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I'm still burning up (precious) brain cells on this, yes interesting, but =
that's one of my questions also, exactly how was the reported gain establis=
hed?I've always gone with the theory that more is better when it comes to t=
urbulence, which requires minimal squish clearance.I would imagine that cha=
mber & piston top configuration, ie flat-tops or a lump on top, may be part=
of the equation as well...Yes compelling discussion!
Glen Efinger
On Friday, January 12, 2024 at 10:57:08 AM EST, Ken Knight <kknight@kla=
env.com> wrote: =20
=20
=20
Interesting discussion and I would agree on point.=C2=A0 What would interes=
ting to know is how the HP change was measured; chassis dyno or engine dyno=
?
=C2=A0
Ken=20
=C2=A0
Sent from Mail for Windows
=C2=A0
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
=C2=A0
Good point.=20
=C2=A0
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
=C2=A0
=20
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<html><head></head><body><div class=3D"ydpc3aa0f24yahoo-style-wrap" style=
=3D"font-family:Arial, Helvetica, sans-serif;font-size:16px;"><div></div>
<div dir=3D"ltr" data-setdir=3D"false">I'm still burning up (precio=
us) brain cells on this, yes interesting, but that's one of my questions al=
so, exactly how was the reported gain established?</div><div dir=3D"ltr" da=
ta-setdir=3D"false">I've always gone with the theory that more is better wh=
en it comes to turbulence, which requires minimal squish clearance.</div><d=
iv dir=3D"ltr" data-setdir=3D"false">I would imagine that chamber & pis=
ton top configuration, ie flat-tops or a lump on top, may be part of the eq=
uation as well...</div><div dir=3D"ltr" data-setdir=3D"false">Yes compellin=
g discussion!</div><div dir=3D"ltr" data-setdir=3D"false"><br></div><div di=
r=3D"ltr" data-setdir=3D"false">Glen Efinger<br></div><div><br></div>
=20
</div><div id=3D"ydp3da3111dyahoo_quoted_5967812695" class=3D"ydp3d=
a3111dyahoo_quoted">
<div style=3D"font-family:'Helvetica Neue', Helvetica, Arial, s=
ans-serif;font-size:13px;color:#26282a;">
=20
<div>
On Friday, January 12, 2024 at 10:57:08 AM EST, Ken Kni=
ght <kknight@klaenv.com> wrote:
</div>
<div><br></div>
<div><br></div>
<div><div id=3D"ydp3da3111dyiv6692933316"><div><div class=
=3D"ydp3da3111dyiv6692933316WordSection1"><p class=3D"ydp3da3111dyiv6692933=
316MsoNormal">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?</p><p class=3D"ydp3da3111dyiv6692933316MsoNormal"> </=
p><p class=3D"ydp3da3111dyiv6692933316MsoNormal">Ken </p><p class=3D"ydp3da=
3111dyiv6692933316MsoNormal"> </p><p class=3D"ydp3da3111dyiv669293331=
6MsoNormal">Sent from <a shape=3D"rect" href=3D"https://go.microsoft.com/fw=
link/?LinkId=3D550986" rel=3D"nofollow" target=3D"_blank">Mail</a> for Wind=
ows</p><p class=3D"ydp3da3111dyiv6692933316MsoNormal"> </p><div id=3D=
"ydp3da3111dyiv6692933316yqt61391" class=3D"ydp3da3111dyiv6692933316yqt3517=
781960"><div style=3D"border-color: rgb(225, 225, 225) currentcolor current=
color; border-style: solid none none; border-width: 1pt medium medium; padd=
ing: 3pt 0in 0in;"><p style=3D"border-color: currentcolor; border-style: no=
ne; border-width: medium; padding: 0in;" class=3D"ydp3da3111dyiv6692933316M=
soNormal"><b>From: </b><a shape=3D"rect" href=3D"mailto:fot@autox.team.net"=
rel=3D"nofollow" target=3D"_blank">Lorne Fritz via Fot</a><br clear=3D"non=
e"><b>Sent: </b>Friday, January 12, 2024 7:13 AM<br clear=3D"none"><b>To: <=
/b><a shape=3D"rect" href=3D"mailto:tr4racing@googlemail.com"; rel=3D"nofoll=
ow" target=3D"_blank">tr4racing@googlemail.com</a><br clear=3D"none"><b>Cc:=
</b><a shape=3D"rect" href=3D"mailto:fot@autox.team.net"; rel=3D"nofollow" =
target=3D"_blank">fot@autox.team.net</a>; <a shape=3D"rect" href=3D"mailto:=
fubog1@aol.com" rel=3D"nofollow" target=3D"_blank">fubog1</a><br clear=3D"n=
one"><b>Subject: </b>Re: [Fot] Piston to head clearance</p></div><p class=
=3D"ydp3da3111dyiv6692933316MsoNormal"> </p><div><p class=3D"ydp3da31=
11dyiv6692933316MsoNormal">Good point. </p></div><p class=3D"ydp3da3111dyiv=
6692933316MsoNormal"> </p><div><div><p class=3D"ydp3da3111dyiv6692933=
316MsoNormal">On Thu, Jan 11, 2024 at 6:45=E2=80=AFPM <<a shape=3D"rect"=
href=3D"mailto:tr4racing@googlemail.com"; rel=3D"nofollow" target=3D"_blank=
">tr4racing@googlemail.com</a>> wrote:</p></div><blockquote style=3D"bor=
der-color: currentcolor currentcolor currentcolor rgb(204, 204, 204); borde=
r-style: none none none solid; border-width: medium medium medium 1pt; padd=
ing: 0in 0in 0in 6pt; margin-left: 4.8pt; margin-right: 0in;"><div><div><di=
v><p class=3D"ydp3da3111dyiv6692933316MsoNormal">That is one thing to consi=
der.</p><p class=3D"ydp3da3111dyiv6692933316MsoNormal">When is turbulence s=
upporting and when is turbulence overdone and disturbing.</p><p class=3D"yd=
p3da3111dyiv6692933316MsoNormal"> </p><p class=3D"ydp3da3111dyiv669293=
3316MsoNormal">I could imagine to force too much turbulence with a very sma=
ll squish gap the flame front expansion is compromised, thus slows down, an=
d lowers the hp output.</p><p class=3D"ydp3da3111dyiv6692933316MsoNormal">T=
hat=E2=80=99s why we had the best power with 0.047=E2=80=9D gap.</p><p clas=
s=3D"ydp3da3111dyiv6692933316MsoNormal"> </p><p class=3D"ydp3da3111dyi=
v6692933316MsoNormal">Cheers</p><p class=3D"ydp3da3111dyiv6692933316MsoNorm=
al">Chris</p><p class=3D"ydp3da3111dyiv6692933316MsoNormal"> </p><p cl=
ass=3D"ydp3da3111dyiv6692933316MsoNormal"> </p><div><div style=3D"bord=
er-style: solid none none; border-width: 1pt medium medium; padding: 3pt 0i=
n 0in; border-color: currentcolor;"><p class=3D"ydp3da3111dyiv6692933316Mso=
Normal"><b><span lang=3D"DE">From:</span></b><span lang=3D"DE"> Fot <<a =
shape=3D"rect" href=3D"mailto:fot-bounces@autox.team.net"; rel=3D"nofollow" =
target=3D"_blank">fot-bounces@autox.team.net</a>> <b>On Behalf Of </b>fu=
bog1 via Fot<br clear=3D"none"><b>Sent:</b> Thursday, January 11, 2024 8:01=
PM<br clear=3D"none"><b>To:</b> Lorne Fritz <<a shape=3D"rect" href=3D"=
mailto:lorne.fritz@gmail.com"; rel=3D"nofollow" target=3D"_blank">lorne.frit=
z@gmail.com</a>>; Steven Belfer <<a shape=3D"rect" href=3D"mailto:ste=
ve@artwithcars.com" rel=3D"nofollow" target=3D"_blank">steve@artwithcars.co=
m</a>><br clear=3D"none"><b>Cc:</b> <a shape=3D"rect" href=3D"mailto:fot=
@autox.team.net" rel=3D"nofollow" target=3D"_blank">fot@autox.team.net</a><=
br clear=3D"none"><b>Subject:</b> Re: [Fot] Piston to head clearance</span>=
</p></div></div><p class=3D"ydp3da3111dyiv6692933316MsoNormal"> </p><d=
iv><div><p class=3D"ydp3da3111dyiv6692933316MsoNormal"><span style=3D"font-=
size:12.0pt;font-family:sans-serif;">Steve nailed it, both on the ##s, &=
; the importance of it.</span></p></div><div><p class=3D"ydp3da3111dyiv6692=
933316MsoNormal"><span style=3D"font-size:12.0pt;font-family:sans-serif;">I=
t 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=3D"ydp3da3111dyiv6692933316MsoNormal"><span style=3D"font-size=
:12.0pt;font-family:sans-serif;">I've run as little as oops not enough ie .=
025 or less, .028 minimum (you won't get any carbon deposit on the squish a=
rea), but to play it safe nowadays I use .030-.032</span></p></div><div><di=
v><div><p class=3D"ydp3da3111dyiv6692933316MsoNormal"><span style=3D"font-s=
ize:12.0pt;font-family:sans-serif;">Also on these engines it's not only a C=
R related issue, the squish is very critical, you want to minimize the clea=
rance between piston top & head to maximize the squish effect, which cr=
eates turbulence, which assists in good combustion...</span></p></div><div>=
<div><p class=3D"ydp3da3111dyiv6692933316MsoNormal"><span style=3D"font-siz=
e:12.0pt;font-family:sans-serif;"> </span></p></div><div><div><p class=
=3D"ydp3da3111dyiv6692933316MsoNormal"><span style=3D"font-size:12.0pt;font=
-family:sans-serif;">Glen Efinger.</span></p></div></div></div></div><div><=
p class=3D"ydp3da3111dyiv6692933316MsoNormal"><span style=3D"font-size:12.0=
pt;font-family:sans-serif;"> </span></p></div></div><div><p class=3D"y=
dp3da3111dyiv6692933316MsoNormal"><span style=3D"font-size:12.0pt;font-fami=
ly:sans-serif;"> </span></p></div></div><div id=3D"ydp3da3111dyiv66929=
33316m_986188904719810780ydpeb00682yahoo_quoted_5223032547"><div><div><p cl=
ass=3D"ydp3da3111dyiv6692933316MsoNormal"><span style=3D"font-size:10.0pt;f=
ont-family:sans-serif;color:#26282A;">On Thursday, January 11, 2024 at 01:0=
0:50 PM EST, Steven Belfer via Fot <<a shape=3D"rect" href=3D"mailto:fot=
@autox.team.net" rel=3D"nofollow" target=3D"_blank">fot@autox.team.net</a>&=
gt; wrote: </span></p></div><div><p class=3D"ydp3da3111dyiv6692933316MsoNor=
mal"><span style=3D"font-size:10.0pt;font-family:sans-serif;color:#26282A;"=
> </span></p></div><div><p class=3D"ydp3da3111dyiv6692933316MsoNormal"=
><span style=3D"font-size:10.0pt;font-family:sans-serif;color:#26282A;">&nb=
sp;</span></p></div><div><div><p class=3D"ydp3da3111dyiv6692933316MsoNormal=
"><span style=3D"font-size:10.0pt;font-family:sans-serif;color:#26282A;">Yo=
u want as little as necessary because this is where your high CR comes from=
. The thickness of the head gasket is the major part of P to H cleara=
nce. I ran .026 P to H clearance at Cal Speedway and the piston kisse=
d the head and I spun a bearing. My machine shop guy likes .040 for s=
afety but I=E2=80=99ve been running .032 and it=E2=80=99s working out great=
<br clear=3D"none">~Steve<br clear=3D"none"><br clear=3D"none"><br clear=3D=
"none">> On Jan 11, 2024, at 9:13=E2=80=AFAM, Lorne Fritz via Fot <<a=
shape=3D"rect" href=3D"mailto:fot@autox.team.net"; rel=3D"nofollow" target=
=3D"_blank">fot@autox.team.net</a>> wrote:<br clear=3D"none">> <br cl=
ear=3D"none">> </span><span style=3D"font-size:10.0pt;font-family:sans-s=
erif;color:#26282A;">=EF=BB=BF</span><span style=3D"font-size:10.0pt;font-f=
amily:sans-serif;color:#26282A;"><br clear=3D"none">> Hi. In the p=
ast I have had pistons hit the head and leave a mark(TR3/4). What pis=
ton to head clearance are most of you running? Thanks in advance, Lor=
ne<br clear=3D"none">> _______________________________________________<b=
r clear=3D"none">> <a shape=3D"rect" href=3D"mailto:fot@autox.team.net"; =
rel=3D"nofollow" target=3D"_blank">fot@autox.team.net</a><br clear=3D"none"=
>> <br clear=3D"none">> <a shape=3D"rect" href=3D"http://www.fot-raci=
ng.com" rel=3D"nofollow" target=3D"_blank">http://www.fot-racing.com</a><br=
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=3D"rect" href=3D"http://autox.team.net/archive"; rel=3D"nofollow" target=3D=
"_blank">http://autox.team.net/archive</a> <a shape=3D"rect" href=3D"http:/=
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div></div></div></blockquote></div><p style=3D"margin-bottom:12.0pt;margin-=
left:4.8pt;" class=3D"ydp3da3111dyiv6692933316MsoNormal"><span style=3D"fon=
t-size:10.0pt;font-family:sans-serif;color:#26282A;"><br clear=3D"none">>=
; <br clear=3D"none">> <br clear=3D"none">______________________________=
_________________<br clear=3D"none"><a shape=3D"rect" href=3D"mailto:fot@au=
tox.team.net" rel=3D"nofollow" target=3D"_blank">fot@autox.team.net</a><br =
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racing.com" rel=3D"nofollow" target=3D"_blank">http://www.fot-racing.com</a=
><br clear=3D"none"><br clear=3D"none">Donate: <a shape=3D"rect" href=3D"ht=
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_______________________________________________
fot@autox.team.net
http://www.fot-racing.com
Archive: http://autox.team.net/archive http://www.team.net/pipermail/fot
--===============2944406252922560307==--
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