REFLECTOR:IO-540

Ronnie Brown reflector@tvbf.org
Thu, 13 May 2004 20:41:24 -0400


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Actually, it is impossible to have anything over 80.  "Compression" =
tests on airplane engines is a misnomer. (well actually, you can measure =
more than 80, you crank up the supply pressure to something higher - but =
this incorrect procedure - see below). =20

The rig used to check "compression" is actually a leakage measuring =
device.  Pressure is adjusted to exactly 80 psi from a regulator, then =
this air passes through a calibrated orifice.  The second gauge reads =
the pressure after the orifice.  If the rings, valves didn't leak at =
all, then this pressure would be 80, since there is no flow into the =
cylinder.

With a normal engine, there is always some leakage.  A small amount of =
leakage would be seen on a new or low time engine, typically 78,79 psi.  =
On a mid time engine, its more like 72-76.  On a worn engine, there will =
be lots of leakage and pressures will be below 70.  Not good for a =
Lycoming.  However Continental on the big bore engines has a new =
procedure that is used to assess the low (55-65 psi) pressures often =
seen on some of their new cylinders/pistons.  This involves boroscoping =
and inspecting valves.  Continental has blessed lower pressures =
providing the mechanic follows the inspection procedures.


  ----- Original Message -----=20
  From: Dennis Huntington=20
  To: reflector@tvbf.org=20
  Sent: Thursday, May 13, 2004 8:08 PM
  Subject: RE: REFLECTOR:IO-540






  Joe

  I dont want to insult anyone, but the compressions in the mid to hig =
70's are good.  In all my years of working planes, I have never seen the =
compression in the 80's.  They may be using a different compression =
gauges. =20

  However...the 300 HP engine may be too heavy for the 173.  I would =
check with Velocity.  I picked the 260 for my xlrg because they told me =
at the time that the weight of the 300 HP would make it hard to keep it =
in the CG

  I have thought of removing my 260 HP and converting it to a Cont 550 =
with turbos.  I Might be persuaded to sell my engine.  It is a Don =
George rebuilt and running great.

  Dennis



  =20

  >From: Joe <jewen@comporium.net>=20
  >Reply-To: reflector@tvbf.org=20
  >To: reflector@tvbf.org=20
  >Subject: REFLECTOR:IO-540=20
  >Date: Thu, 13 May 2004 10:00:31 -0400=20
  >=20
  >I am looking for a used IO-540 for my 173 RG.  I have found one for =
sale by Wentworth Aircraft Salvage. It is a used IO-540 K1E5 (300HP).  =
The specifics on the engine are - it came out of a Bellanca, it has not =
been in service since 1995 or 1996, it has been stored inside, it has =
1200 hours since new, nitrited cylinders, compressions are 76, 78, 74, =
73, 78, 76, for a cost of about 12K.  My greatest concern lies in the =
length of time this has been in storage.=20
  >=20
  >I appreciate anyone's opinion and / or sources for a used IO-540.=20
  >=20
  >Thanks,=20
  >Joe=20


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<DIV><FONT size=3D2>Actually, it is impossible to have anything over =
80.&nbsp;=20
"Compression" tests on airplane engines is a misnomer. (well actually, =
you can=20
measure more than 80, you crank up the supply pressure to something =
higher - but=20
this incorrect procedure - see below).&nbsp; </FONT></DIV>
<DIV><FONT size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT size=3D2>The rig used to check "compression" is actually a =
leakage=20
measuring device.&nbsp; Pressure is adjusted to exactly 80 psi from a =
regulator,=20
then this air passes through a calibrated orifice.&nbsp; The second =
gauge reads=20
the pressure after the orifice.&nbsp; If the rings, valves didn't leak =
at all,=20
then this pressure would be 80, since there is no flow into the=20
cylinder.</FONT></DIV>
<DIV><FONT size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT size=3D2>With a normal engine, there is always some =
leakage.&nbsp; A=20
small amount of leakage would be seen on a new or low time engine, =
typically=20
78,79 psi.&nbsp; On a mid time engine, its more like 72-76.&nbsp; On a =
worn=20
engine, there will be lots of leakage and pressures will be below =
70.&nbsp; Not=20
good for a Lycoming.&nbsp; However Continental on the big bore engines =
has a new=20
procedure that is used to assess the low (55-65 psi) pressures often =
seen on=20
some of their new cylinders/pistons.&nbsp; This involves boroscoping and =

inspecting valves.&nbsp; Continental has blessed lower pressures =
providing the=20
mechanic follows the inspection&nbsp;procedures.</FONT></DIV>
<DIV><FONT size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT size=3D2></FONT>&nbsp;</DIV>
<BLOCKQUOTE=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
  <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
  <DIV=20
  style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
  <A title=3Ddennishuntington@hotmail.com=20
  href=3D"mailto:dennishuntington@hotmail.com">Dennis Huntington</A> =
</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dreflector@tvbf.org=20
  href=3D"mailto:reflector@tvbf.org">reflector@tvbf.org</A> </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Thursday, May 13, 2004 =
8:08=20
PM</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> RE: =
REFLECTOR:IO-540</DIV>
  <DIV><BR></DIV>
  <DIV>
  <P><BR><BR></P>
  <DIV class=3DRTE>
  <P>Joe</P>
  <P>I dont want to insult anyone, but the compressions in the mid to =
hig 70's=20
  are good.&nbsp; In all my years of working planes, I have never seen =
the=20
  compression in the 80's.&nbsp; They may be using a different =
compression=20
  gauges.&nbsp; </P>
  <P>However...the 300 HP engine may be too heavy for the 173.&nbsp; I =
would=20
  check with Velocity.&nbsp; I picked the 260 for my xlrg because they =
told me=20
  at the time that the weight of the 300 HP would make it hard to keep =
it in the=20
  CG</P>
  <P>I have thought of removing my 260 HP and converting it to a Cont =
550 with=20
  turbos.&nbsp; I Might be persuaded to sell my engine.&nbsp; It is a =
Don George=20
  rebuilt and running great.</P>
  <P>Dennis</P>
  <P><BR><BR>&nbsp;</P></DIV>
  <DIV></DIV>&gt;From: Joe &lt;jewen@comporium.net&gt;=20
  <DIV></DIV>&gt;Reply-To: reflector@tvbf.org=20
  <DIV></DIV>&gt;To: reflector@tvbf.org=20
  <DIV></DIV>&gt;Subject: REFLECTOR:IO-540=20
  <DIV></DIV>&gt;Date: Thu, 13 May 2004 10:00:31 -0400=20
  <DIV></DIV>&gt;=20
  <DIV></DIV>&gt;I am looking for a used IO-540 for my 173 =
RG.&nbsp;&nbsp;I have=20
  found one for sale by Wentworth Aircraft Salvage. It is a used IO-540 =
K1E5=20
  (300HP).&nbsp;&nbsp;The specifics on the engine are - it came out of a =

  Bellanca, it has not been in service since 1995 or 1996, it has been =
stored=20
  inside, it has 1200 hours since new, nitrited cylinders, compressions =
are 76,=20
  78, 74, 73, 78, 76, for a cost of about 12K.&nbsp;&nbsp;My greatest =
concern=20
  lies in the length of time this has been in storage.=20
  <DIV></DIV>&gt;=20
  <DIV></DIV>&gt;I appreciate anyone's opinion and / or sources for a =
used=20
  IO-540.=20
  <DIV></DIV>&gt;=20
  <DIV></DIV>&gt;Thanks,=20
  <DIV></DIV>&gt;Joe=20
  <DIV></DIV></DIV><BR clear=3Dall>
  <HR>
  <A href=3D"http://g.msn.com/8HMBENUS/2737??PS=3D47575">Stop worrying =
about=20
  overloading your inbox - get MSN Hotmail Extra Storage!</A>=20
  _______________________________________________ To change your email =
address,=20
  visit http://www.tvbf.org/mailman/listinfo/reflector Visit the =
gallery!=20
  www.tvbf.org/gallery user:pw =3D tvbf:jamaicangoose Check new =
archives:=20
  www.tvbf.org/pipermail Check old archives:=20
  http://www.tvbf.org/archives/velocity/maillist.html =
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