Today's Message Index:
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1. 05:31 AM - High CHT on #2 mystery (Mark T. Mueller)
2. 06:19 AM - Re: High CHT on #2 mystery (flyv35b)
3. 11:08 AM - Re: High CHT on #2 mystery (Gary Vogt)
4. 11:08 AM - Re: High CHT on #2 mystery (Gary Vogt)
Message 1
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| Subject: | High CHT on #2 mystery |
Just picked 33R up from annual inspection yesterday, and when flying back
to my home 'drome I could not keep my #2 CHT under 400 regardless of power
setting, airspeed, or altitude. At 3500' and 2600 RPM in level cruise with
an OAT of 72F #2 hit 440!!! This was NOT the case before annual except in
extended climb. That cylinder is now running a good 30 - 40 hotter than
before annual. The rest of the cylinders are running close to where they
were before annual.
Oil temp stayed below 190.
I asked my IA what had been done, and he said the only thing he had to do
was adjust the timing on one mag by a couple degrees and replaced the
gasket on that mag. I have a LASAR ignition, and he allegedly used the
T-300 tool I provided.
The SB388C test was done, and he stated was well within tolerance, and good
comps on all cylinders.
Prior to annual, the #2 had a much higher EGT than the others, but normal
CHT. All four CHTs were within 20+- during normal cruise. Now they are a
good 40+ difference between #2 and coolest. Front cyls have always run
hotter than rear since my baffling was rebuilt during OH 4 years ago.
Now, the obvious answer is my timing is screwed up, but the motor is
running more smoothly and stronger than ever (smoother than before annual)
and I don't want to give that up. In addition, in my experience owning 33R
it is almost NEVER the "obvious" answer...
I still have to take a day off work and root around to see if there was any
damage to the front baffling when they reassembled the cowling or other
simple things (I am really hoping it's something simple).
Looking for ideas. It is clearly a thermodynamics problem, but what might
be the best way to approach this without sacrificing the best my motor has
run in a while?
Is it possible that low batteries in the T-300 tool might have caused an
error in adjusting timing?
What are common baffling issues that might contribute to such a dramatic
change in #2 CHT without significantly effecting the other cylinders?
Is it possible one cylinder is hypersensitive to timing over all the
others? If so, what might this indicate that doesn't show up on an SB388C
or other routine engine examination during annual?
Thanks in advance,
Mark T. Mueller
Tiger N1533R
Message 2
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| Subject: | Re: High CHT on #2 mystery |
On 3/18/2012 5:30 AM, Mark T. Mueller wrote:
> Just picked 33R up from annual inspection yesterday, and when flying
> back to my home 'drome I could not keep my #2 CHT under 400 regardless
> of power setting, airspeed, or altitude. At 3500' and 2600 RPM in level
> cruise with an OAT of 72F #2 hit 440!!! This was NOT the case before
> annual except in extended climb. That cylinder is now running a good 30
> - 40 hotter than before annual. The rest of the cylinders are running
> close to where they were before annual.
>
> Oil temp stayed below 190.
>
> I asked my IA what had been done, and he said the only thing he had to
> do was adjust the timing on one mag by a couple degrees and replaced the
> gasket on that mag. I have a LASAR ignition, and he allegedly used the
> T-300 tool I provided.
>
> The SB388C test was done, and he stated was well within tolerance, and
> good comps on all cylinders.
>
> Prior to annual, the #2 had a much higher EGT than the others, but
> normal CHT. All four CHTs were within 20+- during normal cruise. Now
> they are a good 40+ difference between #2 and coolest. Front cyls have
> always run hotter than rear since my baffling was rebuilt during OH 4
> years ago.
>
> Now, the obvious answer is my timing is screwed up, but the motor is
> running more smoothly and stronger than ever (smoother than before
> annual) and I don't want to give that up. In addition, in my experience
> owning 33R it is almost NEVER the "obvious" answer...
>
> I still have to take a day off work and root around to see if there was
> any damage to the front baffling when they reassembled the cowling or
> other simple things (I am really hoping it's something simple).
>
> Looking for ideas. It is clearly a thermodynamics problem, but what
> might be the best way to approach this without sacrificing the best my
> motor has run in a while?
>
> Is it possible that low batteries in the T-300 tool might have caused an
> error in adjusting timing?
>
> What are common baffling issues that might contribute to such a dramatic
> change in #2 CHT without significantly effecting the other cylinders?
>
> Is it possible one cylinder is hypersensitive to timing over all the
> others? If so, what might this indicate that doesn't show up on an
> SB388C or other routine engine examination during annual?
>
> Thanks in advance,
>
> Mark T. Mueller
> Tiger N1533R
>
Is your plane an AG-5B? What kind/brand of CHT/EGT instrumentation?
Cliff
Message 3
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| Subject: | Re: High CHT on #2 mystery |
I would double check the timing. -If it seems smoother, it's likely the t
iming was bumped up enough to make a difference. -It's all a compromise.
-EGT vs CHT.-=0A=0A=0A=0A________________________________=0A From: Mark
T. Mueller <mark.t.mueller@comcast.net>=0ATo: teamgrumman-list@matronics.c
om =0ASent: Sunday, March 18, 2012 5:30 AM=0ASubject: TeamGrumman-List: Hig
h CHT on #2 mystery=0A =0A=0AJust picked 33R up from annual inspection yest
erday, and when flying back to my home 'drome I could not keep my #2 CHT un
der 400 regardless of power setting, airspeed, or altitude. -At 3500' and
2600 RPM in level cruise with an OAT of 72F #2 hit 440!!! -This was NOT
the case before annual except in extended climb. -That cylinder is now ru
nning a good 30 - 40 hotter than before annual. -The rest of the cylinder
s are running close to where they were before annual.=0A=0AOil temp stayed
below 190.=0A=0A=0AI asked my IA what had been done, and he said the only t
hing he had to do was adjust the timing on one mag by a couple degrees and
replaced the gasket on that mag. -I have a LASAR ignition, and he alleged
ly used the T-300 tool I provided.=0A=0AThe SB388C test was done, and he st
ated was well within tolerance, and good comps on all cylinders.=0A=0APrior
to annual, the #2 had a much higher EGT than the others, but normal CHT.
-All four CHTs were within 20+- during normal cruise. -Now they are a g
ood 40+ difference between #2 and coolest. -Front cyls have always run ho
tter than rear since my baffling was rebuilt during OH 4 years ago.=0A=0ANo
w, the obvious answer is my timing is screwed up, but the motor is running
more smoothly and stronger than ever (smoother than before annual) and I do
n't want to give that up. -In addition, in my experience owning 33R it is
almost NEVER the "obvious" answer...=0A=0AI still have to take a day off w
ork and root around to see if there was any damage to the front baffling wh
en they reassembled the cowling or other simple things (I am really hoping
it's something simple).=0A=0ALooking for ideas. -It is clearly a thermody
namics problem, but what might be the best way to approach this without sac
rificing the best my motor has run in a while?=0A=0AIs it possible that low
batteries in the T-300 tool might have caused an error in adjusting timing
?=0A=0AWhat are common baffling issues that might contribute to such a dram
atic change in #2 CHT without significantly effecting the other cylinders?
=0A=0AIs it possible one cylinder is hypersensitive to timing over all the
others? -If so, what might this indicate that doesn't show up on an SB388
C or other routine engine examination during annual?=0A=0AThanks in advance
========
Message 4
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| Subject: | Re: High CHT on #2 mystery |
my guess, Cheetah with JPI=0A=0A=0A________________________________=0A From
: flyv35b <flyv35b@minetfiber.com>=0ATo: teamgrumman-list@matronics.com =0A
Sent: Sunday, March 18, 2012 6:19 AM=0ASubject: Re: TeamGrumman-List: High
yv35b@minetfiber.com>=0A=0AOn 3/18/2012 5:30 AM, Mark T. Mueller wrote:=0A>
Just picked 33R up from annual inspection yesterday, and when flying=0A> b
ack to my home 'drome I could not keep my #2 CHT under 400 regardless=0A> o
f power setting, airspeed, or altitude.- At 3500' and 2600 RPM in level
=0A> cruise with an OAT of 72F #2 hit 440!!!- This was NOT the case befor
e=0A> annual except in extended climb.- That cylinder is now running a go
od 30=0A> - 40 hotter than before annual.- The rest of the cylinders are
running=0A> close to where they were before annual.=0A>=0A> Oil temp stayed
below 190.=0A>=0A> I asked my IA what had been done, and he said the only
thing he had to=0A> do was adjust the timing on one mag by a couple degrees
and replaced the=0A> gasket on that mag.- I have a LASAR ignition, and h
e allegedly used the=0A> T-300 tool I provided.=0A>=0A> The SB388C test was
done, and he stated was well within tolerance, and=0A> good comps on all c
ylinders.=0A>=0A> Prior to annual, the #2 had a much higher EGT than the ot
hers, but=0A> normal CHT.- All four CHTs were within 20+- during normal c
ruise.- Now=0A> they are a good 40+ difference between #2 and coolest.-
Front cyls have=0A> always run hotter than rear since my baffling was rebu
ilt during OH 4=0A> years ago.=0A>=0A> Now, the obvious answer is my timing
is screwed up, but the motor is=0A> running more smoothly and stronger tha
n ever (smoother than before=0A> annual) and I don't want to give that up.
- In addition, in my experience=0A> owning 33R it is almost NEVER the "ob
vious" answer...=0A>=0A> I still have to take a day off work and root aroun
d to see if there was=0A> any damage to the front baffling when they reasse
mbled the cowling or=0A> other simple things (I am really hoping it's somet
hing simple).=0A>=0A> Looking for ideas.- It is clearly a thermodynamics
problem, but what=0A> might be the best way to approach this without sacrif
icing the best my=0A> motor has run in a while?=0A>=0A> Is it possible that
low batteries in the T-300 tool might have caused an=0A> error in adjustin
g timing?=0A>=0A> What are common baffling issues that might contribute to
such a dramatic=0A> change in #2 CHT without significantly effecting the ot
her cylinders?=0A>=0A> Is it possible one cylinder is hypersensitive to tim
ing over all the=0A> others?- If so, what might this indicate that doesn'
t show up on an=0A> SB388C or other routine engine examination during annua
l?=0A>=0A> Thanks in advance,=0A>=0A> Mark T. Mueller=0A> Tiger N1533R=0A>
=0AIs your plane an AG-5B?- What kind/brand of CHT/EGT instrumentation?
======================
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