Today's Message Index:
----------------------
1. 06:31 AM - Re: Failed intake valve (Tim Shankland)
2. 08:32 AM - Re: Failed intake valve (Bryan Martin)
3. 02:29 PM - Re: Failed intake valve (ANDY N FULTZ)
4. 04:15 PM - Re: Failed intake valve (Tim Shankland)
Message 1
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| Subject: | Re: Failed intake valve |
Ron,
I think I have had good results on the guide front is that my design has
three radiators and the temperature runs right at 190 degrees.
Tim
From: ron hansen
Sent: Tuesday, December 20, 2016 12:50 AM
Subject: Re: Stratus-List: Failed intake valve
Tim,
Thanks for the info. I had a valve guide failure at <100 hours. I
believe I was running hotter than I thought due to poor fuel
distribution and poor instrumentation, though it was per Stratus
guidelines.
I can't think what the aluminum pieces are in your pic and I've had my
carbs apart, the heads off, and so forth. Sorry, but I'm stumped right
now. Maybe it will come to me.
Nice work getting back safely. It sounds easy, but it's a credit to you
that it sounds easy. That's hugely important to the reputation of
experimental aircraft.
Ron Hansen
On Mon, Dec 19, 2016 at 7:25 PM, Tim Shankland
<tshankland@sbcglobal.net> wrote:
As I sometimes tell my wife when I come home from the airport, I had a
little excitement today, she never like to hear that. The excitement I
had about two weeks ago occurred on climb out, I h was at full power and
about 2500 feet about a mile or so from the airport. There was a
distinct change in engine sound with some loss of power and vibration.
After completing the instant 180 back toward the airport I reduced power
and check gauges. Everything was fine, oil pressure and temperature.
Since I still had power and was high I descended to pattern altitude and
landed. The engine continued to run rough but with no mechanical noise.
I was able to taxi back to the hanger. I quick check showed all plug
wires attached and everything looked normal. Coming back the next day I
pulled the spark plugs, None were damaged although the ones on the port
side looked damp. Checking compression the back port cylinder had zero
compression. I pulled of the cowling and rocker arm covers. The valve
train was intact and working, the only change was that the .014 gap on
the exhaust valve was gone. I loosened the adjustment and checked
compression again still zero. Putting a hose the spark plug hole and
blowing I could hear the sound in the carburetor. I order not to have to
take the engine off I build a stand to hold the engine with the top
mounts removed. The attached picture is what I found. The exhaust valve
showed no damage or change but a large piece of the intake valve was
missing. A little shaking of the head dropped the piece out. It had been
blown into the intake manifold in the head and remained lodged there. As
large as it was it might not have been able to come out unless lined up
perfectly. The only mark on the piston or head was a small scratch that
you could have made with a screwdriver. To make the issue more confusing
the other two small pieces in the picture also fell out of the head.
They are aluminum and look as though they had broken off a cylindrical
section but with otherwise undamaged , thus they did not get into the
combustion chamber. My problem is I don=99t know where they came
from. They are not from the head itself, the manifold in not aluminum
and I can=99t find any damage to the carburetor. I recently
replaced the air filters, maybe they were lodged in there. Has anyone
else had an intake valve fail like this. Being cautious I took the other
head off and both are now in the shop having all valves replaced. I have
a little over 300 hours on the engine and there was no evidence of guide
movement. Any experience with this type of failure would be
appreciated.
Tim Shankland
Message 2
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| Subject: | Re: Failed intake valve |
I had a similar valve failure on my stratus engine several years ago. In
my case, the segment of the valve that broke off fell into the
combustion chamber and destroyed the piston. The piston had two cracks
across the entire face and most of the piston skirt ended up in the oil
pan in several small pieces. Fortunately, the piston remained attached
to the rod and the engine remained running until I could reach the
nearest airport.
Keep in mind that the piston itself is made of aluminum, but I don=99
t see how any pieces of the piston could end up in the head without
obvious damage to the piston. I would take the oil pan off and check for
metal. It would also be a good idea to cut open the oil filter and check
for metal.
You might want to take a good look at the bottom of the piston to check
for damage. I don=99t know if that can be done without splitting
the case, maybe you can get a borescope in there to take a look.
I suppose it=99s possible those metal fragments were lodged in the
head since it was originally built up, but it seems very unlikely. I
would be hesitant to trust that engine again until I found the source of
those pieces or at least verified that there was no damage anywhere
else.
--
Bryan Martin
N61BM, CH 601 XL,
RAM Subaru, Stratus re-drive.
> On Dec 19, 2016, at 10:25 PM, Tim Shankland <tshankland@sbcglobal.net>
wrote:
>
> As I sometimes tell my wife when I come home from the airport, I had a
little excitement today, she never like to hear that. The excitement I
had about two weeks ago occurred on climb out, I h was at full power and
about 2500 feet about a mile or so from the airport. There was a
distinct change in engine sound with some loss of power and vibration.
After completing the instant 180 back toward the airport I reduced power
and check gauges. Everything was fine, oil pressure and temperature.
Since I still had power and was high I descended to pattern altitude and
landed. The engine continued to run rough but with no mechanical noise.
I was able to taxi back to the hanger. I quick check showed all plug
wires attached and everything looked normal. Coming back the next day I
pulled the spark plugs, None were damaged although the ones on the port
side looked damp. Checking compression the back port cylinder had zero
compression. I pulled of the cowling and rocker arm covers. The valve
train was intact and working, the only change was that the .014 gap on
the exhaust valve was gone. I loosened the adjustment and checked
compression again still zero. Putting a hose the spark plug hole and
blowing I could hear the sound in the carburetor. I order not to have to
take the engine off I build a stand to hold the engine with the top
mounts removed. The attached picture is what I found. The exhaust valve
showed no damage or change but a large piece of the intake valve was
missing. A little shaking of the head dropped the piece out. It had been
blown into the intake manifold in the head and remained lodged there. As
large as it was it might not have been able to come out unless lined up
perfectly. The only mark on the piston or head was a small scratch that
you could have made with a screwdriver. To make the issue more confusing
the other two small pieces in the picture also fell out of the head.
They are aluminum and look as though they had broken off a cylindrical
section but with otherwise undamaged , thus they did not get into the
combustion chamber. My problem is I don=99t know where they came
from. They are not from the head itself, the manifold in not aluminum
and I can=99t find any damage to the carburetor. I recently
replaced the air filters, maybe they were lodged in there. Has anyone
else had an intake valve fail like this. Being cautious I took the other
head off and both are now in the shop having all valves replaced. I have
a little over 300 hours on the engine and there was no evidence of guide
movement. Any experience with this type of failure would be
appreciated.
>
> Tim Shankland
Message 3
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| Subject: | Re: Failed intake valve |
Looks and sounds like you got lucky. I had a similar incident at about 285 h
ours except that the entire valve broke on climb out at about 500 AGL. It de
stroyed the piston, bent the connecting rod and locked up the engine. All in
about 2-2.5 seconds. Thankfully I was able to do a 180 and land back on the
runway. Had to replace the engine as I also had holes in the case and a sev
erely damaged cylinder. I replaced mine with a RAM Performance long block.
Been going well now for about 300 hours.
Andy F
Sent from my iPhone
> On Dec 19, 2016, at 9:25 PM, Tim Shankland <tshankland@sbcglobal.net> wrot
e:
>
> As I sometimes tell my wife when I come home from the airport, I had a lit
tle excitement today, she never like to hear that. The excitement I had abou
t two weeks ago occurred on climb out, I h was at full power and about 2500 f
eet about a mile or so from the airport. There was a distinct change in engi
ne sound with some loss of power and vibration. After completing the instant
180 back toward the airport I reduced power and check gauges. Everything w
as fine, oil pressure and temperature. Since I still had power and was high
I descended to pattern altitude and landed. The engine continued to run rou
gh but with no mechanical noise. I was able to taxi back to the hanger. I qu
ick check showed all plug wires attached and everything looked normal. Comin
g back the next day I pulled the spark plugs, None were damaged although the
ones on the port side looked damp. Checking compression the back port cylin
der had zero compression. I pulled of the cowling and rocker arm covers. The
valve train was intact and working, the only change was that the .014 gap o
n the exhaust valve was gone. I loosened the adjustment and checked compress
ion again still zero. Putting a hose the spark plug hole and blowing I could
hear the sound in the carburetor. I order not to have to take the engine of
f I build a stand to hold the engine with the top mounts removed. The attac
hed picture is what I found. The exhaust valve showed no damage or change bu
t a large piece of the intake valve was missing. A little shaking of the hea
d dropped the piece out. It had been blown into the intake manifold in the h
ead and remained lodged there. As large as it was it might not have been abl
e to come out unless lined up perfectly. The only mark on the piston or head
was a small scratch that you could have made with a screwdriver. To make th
e issue more confusing the other two small pieces in the picture also fell o
ut of the head. They are aluminum and look as though they had broken off a c
ylindrical section but with otherwise undamaged , thus they did not get into
the combustion chamber. My problem is I don=99t know where they came f
rom. They are not from the head itself, the manifold in not aluminum and I c
an=99t find any damage to the carburetor. I recently replaced the air f
ilters, maybe they were lodged in there. Has anyone else had an intake valve
fail like this. Being cautious I took the other head off and both are now i
n the shop having all valves replaced. I have a little over 300 hours on the
engine and there was no evidence of guide movement. Any experience with th
is type of failure would be appreciated.
>
> Tim Shankland
> <100_4061.JPG>
Message 4
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| Subject: | Re: Failed intake valve |
Andy F,
Was your failure also an intake valve?
Tim
From: ANDY N FULTZ
Sent: Tuesday, December 20, 2016 5:29 PM
Subject: Re: Stratus-List: Failed intake valve
Looks and sounds like you got lucky. I had a similar incident at about
285 hours except that the entire valve broke on climb out at about 500
AGL. It destroyed the piston, bent the connecting rod and locked up the
engine. All in about 2-2.5 seconds. Thankfully I was able to do a 180
and land back on the runway. Had to replace the engine as I also had
holes in the case and a severely damaged cylinder. I replaced mine with
a RAM Performance long block.
Been going well now for about 300 hours.
Andy F
Sent from my iPhone
On Dec 19, 2016, at 9:25 PM, Tim Shankland <tshankland@sbcglobal.net>
wrote:
As I sometimes tell my wife when I come home from the airport, I had a
little excitement today, she never like to hear that. The excitement I
had about two weeks ago occurred on climb out, I h was at full power and
about 2500 feet about a mile or so from the airport. There was a
distinct change in engine sound with some loss of power and vibration.
After completing the instant 180 back toward the airport I reduced power
and check gauges. Everything was fine, oil pressure and temperature.
Since I still had power and was high I descended to pattern altitude and
landed. The engine continued to run rough but with no mechanical noise.
I was able to taxi back to the hanger. I quick check showed all plug
wires attached and everything looked normal. Coming back the next day I
pulled the spark plugs, None were damaged although the ones on the port
side looked damp. Checking compression the back port cylinder had zero
compression. I pulled of the cowling and rocker arm covers. The valve
train was intact and working, the only change was that the .014 gap on
the exhaust valve was gone. I loosened the adjustment and checked
compression again still zero. Putting a hose the spark plug hole and
blowing I could hear the sound in the carburetor. I order not to have to
take the engine off I build a stand to hold the engine with the top
mounts removed. The attached picture is what I found. The exhaust valve
showed no damage or change but a large piece of the intake valve was
missing. A little shaking of the head dropped the piece out. It had been
blown into the intake manifold in the head and remained lodged there. As
large as it was it might not have been able to come out unless lined up
perfectly. The only mark on the piston or head was a small scratch that
you could have made with a screwdriver. To make the issue more confusing
the other two small pieces in the picture also fell out of the head.
They are aluminum and look as though they had broken off a cylindrical
section but with otherwise undamaged , thus they did not get into the
combustion chamber. My problem is I don=99t know where they came
from. They are not from the head itself, the manifold in not aluminum
and I can=99t find any damage to the carburetor. I recently
replaced the air filters, maybe they were lodged in there. Has anyone
else had an intake valve fail like this. Being cautious I took the other
head off and both are now in the shop having all valves replaced. I have
a little over 300 hours on the engine and there was no evidence of guide
movement. Any experience with this type of failure would be
appreciated.
Tim Shankland
<100_4061.JPG>
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