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Interesting discussion and I would agree on point. What would interesting =
to know is how the HP change was measured; chassis dyno or engine dyno?
Ken=20
Sent from Mail for Windows
From: Lorne Fritz via Fot
Sent: Friday, January 12, 2024 7:13 AM
To: tr4racing@googlemail.com
Cc: fot@autox.team.net; fubog1
Subject: Re: [Fot] Piston to head clearance
Good point.=20
On Thu, Jan 11, 2024 at 6:45=E2=80=AFPM <tr4racing@googlemail.com> wrote:
That is one thing to consider.
When is turbulence supporting and when is turbulence overdone and disturbin=
g.
=C2=A0
I could imagine to force too much turbulence with a very small squish gap t=
he flame front expansion is compromised, thus slows down, and lowers the hp=
output.
That=E2=80=99s why we had the best power with 0.047=E2=80=9D gap.
=C2=A0
Cheers
Chris
=C2=A0
=C2=A0
From: Fot <fot-bounces@autox.team.net> On Behalf Of fubog1 via Fot
Sent: Thursday, January 11, 2024 8:01 PM
To: Lorne Fritz <lorne.fritz@gmail.com>; Steven Belfer <steve@artwithcars.c=
om>
Cc: fot@autox.team.net
Subject: Re: [Fot] Piston to head clearance
=C2=A0
Steve nailed it, both on the ##s, & the importance of it.
It depends on what rods & crank, piston to wall clearance & what RPM, but f=
or most applications that's right in the ballpark.
I've run as little as oops not enough ie .025 or less, .028 minimum (you wo=
n't get any carbon deposit on the squish area), but to play it safe nowaday=
s I use .030-.032
Also on these engines it's not only a CR related issue, the squish is very =
critical, you want to minimize the clearance between piston top & head to m=
aximize the squish effect, which creates turbulence, which assists in good =
combustion...
=C2=A0
Glen Efinger.
=C2=A0
=C2=A0
On Thursday, January 11, 2024 at 01:00:50 PM EST, Steven Belfer via Fot <fo=
t@autox.team.net> wrote:=20
=C2=A0
=C2=A0
You want as little as necessary because this is where your high CR comes fr=
om.=C2=A0 The thickness of the head gasket is the major part of P to H clea=
rance.=C2=A0 I ran .026 P to H clearance at Cal Speedway and the piston kis=
sed the head and I spun a bearing.=C2=A0 My machine shop guy likes .040 for=
safety but I=E2=80=99ve been running .032 and it=E2=80=99s working out gre=
at
~Steve
> On Jan 11, 2024, at 9:13=E2=80=AFAM, Lorne Fritz via Fot <fot@autox.team.=
net> wrote:
>=20
> =EF=BB=BF
> Hi.=C2=A0 In the past I have had pistons hit the head and leave a mark(TR=
3/4).=C2=A0 What piston to head clearance are most of you running? Thanks i=
n advance,=C2=A0 Lorne
> _______________________________________________
> fot@autox.team.net
>=20
> http://www.fot-racing.com
>=20
> Donate: http://www.team.net/donate.html
> Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
> Unsubscribe/Manage: http://autox.team.net/mailman/options/fot/steve@artwi=
thcars.com
>=20
>=20
_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
m
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--></style></head><body lang=3DEN-US link=3Dblue vlink=3D"#954F72" style=3D=
'word-wrap:break-word'><div class=3DWordSection1><p class=3DMsoNormal>Inter=
esting discussion and I would agree on point.=C2=A0 What would interesting =
to know is how the HP change was measured; chassis dyno or engine dyno?</p>=
<p class=3DMsoNormal><o:p> </o:p></p><p class=3DMsoNormal>Ken </p><p c=
lass=3DMsoNormal><o:p> </o:p></p><p class=3DMsoNormal>Sent from <a hre=
f=3D"https://go.microsoft.com/fwlink/?LinkId=3D550986";>Mail</a> for Windows=
</p><p class=3DMsoNormal><o:p> </o:p></p><div style=3D'mso-element:par=
a-border-div;border:none;border-top:solid #E1E1E1 1.0pt;padding:3.0pt 0in 0=
in 0in'><p class=3DMsoNormal style=3D'border:none;padding:0in'><b>From: </b=
><a href=3D"mailto:fot@autox.team.net";>Lorne Fritz via Fot</a><br><b>Sent: =
</b>Friday, January 12, 2024 7:13 AM<br><b>To: </b><a href=3D"mailto:tr4rac=
ing@googlemail.com">tr4racing@googlemail.com</a><br><b>Cc: </b><a href=3D"m=
ailto:fot@autox.team.net">fot@autox.team.net</a>; <a href=3D"mailto:fubog1@=
aol.com">fubog1</a><br><b>Subject: </b>Re: [Fot] Piston to head clearance</=
p></div><p class=3DMsoNormal><o:p> </o:p></p><div><p class=3DMsoNormal=
>Good point. </p></div><p class=3DMsoNormal><o:p> </o:p></p><div><div>=
<p class=3DMsoNormal>On Thu, Jan 11, 2024 at 6:45=E2=80=AFPM <<a href=3D=
"mailto:tr4racing@googlemail.com";>tr4racing@googlemail.com</a>> wrote:</=
p></div><blockquote style=3D'border:none;border-left:solid #CCCCCC 1.0pt;pa=
dding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in'><div><div><div>=
<p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt=
:auto'>That is one thing to consider.</p><p class=3DMsoNormal style=3D'mso-=
margin-top-alt:auto;mso-margin-bottom-alt:auto'>When is turbulence supporti=
ng and when is turbulence overdone and disturbing.</p><p class=3DMsoNormal =
style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><p c=
lass=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:aut=
o'>I could imagine to force too much turbulence with a very small squish ga=
p the flame front expansion is compromised, thus slows down, and lowers the=
hp output.</p><p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-ma=
rgin-bottom-alt:auto'>That=E2=80=99s why we had the best power with 0.047=
=E2=80=9D gap.</p><p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso=
-margin-bottom-alt:auto'> </p><p class=3DMsoNormal style=3D'mso-margin=
-top-alt:auto;mso-margin-bottom-alt:auto'>Cheers</p><p class=3DMsoNormal st=
yle=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>Chris</p><p clas=
s=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'>=
</p><p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-margin-=
bottom-alt:auto'> </p><div><div style=3D'border:none;border-top:solid =
windowtext 1.0pt;padding:3.0pt 0in 0in 0in;border-color:currentcolor curren=
tcolor'><p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-margin-bo=
ttom-alt:auto'><b><span lang=3DDE>From:</span></b><span lang=3DDE> Fot <=
<a href=3D"mailto:fot-bounces@autox.team.net"; target=3D"_blank">fot-bounces=
@autox.team.net</a>> <b>On Behalf Of </b>fubog1 via Fot<br><b>Sent:</b> =
Thursday, January 11, 2024 8:01 PM<br><b>To:</b> Lorne Fritz <<a href=3D=
"mailto:lorne.fritz@gmail.com"; target=3D"_blank">lorne.fritz@gmail.com</a>&=
gt;; Steven Belfer <<a href=3D"mailto:steve@artwithcars.com"; target=3D"_=
blank">steve@artwithcars.com</a>><br><b>Cc:</b> <a href=3D"mailto:fot@au=
tox.team.net" target=3D"_blank">fot@autox.team.net</a><br><b>Subject:</b> R=
e: [Fot] Piston to head clearance</span></p></div></div><p class=3DMsoNorma=
l style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'> </p><d=
iv><div><p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-margin-bo=
ttom-alt:auto'><span style=3D'font-size:12.0pt;font-family:"Arial",sans-ser=
if'>Steve nailed it, both on the ##s, & the importance of it.</span></p=
></div><div><p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-margi=
n-bottom-alt:auto'><span style=3D'font-size:12.0pt;font-family:"Arial",sans=
-serif'>It depends on what rods & crank, piston to wall clearance &=
what RPM, but for most applications that's right in the ballpark.</span></=
p></div><div><p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-marg=
in-bottom-alt:auto'><span style=3D'font-size:12.0pt;font-family:"Arial",san=
s-serif'>I've run as little as oops not enough ie .025 or less, .028 minimu=
m (you won't get any carbon deposit on the squish area), but to play it saf=
e nowadays I use .030-.032</span></p></div><div><div><div><p class=3DMsoNor=
mal style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span styl=
e=3D'font-size:12.0pt;font-family:"Arial",sans-serif'>Also on these engines=
it's not only a CR related issue, the squish is very critical, you want to=
minimize the clearance between piston top & head to maximize the squis=
h effect, which creates turbulence, which assists in good combustion...</sp=
an></p></div><div><div><p class=3DMsoNormal style=3D'mso-margin-top-alt:aut=
o;mso-margin-bottom-alt:auto'><span style=3D'font-size:12.0pt;font-family:"=
Arial",sans-serif'> </span></p></div><div><div><p class=3DMsoNormal st=
yle=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style=3D'f=
ont-size:12.0pt;font-family:"Arial",sans-serif'>Glen Efinger.</span></p></d=
iv></div></div></div><div><p class=3DMsoNormal style=3D'mso-margin-top-alt:=
auto;mso-margin-bottom-alt:auto'><span style=3D'font-size:12.0pt;font-famil=
y:"Arial",sans-serif'> </span></p></div></div><div><p class=3DMsoNorma=
l style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span style=
=3D'font-size:12.0pt;font-family:"Arial",sans-serif'> </span></p></div=
></div><div id=3D"m_986188904719810780ydpeb00682yahoo_quoted_5223032547"><d=
iv><div><p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-margin-bo=
ttom-alt:auto'><span style=3D'font-size:10.0pt;font-family:"Helvetica",sans=
-serif;color:#26282A'>On Thursday, January 11, 2024 at 01:00:50 PM EST, Ste=
ven Belfer via Fot <<a href=3D"mailto:fot@autox.team.net"; target=3D"_bla=
nk">fot@autox.team.net</a>> wrote: </span></p></div><div><p class=3DMsoN=
ormal style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto'><span st=
yle=3D'font-size:10.0pt;font-family:"Helvetica",sans-serif;color:#26282A'>&=
nbsp;</span></p></div><div><p class=3DMsoNormal style=3D'mso-margin-top-alt=
:auto;mso-margin-bottom-alt:auto'><span style=3D'font-size:10.0pt;font-fami=
ly:"Helvetica",sans-serif;color:#26282A'> </span></p></div><div><div><=
p class=3DMsoNormal style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:=
auto'><span style=3D'font-size:10.0pt;font-family:"Helvetica",sans-serif;co=
lor:#26282A'>You want as little as necessary because this is where your hig=
h CR comes from. The thickness of the head gasket is the major part o=
f P to H clearance. I ran .026 P to H clearance at Cal Speedway and t=
he piston kissed the head and I spun a bearing. My machine shop guy l=
ikes .040 for safety but I=E2=80=99ve been running .032 and it=E2=80=99s wo=
rking out great<br>~Steve<br><br><br>> On Jan 11, 2024, at 9:13=E2=80=AF=
AM, Lorne Fritz via Fot <<a href=3D"mailto:fot@autox.team.net"; target=3D=
"_blank">fot@autox.team.net</a>> wrote:<br>> <br>> </span><span st=
yle=3D'font-size:10.0pt;font-family:"Tahoma",sans-serif;color:#26282A'>=EF=
=BB=BF</span><span style=3D'font-size:10.0pt;font-family:"Helvetica",sans-s=
erif;color:#26282A'><br>> Hi. In the past I have had pistons hit t=
he head and leave a mark(TR3/4). What piston to head clearance are mo=
st of you running? Thanks in advance, Lorne<br>> _________________=
______________________________<br>> <a href=3D"mailto:fot@autox.team.net=
" target=3D"_blank">fot@autox.team.net</a><br>> <br>> <a href=3D"http=
://www.fot-racing.com" target=3D"_blank">http://www.fot-racing.com</a><br>&=
gt; <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"htt=
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</a> <a href=3D"http://www.team.net/pipermail/fot"; target=3D"_blank">http:/=
/www.team.net/pipermail/fot</a><br>> Unsubscribe/Manage: <a href=3D"http=
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nk">http://autox.team.net/mailman/options/fot/steve@artwithcars.com</a></sp=
an></p></div></div></div></div></div></div></div></blockquote></div><p clas=
s=3DMsoNormal style=3D'mso-margin-top-alt:auto;margin-bottom:12.0pt;margin-=
left:4.8pt'><span style=3D'font-size:10.0pt;font-family:"Helvetica",sans-se=
rif;color:#26282A'><br>> <br>> <br>__________________________________=
_____________<br><a href=3D"mailto:fot@autox.team.net"; target=3D"_blank">fo=
t@autox.team.net</a><br><br><a href=3D"http://www.fot-racing.com"; target=3D=
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ttp://autox.team.net/archive</a> <a href=3D"http://www.team.net/pipermail/f=
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m</a></span></p><p class=3DMsoNormal><o:p> </o:p></p></div></body></ht=
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