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<DIV><FONT face=Arial size=2>Karl,</FONT></DIV>
<DIV><FONT face=Arial size=2> Thanks for the info. I never put a degree
wheel on a model engine so this is interesting to say the least. I'm surprised
that model 4-strokes have no overlap. Hmm. You'd think that something like the
YS 170 could benefit from that. I don't have as much tuning experience with
2-strokes as I do with 4-strokes (motorcycles). I'd like to do some experiments
with model engines now...</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>John Pavlick<BR><A
href="http://www.idseng.com">http://www.idseng.com</A></FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=kgamueller@rogers.com href="mailto:kgamueller@rogers.com">Karl G.
Mueller</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=jpavlick@idseng.com
href="mailto:jpavlick@idseng.com">jpavlick@idseng.com</A> ; <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">General pattern discussion</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, November 06, 2008 7:19
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion] Engine
tuning info</DIV>
<DIV><BR></DIV>
<DIV>John,</DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Most of the 2C sport engines to be used with a
muffler are timed</FONT></DIV>
<DIV><FONT face=Arial size=2>at about 145-148º exhaust down time.</FONT></DIV>
<DIV><FONT face=Arial size=2>On most of the .60 to 1.60 size, to get the
benefit of the supercharging</FONT></DIV>
<DIV><FONT face=Arial size=2>effect from the pipe, I increase the exhaust
downtime to 155-158º, without</FONT></DIV>
<DIV><FONT face=Arial size=2>changing </FONT><FONT face=Arial size=2>the
intake timing, except for some directional porting for better </FONT></DIV>
<DIV><FONT face=Arial size=2>scavenging </FONT><FONT face=Arial size=2>effect.
This all will not decrease a reliable idle.</FONT></DIV>
<DIV><FONT face=Arial size=2>I believe that the pylon engines are ported to
170º exhaust down time and </FONT></DIV>
<DIV><FONT face=Arial size=2>on those you are not looking for a reliable low
idle. </FONT></DIV>
<DIV><FONT face=Arial size=2>Never tried any work on 4 strokes. To get any
benefit from a pipe on those</FONT></DIV>
<DIV><FONT face=Arial size=2>you would have to have overlapping valve timing,
which none of our model</FONT></DIV>
<DIV><FONT face=Arial size=2>4 stroke </FONT><FONT face=Arial size=2>engines
have.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Karl G. Mueller<BR><A
href="mailto:kgamueller@rogers.com">kgamueller@rogers.com</A><BR></FONT></DIV>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=jpavlick@idseng.com href="mailto:jpavlick@idseng.com">John
Pavlick</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A
title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, November 06, 2008 5:02
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> [NSRCA-discussion] Engine
tuning info</DIV>
<DIV><BR></DIV>
<TABLE cellSpacing=0 cellPadding=0 border=0>
<TBODY>
<TR>
<TD vAlign=top>
<DIV>Has anyone taken the time to measure the port timing of
various model airplane 2C engines? Specifically the OS140 and 160?
Also, if anyone has cam profiles + index info for the YS 160
and 170 4C motors I'd be interested in that as well.</DIV>
<DIV> </DIV>
<DIV>John Pavlick</DIV></TD></TR></TBODY></TABLE>
<P>
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