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Discussion Starter #1
I was wondering if there are any related problems from running a hot engine and then crossing a cold river and submerging the engine under the cold water. Will it affect the strength of the engine casing?
 

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Never heard of such, gaucho10!

Maybe other forum members have direct, personal experience or observation of the phenomenon.

Hey, don't they HEAT-TREAT white-hot (or, red-hot) metal by quenching in cold liquid? :)

Seriously, the heat-capacity of an engine remains borne by not only the metal molecules, but also the coolant and oil present . . . I think it would take a rather frigid body-of-liquid (as in, total immersion in a vat of liquid nitrogen, etc.) to affect materially the structural integrity of engine cases, but . . . only an opinion, a conjecture . . .
 

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Discussion Starter #3
Your theory sounds good to me. I was thinking hot glass into cold water...maybe something similar with a MC engine.
 

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I don't believe there is a problem. If there was, splashing through a deep puddle on a hot day would be too. I have done both with no ill effects.
Regards....justjeff
 

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Never heard of such, gaucho10!

Maybe other forum members have direct, personal experience or observation of the phenomenon.

Hey, don't they TEMPER white-hot metal by quenching in cold liquid? :)

Seriously, the heat-capacity of an engine remains borne by not only the metal molecules, but also the coolant and oil present . . . I think it would take a rather frigid body-of-liquid (as in, total immersion in a vat of liquid nitrogen, etc.) to affect materially the structural integrity of engine cases, but . . . only an opinion, a conjecture . . .
The word is HARDEN. Tempering is done to soften and toughen the previously HARDENED metal to a specific hardness to make it useable without breaking. When hardening the steel is not taken up to "white-hot" but is usually only bright orange.
In the interest of accuracy....Regards....justjeff
 

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I've ridden engine-deep through a few really cold Rocky Mountain streams and small "rivers" with a hot engine and never had an issue with it. I've never heard of anybody cracking a motorcycle engine case riding it through cold water or spraying cold water on the engine while it was still hot.
 

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The word is HARDEN.
I stand corrected!

I substitue, "heat-treat" for "temper," in search of a sufficiently ambiguous weasel-word!

And, maybe the process you describe is sometimes called, "annealing."

You'd never know I once worked for a firm with among the most advanced steel, and even titanium, foundries in the country, would you? Reckon I knew less about metallurgy than the boys on the loading dock! :)
 

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While I've never balked at riding through really cold water with a hot engine, I seem to heed the old warning of not spraying cold water onto a hot engine. Is there a difference? Beats me. I've been warned about this since I first started operating anything with an engine.

I suppose it was more relevant back in the day of cast-iron small engines operating at a million degrees.
 

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While I've never balked at riding through really cold water with a hot engine, I seem to heed the old warning of not spraying cold water onto a hot engine. Is there a difference? Beats me. I've been warned about this since I first started operating anything with an engine.

I suppose it was more relevant back in the day of cast-iron small engines operating at a million degrees.
I have wondered about this many times.
 

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When I was racing stockcars we used to spray water through the radiator and over the engine to cool it down before shutting it off between races. The exhaust system would be literally glowing. I can't imagine the thermal shock but I never saw any adverse effects.
Regards....justjeff
 

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Interesting. I've always thought it was one of those BS biker things like: "NEVER EVER, ever touch your front brake." ;)



When I was racing stockcars we used to spray water through the radiator and over the engine to cool it down before shutting it off between races. The exhaust system would be literally glowing. I can't imagine the thermal shock but I never saw any adverse effects.
Regards....justjeff
 

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Damocles, "Annealing" by quenching in cooler substance. Is to further SOFTEN, SOFT metals. Aluminum hand brake levers and oil line banjo gaskets, come to mind while dealing with KLR.
pdwestman
 

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Damocles, "Annealing" by quenching in cooler substance. Is to further SOFTEN, SOFT metals. Aluminum hand brake levers and oil line banjo gaskets, come to mind while dealing with KLR.
pdwestman
Heating a metal to its critical temperature then cooling it very slowly will anneal it to it's softest state.
Regards....justjeff
 

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Discussion Starter #14
Heating a metal to its critical temperature then cooling it very slowly will anneal it to it's softest state.
Regards....justjeff

So justjeff...your not getting off this easy....explain....

Is a hot KLR engine considered "heating it up to its critical temp."? For discussion sake, lets assume after a long summer ride in Arizona desert.

And then..."cooling it slowly"...For discussion sake (again), is there a difference from dipping the engine into a cold river compared to pressure washing the bike, compared to just running over a puddle of water. Is there any dangerous difference from one to the other?
 

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So justjeff...your not getting off this easy....explain....

Is a hot KLR engine considered "heating it up to its critical temp."? For discussion sake, lets assume after a long summer ride in Arizona desert.

And then..."cooling it slowly"...For discussion sake (again), is there a difference from dipping the engine into a cold river compared to pressure washing the bike, compared to just running over a puddle of water. Is there any dangerous difference from one to the other?
HA ha!
Sorry gaucho this really has no connection to the engine question. The critical temperature I was referring to, say for steel, is in excess of 1800 deg F. A bright orange color. If you heat steel to its critical temp and cool it quickly by submerging it in water or oil it will become hard. It will be very brittle, EASILY broken.
Take that same piece and reheat it to 500deg F itwill turn blue. Quench it in water or oil again and it will soften some what, become less brittle and more impact resistant.This is tempering. The steel becomes very tough and durable.
Take that same piece again, heat it above the critical temp again but cool it slowly. Wrap it in an insulative material and leave it till it is room temp. It will be soft again. This is annealing.
Thus the temps your engine sees will never be high enough to change the molecular structure. Though aluminum can be heat treated it will not change hardness to the extent that steel will.
The materials in your engine have been chosen and used for many years without failing. If there was a problem driving your hot engine into cool water you would hear of many examples...." Joe drove his bike, quad, car, truck in the water, lake, river,puddle and cracked his block. After many years I have never heard of one example of this. Has anyone else?
Regards....justjeff
 

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Discussion Starter #16
JustJeff,

Thanks for the explanation. That is very interesting the way you explained it. I have several friends that for many years were showing me how to heat and dip in cold water, weld, etc doing various home shop projects. I remember them explaining either one or the other as far as what happens when you heat a metal. But I never got it all in one explanation and this really makes sence to me. Thanks again.
 

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JustJeff,

Thanks for the explanation. That is very interesting the way you explained it. I have several friends that for many years were showing me how to heat and dip in cold water, weld, etc doing various home shop projects. I remember them explaining either one or the other as far as what happens when you heat a metal. But I never got it all in one explanation and this really makes sence to me. Thanks again.
I have only brushed with a soft tissue at 20 ft the subject of metallurgy and heat treatment. People study and work with these subjects their whole lives and I am but a lowly beginner. I saw a punch that was hardened but not tempered break into pieces when dropped on the floor. I also saw a custom made milling cutter shatter when it was mistakenly quenched in water rather than oil during hardening. The water cooled it too quickly.
I am glad my explanation helped you.
Best Regards....justjeff
 
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