Lyc IO-540 won't make RPM.

Do you ever have those days where you're just scratching your head?

I've got an IO-540 (strapped to the right side of an E-Model Piper
Aztec) that won't generate full RPM. Let me describe the takeoff
sequence.

During the run-up, both the feather check and the mag check are normal
(done at 1700 RPM and 2000 RPM respectively.) During the takeoff roll,
all seems normal, but initial climb is sluggish (not alarmingly so, but
just enough to notice). The right side RPM indicator shows about 2450
RPM, while the left side is showing just above 2600 RPM (as usual).

When setting climb power, bringing the power back to 25-inches on both
sides will not cause the left side to lose measurable RPM, but the
right side loses about 100. Synchronizing the propellers does cause the
"beating" to go away when the RPM indicators indicate the same RPM, so
I'm confident that the RPM gauge is reading correctly.

During the initial tear down, it was noticed that the set-screw for the
right governor was set at about as high an RPM as possible. So the
initial feeling was that the governor was having a bad day.

So far, we've:
1. Sent he governor out for overhaul. (Prop shop reported that it was
fine.)
2. Swapped the propellers between the engines. (Problem does not follow
the propeller.)
3. Swapped the governors between the engines. (Problem does not follow
the governor.)
4. Verified full travel on the propeller controls (both in the cockpit
and at the governor).

The tech reps are suggesting that we send the engine back to Mattituck
(it's a factory remanufactured engine which has been "Mattitucked" with
about 100 hours on it), but I get the feeling that the tech reps and
mechanics are essentially in guessing mode.

Does anyone have any suggestions on what else to think about before we
pull the engine?

Thanks!

-Rob

Oil pump? Oil galleys and passages through the engine to the governor? I
wonder if the engine or oil pump is providing enough oil volume or pressure
to the governor to hold the prop in full fine pitch. After a previous owner
of our Aztec had our right engine overhauled at Penn Yan the prop would
feather during large power reductions. He pulled the engine, sent it back
to Penn Yan and they found one of the internal oil ports in the engine
leading to the governor had been sized wrong. Sorry I can't be more
specific, but the return paperwork on the engine is pretty non-descript, it
only mentions resizing the oil galley or port to a specific Lycoming service
instruction number.
Jim

wrote in message
ups.com...
Do you ever have those days where you're just scratching your head?

I've got an IO-540 (strapped to the right side of an E-Model Piper
Aztec) that won't generate full RPM. Let me describe the takeoff
sequence.

During the run-up, both the feather check and the mag check are normal
(done at 1700 RPM and 2000 RPM respectively.) During the takeoff roll,
all seems normal, but initial climb is sluggish (not alarmingly so, but
just enough to notice). The right side RPM indicator shows about 2450
RPM, while the left side is showing just above 2600 RPM (as usual).

When setting climb power, bringing the power back to 25-inches on both
sides will not cause the left side to lose measurable RPM, but the
right side loses about 100. Synchronizing the propellers does cause the
"beating" to go away when the RPM indicators indicate the same RPM, so
I'm confident that the RPM gauge is reading correctly.

During the initial tear down, it was noticed that the set-screw for the
right governor was set at about as high an RPM as possible. So the
initial feeling was that the governor was having a bad day.

So far, we've:
1. Sent he governor out for overhaul. (Prop shop reported that it was
fine.)
2. Swapped the propellers between the engines. (Problem does not follow
the propeller.)
3. Swapped the governors between the engines. (Problem does not follow
the governor.)
4. Verified full travel on the propeller controls (both in the cockpit
and at the governor).

The tech reps are suggesting that we send the engine back to Mattituck
(it's a factory remanufactured engine which has been "Mattitucked" with
about 100 hours on it), but I get the feeling that the tech reps and
mechanics are essentially in guessing mode.

Does anyone have any suggestions on what else to think about before we
pull the engine?

Thanks!

-Rob

That's interesting. My thought was that, as the oil pressure was OK (as
is the nitrogen pressure in the propeller hubs) we should be OK. Did
you see normal oil pressure?

Thanks,

-Rob

Jim Burns wrote:
Oil pump? Oil galleys and passages through the engine to the governor? I
wonder if the engine or oil pump is providing enough oil volume or pressure
to the governor to hold the prop in full fine pitch. After a previous owner
of our Aztec had our right engine overhauled at Penn Yan the prop would
feather during large power reductions. He pulled the engine, sent it back
to Penn Yan and they found one of the internal oil ports in the engine
leading to the governor had been sized wrong. Sorry I can't be more
specific, but the return paperwork on the engine is pretty non-descript, it
only mentions resizing the oil galley or port to a specific Lycoming service
instruction number.
Jim

wrote in message
ups.com...
Do you ever have those days where you're just scratching your head?

I've got an IO-540 (strapped to the right side of an E-Model Piper
Aztec) that won't generate full RPM. Let me describe the takeoff
sequence.

During the run-up, both the feather check and the mag check are normal
(done at 1700 RPM and 2000 RPM respectively.) During the takeoff roll,
all seems normal, but initial climb is sluggish (not alarmingly so, but
just enough to notice). The right side RPM indicator shows about 2450
RPM, while the left side is showing just above 2600 RPM (as usual).

When setting climb power, bringing the power back to 25-inches on both
sides will not cause the left side to lose measurable RPM, but the
right side loses about 100. Synchronizing the propellers does cause the
"beating" to go away when the RPM indicators indicate the same RPM, so
I'm confident that the RPM gauge is reading correctly.

During the initial tear down, it was noticed that the set-screw for the
right governor was set at about as high an RPM as possible. So the
initial feeling was that the governor was having a bad day.

So far, we've:
1. Sent he governor out for overhaul. (Prop shop reported that it was
fine.)
2. Swapped the propellers between the engines. (Problem does not follow
the propeller.)
3. Swapped the governors between the engines. (Problem does not follow
the governor.)
4. Verified full travel on the propeller controls (both in the cockpit
and at the governor).

The tech reps are suggesting that we send the engine back to Mattituck
(it's a factory remanufactured engine which has been "Mattitucked" with
about 100 hours on it), but I get the feeling that the tech reps and
mechanics are essentially in guessing mode.

Does anyone have any suggestions on what else to think about before we
pull the engine?

Thanks!

-Rob

Check for camshaft wear.




wrote:
Do you ever have those days where you're just scratching your head?

I've got an IO-540 (strapped to the right side of an E-Model Piper
Aztec) that won't generate full RPM. Let me describe the takeoff
sequence.

During the run-up, both the feather check and the mag check are normal
(done at 1700 RPM and 2000 RPM respectively.) During the takeoff roll,
all seems normal, but initial climb is sluggish (not alarmingly so, but
just enough to notice). The right side RPM indicator shows about 2450
RPM, while the left side is showing just above 2600 RPM (as usual).

When setting climb power, bringing the power back to 25-inches on both
sides will not cause the left side to lose measurable RPM, but the
right side loses about 100. Synchronizing the propellers does cause the
"beating" to go away when the RPM indicators indicate the same RPM, so
I'm confident that the RPM gauge is reading correctly.

During the initial tear down, it was noticed that the set-screw for the
right governor was set at about as high an RPM as possible. So the
initial feeling was that the governor was having a bad day.

So far, we've:
1. Sent he governor out for overhaul. (Prop shop reported that it was
fine.)
2. Swapped the propellers between the engines. (Problem does not follow
the propeller.)
3. Swapped the governors between the engines. (Problem does not follow
the governor.)
4. Verified full travel on the propeller controls (both in the cockpit
and at the governor).

The tech reps are suggesting that we send the engine back to Mattituck
(it's a factory remanufactured engine which has been "Mattitucked" with
about 100 hours on it), but I get the feeling that the tech reps and
mechanics are essentially in guessing mode.

Does anyone have any suggestions on what else to think about before we
pull the engine?

Thanks!

-Rob

A bad cam is one likely problem... The other and more ominous is that
you have a binding engine and are set up for catastrophic
failure/seizure on takeoff... A 100 hour engine that won't make RPM is
a hand grenade with the pin pulled... Don't fly it again and send it
back... Insist they put 3 hours on the dyno after it is repaired and
that it make target HP and RPM...

denny - old pilot with the scars, financial and otherwise, to prove
it...

We didn't own the airplane when this occurred, we bought it just after the
engine came back from Penn Yan and the seller explained it to me. But, yes,
he said oil pressure indicated normal.
Jim

wrote in message
ups.com...
That's interesting. My thought was that, as the oil pressure was OK (as
is the nitrogen pressure in the propeller hubs) we should be OK. Did
you see normal oil pressure?

Thanks,

-Rob

Jim Burns wrote:
Oil pump? Oil galleys and passages through the engine to the governor?
I
wonder if the engine or oil pump is providing enough oil volume or
pressure
to the governor to hold the prop in full fine pitch. After a previous
owner
of our Aztec had our right engine overhauled at Penn Yan the prop would
feather during large power reductions. He pulled the engine, sent it
back
to Penn Yan and they found one of the internal oil ports in the engine
leading to the governor had been sized wrong. Sorry I can't be more
specific, but the return paperwork on the engine is pretty non-descript,
it
only mentions resizing the oil galley or port to a specific Lycoming
service
instruction number.
Jim

wrote in message
ups.com...
Do you ever have those days where you're just scratching your head?

I've got an IO-540 (strapped to the right side of an E-Model Piper
Aztec) that won't generate full RPM. Let me describe the takeoff
sequence.

During the run-up, both the feather check and the mag check are normal
(done at 1700 RPM and 2000 RPM respectively.) During the takeoff roll,
all seems normal, but initial climb is sluggish (not alarmingly so,
but
just enough to notice). The right side RPM indicator shows about 2450
RPM, while the left side is showing just above 2600 RPM (as usual).

When setting climb power, bringing the power back to 25-inches on both
sides will not cause the left side to lose measurable RPM, but the
right side loses about 100. Synchronizing the propellers does cause
the
"beating" to go away when the RPM indicators indicate the same RPM, so
I'm confident that the RPM gauge is reading correctly.

During the initial tear down, it was noticed that the set-screw for
the
right governor was set at about as high an RPM as possible. So the
initial feeling was that the governor was having a bad day.

So far, we've:
1. Sent he governor out for overhaul. (Prop shop reported that it was
fine.)
2. Swapped the propellers between the engines. (Problem does not
follow
the propeller.)
3. Swapped the governors between the engines. (Problem does not follow
the governor.)
4. Verified full travel on the propeller controls (both in the cockpit
and at the governor).

The tech reps are suggesting that we send the engine back to Mattituck
(it's a factory remanufactured engine which has been "Mattitucked"
with
about 100 hours on it), but I get the feeling that the tech reps and
mechanics are essentially in guessing mode.

Does anyone have any suggestions on what else to think about before we
pull the engine?

Thanks!

-Rob

Trust me. I'm not flying an airplane with unexplained power loss or a
misbehaving propeller. If you lose the left one, the right one is
sick. If you lose the right one, maybe it won't feather. (I plan on
getting old.)

I'm just trying to figure out if there is something else to look at
before things get really expensive and time consuming. (It wouldn't be
fun to pull the engine and send it out to have it turn out to be fine,
and you just can't swap them around as easily as governors. :-)).

-Rob

Denny wrote:
A bad cam is one likely problem... The other and more ominous is that
you have a binding engine and are set up for catastrophic
failure/seizure on takeoff... A 100 hour engine that won't make RPM is
a hand grenade with the pin pulled... Don't fly it again and send it
back... Insist they put 3 hours on the dyno after it is repaired and
that it make target HP and RPM...

denny - old pilot with the scars, financial and otherwise, to prove
it...

A couple of choices: Engine isn't producing full
horsepower-- or prop/gov are faulty.

If the prop will run at command RPM with variation
in manifold pressure while in flight, I'd say governor
is OK. If it won't go to redline, but runs correctly
at other rpms, it's a linkage or command problem.

Some props won't go clear to redline until you
roll along awhile. That is a function of the fine
pitch setting on the prop. Props should be alike.

When you are tooling along, it should go to
redline rpm no problem even if engine is pretty
lame. As you change manifold pressure, does
the rpm overshoot and undershoot the target by
small amounts? That would be normal.

If it's low rpm only on takeoff, it could be the
prop is on the fine pitch stop and the engine
just can't spin it to red line there. If it's the
engine, I'm in agreement with the camshaft
crowd. This is a problem on Dukes. On
those, you can detect the problem by comparing
fuel flows... if the ff is low, the engine isn't pumping
enough air which is usually a cam.

I'd think if it was a friction problem it would have
destroyed itself early in the flight. Think of the
kilowatts of power involved!!

Bill Hale BPPP instructor/ A&P


wrote:
Trust me. I'm not flying an airplane with unexplained power loss or a
misbehaving propeller. If you lose the left one, the right one is
sick. If you lose the right one, maybe it won't feather. (I plan on
getting old.)

I'm just trying to figure out if there is something else to look at
before things get really expensive and time consuming. (It wouldn't be
fun to pull the engine and send it out to have it turn out to be fine,
and you just can't swap them around as easily as governors. :-)).

-Rob

Denny wrote:
A bad cam is one likely problem... The other and more ominous is that
you have a binding engine and are set up for catastrophic
failure/seizure on takeoff... A 100 hour engine that won't make RPM is
a hand grenade with the pin pulled... Don't fly it again and send it
back... Insist they put 3 hours on the dyno after it is repaired and
that it make target HP and RPM...

denny - old pilot with the scars, financial and otherwise, to prove
it...

Denny wrote:
A bad cam is one likely problem...


I give em 100 to 300 hours.
If it has been reground and not properly hardened.

And if it is, then I would worry about the other side.

What I don't know is why he would take a factory reman and send it to an
engine overhaul shop?

John

On 11 Dec 2006 05:35:14 -0800, wrote:


The tech reps are suggesting that we send the engine back to Mattituck
(it's a factory remanufactured engine which has been "Mattitucked" with
about 100 hours on it), but I get the feeling that the tech reps and
mechanics are essentially in guessing mode.

snip

Are we talking to Lycoming tech reps? Perhaps they need to re-read
this:

http://www.lycoming.textron.com/supp...ns/SI1462A.pdf

My first thought is that you really need to verify the governor oil
path to the propeller via the governor pad/crankcase through a passage
in the front main bearing out the center of the crankshaft.

If there is a governed oil loss at the crank/main bearing the engine
will NOT turn up TO RPM.

A restriction/reduction in the engine oil pressure supplied to the
governor can have the same effect, but is not as common.

If either happens on the most common single-engine installation
(governor oil to increase pitch) you can't reduce prop RPM with the
prop control on TO, on a twin (governor oil to decrease pitch), you
can't make TO RPM.

Haven't tallked to anybody at Mattituck for years, what do they say??

Regards;

TC