sticky valve or

[Dick]

Old WW2 mechanic says he hears a sticky valve on my C-85 when I fire up for
first time in morning but can't describe the sound and says it lasts only as
long as a finger snap.

Wants me to add Marvel Mystery oil. I use Aeroshell 100 (50 weight) and
change it every 25 hours.

I can't detect any roughness upon initial start around 900-1000 rpm in front
of my hanger nor during the taxi a couple of minutes to a runup spot. On
throttling up to 1500 for the mag check, I notice a slight hesitation around
11-1200 rpm that goes away quickly and thought was just from the low speed
taxi.

Since I had to put a rental down about 7 years ago for a valve problem (per
the FBO), there is a little "pucker" factor regarding this conversation <G>.

Light Plane Maintenance book references "hand proping before first start of
day to find 'flat' cylinder". Not sure I can identify a rapid falloff in
turning resistance (books definition).

Concern doesn't seem to get to the point where the "cold cylinder" test is
applicable as doesn't last long (his finger snap).

Am I chasing nothing or what is a valid approach?

Thanks, Dick

[Scott]

Try the MARVEL!! We've been using it (dad & I) for 30 some years mixed
in with the gas but I now think I will also use some in the oil). The
first time I didn't use it (along with 100LL on a cross country trip) I
stuck a valve with my A-65. Ran Marvel after the event, but was unable
to unstick it. Decided to pull all cylinders and have the 100 Octane
valves installed. So Marvel at something like $10/gallon, or $2000 to
have the cylinders re-worked. I could buy lots of Marvel for $2000...

Scott


Dick wrote:
> Old WW2 mechanic says he hears a sticky valve on my C-85 when I fire up for
> first time in morning but can't describe the sound and says it lasts only as
> long as a finger snap.
>
> Wants me to add Marvel Mystery oil. I use Aeroshell 100 (50 weight) and
> change it every 25 hours.
>
> I can't detect any roughness upon initial start around 900-1000 rpm in front
> of my hanger nor during the taxi a couple of minutes to a runup spot. On
> throttling up to 1500 for the mag check, I notice a slight hesitation around
> 11-1200 rpm that goes away quickly and thought was just from the low speed
> taxi.
>
> Since I had to put a rental down about 7 years ago for a valve problem (per
> the FBO), there is a little "pucker" factor regarding this conversation <G>.
>
> Light Plane Maintenance book references "hand proping before first start of
> day to find 'flat' cylinder". Not sure I can identify a rapid falloff in
> turning resistance (books definition).
>
> Concern doesn't seem to get to the point where the "cold cylinder" test is
> applicable as doesn't last long (his finger snap).
>
> Am I chasing nothing or what is a valid approach?
>
> Thanks, Dick
>
>

[[email protected]]

Scott wrote:
> Try the MARVEL!! We've been using it (dad & I) for 30 some years
mixed
> in with the gas but I now think I will also use some in the oil).
The
> first time I didn't use it (along with 100LL on a cross country trip)
I
> stuck a valve with my A-65. Ran Marvel after the event, but was
unable
> to unstick it. Decided to pull all cylinders and have the 100 Octane

> valves installed. So Marvel at something like $10/gallon, or $2000
to
> have the cylinders re-worked. I could buy lots of Marvel for
$2000...
>
> Scott
>
>
> Dick wrote:
> > Old WW2 mechanic says he hears a sticky valve on my C-85 when I
fire up for
> > first time in morning but can't describe the sound and says it
lasts only as
> > long as a finger snap.
> >
> > Wants me to add Marvel Mystery oil. I use Aeroshell 100 (50 weight)
and
> > change it every 25 hours.
> >
> > I can't detect any roughness upon initial start around 900-1000 rpm
in front
> > of my hanger nor during the taxi a couple of minutes to a runup
spot. On
> > throttling up to 1500 for the mag check, I notice a slight
hesitation around
> > 11-1200 rpm that goes away quickly and thought was just from the
low speed
> > taxi.
> >
> > Since I had to put a rental down about 7 years ago for a valve
problem (per
> > the FBO), there is a little "pucker" factor regarding this
conversation <G>.
> >
> > Light Plane Maintenance book references "hand proping before first
start of
> > day to find 'flat' cylinder". Not sure I can identify a rapid
falloff in
> > turning resistance (books definition).
> >
> > Concern doesn't seem to get to the point where the "cold cylinder"
test is
> > applicable as doesn't last long (his finger snap).
> >
> > Am I chasing nothing or what is a valid approach?
> >
> > Thanks, Dick
> >
> >

************************************************** ********************************

I have used MMO in my vehicles and tractors and all other internal
combustion equipment for 50+ years and depend on it to help prolong the
life. Will in plane engines also.
Good luck.

Bob Olds RV-4
Charleston,Arkansas


************************************************** *******************************

[Stealth Pilot]

On Sun, 22 May 2005 11:54:45 GMT, "Dick" > wrote:

>Old WW2 mechanic says he hears a sticky valve on my C-85 when I fire up for
>first time in morning but can't describe the sound and says it lasts only as
>long as a finger snap.
>
<snip>
>
>Am I chasing nothing or what is a valid approach?
>
>Thanks, Dick
>

get someone else to start your aircraft and stand beside him
listening. obviously he thinks he can hear something.
probably a clack clack clack sound which quickly vanishes as the valve
frees up and goes back to tolerances with the rocker.

just a thought.
Stealth Pilot
Australia.

[Dick]

good thought. Another I heard is to pull prop thru all 4 cylinders and feel
for "flat" cylinder.
"Stealth Pilot" > wrote in message
...
> On Sun, 22 May 2005 11:54:45 GMT, "Dick" > wrote:
>
>>Old WW2 mechanic says he hears a sticky valve on my C-85 when I fire up
>>for
>>first time in morning but can't describe the sound and says it lasts only
>>as
>>long as a finger snap.
>>
> <snip>
>>
>>Am I chasing nothing or what is a valid approach?
>>
>>Thanks, Dick
>>
>
> get someone else to start your aircraft and stand beside him
> listening. obviously he thinks he can hear something.
> probably a clack clack clack sound which quickly vanishes as the valve
> frees up and goes back to tolerances with the rocker.
>
> just a thought.
> Stealth Pilot
> Australia.

[Scott]

And if you're REALLY (un)lucky (like I was), you might hear air rushing
past a stuck exhaust valve and hear the hiss out the exhaust pipe when
pulling it through. Then you'd have it narrowed down to 2 cylinders...

Scott



Dick wrote:

> good thought. Another I heard is to pull prop thru all 4 cylinders and feel
> for "flat" cylinder.
> "Stealth Pilot" > wrote in message
> ...
>
>>On Sun, 22 May 2005 11:54:45 GMT, "Dick" > wrote:
>>
>>
>>>Old WW2 mechanic says he hears a sticky valve on my C-85 when I fire up
>>>for
>>>first time in morning but can't describe the sound and says it lasts only
>>>as
>>>long as a finger snap.
>>>
>>
>><snip>
>>
>>>Am I chasing nothing or what is a valid approach?
>>>
>>>Thanks, Dick
>>>
>>
>>get someone else to start your aircraft and stand beside him
>>listening. obviously he thinks he can hear something.
>>probably a clack clack clack sound which quickly vanishes as the valve
>>frees up and goes back to tolerances with the rocker.
>>
>>just a thought.
>>Stealth Pilot
>>Australia.
>
>
>

[Jan Carlsson]

If following the firing order it is easy to know what cylinder it is.

But I got the feeling it can be the hydraulic lifter that is slow to fill up
after engine start, it usually make a ticking sound that quit after a few
seconds.

pull the prop slow and then fast and listen from the exhausts (or carb) and
you know where to start looking.

Jan
www.jcpropellerdesign.com

"Scott" > skrev i meddelandet
...
> And if you're REALLY (un)lucky (like I was), you might hear air rushing
> past a stuck exhaust valve and hear the hiss out the exhaust pipe when
> pulling it through. Then you'd have it narrowed down to 2 cylinders...
>
> Scott
>
>
>
> Dick wrote:
>
> > good thought. Another I heard is to pull prop thru all 4 cylinders and
feel
> > for "flat" cylinder.
> > "Stealth Pilot" > wrote in message
> > ...
> >
> >>On Sun, 22 May 2005 11:54:45 GMT, "Dick" > wrote:
> >>
> >>
> >>>Old WW2 mechanic says he hears a sticky valve on my C-85 when I fire up
> >>>for
> >>>first time in morning but can't describe the sound and says it lasts
only
> >>>as
> >>>long as a finger snap.
> >>>
> >>
> >><snip>
> >>
> >>>Am I chasing nothing or what is a valid approach?
> >>>
> >>>Thanks, Dick
> >>>
> >>
> >>get someone else to start your aircraft and stand beside him
> >>listening. obviously he thinks he can hear something.
> >>probably a clack clack clack sound which quickly vanishes as the valve
> >>frees up and goes back to tolerances with the rocker.
> >>
> >>just a thought.
> >>Stealth Pilot
> >>Australia.
> >
> >
> >

[Robert M. Gary]

I would do a wobble test. If you do have a slight stick to the valve it
will get worse and at some point could cause in flight problems. A
wobble test should set your mind at ease.

[Deborah McFarland]

Dick,

The hesitation at 1100-1200 rpms in a C-85 is normal. I have it on mine (275
smh with 0-200 conversion stc) as do most of my Luscombe brethren with the
C-85.

I recently had an exhaust valve to stick in flight. It was interesting to
say the least, and in reaction to that experience I would like to pursue a
glider rating ;-).

My valve in my 275 hour ECI cylinder was stuck but good. My engine guy
reamed it out a little as he thought the clearance was a little tight. MMO
is now part of my regular maintenance routine.


Deb

--
1946 Luscombe 8A (His)
1948 Luscombe 8E (Hers)
1954 Cessna 195B, restoring (Ours)
Jasper, Ga. (JZP)

"Dick" > wrote in message
...
> Old WW2 mechanic says he hears a sticky valve on my C-85 when I fire up
> for first time in morning but can't describe the sound and says it lasts
> only as long as a finger snap.
>
> Wants me to add Marvel Mystery oil. I use Aeroshell 100 (50 weight) and
> change it every 25 hours.
>
> I can't detect any roughness upon initial start around 900-1000 rpm in
> front of my hanger nor during the taxi a couple of minutes to a runup
> spot. On throttling up to 1500 for the mag check, I notice a slight
> hesitation around 11-1200 rpm that goes away quickly and thought was just
> from the low speed taxi.
>
> Since I had to put a rental down about 7 years ago for a valve problem
> (per the FBO), there is a little "pucker" factor regarding this
> conversation <G>.
>
> Light Plane Maintenance book references "hand proping before first start
> of day to find 'flat' cylinder". Not sure I can identify a rapid falloff
> in turning resistance (books definition).
>
> Concern doesn't seem to get to the point where the "cold cylinder" test is
> applicable as doesn't last long (his finger snap).
>
> Am I chasing nothing or what is a valid approach?
>
> Thanks, Dick
>

[[email protected]]

Deborah McFarland wrote:
> Dick,
>
> The hesitation at 1100-1200 rpms in a C-85 is normal. I have it on
mine (275
> smh with 0-200 conversion stc) as do most of my Luscombe brethren
with the
> C-85.

This is fairly common on a lot of carbureted engines. It usually
occurs at the point where the carb is shifting from the idle circuit to
the main jet.

John Galban=====>N4BQ (PA28-180)

[[email protected]]

Dick wrote:
<snip>
> Light Plane Maintenance book references "hand proping before first
start of
> day to find 'flat' cylinder". Not sure I can identify a rapid falloff
in
> turning resistance (books definition).
>
I think you can. It should be pretty straight forward. As you
rotate the prop you can feel the resistance from each cylinder on the
compression stroke. If you hit a cyl. with a stuck valve, you'll
notice the difference in resistance right away. If it's quiet, you
should also hear hissing at the exhaust pipe if it's an exhaust valve.


John Galban=====>N4BQ (PA28-180)

[Dick]

Could you describe the "wobble test"? Not familiar with the term.
Thans, Dick
"Robert M. Gary" > wrote in message
oups.com...
>I would do a wobble test. If you do have a slight stick to the valve it
> will get worse and at some point could cause in flight problems. A
> wobble test should set your mind at ease.
>

[Dick]

Two of us tried the "armstrong method" (rotating by hand) yesterday and both
thought we got very slightly lower resistance, but on different cylinders on
opposite sides of the engine. Him #1 and me #2 &#4..

Decided to do a "differential test" with the engine cold, rather than warmed
up. Our thought being that any matter between seat and valve would
indicate a lower reading.

Observed 78/80 on three and 77/80 on the fourth. For last 5 years the
readings have been in the 76-78 over 80 psi range.

Don't know if it matters in my case, but realize now that I've never
listened for any leaks.

My helper did mention that he thought the leakdown period should be about 5
minutes instead of just holding 80 psi long enough to observe where
indicator stops...

Thanks, Dick

ps Glad to hear that 11-1200 rpm hesitation is normal.

[Corky Scott]

On Tue, 24 May 2005 11:03:11 GMT, "Dick" > wrote:

>Could you describe the "wobble test"? Not familiar with the term.
>Thans, Dick
>"Robert M. Gary" > wrote in message
oups.com...
>>I would do a wobble test. If you do have a slight stick to the valve it
>> will get worse and at some point could cause in flight problems. A
>> wobble test should set your mind at ease.

It literally means removing the rocker arm and valve spring, grabbing
the valve stem and seeing if you can wobble it back and forth. If you
can it means the valve guide is worn.

The valve guide has to hold the valve in it's cylinder without
wobbling because if it's wobbling it isn't seating on the valve seat.
If it isn't seating on the valve seat properly, it's leaking. If it's
leaking, it's either burned or about to be burned (if we're talking
about exhaust valves).

See: http://egaa.home.mindspring.com/engine1.htm for an extremely
comprehensive look at the issue of valve guide wear in parallel valve
Lycoming engines.

Corky Scott

[Robert M. Gary]

Here are some interesting pictures of what can happen when the engine
is unhappy...

http://carneyaviation.com/enginefire/


-Robert

[Morgans]

"Robert M. Gary" > wrote in message
oups.com...
> Here are some interesting pictures of what can happen when the engine
> is unhappy...
>
> http://carneyaviation.com/enginefire/

Ahh, that's not so bad! Find all the pieces, and weld them back together.
Try to get to that TBO, that you got cheated from! ;-)
--
Jim in NC

[Scott]

They call that the "Continental cough"...My A-65 doesn't do it, my dad's
C-85 doesn't do it, but my old C-85 on my Chief did. Don't think that
is worth worrying about...

Scott
http://corbenflyer.tripod.com


Dick wrote:

> Two of us tried the "armstrong method" (rotating by hand) yesterday and both
> thought we got very slightly lower resistance, but on different cylinders on
> opposite sides of the engine. Him #1 and me #2 &#4..
>
> Decided to do a "differential test" with the engine cold, rather than warmed
> up. Our thought being that any matter between seat and valve would
> indicate a lower reading.
>
> Observed 78/80 on three and 77/80 on the fourth. For last 5 years the
> readings have been in the 76-78 over 80 psi range.
>
> Don't know if it matters in my case, but realize now that I've never
> listened for any leaks.
>
> My helper did mention that he thought the leakdown period should be about 5
> minutes instead of just holding 80 psi long enough to observe where
> indicator stops...
>
> Thanks, Dick
>
> ps Glad to hear that 11-1200 rpm hesitation is normal.
>
>
>
>

[David O]

"Deborah McFarland" > wrote:

>Dick,
>
>The hesitation at 1100-1200 rpms in a C-85 is normal. I have it on mine (275
>smh with 0-200 conversion stc) as do most of my Luscombe brethren with the
>C-85.
>
>I recently had an exhaust valve to stick in flight. It was interesting to
>say the least, and in reaction to that experience I would like to pursue a
>glider rating ;-).
>
>My valve in my 275 hour ECI cylinder was stuck but good. My engine guy
>reamed it out a little as he thought the clearance was a little tight. MMO
>is now part of my regular maintenance routine.
>
>
>Deb


Hey Debby, it's been far too long. Does the gang still get together
Saturday afternoons at JZP? Gotta catch up.

David O

[nrp]

Wow - what mayhem! I hope you'll post the prognostication on what
failed first. Congrats on a safe landing.

>From your pix it could look like the con rod failed, but were either of
the the rod bolts found? There were some bogus bolts some years back
now removed by an AD and a lot of bogus bolt publicity. I understand
the normal spec for Lycoming rod bolts does not involve tightening only
to a torque, but rather ends with a turn-of-the-wrench method. If the
bolt strength happens to be low, the usual torque-only procedure won't
detect it unless the mechanic is very experienced and suspicious.

Be careful that failed parts don't mysteriously get lost by those that
might have some resposnibility for this mechanical carnage.