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<div dir="ltr" data-setdir="false">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 established?</div><div dir="ltr" data-setdir="false">I've always gone with the theory that more is better when it comes to turbulence, which requires minimal squish clearance.</div><div dir="ltr" data-setdir="false">I would imagine that chamber & piston top configuration, ie flat-tops or a lump on top, may be part of the equation as well...</div><div dir="ltr" data-setdir="false">Yes compelling discussion!</div><div dir="ltr" data-setdir="false"><br></div><div dir="ltr" data-setdir="false">Glen Efinger<br></div><div><br></div>
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On Friday, January 12, 2024 at 10:57:08 AM EST, Ken Knight <kknight@klaenv.com> wrote:
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<div><div id="ydp3da3111dyiv6692933316"><div><div class="ydp3da3111dyiv6692933316WordSection1"><p class="ydp3da3111dyiv6692933316MsoNormal">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="ydp3da3111dyiv6692933316MsoNormal"> </p><p class="ydp3da3111dyiv6692933316MsoNormal">Ken </p><p class="ydp3da3111dyiv6692933316MsoNormal"> </p><p class="ydp3da3111dyiv6692933316MsoNormal">Sent from <a shape="rect" href="https://go.microsoft.com/fwlink/?LinkId=550986" rel="nofollow" target="_blank">Mail</a> for Windows</p><p class="ydp3da3111dyiv6692933316MsoNormal"> </p><div id="ydp3da3111dyiv6692933316yqt61391" class="ydp3da3111dyiv6692933316yqt3517781960"><div style="border-color: rgb(225, 225, 225) currentcolor currentcolor; border-style: solid none none; border-width: 1pt medium medium; padding: 3pt 0in 0in;"><p style="border-color: currentcolor; border-style: none; border-width: medium; padding: 0in;" class="ydp3da3111dyiv6692933316MsoNormal"><b>From: </b><a shape="rect" href="mailto:fot@autox.team.net" rel="nofollow" target="_blank">Lorne Fritz via Fot</a><br clear="none"><b>Sent: </b>Friday, January 12, 2024 7:13 AM<br clear="none"><b>To: </b><a shape="rect" href="mailto:tr4racing@googlemail.com" rel="nofollow" target="_blank">tr4racing@googlemail.com</a><br clear="none"><b>Cc: </b><a shape="rect" href="mailto:fot@autox.team.net" rel="nofollow" target="_blank">fot@autox.team.net</a>; <a shape="rect" href="mailto:fubog1@aol.com" rel="nofollow" target="_blank">fubog1</a><br clear="none"><b>Subject: </b>Re: [Fot] Piston to head clearance</p></div><p class="ydp3da3111dyiv6692933316MsoNormal"> </p><div><p class="ydp3da3111dyiv6692933316MsoNormal">Good point. </p></div><p class="ydp3da3111dyiv6692933316MsoNormal"> </p><div><div><p class="ydp3da3111dyiv6692933316MsoNormal">On Thu, Jan 11, 2024 at 6:45 PM <<a shape="rect" href="mailto:tr4racing@googlemail.com" rel="nofollow" target="_blank">tr4racing@googlemail.com</a>> wrote:</p></div><blockquote style="border-color: currentcolor currentcolor currentcolor rgb(204, 204, 204); border-style: none none none solid; border-width: medium medium medium 1pt; padding: 0in 0in 0in 6pt; margin-left: 4.8pt; margin-right: 0in;"><div><div><div><p class="ydp3da3111dyiv6692933316MsoNormal">That is one thing to consider.</p><p class="ydp3da3111dyiv6692933316MsoNormal">When is turbulence supporting and when is turbulence overdone and disturbing.</p><p class="ydp3da3111dyiv6692933316MsoNormal"> </p><p class="ydp3da3111dyiv6692933316MsoNormal">I could imagine to force too much turbulence with a very small squish gap the flame front expansion is compromised, thus slows down, and lowers the hp output.</p><p class="ydp3da3111dyiv6692933316MsoNormal">That’s why we had the best power with 0.047” gap.</p><p class="ydp3da3111dyiv6692933316MsoNormal"> </p><p class="ydp3da3111dyiv6692933316MsoNormal">Cheers</p><p class="ydp3da3111dyiv6692933316MsoNormal">Chris</p><p class="ydp3da3111dyiv6692933316MsoNormal"> </p><p class="ydp3da3111dyiv6692933316MsoNormal"> </p><div><div style="border-style: solid none none; border-width: 1pt medium medium; padding: 3pt 0in 0in; border-color: currentcolor;"><p class="ydp3da3111dyiv6692933316MsoNormal"><b><span lang="DE">From:</span></b><span lang="DE"> Fot <<a shape="rect" href="mailto:fot-bounces@autox.team.net" rel="nofollow" target="_blank">fot-bounces@autox.team.net</a>> <b>On Behalf Of </b>fubog1 via Fot<br clear="none"><b>Sent:</b> Thursday, January 11, 2024 8:01 PM<br clear="none"><b>To:</b> Lorne Fritz <<a shape="rect" href="mailto:lorne.fritz@gmail.com" rel="nofollow" target="_blank">lorne.fritz@gmail.com</a>>; Steven Belfer <<a shape="rect" href="mailto:steve@artwithcars.com" rel="nofollow" target="_blank">steve@artwithcars.com</a>><br clear="none"><b>Cc:</b> <a shape="rect" href="mailto:fot@autox.team.net" rel="nofollow" target="_blank">fot@autox.team.net</a><br clear="none"><b>Subject:</b> Re: [Fot] Piston to head clearance</span></p></div></div><p class="ydp3da3111dyiv6692933316MsoNormal"> </p><div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="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="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:12.0pt;font-family: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="ydp3da3111dyiv6692933316MsoNormal"><span style="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 area), but to play it safe nowadays I use .030-.032</span></p></div><div><div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:12.0pt;font-family: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 squish effect, which creates turbulence, which assists in good combustion...</span></p></div><div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:12.0pt;font-family:sans-serif;"> </span></p></div><div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:12.0pt;font-family:sans-serif;">Glen Efinger.</span></p></div></div></div></div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:12.0pt;font-family:sans-serif;"> </span></p></div></div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:12.0pt;font-family:sans-serif;"> </span></p></div></div><div id="ydp3da3111dyiv6692933316m_986188904719810780ydpeb00682yahoo_quoted_5223032547"><div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:10.0pt;font-family:sans-serif;color:#26282A;">On Thursday, January 11, 2024 at 01:00:50 PM EST, Steven Belfer via Fot <<a shape="rect" href="mailto:fot@autox.team.net" rel="nofollow" target="_blank">fot@autox.team.net</a>> wrote: </span></p></div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:10.0pt;font-family:sans-serif;color:#26282A;"> </span></p></div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:10.0pt;font-family:sans-serif;color:#26282A;"> </span></p></div><div><div><p class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:10.0pt;font-family:sans-serif;color:#26282A;">You 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 clearance. I ran .026 P to H clearance at Cal Speedway and the piston kissed the head and I spun a bearing. My machine shop guy likes .040 for safety but I’ve been running .032 and it’s working out great<br clear="none">~Steve<br clear="none"><br clear="none"><br clear="none">> On Jan 11, 2024, at 9:13 AM, Lorne Fritz via Fot <<a shape="rect" href="mailto:fot@autox.team.net" rel="nofollow" target="_blank">fot@autox.team.net</a>> wrote:<br clear="none">> <br clear="none">> </span><span style="font-size:10.0pt;font-family:sans-serif;color:#26282A;"></span><span style="font-size:10.0pt;font-family:sans-serif;color:#26282A;"><br clear="none">> Hi. In the past I have had pistons hit the head and leave a mark(TR3/4). What piston to head clearance are most of you running? Thanks in advance, Lorne<br clear="none">> _______________________________________________<br clear="none">> <a shape="rect" href="mailto:fot@autox.team.net" rel="nofollow" target="_blank">fot@autox.team.net</a><br clear="none">> <br clear="none">> <a shape="rect" href="http://www.fot-racing.com" rel="nofollow" target="_blank">http://www.fot-racing.com</a><br clear="none">> <br clear="none">> Donate: <a shape="rect" href="http://www.team.net/donate.html" rel="nofollow" target="_blank">http://www.team.net/donate.html</a><br clear="none">> Archive: <a shape="rect" href="http://autox.team.net/archive" rel="nofollow" target="_blank">http://autox.team.net/archive</a> <a shape="rect" href="http://www.team.net/pipermail/fot" rel="nofollow" target="_blank">http://www.team.net/pipermail/fot</a><br clear="none">> Unsubscribe/Manage: <a shape="rect" href="http://autox.team.net/mailman/options/fot/steve@artwithcars.com" rel="nofollow" target="_blank">http://autox.team.net/mailman/options/fot/steve@artwithcars.com</a></span></p></div></div></div></div></div></div></div></blockquote></div><p style="margin-bottom:12.0pt;margin-left:4.8pt;" class="ydp3da3111dyiv6692933316MsoNormal"><span style="font-size:10.0pt;font-family:sans-serif;color:#26282A;"><br clear="none">> <br clear="none">> <br clear="none">_______________________________________________<br clear="none"><a shape="rect" href="mailto:fot@autox.team.net" rel="nofollow" target="_blank">fot@autox.team.net</a><br clear="none"><br clear="none"><a shape="rect" href="http://www.fot-racing.com" rel="nofollow" target="_blank">http://www.fot-racing.com</a><br clear="none"><br clear="none">Donate: <a shape="rect" href="http://www.team.net/donate.html" rel="nofollow" target="_blank">http://www.team.net/donate.html</a><br clear="none">Archive: <a shape="rect" href="http://autox.team.net/archive" rel="nofollow" target="_blank">http://autox.team.net/archive</a> <a shape="rect" href="http://www.team.net/pipermail/fot" rel="nofollow" target="_blank">http://www.team.net/pipermail/fot</a><br clear="none">Unsubscribe/Manage: <a shape="rect" href="http://autox.team.net/mailman/options/fot/fubog1@aol.com" rel="nofollow" target="_blank">http://autox.team.net/mailman/options/fot/fubog1@aol.com</a></span></p></div><p class="ydp3da3111dyiv6692933316MsoNormal"> </p></div></div></div></div>
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