Subject: Re: [Fot] Collective wisdom

From: Scott Janzen via Fot <[email-masked]>
Date: Tue, 20 Jan 2026 18:35:55 -0500

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<html class=3D"apple-mail-supports-explicit-dark-mode"><head><meta http-equi=
v=3D"content-type" content=3D"text/html; charset=3Dutf-8"></head><body dir=3D=
"auto">I=E2=80=99ve never understood overflow tanks to need =E2=80=9Cflow=E2=
=80=9D. Plz correct me if I=E2=80=99m wrong, but i thought they were there j=
ust to provide for the expansion and contraction of coolant when heated, etc=
<br id=3D"lineBreakAtBeginningOfSignature"><div dir=3D"ltr">Sent from my iPh=
one</div><div dir=3D"ltr"><br><blockquote type=3D"cite">On Jan 20, 2026, at 6=
:31=E2=80=AFPM, vfracing--- via Fot &lt;[email-masked]&gt; wrote:<br><br=
></blockquote></div><blockquote type=3D"cite"><div dir=3D"ltr">=EF=BB=BF<div=
 class=3D"ydp223f9f02yahoo-style-wrap" style=3D"font-family:arial;font-size:=
16px;"><div></div>
        <div dir=3D"ltr" data-setdir=3D"false">Chuck;</div><div dir=3D"ltr" d=
ata-setdir=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false">That h=
eater core port on the back of the head provides flow to an otherwise blind s=
pot in the head over an exhaust valve. &nbsp;On a race car without flow thro=
ugh that port it could lead to early exhaust valve failure. &nbsp;The best w=
ay to ensure flow is to plumb it to the intake side of the water pump, set u=
p as if there were a heater installed. &nbsp;We control the flow by using a 5=
/16 line, providing some flow but not overly bypassing anything. &nbsp;</div=
><div dir=3D"ltr" data-setdir=3D"false"><br></div><div dir=3D"ltr" data-setd=
ir=3D"false">&nbsp;Note that blocking that flow on a street-driven engine is=
 OK as the exhaust valve is not overly stressed during street driving compar=
ed to what we do on-track!</div><div dir=3D"ltr" data-setdir=3D"false"><br><=
/div><div dir=3D"ltr" data-setdir=3D"false">Hope this helps.</div><div dir=3D=
"ltr" data-setdir=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false"=
>Phil</div><div dir=3D"ltr" data-setdir=3D"false"><br></div><div dir=3D"ltr"=
 data-setdir=3D"false"><br></div><div><br></div>
       =20
        </div><div id=3D"yahoo_quoted_9332275551" class=3D"yahoo_quoted"><di=
v class=3D"yahoo-style-wrap" style=3D"font-family:arial;font-size:16px;">
            <div style=3D"font-family:'Helvetica Neue', Helvetica, Arial, sa=
ns-serif;font-size:13px;color:#26282a;">
               =20
                <div class=3D"quoted-text-header">
                        On Tuesday, January 20, 2026 at 04:16:51 PM EST, Chu=
ck Gee via Fot &lt;[email-masked]&gt; wrote:
                    </div>
                </div><div style=3D"font-family:'Helvetica Neue', Helvetica,=
 Arial, sans-serif;font-size:13px;color:#26282a;border-left: 1px solid #ccc;=
padding-left: 8px;margin: 0px 0px 0px 8px" class=3D"inline_reply_quote_conta=
iner">
                <div><br></div><div><br></div>
                <div><div dir=3D"ltr">Hello all,<br></div><div dir=3D"ltr"><=
br></div><div dir=3D"ltr">In an effort to constantly improve the car, I=E2=80=
=99ve been looking at the cooling system on my TR4.&nbsp; It currently has a=
 header tank mounted to the firewall that functions as the high spot in the s=
ystem.&nbsp; This tank feeds the top of the radiator but doesn=E2=80=99t rea=
lly circulate during operation.&nbsp; I=E2=80=99ve been thinking of plumbing=
 the feed off of the back of the head into the top of the tank so that it ci=
rculates.&nbsp; <br></div><div dir=3D"ltr"><br></div><div dir=3D"ltr">Normal=
ly this rear head feed is plumbed to the back of the water pump.&nbsp; In an=
 exercise of overthinking, I=E2=80=99m not sure if there will be sufficient c=
irculation since the tank is plumbed to the radiator.&nbsp; Does it matter?&=
nbsp; What is the collective wisdom?<br></div><div dir=3D"ltr"><br></div><di=
v dir=3D"ltr">Here are some pictures to help illustrate.<br></div><div dir=3D=
"ltr"><br></div><div dir=3D"ltr">Thanks,<br></div><div dir=3D"ltr"><br></div=
><div dir=3D"ltr">Chuck<br></div><div dir=3D"ltr"><br></div><br>____________=
___________________________________<br><a ymailto=3D"mailto:[email-masked]=
et" href=3D"mailto:[email-masked]">[email-masked]</a><br><br><a href=
=3D"http://www.fot-racing.com" target=3D"_blank">http://www.fot-racing.com</=
a><br><br>Donate: <a href=3D"http://www.team.net/donate.html" target=3D"_bla=
nk">http://www.team.net/donate.html</a><br>Archive: <a href=3D"http://autox.=
team.net/archive" target=3D"_blank">http://autox.team.net/archive</a> <a hre=
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mailman/options/fot/[email-masked]" target=3D"_blank">http://autox.team.ne=
t/mailman/options/fot/[email-masked]</a><br><br><br></div>
            </div>
        </div></div><span>_______________________________________________</s=
pan><br><span>[email-masked]</span><br><span></span><br><span>http://www=
.fot-racing.com</span><br><span></span><br><span>Donate: http://www.team.net=
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_______________________________________________
[email-masked]

http://www.fot-racing.com

Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot

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---

From: Chuck Gee via Fot <[email-masked]>
Date: Tue, 20 Jan 2026 18:55:36 -0500

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<html><head><meta http-equiv=3D"content-type" content=3D"text/html; charset=3D=
utf-8"></head><body dir=3D"auto">I=E2=80=99m more concerned about getting fl=
ow out of the back of the head. &nbsp;The header tank location on my car is a=
 convenient spot for me to make that work. &nbsp;I may just do what Phil and=
 Dave Gott do and plumb that spot directly to the water pump.<div><br id=3D"=
lineBreakAtBeginningOfSignature"><div dir=3D"ltr">Chuck</div><div dir=3D"ltr=
"><br><blockquote type=3D"cite">On Jan 20, 2026, at 6:36=E2=80=AFPM, Scott J=
anzen &lt;[email-masked]&gt; wrote:<br><br></blockquote></div><blockquote ty=
pe=3D"cite"><div dir=3D"ltr">=EF=BB=BF<meta http-equiv=3D"content-type" cont=
ent=3D"text/html; charset=3Dutf-8">I=E2=80=99ve never understood overflow ta=
nks to need =E2=80=9Cflow=E2=80=9D. Plz correct me if I=E2=80=99m wrong, but=
 i thought they were there just to provide for the expansion and contraction=
 of coolant when heated, etc<br id=3D"lineBreakAtBeginningOfSignature"><div d=
ir=3D"ltr">Sent from my iPhone</div><div dir=3D"ltr"><br><blockquote type=3D=
"cite">On Jan 20, 2026, at 6:31=E2=80=AFPM, vfracing--- via Fot &lt;fot@auto=
x.team.net&gt; wrote:<br><br></blockquote></div><blockquote type=3D"cite"><d=
iv dir=3D"ltr">=EF=BB=BF<div class=3D"ydp223f9f02yahoo-style-wrap" style=3D"=
font-family:arial;font-size:16px;"><div></div>
        <div dir=3D"ltr" data-setdir=3D"false">Chuck;</div><div dir=3D"ltr" d=
ata-setdir=3D"false"><br></div><div dir=3D"ltr" data-setdir=3D"false">That h=
eater core port on the back of the head provides flow to an otherwise blind s=
pot in the head over an exhaust valve. &nbsp;On a race car without flow thro=
ugh that port it could lead to early exhaust valve failure. &nbsp;The best w=
ay to ensure flow is to plumb it to the intake side of the water pump, set u=
p as if there were a heater installed. &nbsp;We control the flow by using a 5=
/16 line, providing some flow but not overly bypassing anything. &nbsp;</div=
</span><br></div></blockquote></div></blockquote></div></body></html>=

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From: "JS Performance Motoring, LLC via Fot" <[email-masked]>
Date: Tue, 20 Jan 2026 21:37:14 -0500

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An overflow tank does not flow.
A header tank or surge tank does flow, and helps burp any steam or air
pockets that are trapped in the engine.

Two different approaches.  I prefer the latter, but many are successfully
running the simpler overflow tank setup.

Jason Sukey
JS Performance Motoring, LLC
440.984.7720
[email-masked]
www.jspmparts.com
https://www.facebook.com/JSPerformanceMotoring/

On Tue, Jan 20, 2026 at 9:12=E2=80=AFPM Scott Janzen via Fot <[email-masked]=
m.net>
wrote:

> I=E2=80=99ve never understood overflow tanks to need =E2=80=9Cflow=E2=80=
=9D. Plz correct me if I=E2=80=99m
> wrong, but i thought they were there just to provide for the expansion an=
d
> contraction of coolant when heated, etc
> Sent from my iPhone
>
> On Jan 20, 2026, at 6:31=E2=80=AFPM, vfracing--- via Fot <[email-masked].=
net>
> wrote:
>
> =EF=BB=BF
> Chuck;
>
> That heater core port on the back of the head provides flow to an
> otherwise blind spot in the head over an exhaust valve.  On a race car
> without flow through that port it could lead to early exhaust valve
> failure.  The best way to ensure flow is to plumb it to the intake side o=
f
> the water pump, set up as if there were a heater installed.  We control t=
he
> flow by using a 5/16 line, providing some flow but not overly bypassing
> anything.
>
>  Note that blocking that flow on a street-driven engine is OK as the
> exhaust valve is not overly stressed during street driving compared to wh=
at
> we do on-track!
>
> Hope this helps.
>
> Phil
>
>
>
> On Tuesday, January 20, 2026 at 04:16:51 PM EST, Chuck Gee via Fot <
> [email-masked]> wrote:
>
>
> Hello all,
>
> In an effort to constantly improve the car, I=E2=80=99ve been looking at =
the
> cooling system on my TR4.  It currently has a header tank mounted to the
> firewall that functions as the high spot in the system.  This tank feeds
> the top of the radiator but doesn=E2=80=99t really circulate during opera=
tion.
> I=E2=80=99ve been thinking of plumbing the feed off of the back of the he=
ad into
> the top of the tank so that it circulates.
>
> Normally this rear head feed is plumbed to the back of the water pump.  I=
n
> an exercise of overthinking, I=E2=80=99m not sure if there will be suffic=
ient
> circulation since the tank is plumbed to the radiator.  Does it matter?
> What is the collective wisdom?
>
> Here are some pictures to help illustrate.
>
> Thanks,
>
> Chuck
>
>
> Donate: http://www.team.net/donate.html
> Unsubscribe/Manage:
> http://autox.team.net/mailman/options/fot/[email-masked]
>
>
> Donate: http://www.team.net/donate.html
> Unsubscribe/Manage:
> http://autox.team.net/mailman/options/fot/[email-masked]
>
>
> Donate: http://www.team.net/donate.html
> Unsubscribe/Manage <http://www.team.net/pipermail/fotUnsubscribe/Manage>:
> http://autox.team.net/mailman/options/fot/[email-masked]
>
>
>

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<div dir=3D"ltr"><div>An overflow tank does not flow.</div><div>A header ta=
nk or surge tank does flow, and helps burp any steam or air pockets that ar=
e trapped in the engine.=C2=A0=C2=A0</div><div><br></div><div>Two different=
 approaches.=C2=A0 I prefer the latter, but many are successfully running t=
he simpler overflow tank setup.</div><div><br></div><div><br></div><div>Jas=
on Sukey</div><div><div dir=3D"ltr" class=3D"gmail_signature" data-smartmai=
l=3D"gmail_signature"><div dir=3D"ltr"><div dir=3D"ltr"><div dir=3D"ltr"><d=
iv dir=3D"ltr"><div dir=3D"ltr"><div><span></span><span></span>JS Performan=
ce Motoring, LLC<br></div><div>440.984.7720</div><div><a href=3D"mailto:jas=
[email-masked]" target=3D"_blank">jason@jsperformancemotoring=
.com</a><br></div><div><a href=3D"http://www.jspmparts.com" target=3D"_blan=
k">www.jspmparts.com</a></div><div><a href=3D"https://www.facebook.com/JSPe=
rformanceMotoring/" target=3D"_blank">https://www.facebook.com/JSPerformanc=
eMotoring/</a><br></div></div></div></div></div></div></div></div><br></div=
><br><div class=3D"gmail_quote gmail_quote_container"><div dir=3D"ltr" clas=
s=3D"gmail_attr">On Tue, Jan 20, 2026 at 9:12=E2=80=AFPM Scott Janzen via F=
ot &lt;<a href=3D"mailto:[email-masked]">[email-masked]</a>&gt; wro=
te:<br></div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px =
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir=3D"=
auto">I=E2=80=99ve never understood overflow tanks to need =E2=80=9Cflow=E2=
=80=9D. Plz correct me if I=E2=80=99m wrong, but i thought they were there =
just to provide for the expansion and contraction of coolant when heated, e=
tc<br id=3D"m_3139223990580268867lineBreakAtBeginningOfSignature"><div dir=
=3D"ltr">Sent from my iPhone</div><div dir=3D"ltr"><br><blockquote type=3D"=
cite">On Jan 20, 2026, at 6:31=E2=80=AFPM, vfracing--- via Fot &lt;<a href=
=3D"mailto:[email-masked]" target=3D"_blank">[email-masked]</a>&gt;=
 wrote:<br><br></blockquote></div><blockquote type=3D"cite"><div dir=3D"ltr=
">=EF=BB=BF<div style=3D"font-family:arial;font-size:16px"><div></div>
        <div dir=3D"ltr">Chuck;</div><div dir=3D"ltr"><br></div><div dir=3D=
"ltr">That heater core port on the back of the head provides flow to an oth=
erwise blind spot in the head over an exhaust valve.=C2=A0 On a race car wi=
thout flow through that port it could lead to early exhaust valve failure.=
=C2=A0 The best way to ensure flow is to plumb it to the intake side of the=
 water pump, set up as if there were a heater installed.=C2=A0 We control t=
he flow by using a 5/16 line, providing some flow but not overly bypassing =
anything. =C2=A0</div><div dir=3D"ltr"><br></div><div dir=3D"ltr">=C2=A0Not=
e that blocking that flow on a street-driven engine is OK as the exhaust va=
lve is not overly stressed during street driving compared to what we do on-=
track!</div><div dir=3D"ltr"><br></div><div dir=3D"ltr">Hope this helps.</d=
iv><div dir=3D"ltr"><br></div><div dir=3D"ltr">Phil</div><div dir=3D"ltr"><=
br></div><div dir=3D"ltr"><br></div><div><br></div>
       =20
        </div><div id=3D"m_3139223990580268867yahoo_quoted_9332275551"><div=
 style=3D"font-family:arial;font-size:16px">
            <div style=3D"font-family:&quot;Helvetica Neue&quot;,Helvetica,=
Arial,sans-serif;font-size:13px;color:rgb(38,40,42)">
               =20
                <div>
                        On Tuesday, January 20, 2026 at 04:16:51 PM EST, Ch=
uck Gee via Fot &lt;<a href=3D"mailto:[email-masked]" target=3D"_blank"=
>[email-masked]</a>&gt; wrote:
                    </div>
                </div><div style=3D"font-family:&quot;Helvetica Neue&quot;,=
Helvetica,Arial,sans-serif;font-size:13px;color:rgb(38,40,42);border-left:1=
px solid rgb(204,204,204);padding-left:8px;margin:0px 0px 0px 8px">
                <div><br></div><div><br></div>
                <div><div dir=3D"ltr">Hello all,<br></div><div dir=3D"ltr">=
<br></div><div dir=3D"ltr">In an effort to constantly improve the car, I=E2=
=80=99ve been looking at the cooling system on my TR4.=C2=A0 It currently h=
as a header tank mounted to the firewall that functions as the high spot in=
 the system.=C2=A0 This tank feeds the top of the radiator but doesn=E2=80=
=99t really circulate during operation.=C2=A0 I=E2=80=99ve been thinking of=
 plumbing the feed off of the back of the head into the top of the tank so =
that it circulates.=C2=A0 <br></div><div dir=3D"ltr"><br></div><div dir=3D"=
ltr">Normally this rear head feed is plumbed to the back of the water pump.=
=C2=A0 In an exercise of overthinking, I=E2=80=99m not sure if there will b=
e sufficient circulation since the tank is plumbed to the radiator.=C2=A0 D=
oes it matter?=C2=A0 What is the collective wisdom?<br></div><div dir=3D"lt=
r"><br></div><div dir=3D"ltr">Here are some pictures to help illustrate.<br=
></div><div dir=3D"ltr"><br></div><div dir=3D"ltr">Thanks,<br></div><div di=
r=3D"ltr"><br></div><div dir=3D"ltr">Chuck<br></div><div dir=3D"ltr"><br></=
div><br>_______________________________________________<br><a href=3D"mailt=
o:[email-masked]" target=3D"_blank">[email-masked]</a><br><br><a hr=
ef=3D"http://www.fot-racing.com" target=3D"_blank">http://www.fot-racing.co=
m</a><br><br>Donate: <a href=3D"http://www.team.net/donate.html" target=3D"=
_blank">http://www.team.net/donate.html</a><br>Archive: <a href=3D"http://a=
utox.team.net/archive" target=3D"_blank">http://autox.team.net/archive</a> =
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x.team.net/mailman/options/fot/[email-masked]</a><br><br><br></div>
            </div>
        </div></div><span>_______________________________________________</=
span><br><span><a href=3D"mailto:[email-masked]" target=3D"_blank">fot@=
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iv>_______________________________________________<br>
<a href=3D"mailto:[email-masked]" target=3D"_blank">[email-masked]<=
/a><br>
<br>
<a href=3D"http://www.fot-racing.com" rel=3D"noreferrer" target=3D"_blank">=
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Archive: <a href=3D"http://autox.team.net/archive" rel=3D"noreferrer" targe=
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br>
<br>
<br>
</blockquote></div>

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