Today's Message Index:
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1. 07:19 AM - Re: Tip of the Week - spark plug sockets (linn walters)
2. 07:31 AM - Re: Tip of the Week - spark plug sockets (Gil Alexander)
3. 08:38 AM - Re: Tip of the Week - spark plug sockets (flyv35b)
4. 09:41 AM - Re: Tip of the Week - spark plug sockets (linn walters)
Message 1
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| Subject: | Re: Tip of the Week - spark plug sockets |
--> TeamGrumman-List message posted by: linn walters <lwalters2@cfl.rr.com>
Gil Alexander wrote:
>--> TeamGrumman-List message posted by: Gil Alexander <gilalex@earthlink.net>
>
>
>Linn ...Sorry .... I should have said - lead fouling.
>
>The top plugs are REM40 (or maybe REM38, I need to check) and near perfect,
>the new REM37BY bottom plugs are lead fouled in 30 hrs.
>
Were they detectable during a mag check?
>You are right, I think I need to lean more aggressively.... I only monitor
>#4 for CHT/EGT, and I guess I listened to too many horror stories of
>burning up exhaust valves. On the vacation trip we just took (25 hrs in 2
>weeks) I leaned to peak rpm, and then pushed in 2 clicks.
>
This should work. I do that ALL the time .... taxi, takeoff,
cruise,landing, taxi ..... ALL the time. I pulled the mixture out on
the ground like you do (- 2 clicks) and painted the shaft with metal
blueing. I just pull it out to the same place each time after startup.
It'll change in cruise.
>Perhaps I should run at peak rpm??
>
I wouldn't do that. Your chance of burning a valve is higher.
>Before I pulled the plugs, I had a dynamic prop balance check, I didn't
>think the new plugs would foul that quickly.
>Balance was within spec. at 0.12, and no weights were added.
>
Don't know what the connection is ..... unless you were chasing vibration.
>
> ...gil A
>
>PS I have a PowerFlow exhaust installed. Engine is 1998 Lyc. O/H with 470 TTE
>
The 37BYs may still collect lead in the bottom. What makes them better
then the 40s is that the lead won't short out the plug because it's
hanging so far out there. The next time you pull the plugs, reattach
them to an impulse mag lead and hold the plug to ground. See what kind
of spark you get when the impulse fires. You could have a bad plug.
One other thought is that ylou have an intake leak that is causing the
engine to stumble while the other cylinders are still rich. Easy to
check. Clean out your shop-vac really good and convert it to blow.
Stuff the hose in the intake and pack with rags. Turn on the vac and
spray soapy water everywhere and look for bubbles. Good luck.
Linn
Message 2
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| Subject: | Re: Tip of the Week - spark plug sockets |
--> TeamGrumman-List message posted by: Gil Alexander <gilalex@earthlink.net>
At 10:20 AM 10/9/2003 -0400, you wrote:
>One other thought is that you have an intake leak that is causing the
>engine to stumble while the other cylinders are still rich.
Linn,
Would this show up in the plugs, with the leaner cylinder plug
looking different?
gil A
77 Tiger, N28478, at 57AZ
<html>
<font size=3>At 10:20 AM 10/9/2003 -0400, you wrote:<br>
<blockquote type=cite class=cite cite>One other thought is that you have
an intake leak that is causing the <br>
engine to stumble while the other cylinders are still rich.
</font></blockquote><br>
Linn,<br>
Would this show up in
the plugs, with the leaner cylinder plug looking different?<br>
<br>
gil A<br>
<br>
<x-sigsep><p></x-sigsep>
<font size=3><i>77 Tiger, N28478, at 57AZ </font></i></html>
Message 3
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| Subject: | Re: Tip of the Week - spark plug sockets |
--> TeamGrumman-List message posted by: "flyv35b" <flyv35b@juno.com>
> You are right, I think I need to lean more aggressively.... I only monitor
> #4 for CHT/EGT, and I guess I listened to too many horror stories of
> burning up exhaust valves. On the vacation trip we just took (25 hrs in 2
> weeks) I leaned to peak rpm, and then pushed in 2 clicks.
> Perhaps I should run at peak rpm??
>
You are running WAY to rich and leaning would definetely help the lead
fouling problem.
If you read Lycoming's discussion about leaning and look at the EGT, CHT and
power curves that they publish in their engine operator's manual you will
note that operating on the rich side of best power (maximum rpm) is very
rich and not recommended. Lycoming allows operation AT PEAK EGT at power
settings of 75% and lower. And this means that you lean until engine
roughness is noted and then enrichen JUST ENOUGH to obtain smooth operation.
This might mean only one click or possibly 2 on the mixture control. If you
have an EGT gauge you will see that 2 clicks makes a very significant
reduction in EGT temperature, possibly 75F. Best power (max. RPM) occurs at
about 125F below peak EGT and with another 2 clicks rich you are probably
running at about 200F below peak EGT, when you want to be running right at
peak EGT. You will also note from the curve that at peak EGT the cylinder
head temperature is significantly lower than at best power mixture. So you
are doing you engine a favor by running leaner because the CHTs are lower
and their are much less DEPOSITS forming on the pistons, valves and plugs as
well as contamination of the oil. And you will obtain much lower fuel
consumption by operating this way, possibly about 2 GPH. If you have a fuel
flow gauge such as the JPI FS-450 or EI FP-5L you will readily see the
relationship that mixture has on EGT, CHT and fuel flow and it is rather
shocking. You can also then use Lycoming's LEAN fuel flow figures in the
performance section of your POH as a close guide on how to adjust the
mixture setting and then taylor it from there with EGT info and smooth
operation.
With a carbureted engine which has poor mixture distribution (variation from
one cylinder to another) you can operate at peak EGT (or close to peak) with
probably only one or maybe two cylinders and therefore have to settle for
operating as lean as possible and still obtain smooth operation. Some
cylinders will be on the rich side and operating richer than desired but
there is essentially nothing you can do about that. By operating this way
you should be able to run as much as 100hr without fouling or cleaning your
spark plugs. I have done this many times even with the standard REM38E
plugs on a Tiger. A 150 hp Cheetah will probably require more often plug
cleaning when operated on 100LL since it was designed for 80 octane and
doesn't like lead as well. But the higher EGTs will keep the plugs and
other parts cleaner than running to rich. And at the lower power settings
their is nothing that you can do that will result in detonation IF the
ignition system is maintained properly.
Cliff A&P/IA
----- Original Message -----
From: "Gil Alexander" <gilalex@earthlink.net>
Subject: Re: TeamGrumman-List: Tip of the Week - spark plug sockets
> --> TeamGrumman-List message posted by: Gil Alexander
<gilalex@earthlink.net>
>
>
> Linn ...Sorry .... I should have said - lead fouling.
>
> The top plugs are REM40 (or maybe REM38, I need to check) and near
perfect,
> the new REM37BY bottom plugs are lead fouled in 30 hrs.
>
> You are right, I think I need to lean more aggressively.... I only monitor
> #4 for CHT/EGT, and I guess I listened to too many horror stories of
> burning up exhaust valves. On the vacation trip we just took (25 hrs in 2
> weeks) I leaned to peak rpm, and then pushed in 2 clicks.
> Perhaps I should run at peak rpm??
>
> Before I pulled the plugs, I had a dynamic prop balance check, I didn't
> think the new plugs would foul that quickly.
> Balance was within spec. at 0.12, and no weights were added.
>
> ...gil A
>
> PS I have a PowerFlow exhaust installed. Engine is 1998 Lyc. O/H with
470 TTE
>
> At 01:16 AM 10/9/2003 -0400, you wrote:
> >--> TeamGrumman-List message posted by: linn walters
<lwalters2@cfl.rr.com>
> >
> >Gil Alexander wrote:
> >
> > >--> TeamGrumman-List message posted by: Gil Alexander
> > <gilalex@earthlink.net>
> > >
> > >
> > >Guys,
> > > Another option...
> > >
> > >1. Buy Autolite (Unison) spark plugs - the preferred REM37BY.
> > >2. Take a 7/8 deep socket and trim it's length to 2 3/4 inches (mine
was
> > >3 1/4 inches)
> > >
> > > In concert with the shorter Autolite plugs, this cut down socket
can
> > >now be used with a regular handle and still fit down inside the baffles
on
> > >#3 and #4 cylinders.
> > >
> > > No special tools needed, I just used cut-off wheel in my trusty
> > >Dremel. just make sure your deep socket has it's flutes going down
deep
> > >into the socket so it will grip after you cut it down. My Craftsman
deep
> > >socket was OK, but a cheapo Chinese socket was not modifiable.
> > >
> > > ...hope this helps someone.....
> > >
> > > gil in Tucson...
> > >making a new #2 cylinder baffle that was screwed up by previous baffle
> > work...
> > >...and I'm still fouling the lower plugs - even with REM37BY's ...:^(
> > >
> >Fouling with what? REM37BY's won't help with oil ...... but will help
> >with lead fouling. But then so will agressive leaning. :-D .
> >Linn
> >
> >
>
>
> <html>
> <font size=3>Linn ...Sorry .... I should have said - lead
> fouling. <br>
> <br>
> The top plugs are REM40 (or maybe REM38, I need to check) and near
> perfect, the new REM37BY bottom plugs are lead fouled in 30 hrs.<br>
> <br>
> You are right, I think I need to lean more aggressively.... I only
> monitor #4 for CHT/EGT, and I guess I listened to too many horror stories
> of burning up exhaust valves. On the vacation trip we just took (25
> hrs in 2 weeks) I leaned to peak rpm, and then pushed in 2 clicks.<br>
> Perhaps I should run at peak rpm??<br>
> <br>
> Before I pulled the plugs, I had a dynamic prop balance check, I didn't
> think the new plugs would foul that quickly. <br>
> Balance was within spec. at 0.12, and no weights were added.<br>
> <br>
> ...gil A<br>
> <br>
> PS I have a PowerFlow exhaust installed. Engine is 1998 Lyc.
> O/H with 470 TTE<br>
> <br>
> At 01:16 AM 10/9/2003 -0400, you wrote:<br>
> <blockquote type=cite class=cite cite>--> TeamGrumman-List message
> posted by: linn walters <lwalters2@cfl.rr.com><br>
> <br>
> Gil Alexander wrote:<br>
> <br>
> >--> TeamGrumman-List message posted by: Gil Alexander
> <gilalex@earthlink.net><br>
> ><br>
> ><br>
> >Guys,<br>
> > Another option...<br>
> ><br>
> >1. Buy Autolite (Unison) spark plugs - the preferred
> REM37BY.<br>
> >2. Take a 7/8 deep socket and trim it's length to 2 3/4
> inches (mine was <br>
> >3 1/4 inches)<br>
> ><br>
> > In concert with the shorter
> Autolite plugs, this cut down socket can <br>
> >now be used with a regular handle and still fit down inside the
> baffles on <br>
> >#3 and #4 cylinders.<br>
> ><br>
> > No special tools needed, I just
> used cut-off wheel in my trusty <br>
> >Dremel. just make sure your deep socket has it's flutes going
> down deep <br>
> >into the socket so it will grip after you cut it down. My
> Craftsman deep <br>
> >socket was OK, but a cheapo Chinese socket was not modifiable.<br>
> ><br>
> > ...hope this helps
> someone.....<br>
> ><br>
> > gil in
> Tucson...<br>
> >making a new #2 cylinder baffle that was screwed up by previous
> baffle work...<br>
> >...and I'm still fouling the lower plugs - even with REM37BY's
> ...:^(<br>
> ><br>
> Fouling with what? REM37BY's won't help with oil ......
> but will help <br>
> with lead fouling. But then so will agressive leaning. :-D .<br>
> Linn<br>
> <br>
> <br>
> - The TeamGrumman-List Email Forum -<br>
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Message 4
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| Subject: | Re: Tip of the Week - spark plug sockets |
--> TeamGrumman-List message posted by: linn walters <lwalters2@cfl.rr.com>
Gil Alexander wrote:
>--> TeamGrumman-List message posted by: Gil Alexander <gilalex@earthlink.net>
>
>
>At 10:20 AM 10/9/2003 -0400, you wrote:
>
>
>>One other thought is that you have an intake leak that is causing the
>>engine to stumble while the other cylinders are still rich.
>>
>>
>
>Linn,
> Would this show up in the plugs, with the leaner cylinder plug
>looking different?
>
> gil A
>
>
>77 Tiger, N28478, at 57AZ
>
>
Can't really say since other factors such as ring sealing etc. also play
a part in the color of the plug tips, but it might. the problem is
comparing the slight difference in tan color between plugs. Couldn't
hurt to take a look, though!!!
Linn
<html>
<head>
<title></title>
</head>
<body text="#000000" bgcolor="#ffffff">
Gil Alexander wrote:<br>
<blockquote type="cite"
cite="mid200310091431.h99EVkp01322@matronics.com">
<pre wrap="">--> TeamGrumman-List message posted by: Gil Alexander <a class="moz-txt-link-rfc2396E" href="mailto:gilalex@earthlink.net"><gilalex@earthlink.net></a>
At 10:20 AM 10/9/2003 -0400, you wrote:
</pre>
<blockquote type="cite">
<pre wrap="">One other thought is that you have an intake leak that is causing
the
engine to stumble while the other cylinders are still rich.
</pre>
</blockquote>
<pre wrap=""><!---->
Linn,
Would this show up in the plugs, with the leaner cylinder plug
looking different?
gil A
77 Tiger, N28478, at 57AZ
</pre>
</blockquote>
Can't really say since other factors such as ring sealing etc. also
play a part in the color of the plug tips, but it might. the problem
is comparing the slight difference in tan color between plugs.
Couldn't hurt to take a look, though!!!<br>
Linn<br>
</body>
</html>
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