Subject: Re: [TR] water pump

From: Greg Lemon <[email-masked]>
Date: Sun, 28 Jul 2019 22:02:51 -0500

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I read the reply and my first response was, "don't you want the water to
pick up more heat in the engine so it can shed it in the radiator?" Then I
thought some more, I think the point is higher flow gives you closer to
equilibrium, rather than hotter water in the engine and cooler in the
radiator, and since the engine is the hot spot the closer you can get to
equilibrium on the temp the better??

Greg Lemon
TR250 (which has always run between the little dots in the middle of the
gauge once warmed up, so my interest is purely acedemic)

On Sun, Jul 28, 2019, 6:35 PM dave <[email-masked]> wrote:

> In the last few weeks there was some discussion about the new vs old water
> pumps.  Someone postulated that the newer water pumps move water faster
> through the radiator, which results in less cooling and a hotter engine.  I
> asked my nephew, a mechanical engineer who is also a car person, about
> this.  here is his reply:
>
>
>
> I think the point of confusion is the notion that increasing flow rate is
> a bad thing. I get the basic thought of it spending less time in the
> radiator but it's one of those things that sounds correct without having
> any real science to back it up. One of the rules of thermodynamics is that
> flow rate and heat transfer are directly proportional. If you increase flow
> rate and all other things remain constant then you will reduce temperature.
>
>
>
> For your specific use case, you're improving the efficiency of cooling
> because the fluid is moving more quickly through the engine. It's better to
> keep fluid at as low of a temperature as possible and moving it very
> quickly means that each molecule is exposed to the heat for less time. When
> it gets to the radiator there isn't as much heat to be removed so spending
> less time in the radiator becomes a moot point.
> ** [email-masked] **
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/pipermail/triumphs
> http://www.team.net/archive
>
> Unsubscribe/Manage:
> http://autox.team.net/mailman/options/triumphs/[email-masked]
>

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<div dir=3D"auto">I read the reply and my first response was, &quot;don&#39=
;t you want the water to pick up more heat in the engine so it can shed it =
in the radiator?&quot; Then I thought some more, I think the point is highe=
r flow gives you closer to equilibrium, rather than hotter water in the eng=
ine and cooler in the radiator, and since the engine is the hot spot the cl=
oser you can get to equilibrium on the temp the better??<div dir=3D"auto"><=
br></div><div dir=3D"auto">Greg Lemon</div><div dir=3D"auto">TR250 (which h=
as always run between the little dots in the middle of the gauge once warme=
d up, so my interest is purely acedemic)</div></div><br><div class=3D"gmail=
_quote"><div dir=3D"ltr" class=3D"gmail_attr">On Sun, Jul 28, 2019, 6:35 PM=
 dave &lt;<a href=3D"mailto:[email-masked]">[email-masked]</a>&gt; wrot=
e:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;bo=
rder-left:1px #ccc solid;padding-left:1ex"><div lang=3D"EN-US" link=3D"#056=
3C1" vlink=3D"#954F72"><div class=3D"m_-8862082340982648424WordSection1"><p=
 class=3D"MsoNormal">In the last few weeks there was some discussion about =
the new vs old water pumps.=C2=A0 Someone postulated that the newer water p=
umps move water faster through the radiator, which results in less cooling =
and a hotter engine.=C2=A0 I asked my nephew, a mechanical engineer who is =
also a car person, about this.=C2=A0 here is his reply:<u></u><u></u></p><p=
 class=3D"MsoNormal"><u></u>=C2=A0<u></u></p><p class=3D"MsoNormal">I think=
 the point of confusion is the notion that increasing flow rate is a bad th=
ing. I get the basic thought of it spending less time in the radiator but i=
t&#39;s one of those things that sounds correct without having any real sci=
ence to back it up. One of the rules of thermodynamics is that flow rate an=
d heat transfer are directly proportional. If you increase flow rate and al=
l other things remain constant then you will reduce temperature.<u></u><u><=
/u></p><p class=3D"MsoNormal"><u></u>=C2=A0<u></u></p><p class=3D"MsoNormal=
">For your specific use case, you&#39;re improving the efficiency of coolin=
g because the fluid is moving more quickly through the engine. It&#39;s bet=
ter to keep fluid at as low of a temperature as possible and moving it very=
 quickly means that each molecule is exposed to the heat for less time. Whe=
n it gets to the radiator there isn&#39;t as much heat to be removed so spe=
nding less time in the radiator becomes a moot point.<u></u><u></u></p></di=
v></div>** <a href=3D"mailto:[email-masked]" target=3D"_blank" rel=
=3D"noreferrer">[email-masked]</a> **<br>
<br>
errer" target=3D"_blank">http://www.team.net/donate.html</a><br>
Archive: <a href=3D"http://www.team.net/pipermail/triumphs" rel=3D"noreferr=
er noreferrer" target=3D"_blank">http://www.team.net/pipermail/triumphs</a>=
=C2=A0 <a href=3D"http://www.team.net/archive" rel=3D"noreferrer noreferrer=
" target=3D"_blank">http://www.team.net/archive</a><br>
<br>
hs/[email-masked]" rel=3D"noreferrer noreferrer" target=3D"_blank">http:/=
/autox.team.net/mailman/options/triumphs/[email-masked]</a><br>
</blockquote></div>

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** [email-masked] **

Archive: http://www.team.net/pipermail/triumphs  http://www.team.net/archive

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From: Randall <[email-masked]>
Date: Mon, 29 Jul 2019 00:06:59 -0500

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Here=E2=80=99s a couple of questions you can ask your nephew:

1) On the high pressure side of a TR2 through early TR4 radiator sits a 4 p=
si pressure relief valve (aka radiator cap).  What happens when the dynamic=
 head substantially exceeds 4 psi?
2) What happens when the water pump cavitates?
3) The TR2-4 water pump uses a spring-loaded face seal to keep coolant insi=
de.  What happens if the dynamic coolant pressure at the seal goes substant=
ially below the atmospheric pressure outside the seal?

(1) in particular, I believe, is the main origin for the old myth about the=
 coolant moving too fast without a thermostat or restrictor plate.  It real=
ly can cause overheating, just not (directly) because the coolant is moving=
 too fast.

Sent from Mail for Windows 10

From: dave
Sent: Sunday, July 28, 2019 6:35 PM
Subject: [TR] water pump

In the last few weeks there was some discussion about the new vs old water =
pumps.=C2=A0 Someone postulated that the newer water pumps move water faste=
r through the radiator, which results in less cooling and a hotter engine.=
=C2=A0 I asked my nephew, a mechanical engineer who is also a car person, a=
bout this.=C2=A0 here is his reply:

I think the point of confusion is the notion that increasing flow rate is a=
 bad thing. I get the basic thought of it spending less time in the radiato=
r but it's one of those things that sounds correct without having any real =
science to back it up. One of the rules of thermodynamics is that flow rate=
 and heat transfer are directly proportional. If you increase flow rate and=
 all other things remain constant then you will reduce temperature.

For your specific use case, you're improving the efficiency of cooling beca=
use the fluid is moving more quickly through the engine. It's better to kee=
p fluid at as low of a temperature as possible and moving it very quickly m=
eans that each molecule is exposed to the heat for less time. When it gets =
to the radiator there isn't as much heat to be removed so spending less tim=
e in the radiator becomes a moot point.

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--></style></head><body lang=3DEN-US link=3Dblue vlink=3D"#954F72"><div cla=
ss=3DWordSection1><p class=3DMsoNormal>Here=E2=80=99s a couple of questions=
 you can ask your nephew:</p><p class=3DMsoNormal><o:p>&nbsp;</o:p></p><ol =
style=3D'margin-top:0in' start=3D1 type=3D1><li class=3DMsoListParagraph st=
yle=3D'margin-left:0in;mso-list:l0 level1 lfo1'>On the high pressure side o=
f a TR2 through early TR4 radiator sits a 4 psi pressure relief valve (aka =
radiator cap).=C2=A0 What happens when the dynamic head substantially excee=
ds 4 psi?</li><li class=3DMsoListParagraph style=3D'margin-left:0in;mso-lis=
t:l0 level1 lfo1'>What happens when the water pump cavitates?</li><li class=
=3DMsoListParagraph style=3D'margin-left:0in;mso-list:l0 level1 lfo1'>The T=
R2-4 water pump uses a spring-loaded face seal to keep coolant inside.=C2=
=A0 What happens if the dynamic coolant pressure at the seal goes substanti=
ally below the atmospheric pressure outside the seal?</li></ol><p class=3DM=
soNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>(1) in particular, I bel=
ieve, is the main origin for the old myth about the coolant moving too fast=
 without a thermostat or restrictor plate.=C2=A0 It really can cause overhe=
ating, just not (directly) because the coolant is moving too fast.</p><p cl=
ass=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>Sent from <a href=
=3D"https://go.microsoft.com/fwlink/?LinkId=3D550986">Mail</a> for Windows =
10</p><p class=3DMsoNormal><o:p>&nbsp;</o:p></p><div style=3D'mso-element:p=
ara-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in=
 0in 0in'><p class=3DMsoNormal style=3D'border:none;padding:0in'><b>From: <=
/b><a href=3D"mailto:[email-masked]">dave</a><br><b>Sent: </b>Sunday, Jul=
y 28, 2019 6:35 PM<br><b>Subject: </b>[TR] water pump</p></div><p class=3DM=
soNormal><o:p>&nbsp;</o:p></p><p class=3DMsoNormal>In the last few weeks th=
ere was some discussion about the new vs old water pumps.&nbsp; Someone pos=
tulated that the newer water pumps move water faster through the radiator, =
which results in less cooling and a hotter engine.&nbsp; I asked my nephew,=
 a mechanical engineer who is also a car person, about this.&nbsp; here is =
his reply:<o:p></o:p></p><p class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=
=3DMsoNormal>I think the point of confusion is the notion that increasing f=
low rate is a bad thing. I get the basic thought of it spending less time i=
n the radiator but it's one of those things that sounds correct without hav=
ing any real science to back it up. One of the rules of thermodynamics is t=
hat flow rate and heat transfer are directly proportional. If you increase =
flow rate and all other things remain constant then you will reduce tempera=
ture.<o:p></o:p></p><p class=3DMsoNormal><o:p>&nbsp;</o:p></p><p class=3DMs=
oNormal>For your specific use case, you're improving the efficiency of cool=
ing because the fluid is moving more quickly through the engine. It's bette=
r to keep fluid at as low of a temperature as possible and moving it very q=
uickly means that each molecule is exposed to the heat for less time. When =
it gets to the radiator there isn't as much heat to be removed so spending =
less time in the radiator becomes a moot point.<o:p></o:p></p><p class=3DMs=
oNormal><o:p>&nbsp;</o:p></p></div></body></html>=

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From: Greg Lemon <[email-masked]>
Date: Mon, 29 Jul 2019 09:31:24 -0500

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--000000000000fb9ac8058ed2bf9d

Michael, yes, but you are writing your answer from a modern car ideal
engineering standpoint, the increased flow argument as we usually talk
about it with British cars isn't about which is better for maintaining
ideal temperature, it is about which is better for lowering engine temps,
at least that is the way most are looking at it I think.

Greg

On Sun, Jul 28, 2019, 10:29 PM Michael Porter <[email-masked]> wrote:

> On 7/28/2019 9:02 PM, Greg Lemon wrote:
>
> On the basis of thermodynamics, no.  Heat transfer depends upon the
> temperature differential.  The higher the delta-t, the greater the heat
> transfer.
>
> This is complicated a bit by engine temperature affecting fuel
> efficiency.  The hotter the engine runs, the higher the efficiency of  the
> engine because the heat transfer delta-t from combustion gases to the
> engine parts is lower, so more heat energy is available to do work.  This
> is why virtually every manufacturer was doing R&D on very high-temperature
> ceramic engines in the `80s and `90s (which invariably was not workable
> because ceramics were extremely sensitive to thermal shocks, and there were
> a lot of practical limitations to ceramics, like making durable threads in
> ceramic parts).
>
> But, if we're talking heat *rejection*, a big delta-t is desirable.  At
> the same time, elevating the engine temperature is helpful in terms of
> efficiency (which is why, as manufacturing processes became better,
> aluminum heads became common, gaskets got better, engine operating
> temperatures went up, from ~ 160 deg. F in the `40s, to ~ 180 deg. in the
> `50s-`60s, to ~ 195 deg. today.
>
> So, the optimum would be a system which maintains a high engine operating
> temperature and a cooling system which rejects as much heat as possible, so
> that the inlet coolant to the engine is as low as possible, in order to
> remove as much waste heat as is practicable without depressing engine
> temperature (which is why the thermostat is still in use).  All this needs
> to be done at pressures which prevent nucleate boiling, which greatly
> reduces heat transfer.
>
>
> Cheers.
>
> --
>
>
> Michael Porter
> Roswell, NM
>
>
> Never let anyone drive you crazy when you know it's within walking distance....
>
>

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<div dir=3D"auto"><div dir=3D"auto"></div>Michael, yes, but you are writing=
 your answer from a modern car ideal engineering standpoint, the increased =
flow argument as we usually talk about it with British cars isn&#39;t about=
 which is better for maintaining ideal temperature, it is about which is be=
tter for lowering engine temps, at least that is the way most are looking a=
t it I think.<div dir=3D"auto"><br></div><div dir=3D"auto">Greg</div><div d=
ir=3D"auto"><br><div class=3D"gmail_quote" dir=3D"auto"><div dir=3D"ltr" cl=
ass=3D"gmail_attr">On Sun, Jul 28, 2019, 10:29 PM Michael Porter &lt;<a hre=
f=3D"mailto:[email-masked]" target=3D"_blank" rel=3D"noreferrer">mdporter=
@dfn.com</a>&gt; wrote:<br></div><blockquote class=3D"gmail_quote" style=3D=
"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
 =20
   =20
 =20
  <div text=3D"#000000" bgcolor=3D"#FFFFFF">
    <div class=3D"m_2758578669474107067m_-6730512637779744281moz-cite-prefi=
x">On 7/28/2019 9:02 PM, Greg Lemon wrote:<br>
    </div>
    <blockquote type=3D"cite">
     =20
      <div dir=3D"auto">I read the reply and my first response was, &quot;d=
on&#39;t
        you want the water to pick up more heat in the engine so it can
        shed it in the radiator?&quot; Then I thought some more, I think th=
e
        point is higher flow gives you closer to equilibrium, rather
        than hotter water in the engine and cooler in the radiator, and
        since the engine is the hot spot the closer you can get to
        equilibrium on the temp the better??
        <div dir=3D"auto"><br>
        </div>
      </div>
    </blockquote>
    <p>On the basis of thermodynamics, no.=C2=A0 Heat transfer depends upon
      the temperature differential.=C2=A0 The higher the delta-t, the great=
er
      the heat transfer.</p>
    <p>This is complicated a bit by engine temperature affecting fuel
      efficiency.=C2=A0 The hotter the engine runs, the higher the efficien=
cy
      of=C2=A0 the engine because the heat transfer delta-t from combustion
      gases to the engine parts is lower, so more heat energy is
      available to do work.=C2=A0 This is why virtually every manufacturer
      was doing R&amp;D on very high-temperature ceramic engines in the
      `80s and `90s (which invariably was not workable because ceramics
      were extremely sensitive to thermal shocks, and there were a lot
      of practical limitations to ceramics, like making durable threads
      in ceramic parts).</p>
    <p>But, if we&#39;re talking heat <i>rejection</i>, a big delta-t is
      desirable.=C2=A0 At the same time, elevating the engine temperature i=
s
      helpful in terms of efficiency (which is why, as manufacturing
      processes became better, aluminum heads became common, gaskets got
      better, engine operating temperatures went up, from ~ 160 deg. F
      in the `40s, to ~ 180 deg. in the `50s-`60s, to ~ 195 deg. today.</p>
    <p>So, the optimum would be a system which maintains a high engine
      operating temperature and a cooling system which rejects as much
      heat as possible, so that the inlet coolant to the engine is as
      low as possible, in order to remove as much waste heat as is
      practicable without depressing engine temperature (which is why
      the thermostat is still in use).=C2=A0 All this needs to be done at
      pressures which prevent nucleate boiling, which greatly reduces
      heat transfer.</p>
    <p><br>
    </p>
    <p>Cheers.<br>
    </p>
    <pre class=3D"m_2758578669474107067m_-6730512637779744281moz-signature"=
 cols=3D"72">--=20

Michael Porter
Roswell, NM

Never let anyone drive you crazy when you know it&#39;s within walking dist=
ance....</pre>
  </div>

</blockquote></div></div></div>

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