keeping it above the freezing point... just as faster moving coolant is more effective at removing heat from your engine. The temperature change of the faster moving fluid is less, but the actual amount of heat transferred is greater, since the rate of heat transfer is proportional to the temperature difference.

    Dana
    Dana, here is an explanation of where I think the more flow equals more cooling is an incomplete observation. I do agree that in general, thats the basic thing that we see happen everyday. But, it happens within a range of temperature where it CAN work. Look at your typical automotive radiator. On its own, it is inable to sufficiently furnish enough heat transfer to the atmosphere to keep an engine cool. To give it the best chance of keeping up with the heat dissipation needs of an engine, manufacturers enlarge the radiators, they give them more cores,double and triple pass. They went from copper to aluminum. Still with all these innovations a basic radiator won't always cool an engine. Then they adapted fans and shrouds to artificially increase the cooling with forced air movement whether driving or idling. Its always been a struggle to remove sufficient heat
    If the ability of the heat transferring aluminum fins was unlimited, radiators would only need 1 fin.Obviously that isn't the case. Given the propensity of automotive manufacturers to reduce parts count to save money, it seems logical that if increasing the speed of the circulatory water would on its own effectively lower water temps, they would do away with larger more expensive radiators, cooling fans and shrouding. They could place radiators somewhere other than the front of the vehicle and create more aerodynamic designs. If an engine is running hot, just pump the water faster.
    The reason they don't just do that is because the radiator has a limit to its thermal efficiency. While increasing coolant speed CAN/WILL have an effect on that thermal efficiency up to a point, the radiator would eventually reach a point where the area it has available to dissipate the heat has reached its maximum. A radiator does not have an infinite ability to transfer heat. I think that really is the issue. Its not that more coolant is not capable of carrying away more heat, but that the medium (radiator) does not have sufficient transfer area to utilize the benefit of the additional flow. I think thats a pretty easy concept, and I don't think it breaks any laws of physics. Anyway, that's my respectful opinion of why increased flow doesn't always have to generate more cooling. Look at Subaru engines and their history with overheating and blowing head gaskets. The factory didn't just take the simple step to just leave the thermostat out, or
    to increase flow and keep temps lower. I believe they took steps to alleviate a bad design feature caused by a hot spot and a poor head gasket. You have to look realistically at solutions to problems inheirent in differing designs and take the appropriate action to solve the problem. Will removing a thermostat always cause overheating...No.
    Will moving the coolant faster always solve a problem. I don't think it will.
    Thinking about it from an airplane point of view, we have all read about the trial and error problems encountered by builders using radiators. They try one or two or even three radiators with placements from above to below the engine, in front, in back, everywhere. This demonstrates that depending on placement, area, air flow, and even coolant flow and air entrapment, that they have difficulty cooling. If speeding up the coolant flow was the simple answer, thats what they would be doing. Simply change the pulley sizes and your problem would go away. So, again, with all due respect I continue to believe that the ability of the radiator to dissipate heat is not infinite, is actually complying with the laws of physics, and can reach a point where additional flow does
    not provide any additional benefit.

    Its not about the ability of additional coolant flow being ABLE to give up more heat, but about the chosen device having sufficient means to take advantage of the additional capacity.

    PS: Great article in Kitplanes
    Last edited by Winginit; January 6th, 2017 at 12:23 PM.
    https://www.youtube.com/watch?v=PdY9s9kxv14

    Everything I post is just my misguided personal opinion !
    Look for Torque and you will find HP !

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    Registered User bmcj's Avatar
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    Re: Removing thermostat from water cooled engine.

    Quote Originally Posted by Winginit View Post
    If an engine is running hot, just pump the water faster.
    The reason they don't just do that is because the radiator has a limit to its thermal efficiency. While increasing coolant speed CAN/WILL have an effect on that thermal efficiency up to a point, the radiator would eventually reach a point where the area it has available to dissipate the heat has reached its maximum. A radiator does not have an infinite ability to transfer heat. I think that really is the issue. Its not that more coolant is not capable of carrying away more heat, but that the medium (radiator) does not have sufficient transfer area to utilize the benefit of the additional flow. I think thats a pretty easy concept, and I don't think it breaks any laws of physics. Anyway, that's my respectful opinion of why increased flow doesn't always have to generate more cooling.

    PS: Great article in Kitplanes
    I think this says a lot and makes good sense. It's not the single-point design that does the job, but a chain of elements and processes that must match each other well to do the best job.

    (I'd also like to highlight the statement that auto manufacturers put in fans to increase the flow rate of air through the radiator... a good real life example of increased flow rate yielding increased cooling capacity.)

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    Registered User BJC's Avatar
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    Re: Removing thermostat from water cooled engine.

    Quote Originally Posted by Autodidact View Post
    Are there other areas in our society where it is necessary to profess belief in a falsehood in order to advance socially and economically? I ask this question at the risk of the thread getting closed, but how can this question not arise from the OP's formulation of the story?
    Absolutely, but to keep this related to HBA, I will point out that when heat from that car radiator is transferred to the atmosphere, the air gets hotter, my engine produces less power, because it can't make as much torque, the propeller, which is like a CVT because it is a CS propeller, doesn't make as much thrust, and the wing doesn't generate as much lift. With the growth in numbers of people driving cars with IC engines, it won't be long before either I will need to go on a serious weight loss program, or my airplane won't get off the ground.

    https://www.merriam-webster.com/dictionary/cold


    BJC

  13. #174
    Moderator Topaz's Avatar
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    Re: Removing thermostat from water cooled engine.

    Quote Originally Posted by Hot Wings View Post
    We need a new feature on HBA:

    Add an ignore thread button and an anonymous read at your own risk counter attached to the thread title. Might give us some warning...
    Rather than another technological solution, I would prefer that people simply consider why they're here and what they want to achieve by any given post. This thread is an example of what are nearly troll-threads (from several authors), where the author seems to be deliberately trying to stir up argument by posting something controversial and then endlessly arguing the point with anyone who dares post a reply.

    If your goal with any thread is to "set people straight", "show them what I know", "see who knows their stuff", or otherwise deliberately provoke controversy and argument, then you're here at HBA for the wrong reasons. I know arguing on the Internet has become the grand sport of the 21st century, but if that's what you really want to do, please take it to Facebook or some other place.

    To keep these threads to a minimum, the best thing everyone can do when they see one is ... nothing. Don't reply, don't tell them how they're wrong, just ignore the whole thing. Don't feed the troll. Don't be this guy:


    This thread really has nothing to do with homebuilt airplanes, despite the fact that (most) homebuilt airplanes have engines. As such, it's off-topic for this forum, has been achieving nothing but endless argument and, therefore...

    Moderator Note: Thread closed.
    Last edited by Topaz; January 6th, 2017 at 01:14 PM.
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  15. #175
    Moderator Dana's Avatar
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    Re: Removing thermostat from water cooled engine.

    Quote Originally Posted by Winginit View Post
    Dana, here is an explanation of where I think the more flow equals more cooling is an incomplete observation. I do agree that in general, thats the basic thing that we see happen everyday. But, it happens within a range of temperature where it CAN work...

    <snip>

    Its not about the ability of additional coolant flow being ABLE to give up more heat, but about the chosen device having sufficient means to take advantage of the additional capacity.
    No objection to anything you said. Certainly there are many reasons why faster moving coolant might cool no better in a specific system / situation, and might even be worse. All I was saying (and what Tony refuses to believe) is that all other things being equal, a faster moving fluid will improve heat transfer, i.e. no such thing as "moving too fast to take the heat away".

    Dana

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    Super Moderator Midniteoyl's Avatar
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    Re: Removing thermostat from water cooled engine.

    Ok.. I'm thinking the confusion is a mix up between different things..

    The whole 'valve will burn up' thing is not from removing the thermostat, but from losing coolant system pressure. The job of the pressure in the system is two fold: to increase the boiling point of the water and to raising the cavitation point.

    The first is what Tony is talking about. The heat around the exhaust valves is so high that without the added pressure to raise the boiling point, the water will flash to steam, prevent the flow of water (and thus cooling) and will burn up the valves in short order.

    Having increased pressure also increases the cavitation margin for the pump impellers. Without it, your pump will cavitate, slowing or even stopping coolant flow. Even at low levels of cavitation, air is introduced to the system which obviously doesn't cool very well and if that air finds its way to the heads, you once again have the exhaust valve cooling problem. The net effect is a poorly cooling engine that will end up burning itself up.

    The 'tiny hole in the thermostat' is *not* 'to release steam', but to purge air from the engine, and around the thermostat, while filling the cooling system. As said, air is bad, and you need to remove as much as possible. Its important to note that now-a-days this hole is not always there. In fact, most engines in use today do not have them as they implore a different method of purging, such as cracking open a 1/8" plug or cap high up on the engine, because the thermostat location is no longer the highest point in the system as it was on the older engines. In the ones that do, the reason you place the hole 'up' instead of 'down' is that, obviously, air rises and if the hole is down you will not remove all of it, and this air, even if its a little, will displace the water around the thermostat and not allow it to function properly, causing it to open late and open less when it does, which, of course, leads right back to the engine over heating. Also, ever notice that the hole has a 'stopper' in it? Thats there because when the engine is first started, there is no pressure in the system so the hole is open, allowing any air around the thermostat to purge. Once any air is removed and the coolant begins to flow, the stopper is pushed against the hole, sealing it, stopping any flow through it, allowing the thermostat to work properly.

    Ok, all that said, the reason some of you notice that removing the thermostat altogether, with no other changes, causes overheating is not because 'faster water removes less heat', but because of less pressure in the system. This is caused by a system that was poorly designed in the first place. Adding a thermostat or 'restrictor plate' decreases flow in the system, yes, but its not the slower flow that improves the cooling, its the added pressure behind the thermostat/restriction. If your system can handle the pressure, the same thing can achieved by upping the pressure in the system over all. This is usually done by going to a higher rated radiator/coolant reservoir cap.



    I wasnt Valor vicTorian in any class, but I did sleep in a Holiday Express last night
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