Why is LOP (lean of peak) controversial?

[Andrew Gideon]

I'm not asking about LOP itself, but why it's so "hot" <snicker> a topic.
It would seem to be a simple thing to me: the cylinders run at decent
temperatures LOP or they do not. What else is there?

I know at least one person in person, and others from their postings, that
are getting success running LOP. I also know at least two persons that
think that LOP is some myth that kills cylinders. One of those two people
tells a story of someone that bought gami injectors, ran LOP, and then
cooked four of six cylinders.

What I don't understand - and what that person hasn't answered, BTW,
perhaps because he doesn't know - is why that person that "cooked" four
cylinders would have failed to see a problem immediately on his CHT probes.

So...what am I missing?

- Andrew

[[email protected]]

Because in years past, several respected gurus of the GA field had
stated that LOP would "burn the engine up" if you did it, and
recommended running ROP. In fact, Lycoming actually recommended running
50 deg ROP at full power operation, which G. Braly's research has shown
is the absolute worst place to run. Many are probably just trying to
cover their ass for being so wrong in the past. At least that is my
take, since I believe as you do that it is either true or it isn't.
Good point.

Bud


Andrew Gideon wrote:
> I'm not asking about LOP itself, but why it's so "hot" <snicker> a topic.
> It would seem to be a simple thing to me: the cylinders run at decent
> temperatures LOP or they do not. What else is there?
>
> I know at least one person in person, and others from their postings, that
> are getting success running LOP. I also know at least two persons that
> think that LOP is some myth that kills cylinders. One of those two people
> tells a story of someone that bought gami injectors, ran LOP, and then
> cooked four of six cylinders.
>
> What I don't understand - and what that person hasn't answered, BTW,
> perhaps because he doesn't know - is why that person that "cooked" four
> cylinders would have failed to see a problem immediately on his CHT probes.
>
> So...what am I missing?
>
> - Andrew

[Mark Hansen]

On 09/26/06 15:38, Andrew Gideon wrote:
> I'm not asking about LOP itself, but why it's so "hot" <snicker> a topic.
> It would seem to be a simple thing to me: the cylinders run at decent
> temperatures LOP or they do not. What else is there?
>
> I know at least one person in person, and others from their postings, that
> are getting success running LOP. I also know at least two persons that
> think that LOP is some myth that kills cylinders. One of those two people
> tells a story of someone that bought gami injectors, ran LOP, and then
> cooked four of six cylinders.
>
> What I don't understand - and what that person hasn't answered, BTW,
> perhaps because he doesn't know - is why that person that "cooked" four
> cylinders would have failed to see a problem immediately on his CHT probes.
>
> So...what am I missing?
>
> - Andrew
>

I think John Deakin covered this topic in one of his columns. He explained
why most of the POHs are worded the way they are, even when it doesn't make
sense. For example, have a look at this article (I think this is the right
one - I can't find the index to his articles on the AVWeb site any longer):

<http://www.avweb.com/news/pelican/186216-1.html>

My impression of the point he tried to make was that the manufacturers
believe LOP operations is hard to get right unless you really know what
you're doing (and have the proper measuring equipment, i.e.: EGT) and that
ROP operations is "safer" from a legal standpoint.

.... but it's been a while since I've read his articles on the topic, so
I could be off here.

--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

[Peter R.]

Andrew Gideon > wrote:

> I know at least one person in person, and others from their postings, that
> are getting success running LOP.

You can add me to the list of aircraft owners who religiously run LOP. I
bought my aircraft from a pilot who also operated the engine LOP, and I was
able to get about 2,600 hours out of an engine that had an 1,800 hours TBO.
In the interest of full disclosure there was some cylinder work done to the
engine early on, but I can guarantee it was not because a cylinder got
cooked. It probably had to do with the fact that they were Continental
cylinders. :)

In my case, my engine's cylinder head temperatures rarely get above 310
degrees F and most times operate in the 285 degree F range during cruise
flight. The times they do climb to 310 or 320 degrees F is when I am
climbing to altitude on a very hot day.

One note: Running LOP requires a meticulously maintained ignition system.
Plugs need to be cleaned every 100 hours or so, plug wires need to be
inspected and replaced if needed, magnetos have to be operating to
capacity, and capacitors cannot fail.

Something as simple as one fouled plug can result in unacceptably high
exhaust gas temperatures that lead to a higher than desired turbo-inlet
temperatures.

> I also know at least two persons that
> think that LOP is some myth that kills cylinders. One of those two people
> tells a story of someone that bought gami injectors, ran LOP, and then
> cooked four of six cylinders.

Without knowing their specifics, I can say with experience of operating a
turbo-normalized Bonanza that running LOP does introduce the RISK of
cooking cylinders, but this risk is easily managed, in part, by including
the engine analyzer in one's scan every minute or two.

Leaning to a lean of peak temperature involves pulling the mixture PAST
peak temperature to a relative fuel flow, then allowing airspeed and engine
temperatures to stabilize (perhaps a few minutes of level flight). Once
stable, the mixture is then enrichened to peak temperature in order to
discover peak temperature and then steadily but without delay leaned back
to about 75 degrees lean of peak.

Constant monitoring of the engine analyzer gauge and fine tuning of the
mixture knob is mandatory.

Changing altitudes (usually descending), even in my turbo-normalized
aircraft, does require a slight change in mixture or temperatures can begin
to climb.

> What I don't understand - and what that person hasn't answered, BTW,
> perhaps because he doesn't know - is why that person that "cooked" four
> cylinders would have failed to see a problem immediately on his CHT probes.

My speculation is that it could be one of three reasons. First, but most
unlikely, perhaps the probes were incorrectly installed. Second, maybe
this owner failed to monitor his engine analyzer often enough, which could
be a result of the location of the gauge in the panel or simply the pilot's
weaker instrument scanning discipline. And thirdly, this owner may not
have had the engine analyzer high-temperature alarms properly set up?
Again, just speculation here.

--
Peter

[Peter R.]

"Peter R." > wrote:

> In my case, my engine's cylinder head temperatures rarely get above 310
> degrees F and most times operate in the 285 degree F range during cruise
> flight. The times they do climb to 310 or 320 degrees F is when I am
> climbing to altitude on a very hot day.

I should have included that 380 degrees F is considered the absolute top
end of the safe temperature curve, at least according to Tornado Alley
Turbo and GAMI, both of whom have done extensive testing of LOP operations.

Even on a hot day at higher density altitude (and effectively less ram air
cooling), 320 degrees F is the highest I have seen my cylinder head
temperatures reach.

--
Peter

[tony roberts[_1_]]

> So...what am I missing?
>
> - Andrew


Hi Andrew

Google Walter Atkinson LOP.
He is the most knowledgeable that I know of on aircraft engines and is
always happy to discuss engine questions - especially LOP.
If you just want to read what he has to say, search the archives in the
Cessna and Piper groups.

HTH

Tony

--

Tony Roberts
PP-ASEL
VFR OTT
Night
Cessna 172H C-GICE

[Matt Barrow]

"Mark Hansen" > wrote in message
...
>
> I think John Deakin covered this topic in one of his columns. He explained
> why most of the POHs are worded the way they are, even when it doesn't
> make
> sense. For example, have a look at this article (I think this is the right
> one - I can't find the index to his articles on the AVWeb site any
> longer):

http://www.avweb.com/news/pelican/

>
> <http://www.avweb.com/news/pelican/186216-1.html>
>
> My impression of the point he tried to make was that the manufacturers
> believe LOP operations is hard to get right unless you really know what
> you're doing (and have the proper measuring equipment, i.e.: EGT) and that
> ROP operations is "safer" from a legal standpoint.
>
> ... but it's been a while since I've read his articles on the topic, so
> I could be off here.

Read #8, 15, 16 and particularly #18. Those are the basis of the Advanced
Pilot Seminars http://www.advancedpilot.com/index.html (Well worth a couple
thousand $$ to protect a $25-30K engine...not to mention your butt).

If applicable, read the Turbo's series, #31-36, and #59, 63,64 as well.

--
Matt
---------------------
Matthew W. Barrow
Site-Fill Homes, LLC.
Montrose, CO (MTJ)

[Dan Luke]

"Andrew Gideon" wrote:

>
> One of those two people tells a story of someone that bought gami
> injectors, ran LOP, and then cooked four of six cylinders.


Another example of how a little knowledge is a dangerous thing.

*Improper* LOP operating technique can harm cylinders, even cause
catastrophic failure by detonation.

--
Dan
C172RG at BFM

[Andrew Gideon]

On Wed, 27 Sep 2006 09:20:12 -0500, Dan Luke wrote:

> *Improper* LOP operating technique can harm cylinders, even cause
> catastrophic failure by detonation.

Hmm. Detonation, if I follow all this correctly, yields lower EGTs. So
someone leaning by EGT could be fooled into thinking that all is well,
even while cylinders are being damaged. This is exactly the type of idea
I was missing; now I think I see.

But CHT goes up, right? Would it go up enough (ie. beyond 400) to raise a
pilot's concern?

- Andrew

[Matt Barrow]

"Andrew Gideon" > wrote in message
...
> On Wed, 27 Sep 2006 09:20:12 -0500, Dan Luke wrote:
>
>> *Improper* LOP operating technique can harm cylinders, even cause
>> catastrophic failure by detonation.
>
> Hmm. Detonation, if I follow all this correctly, yields lower EGTs. So
> someone leaning by EGT could be fooled into thinking that all is well,
> even while cylinders are being damaged. This is exactly the type of idea
> I was missing; now I think I see.
>
> But CHT goes up, right? Would it go up enough (ie. beyond 400) to raise a
> pilot's concern?
>

http://www.avweb.com/news/pelican/182132-1.html

Pelican's Perch #43:
Detonation Myths

We've all been taught about detonation in piston aircraft engines. It's what
occurs when combustion pressure and temperature get so high that the
fuel/air mixture to explodes violently instead of burning smoothly, and it
can destroy an engine in a matter of seconds. Right? Well, not exactly.
AVweb's John Deakin reviews the latest research, and demonstrates that
detonation occurs in various degrees - much like icing and turbulence - with
the milder forms not being particularly harmful. Heavy detonation is
definitely destructive, and the Pelican offers some concrete data on how to
avoid it.
---------------------

[Matt Barrow]

"Dan Luke" > wrote in message
...
>
> "Andrew Gideon" wrote:
>
>>
>> One of those two people tells a story of someone that bought gami
>> injectors, ran LOP, and then cooked four of six cylinders.
>
>
> Another example of how a little knowledge is a dangerous thing.
>
> *Improper* LOP operating technique can harm cylinders, even cause
> catastrophic failure by detonation.
>
As can *proper* ROP operating techniques...particularly the 50ROP as
recommended by some POH's.

The biggest problem is getting LOP, then enriching "just to be on the safe
side", usually right into the worst possible operating range.

[Matt Barrow]

"Peter R." > wrote in message
...
> "Peter R." > wrote:
>
>> In my case, my engine's cylinder head temperatures rarely get above 310
>> degrees F and most times operate in the 285 degree F range during cruise
>> flight. The times they do climb to 310 or 320 degrees F is when I am
>> climbing to altitude on a very hot day.
>
> I should have included that 380 degrees F is considered the absolute top
> end of the safe temperature curve, at least according to Tornado Alley
> Turbo and GAMI, both of whom have done extensive testing of LOP
> operations.
>
> Even on a hot day at higher density altitude (and effectively less ram air
> cooling), 320 degrees F is the highest I have seen my cylinder head
> temperatures reach.

What % of power are you using? I'm usually around 360-370, but I'm running
70-75%.

[Peter R.]

Matt Barrow > wrote:

> What % of power are you using? I'm usually around 360-370, but I'm running
> 70-75%.

I also cruise around 75% of the IO-520's 285 hp.

--
Peter

[Jon Kraus]

I ussed to be timid on the "red knob" easing it out until I hit peak EGT
and then kept going until I would get 20 degrees or more LOP and then
stay there. That technique though probably OK, kept me in the red box a
little longer than I preferred.

My current technique is to get to cruising altitude and then do "the big
pull" on the mixuture until a definite power loss is noticed. I know
know I am way on the LOP side so I come in a tad to smooth it out and
note the EGT and CYL head temps. Both are nice and cool ( CYL < 400 &
EGT < 1400). I'm usually cruising at 150 + KIAS nad 9 GPH. Gotta love
those Mooney's.

Jon Kraus
'79 Mooney 201
4443H @ UMP

Dan Luke wrote:
> "Andrew Gideon" wrote:
>
>
>>One of those two people tells a story of someone that bought gami
>>injectors, ran LOP, and then cooked four of six cylinders.
>
>
>
> Another example of how a little knowledge is a dangerous thing.
>
> *Improper* LOP operating technique can harm cylinders, even cause
> catastrophic failure by detonation.
>

[Thomas Borchert]

Andrew,

> So...what am I missing?
>

The inertia of the pilot population, myths, misinformation, engine
manufacturer's law departments - all factors. "Show me the numbers" is
the old trick to silence the LOP opponents. They can't.

I take it you are familiar with John Deakin's columns on the topic and
engine management in general at avweb.com?

--
Thomas Borchert (EDDH)

[[email protected]]

: I take it you are familiar with John Deakin's columns on the topic and
: engine management in general at avweb.com?

These articles basically say:

- LOP done improperly *WILL* damage engines. Only at 75% or less can it be done
safely.
- Absolute EGT doesn't matter... CHT primarily controls detonation margin, top end
longevity, and exhaust valve temperatures. (Lycoming and Cont have too high of
redlines... 400 CHT is as high as should be periodically seen... 375 max continuous)
- ANY leaks in ANY valves are unacceptable and will cause damage, LOP or not.
- ROP provides the most power for a single "power setting" (i.e. MP+RPM setting...
*actual* power setting also includes the mixture). Thus marketing likes ROP since it
makes the plane go faster on paper.

I use these articles (and Lycomings recommendations) to operate my 180 hp
Lycoming O-360. It's carb'd so LOP doesn't quite get there. Below 75%, I can do
anything I want with the mixture so long as CHT stays cool enough. I typically
consider 65% power and 350 CHT my maximums. At those settings, I can lean to
where there is a noticable power loss, but before it's rough, and 8-8.5 gph.

-Cory

--

************************************************** ***********************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[Matt Barrow]

"Peter R." > wrote in message
...
> Matt Barrow > wrote:
>
>> What % of power are you using? I'm usually around 360-370, but I'm
>> running
>> 70-75%.
>
> I also cruise around 75% of the IO-520's 285 hp.
>
What altitude? FF?

[Peter R.]

Matt Barrow > wrote:

> "Peter R." > wrote in message
> ...
>> Matt Barrow > wrote:
>>
>>> What % of power are you using? I'm usually around 360-370, but I'm
>>> running
>>> 70-75%.
>>
>> I also cruise around 75% of the IO-520's 285 hp.
>>
> What altitude? FF?

In summer temperatures at 12,000-15,000 feet I get about 187-190 kts TAS at
about 15 gph. In the winter, I see 175-180 kts TAS and 16.5 gph or so.

--
Peter

[Doug[_1_]]

One thing no one has mentioned is LOP may not be possible with
carbureted engines. The flows to each cylinder just aren't consistent
enough to make it work. Also you really need CHT and EGT guage on each
cylinder to do it right. The problem with LOP, isn't running LOP, its
that you are running peak and THINKING you are running LOP. The same
could be said of running rich of peak too. Running AT peak is really
only a problem at higher power settings. So most of this LOP stuff is
really for turbocharged fuel injected engines. I said MOST. Some people
with just fuel injection use LOP and a FEW at least claim to use it
with carburetion.

LOP works, but I think you have to really know what you are doing and
have the right equipment. But if you are running at 65% power or below,
it doesn't hurt to try it, no matter what sort of equipment you have
(unless of course you dont even have a mixture knob :-))

Thomas Borchert wrote:
> Andrew,
>
> > So...what am I missing?
> >
>
> The inertia of the pilot population, myths, misinformation, engine
> manufacturer's law departments - all factors. "Show me the numbers" is
> the old trick to silence the LOP opponents. They can't.
>
> I take it you are familiar with John Deakin's columns on the topic and
> engine management in general at avweb.com?
>
> --
> Thomas Borchert (EDDH)

[Mark Hansen]

On 09/26/06 15:38, Andrew Gideon wrote:
> I'm not asking about LOP itself, but why it's so "hot" <snicker> a topic.
> It would seem to be a simple thing to me: the cylinders run at decent
> temperatures LOP or they do not. What else is there?
>
> I know at least one person in person, and others from their postings, that
> are getting success running LOP. I also know at least two persons that
> think that LOP is some myth that kills cylinders. One of those two people
> tells a story of someone that bought gami injectors, ran LOP, and then
> cooked four of six cylinders.
>
> What I don't understand - and what that person hasn't answered, BTW,
> perhaps because he doesn't know - is why that person that "cooked" four
> cylinders would have failed to see a problem immediately on his CHT probes.
>
> So...what am I missing?
>
> - Andrew
>

How's this for timing. Mike Busch at AVWeb just wrote a new "The Savvy Aviator"
column on this very topic. Have a look:

<http://www.avweb.com/news/savvyaviator/193242-1.html>



--
Mark Hansen, PP-ASEL, Instrument Airplane
Cal Aggie Flying Farmers
Sacramento, CA

[[email protected]]

Doug > wrote:
: One thing no one has mentioned is LOP may not be possible with
: carbureted engines. The flows to each cylinder just aren't consistent
: enough to make it work. Also you really need CHT and EGT guage on each
: cylinder to do it right. The problem with LOP, isn't running LOP, its
: that you are running peak and THINKING you are running LOP. The same
: could be said of running rich of peak too. Running AT peak is really
: only a problem at higher power settings. So most of this LOP stuff is
: really for turbocharged fuel injected engines. I said MOST. Some people
: with just fuel injection use LOP and a FEW at least claim to use it
: with carburetion.

: LOP works, but I think you have to really know what you are doing and
: have the right equipment. But if you are running at 65% power or below,
: it doesn't hurt to try it, no matter what sort of equipment you have
: (unless of course you dont even have a mixture knob :-))

I guess that's what I was trying to say. I'm assuming that most people
reading the thread know that carb'd engines (particularly 6's) generally have too poor
fuel/air distribution between the cylinders to run LOP.

I do know that I am running about half of my cylinders slightly LOP and about
half AT peak. Although the EGT is higher than LOP, the CHT is *lower*, and thus
should have cooler exhaust valves (or at least about the same). That's also why I
tend to limit myself to 65-70% at most. A little safety margin. Besides for my bird
(PA-28), the airframe doesn't buy much speed increase from 65-75% on a 180hp engine.
It's not worth the extra fuel burn for the additional 5 mph or so.

Again, the *at peak* operating condition is mentioned in one of the Lycoming
publications as the "best economy cruise" setting and is considered acceptable.

-Cory

--

************************************************** ***********************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[Andrew Gideon]

On Thu, 28 Sep 2006 08:07:22 -0700, Mark Hansen wrote:

> How's this for timing. Mike Busch at AVWeb just wrote a new "The Savvy
> Aviator" column on this very topic. Have a look:
>
> <http://www.avweb.com/news/savvyaviator/193242-1.html>

I'd just read it this morning. It doesn't actually address the aspect
that's leaving me puzzled: how someone can complain about "burning
cylinders" w/o seeing this ahead of time on an engine monitor.

But I think I saw one possible answer in this thread: if detonation is
occurring, EGTs (the metric used because it is quickly responsive to
mixture change) will drop but CHTs will - less quickly - go up. Someone
posted that detonation can ruin a cylinder very quickly (ie. a small
number of minutes, as I interpreted what I read).

So someone might not have evidence of detonation until it is too late.

Is this correct, or have I missed/misunderstood some aspect?

I still don't quite get why LOP would bring on detonation (even after
reading http://www.avweb.com/news/pelican/182132-1.html but I'm still
digesting parts of it).

- Andrew

[RK Henry]

On 28 Sep 2006 07:58:18 -0700, "Doug" >
wrote:

>One thing no one has mentioned is LOP may not be possible with
>carbureted engines. The flows to each cylinder just aren't consistent
>enough to make it work.

This may not be a problem if you're flying with autogas. I've noticed
in my Warrior that leaning too much causes roughness and missing when
flying with 100LL. I'm sure that everyone else has noticed the same
thing. When running on autogas, you can lean aggressively and the
engine continues to run smoothly. I've wondered what causes the
difference, and how much I can take advantage of it without proper
instrumentation. I've read that generally you can lean as aggressively
you want as long as you're below 75% power.

I've wondered if the smoothness might be due to cleaner plugs, but
100LL causes lean roughness even with new plugs. I've also wondered if
those ads that the oil companies used to run about their gasolines
making your car's engine run smoother due to better fuel distribution
suggest an explanation of the difference. I've suspected that this
might explain it. If true, it might be another reason to get the
autogas STC--better fuel economy.

RK Henry

[[email protected]]

: This may not be a problem if you're flying with autogas. I've noticed
: in my Warrior that leaning too much causes roughness and missing when
: flying with 100LL. I'm sure that everyone else has noticed the same
: thing. When running on autogas, you can lean aggressively and the
: engine continues to run smoothly. I've wondered what causes the
: difference, and how much I can take advantage of it without proper
: instrumentation. I've read that generally you can lean as aggressively
: you want as long as you're below 75% power.

... *and* <400 degrees CHT.

: I've wondered if the smoothness might be due to cleaner plugs, but
: 100LL causes lean roughness even with new plugs. I've also wondered if
: those ads that the oil companies used to run about their gasolines
: making your car's engine run smoother due to better fuel distribution
: suggest an explanation of the difference. I've suspected that this
: might explain it. If true, it might be another reason to get the
: autogas STC--better fuel economy.

I haven't really noticed much different in mine whether running autogas or
100LL. One possible reason could be vapor pressure. I bought the vapor pressure
tester along with my autogas STC just so I could check for vapor-lock in the summer.
The 100LL has a slightly lower volatility than the autogas, at least here. If to
autogas vaporizes better and easier, it could do it sooner out of the carb jet and
make for a better distribution.

-Cory

--

************************************************** ***********************
* Cory Papenfuss, Ph.D., PPSEL-IA *
* Electrical Engineering *
* Virginia Polytechnic Institute and State University *
************************************************** ***********************

[[email protected]]

Peter R. wrote:
> Matt Barrow > wrote:
>
> > "Peter R." > wrote in message
> > ...
> >> Matt Barrow > wrote:
> >>
> >>> What % of power are you using? I'm usually around 360-370, but I'm
> >>> running
> >>> 70-75%.
> >>
> >> I also cruise around 75% of the IO-520's 285 hp.
> >>
> > What altitude? FF?
>
> In summer temperatures at 12,000-15,000 feet I get about 187-190 kts TAS at
> about 15 gph. In the winter, I see 175-180 kts TAS and 16.5 gph or so.
>
> --
> Peter

Unless the LOP "formulas" have changed (which IS entirely possible,
been a few years since I had to think/worry about it) anything much
over 14.5 GPH would be considered higher than 75% power.

285 HP x .75 = 213.75 HP / 14.9 HP/G = approx 14.3 GPH @ 75% operating
LOP

If your CHT's are closer to 300 F than 400 F running those settings,
you've got one of the "cooler" installations that I've ever heard of...

TC

[Peter R.]

" > wrote:

> If your CHT's are closer to 300 F than 400 F running those settings,
> you've got one of the "cooler" installations that I've ever heard of...

The cylinders are new Superior Millennium cylinders with about 250 hours on
them, if that has anything to do with the cooler temperatures.

And yes, my engine's CHTs are normally below or around 300 and have never
approached 400, routinely. If you would like some verification of this, I
would be happy to upload my engine monitor data (from several months ago, I
have yet to download a current set), which is in the latest JPI format, to
a free host site for anyone's perusal.

--
Peter

[karl gruber[_1_]]

You more than likely have an CHT indication problem. There is no reason your
airplane should run much cooler than the fleet.

Karl


"Peter R." > wrote in message
...
> " > wrote:
>
>> If your CHT's are closer to 300 F than 400 F running those settings,
>> you've got one of the "cooler" installations that I've ever heard of...
>
> The cylinders are new Superior Millennium cylinders with about 250 hours
> on
> them, if that has anything to do with the cooler temperatures.
>
> And yes, my engine's CHTs are normally below or around 300 and have never
> approached 400, routinely. If you would like some verification of this, I
> would be happy to upload my engine monitor data (from several months ago,
> I
> have yet to download a current set), which is in the latest JPI format, to
> a free host site for anyone's perusal.
>
> --
> Peter

[Ray Andraka]

Peter R. wrote:
> " > wrote:
>
>
>>If your CHT's are closer to 300 F than 400 F running those settings,
>>you've got one of the "cooler" installations that I've ever heard of...
>
>
> The cylinders are new Superior Millennium cylinders with about 250 hours on
> them, if that has anything to do with the cooler temperatures.
>
> And yes, my engine's CHTs are normally below or around 300 and have never
> approached 400, routinely. If you would like some verification of this, I
> would be happy to upload my engine monitor data (from several months ago, I
> have yet to download a current set), which is in the latest JPI format, to
> a free host site for anyone's perusal.
>

Is your JPI set up for the correct probe type? Your CHTs sound awful low

[[email protected]]

Peter R. wrote:
> " > wrote:
>
> > If your CHT's are closer to 300 F than 400 F running those settings,
> > you've got one of the "cooler" installations that I've ever heard of...
>
> The cylinders are new Superior Millennium cylinders with about 250 hours on
> them, if that has anything to do with the cooler temperatures.
>
> And yes, my engine's CHTs are normally below or around 300 and have never
> approached 400, routinely. If you would like some verification of this, I
> would be happy to upload my engine monitor data (from several months ago, I
> have yet to download a current set), which is in the latest JPI format, to
> a free host site for anyone's perusal.
>
> --
> Peter

I'm not doubting your numbers-but am not sure if the LOP people are
still using 14.9 HP/G. Sounds to me like you've got an engine to hang
on to.

If you could spare the extra weight, I'd consider adding a pre-oiler
and flying that engine as long as I could...

Regards;

TC

[Mike Noel]

One fly in the ointment for safe leaning is the likelihood of mechanical
tachs not telling the truth. When my mechanical tach says 2400 RPM, my
handheld optical tach tells me 2480. One of these days I'll replace that
old analog tach with an ignition based instrument.

--
Best Regards,
Mike

http://photoshow.comcast.net/mikenoel

"Peter R." > wrote in message
...
> " > wrote:
>
>> If your CHT's are closer to 300 F than 400 F running those settings,
>> you've got one of the "cooler" installations that I've ever heard of...
>
> The cylinders are new Superior Millennium cylinders with about 250 hours
> on
> them, if that has anything to do with the cooler temperatures.
>
> And yes, my engine's CHTs are normally below or around 300 and have never
> approached 400, routinely. If you would like some verification of this, I
> would be happy to upload my engine monitor data (from several months ago,
> I
> have yet to download a current set), which is in the latest JPI format, to
> a free host site for anyone's perusal.
>
> --
> Peter

[karl gruber[_1_]]

They are.

Karl
> wrote in message
ps.com...
>
> I'm not doubting your numbers-but am not sure if the LOP people are
> still using 14.9 HP/G.

[Newps]

Peter R. wrote:
> " > wrote:
>
>
>>If your CHT's are closer to 300 F than 400 F running those settings,
>>you've got one of the "cooler" installations that I've ever heard of...
>
>
> The cylinders are new Superior Millennium cylinders with about 250 hours on
> them, if that has anything to do with the cooler temperatures.

Hey, I have Superior Milleniums on my Bo too. Bet you didn't get yours
for free like I did.



>
> And yes, my engine's CHTs are normally below or around 300 and have never
> approached 400, routinely.

I would have to work to get my CHT's anywhere near 400.

[Thomas Borchert]

Doug,

You're right about carb'd engines. However, I still think it is vital
to understand the basic principles of how the engine works, carb'd or
not. And "leaner=hotter" or "richer=better" is simply wrong.

> The problem with LOP, isn't running LOP, its
> that you are running peak and THINKING you are running LOP.
>

Not if you are below 75 percent power. Then the problem pretty much
goes away.

--
Thomas Borchert (EDDH)

[Matt Barrow]

"Newps" > wrote in message
. ..
>
>
> Peter R. wrote:
>> " > wrote:
>>
>>
>>>If your CHT's are closer to 300 F than 400 F running those settings,
>>>you've got one of the "cooler" installations that I've ever heard of...

Quite! I have SM's in my TNIO-550 (albeit they have over 1700 hours, but
they are not markedly different than when they were new) and they typically
run about 340-360 with a very occasional high of 380.

Quite interesting how is are not only low, but verging on cold. :~)

>>
>>
>> The cylinders are new Superior Millennium cylinders with about 250 hours
>> on
>> them, if that has anything to do with the cooler temperatures.
>
> Hey, I have Superior Milleniums on my Bo too. Bet you didn't get yours
> for free like I did.

Weren't you having trouble with the folks at Millennium? What's the poop?

[Newps]

Matt Barrow wrote:

>>
>>Hey, I have Superior Milleniums on my Bo too. Bet you didn't get yours
>>for free like I did.
>
>
> Weren't you having trouble with the folks at Millennium? What's the poop?

I never had Milleniums. The guy who owns Pponk told me he would not
sell me Milleniums unless I absolutely had to have them. They were
having warranty issues with Superior. I don't know if that has changed
or not, I hope so. At my annual last month I had a bad cylinder, the
head was pulling apart from the base. I mentioned this fact on a Beech
email list that I am involved with. One of the vice presidents of
Superior, who flies a Baron, contacted me and originally offered me a
free cylinder assembly if I would send them the bad cylinder. I said
sure. Then the next day they offered me 6 cylinders if I would send all
six of mine back to them. I said sure. When I originally posted my
email I mentioned that my cylinders were .010 oversize and I think they
realized that sending me one free cylinder was kind of silly, I couldn't
use it. I was just going to sell it on ebay. Then they sent an email
saying they would pay for next day air both ways and then another email
saying they would pay for removal and replacement, which was $1500. I
now have about 7 hours on my top overhaul. I also get a 3 year/500 hour
no questions asked warranty which everbody who buys their cylinders
gets. So that was about a $9000 deal I got just for mentioning my
original cylinder problem. They couldn't have been nicer, hopefully
that will be everybodys experience when dealing with them for whatever
reason.

[Peter R.]

karl gruber > wrote:

> You more than likely have an CHT indication problem. There is no reason your
> airplane should run much cooler than the fleet.

On all six probes? That seems a tad unlikely. Additionally, are you
really in a position to speak for the fleet?

In any regard and given the responses here, I have a call in to Tornado
Alley Turbo's director of maintenance. If anyone will have the most
accurate response, it will be this person. When I receive a response I
will post it here.

Oh, I just remembered that I had sent TATurbo my JPI data file after the
first 50 hours on this rebuilt engine, sometime late spring 2004. They
responded that all data points (including the CHTs) looked well within
accepted ranges. Had they had a concern about CHTs, that would have been a
perfect opportunity to raise it with me.

--
Peter

[Peter R.]

Ray Andraka > wrote:

> Is your JPI set up for the correct probe type?

Could you expand on this? I do not know the answer and if this might be
the case, I would like to be able to approach my mechanic with an educated
question.


--
Peter

[Peter R.]

Newps > wrote:

> I would have to work to get my CHT's anywhere near 400.

What do you see routinely during cruise?

--
Peter

[Peter R.]

Peter > wrote:

> What aircraft is this?

A Bonanza V35B with an IO-520. Engine monitor is a JPI 800.
--
Peter

[Peter R.]

Newps > wrote:

> I mentioned this fact on a Beech
> email list that I am involved with.

What list is this?

--
Peter

[karl gruber[_1_]]

"Peter R." > wrote in message
...
> karl gruber > wrote:
>
>> You more than likely have an CHT indication problem. There is no reason
>> your
>> airplane should run much cooler than the fleet.
>
> On all six probes? That seems a tad unlikely. Additionally, are you
> really in a position to speak for the fleet?

All six probes............yes that would be MORE likely an indication
problem.

And yes, I am in a good position to speak for the fleet.

Karl

[Peter R.]

karl gruber > wrote:

> .yes that would be MORE likely an indication
> problem.

OK. As I indicated I am not taking the responses here lightly and should
have an answer over the next few days. In fact, I will also call JPI to
solicit their input on CHT probes.

> And yes, I am in a good position to speak for the fleet.

I am sincerely curious, how did you get in such a position?

--
Peter

[karl gruber[_1_]]

> I am sincerely curious, how did you get in such a position?
>
> --
> Peter

Experience. I installed and flew multi-probed engine analyzers in the late
60's. Since then I've flown 100s of light aircraft commercially, as a ferry
pilot and instructor. I've flown with my friend, John Deakin, both in his
Bonanza and my Cessna 185. I doubt that your Bonanza is somehow set up that
your CHTs would be 60-80 degrees below many other Bonanzas or John's,
especially since he is so fastidious about his installation.

Best,
Karl

[Peter R.]

karl gruber > wrote:

> . I doubt that your Bonanza is somehow set up that
> your CHTs would be 60-80 degrees below many other Bonanzas or John's,
> especially since he is so fastidious about his installation.

Woah, now I am really listening. :) Drop names like that and I am all
ears.

This is the type of **** that scares me about aircraft ownership. Here I
am, fat, dumb, and happy thinking with a data point of one that hot CHTs
are not an issue with my aircraft and then something like this comes out of
my blind side to smack me in the face.

I transitioned to this aircraft from a Cessna 172 that had nothing except
poor analog FF and EGT gauges. Thus, when I was introduced to the world
of engine monitors, I relied on the experience of the previous owner of
this aircraft, who, as a 1,500 hour Bonanza pilot, also sang the praises of
how cool the CHTs ran during cruise.

Man, if my JPI probes are off by 60-80 degrees, I am going to have some
serious questions of TA Turbo, JPI, and my mechanic.

In your experience, what would cause such an error?

--
Peter

[karl gruber[_1_]]

> In your experience, what would cause such an error?
>
> --
> Peter

I don't know. What does the JPI read when you first walk into the hangar? I
suspect something in the JPI panel unit. It's just an airplane part, and
every one of those things are going to break or quit SOMETIME!

Call TA...............see what they say.

Best,
Karl

[Peter R.]

karl gruber > wrote:

> It's just an airplane part, and
> every one of those things are going to break or quit SOMETIME!

Agreed, except that it seems strange to me that if something in this unit
did fail, the failure only shows up as a percentage drop in CHTs.


--
Peter

[Ray Andraka]

Peter R. wrote:

> Ray Andraka > wrote:
>
>
>>Is your JPI set up for the correct probe type?
>
>
> Could you expand on this? I do not know the answer and if this might be
> the case, I would like to be able to approach my mechanic with an educated
> question.
>
>

There are two types of thermocouples used for EGTs. K type and J type.
Each has a different coefficient for output voltage vs temperature. If
you have JPI probes, then that should not be a problem. If you used
other probes, they might not be the correct type, which would give
readings that are scaled.

Another possibility is if the probe wires were extended with wire other
than thermocouple wire, the junction between the thermocouple wire and
the extension wire will add an additional thermocouple to the loop,
introducing an offset voltage at the instrument. The offset voltage
will translate to an offset temperature indication that is proportional
to the temperature at the junction.

[Newps]

Peter R. wrote:

> Newps > wrote:
>
>
>>I would have to work to get my CHT's anywhere near 400.
>
>
> What do you see routinely during cruise?

I have the factory instruments, no engine monitor. This afternoon I
flew up to check out some bird hunting grounds near the Canadian border.
At 9500, wide open throttle and 2500 I was getting CHT's at 300
degrees. OAT was 40F. On the way back we flew at between 3 and 4
thousand. 24 inches and 2500 rpm, a little over 74%. I was seeing 350F
on the CHT at an OAT of 70F. I was about 30-40 LOP the whole way back,
burning 14 GPH, indicating 175-177 mph.

[Newps]

Peter R. wrote:

> Newps > wrote:
>
>
>> I mentioned this fact on a Beech
>>email list that I am involved with.
>
>
> What list is this?


http://lists.aviating.com/mailman/listinfo/beech-owners

[Matt Barrow]

"Peter R." > wrote in message
...
> karl gruber > wrote:
>
>> . I doubt that your Bonanza is somehow set up that
>> your CHTs would be 60-80 degrees below many other Bonanzas or John's,
>> especially since he is so fastidious about his installation.
>
> Woah, now I am really listening. :) Drop names like that and I am all
> ears.

Name dropping, or refering to a fellow whose numbers are much higher than
yours (on the record) and whose setup and installation were done by the same
company.

>
> This is the type of **** that scares me about aircraft ownership. Here I
> am, fat, dumb, and happy thinking with a data point of one that hot CHTs
> are not an issue with my aircraft and then something like this comes out
> of
> my blind side to smack me in the face.

WTF?

>
> I transitioned to this aircraft from a Cessna 172 that had nothing except
> poor analog FF and EGT gauges. Thus, when I was introduced to the world
> of engine monitors, I relied on the experience of the previous owner of
> this aircraft, who, as a 1,500 hour Bonanza pilot, also sang the praises
> of
> how cool the CHTs ran during cruise.
>
> Man, if my JPI probes are off by 60-80 degrees, I am going to have some
> serious questions of TA Turbo, JPI, and my mechanic.

That's what a bunch here have been telling you. As well, is the problem
TATurbo (they did your's, Deakin's, mine, hundreds of others, but your's is
the anomaly.

I suspect you've been to the APS seminar, and you didn't notice something
wrong in your numbers? Then, too, it's not unheard of that an installation
(probes, analyzer, etc) would fail shortly after being placed in service.

I'm not sure, but it seems you're having a bad reaction to the news that
something isn't kosher with your airplane.


--
Matt
---------------------
Matthew W. Barrow
Site-Fill Homes, LLC.
Montrose, CO (MTJ)

[Peter R.]

Matt Barrow > wrote:

> That's what a bunch here have been telling you. As well, is the problem
> TATurbo (they did your's, Deakin's, mine, hundreds of others, but your's is
> the anomaly.
>
> I suspect you've been to the APS seminar, and you didn't notice something
> wrong in your numbers? Then, too, it's not unheard of that an installation

Hey, I wasn't born with A&P knowledge and I have yet to go to an ABS BPPP
pilot or maintenance clinic. As you probably know, I am using the aircraft
to commute weekly to work and, thus far, I have failed to make time for
either, as work and family commitments took priority.

When the previous owner, who used to run an auto race team and perform his
own maintenance on both autos and airplanes, sung the praises of how cool
the cylinders ran on this aircraft, I assumed he knew what he was talking
about. This began my education in temperature management and set my
expectations.

No where have I read, prior to this thread, that temperatures above 300 but
below 350 degrees indicate a problem with the engine monitor. No where.

Initially, I agree that I reacted somewhat defensively here, but that has
changed and now I am definitely taking the responses here seriously by
contacting both TA Turbo and JPI to get this issue resolved.

What concerns me more than my newsgroup reputation is that, with incorrect
CHT readings, I have no idea where these cylinders are really operating.


--
Peter

[Peter R.]

Ray Andraka > wrote:

> There are two types of thermocouples used for EGTs.

Thanks, Ray. Just confirmed with the mechanic that the probes and wiring
are JPI, so now it seems to come down to the EDM-800 itself.

Awaiting JPIs response now.

--
Peter

[Peter R.]

karl gruber > wrote:

> Call TA...............see what they say.

FWIW, I just got off the phone with both TA Turbo and JPI.

TA Turbo stated that, while low of average, seeing 320 degrees as the
hottest CHT at 12,000 feet with WOT, 2500 RPMs and about 70 degrees LOP is
*not* unrealistic.

JPI's very overworked tech (I was on hold for one hour) gave me three tests
to ensure the unit is working correctly:

1) Confirm that CHT and EGT are registering ambient temperature when the
aircraft has been shut down for a day or so. Of course, my aircraft's
Tannis heater is plugged in today so this test will have to wait until I
fly to my destination this week and let it sit for a couple of days.

2) Pull the probe and submerge it in boiling water to confirm that it reads
212 degrees F.

3) Separate the probe from the wire and measure the probe's resistance. It
should register 1.3 to 2.0 olms.

I will start with number one this week, then perhaps move on to 2 and 3
next week when my aircraft goes in for a 50 hr oil change and other sundry
items.


--
Peter

[Matt Barrow]

"Peter R." > wrote in message
...
> Matt Barrow > wrote:
>
>
> No where have I read, prior to this thread, that temperatures above 300
> but
> below 350 degrees indicate a problem with the engine monitor. No where.

That's not the point except you're jumping ahead in the troubleshooting
sequence.
>
> Initially, I agree that I reacted somewhat defensively here, but that has
> changed and now I am definitely taking the responses here seriously by
> contacting both TA Turbo and JPI to get this issue resolved.
>
> What concerns me more than my newsgroup reputation is that, with incorrect
> CHT readings, I have no idea where these cylinders are really operating.

The primary point is that your CHT reading were not just low, buy WAY low.
It takes some "getting to" to find if it's the JPI, the probes, the baffling
(do you have TA's "Liquid Air" baffles?), or any of a myriad potential
problems.

Here's an analogy: When my daughter bought her 2006 Honda Civic, she was
getting 28 miles a gallon instead of the more typical 38-40MPG. When we
took it back to the dealer, one of his questions asked of her was what she
thought the problem was. She responded that the problem is ..."it's getting
12-14 MPG less than it should." She didn't jump to conclusions.

Deakin's temps are higher than mine, but I'll run 75% and even up to 80% of
power, so being off 20 degrees is, to me, not a _shocker_.

You might just be one incredibly lucky pilot/owner. Certainly nothing wrong
with that.

On the other hand, those people that are pushing 400 for their CHT's should
be asking question if nothing else to find a better way to operate their
engines. In light of the number of Bo's that have top overhauls at 600 or so
hours, perhaps _they_ should be asking questions and doing some digging.

Now, if my Toyota Four Runner was getting 26 MPG, I'd be really happy, but
I'd be rather curious...or maybe _suspicious_ is the right word.

Hope yours is just a "happy engine".

--
Matt
---------------------
Matthew W. Barrow
Site-Fill Homes, LLC.
Montrose, CO (MTJ)

[Peter R.]

Matt Barrow > wrote:

> That's not the point except you're jumping ahead in the troubleshooting
> sequence.

Ok, but I was simply attempting to explain the reason for my "blissful"
ignorance. I didn't read John Deakin's articles the first time and think,
"Gee, my temperatures are so much lower than what he is cautioning against
that *my engine* must have some other explainable problem."

Instead, I simply read it and thought, "Hmm, looks like overheating
cylinders are not my problem."

> The primary point is that your CHT reading were not just low, buy WAY low.

Again, TA Turbo didn't say to me on the phone today that my reported CHTs
were WAY low. "Lower than average, but not unbelievable" was the phrase
used.

> It takes some "getting to" to find if it's the JPI, the probes, the baffling
> (do you have TA's "Liquid Air" baffles?), or any of a myriad potential
> problems.

The aircraft has the optional TA cheek plate louvers installed for summer
flying (as opposed to the shark-gill louvers, which is what I use in
winter), which provides a 10-20 degree lower CHT, and it has a TA optional
cooling baffling installed on the pilot's left of the cowl opening, which I
believe is to allow better airflow to the back cylinders.

In addition to the JPI tests pointed out elsewhere, I was also given
another pointer by TA Turbo. I need to check the probe wiring and compare
that with the setting in the JPI. If yellow/red wiring from the probes is
present, the JPI should be set to "K thermocouple." White/red is "J
thermocouple."

The TATurbo maintenance director said that an incorrect setting in the
EDM-800 would result in a minus 40 degree difference from actual CHT
reading. He then commented that if I see 320 degrees on hot day and this
error were present, he would still be impressed with an actual 360 degree
CHT.


--
Peter