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<DIV><FONT face=Arial size=2>Bob,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Note that there is a thicker tubing that most of us
are using. I think that it has a 1/16" wall thickness. I believe that this may
be your problem. I have been using the thicker tubing for several years without
a failure.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Cheers,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Ken Blackwell</FONT></DIV>
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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=getterflash@yahoo.com href="mailto:getterflash@yahoo.com">Bob
Kane</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">nsrca</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, October 09, 2003 8:31
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Teflon headers, followup</DIV>
<DIV><BR></DIV>
<DIV>I thought I would let you know what is going on with my teflon header
issues. I was using blue teflon 5/8 ID, 3/4 OD PTFE ordered from
McMaster-Carr, and getting as few as 6 flights from the header. Setup is YS140
Fizzle, Hyde mount, NMP High Performance header, Johnson SQ pipe on a single
Lord mount. </DIV>
<DIV> </DIV>
<DIV>It was time to get some more teflon, so I ordered semi-clear part#
5033K39 (5/8ID, 3/4OD), and a short piece of 5239K19 (3/4ID, .040 wall
thickness). The larger size is a slip-fit over the 3/4OD stuff. I use a 1.5"
piece of it over the end of the header where it is clamped to the header
brace. One other procedural change I made was to place the clamp over the
teflon in front of the bead in the steel header instead of directly over it.
The teflon formerly failed at the bead, moving the clamp ahead of the bead
seems to reduce the erosion of the teflon.</DIV>
<DIV> </DIV>
<DIV>Well, they still fail, but are lasting quite a bit longer. Now the
failure point is right where small teflon exits the larger teflon
bushing. Judging from the looks of the header where it failed, it could
be caused by torsional vibration between the Hyde-mounted engine and single
soft point mounted pipe. There might be some kind of harmonic thing going on
where the engine is going one way and the pipe is going the other, and
the teflon has to twist. I have noticed the teflon softens quite a bit when
heated and may not be up to the mechanical demands put on it from
vibration. </DIV>
<DIV> </DIV>
<DIV>For those of you getting long header life, are your engine and pipe soft
mounted? </DIV>
<DIV> </DIV>
<DIV>BTW, I must praise McMaster-Carr for their delivery service. I ordered on
Monday morning, the teflon arrived Tuesday evening by standard ground
UPS.</DIV><BR><BR>Bob Kane<BR>getterflash@yahoo.com
<P>
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