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Failed intake valve

 
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tshankland(at)sbcglobal.n
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PostPosted: Mon Dec 19, 2016 7:26 pm    Post subject: Failed intake valve Reply with quote

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’t know where they came from. They are not from the head itself, the manifold in not aluminum and I can’t 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


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ronhansen123(at)gmail.com
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PostPosted: Mon Dec 19, 2016 9:50 pm    Post subject: Failed intake valve Reply with quote

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(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
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’t know where they came from. They are not from the head itself, the manifold in not aluminum and I can’t 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



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tshankland(at)sbcglobal.n
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PostPosted: Tue Dec 20, 2016 6:31 am    Post subject: Failed intake valve Reply with quote

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 (ronhansen123(at)gmail.com)
Sent: Tuesday, December 20, 2016 12:50 AM
To: stratus-list(at)matronics.com (stratus-list(at)matronics.com)
Subject: Re: 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(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
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’t know where they came from. They are not from the head itself, the manifold in not aluminum and I can’t 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



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bryanmaxmartin(at)yahoo.c
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PostPosted: Tue Dec 20, 2016 8:32 am    Post subject: Failed intake valve Reply with quote

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’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’t 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’s 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.


Quote:
On Dec 19, 2016, at 10:25 PM, Tim Shankland <tshankland(at)sbcglobal.net (tshankland(at)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’t know where they came from. They are not from the head itself, the manifold in not aluminum and I can’t 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




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andynfultz(at)bellsouth.n
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PostPosted: Tue Dec 20, 2016 2:29 pm    Post subject: Failed intake valve Reply with quote

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(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
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’t know where they came from. They are not from the head itself, the manifold in not aluminum and I can’t 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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tshankland(at)sbcglobal.n
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PostPosted: Tue Dec 20, 2016 4:15 pm    Post subject: Failed intake valve Reply with quote

Andy F,
Was your failure also an intake valve?
Tim

From: ANDY N FULTZ (andynfultz(at)bellsouth.net)
Sent: Tuesday, December 20, 2016 5:29 PM
To: stratus-list(at)matronics.com (stratus-list(at)matronics.com)
Subject: Re: 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(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
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’t know where they came from. They are not from the head itself, the manifold in not aluminum and I can’t 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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andynfultz(at)bellsouth.n
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PostPosted: Tue Dec 27, 2016 7:21 am    Post subject: Failed intake valve Reply with quote

Sorry Tim for taking so long to reply, but just made it back to the hangar to confirm. It was an exhaust valve on the number 3 cylinder.
Andy F

Sent from my iPhone

On Dec 20, 2016, at 6:15 PM, Tim Shankland <tshankland(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
Andy F,
Was your failure also an intake valve?
Tim

From: ANDY N FULTZ (andynfultz(at)bellsouth.net)
Sent: Tuesday, December 20, 2016 5:29 PM
To: stratus-list(at)matronics.com (stratus-list(at)matronics.com)
Subject: Re: 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(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
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’t know where they came from. They are not from the head itself, the manifold in not aluminum and I can’t 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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tshankland(at)sbcglobal.n
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PostPosted: Wed Dec 28, 2016 3:15 pm    Post subject: Failed intake valve Reply with quote

Andy F,
That fits in with what I would expect, exhaust valves tend to fail due the the heat but mine is the first I have heard of of an intake valve just breaking. I am picking up both heads tomorrow. I had all the valves replaced. For the cost it is not worth the risk.

Tim

From: ANDY N FULTZ (andynfultz(at)bellsouth.net)
Sent: Tuesday, December 27, 2016 10:21 AM
To: stratus-list(at)matronics.com (stratus-list(at)matronics.com)
Subject: Re: Failed intake valve


Sorry Tim for taking so long to reply, but just made it back to the hangar to confirm. It was an exhaust valve on the number 3 cylinder.

Andy F

Sent from my iPhone

On Dec 20, 2016, at 6:15 PM, Tim Shankland <tshankland(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
Andy F,
Was your failure also an intake valve?
Tim

From: ANDY N FULTZ (andynfultz(at)bellsouth.net)
Sent: Tuesday, December 20, 2016 5:29 PM
To: stratus-list(at)matronics.com (stratus-list(at)matronics.com)
Subject: Re: 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(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
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’t know where they came from. They are not from the head itself, the manifold in not aluminum and I can’t 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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andynfultz(at)bellsouth.n
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PostPosted: Wed Dec 28, 2016 6:01 pm    Post subject: Failed intake valve Reply with quote

I'm just glad your valve problem didn't cost you an entire long block like mine did 😀. Good luck getting back in the air soon.
Andy F

Sent from my iPhone

On Dec 28, 2016, at 5:15 PM, Tim Shankland <tshankland(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
Andy F,
That fits in with what I would expect, exhaust valves tend to fail due the the heat but mine is the first I have heard of of an intake valve just breaking. I am picking up both heads tomorrow. I had all the valves replaced. For the cost it is not worth the risk.

Tim

From: ANDY N FULTZ (andynfultz(at)bellsouth.net)
Sent: Tuesday, December 27, 2016 10:21 AM
To: stratus-list(at)matronics.com (stratus-list(at)matronics.com)
Subject: Re: Failed intake valve


Sorry Tim for taking so long to reply, but just made it back to the hangar to confirm. It was an exhaust valve on the number 3 cylinder.

Andy F

Sent from my iPhone

On Dec 20, 2016, at 6:15 PM, Tim Shankland <tshankland(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
Andy F,
Was your failure also an intake valve?
Tim

From: ANDY N FULTZ (andynfultz(at)bellsouth.net)
Sent: Tuesday, December 20, 2016 5:29 PM
To: stratus-list(at)matronics.com (stratus-list(at)matronics.com)
Subject: Re: 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(at)sbcglobal.net (tshankland(at)sbcglobal.net)> wrote:
Quote:
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’t know where they came from. They are not from the head itself, the manifold in not aluminum and I can’t 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

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