help needed
Mon Feb 14, 2011 12:00 pm
Hi
I am a french past flight engineer, retired since 12 years and I share my time between a little aircraft museum and training students in aircraft maintenance.
I have a problem with a Continental W670A engine fitted on a Morane 317 we have enterely rebuilted. Does somebody can give me the diagram for the opening and closing of the inlet and exhaust valves.
We have overhauled this engine due to internal rust and we have no manual giving indication on the right position of the camplate plate when the piston of the N°1 cylinder is a the "high dead point" (sorry but I am french and I dont know perfectly the right words)
Every information about will be welcomed
Thanks
I am a french past flight engineer, retired since 12 years and I share my time between a little aircraft museum and training students in aircraft maintenance.
I have a problem with a Continental W670A engine fitted on a Morane 317 we have enterely rebuilted. Does somebody can give me the diagram for the opening and closing of the inlet and exhaust valves.
We have overhauled this engine due to internal rust and we have no manual giving indication on the right position of the camplate plate when the piston of the N°1 cylinder is a the "high dead point" (sorry but I am french and I dont know perfectly the right words)
Every information about will be welcomed
Thanks
Re: help needed
Mon Feb 14, 2011 12:32 pm
How did you overhaul the engine without the overhaul manual? The pinch bolt between the two crankshaft halves needs to be torqued to obtain the proper bolt stretch.
Top Dead Center is the American term for when the piston is at the top of its stroke.
Top Dead Center is the American term for when the piston is at the top of its stroke.
Re: help needed
Tue Feb 15, 2011 1:08 pm
Hello bdk
Thanks for your awser.
We effectively have the manual and the man in charge of this engine tolds me the pinch bolt has
been properly torqued.
This engine runs properly between idle and 1800 RPM but when we wants to increase the RPM, we ear some bad noise coming out from the exhaust pipes.
We suspect an earlier opening of the exhaust valves but we are not 100% sure of that.
If you have the diagram (or any other thing showing the ajustments for a good timing of the valves), we will be able to check it
Regards
Thanks for your awser.
We effectively have the manual and the man in charge of this engine tolds me the pinch bolt has
been properly torqued.
This engine runs properly between idle and 1800 RPM but when we wants to increase the RPM, we ear some bad noise coming out from the exhaust pipes.
We suspect an earlier opening of the exhaust valves but we are not 100% sure of that.
If you have the diagram (or any other thing showing the ajustments for a good timing of the valves), we will be able to check it
Regards
Re: help needed
Tue Feb 15, 2011 7:55 pm
Hopefully someone will have a good answer. When I sold my Stearman, all my W670 manuals went with it.
About all you can do from the outside is to adjust the valve clearances at the rocker arms. To change the cam timing you have to pull the engine apart (take off the accessory case). If that is the problem, you might also see contact between the valves and the pistons. Look inside the spark plug holes with a flashlight and inspect the tops of the pistons. The pistons may not be able to touch the valves, but if they did, you'll need to remove the valves to make sure they aren't bent and that the valve guides aren't damaged.
Which propeller do you have? The steel bladed McCauley prop has an RPM range that you have to avoid and that should be placarded in the cockpit. I'm not sure, but the other props may have similar limitations. Also make sure that the pin is in place on the prop shaft spline so that the prop is indexed correctly to the crankshaft. There is a blind spline inside the hub that lines up with the location of that pin.
Check the oil screen for metal parts. My engine began to fail when the cage around the crankshaft ball bearings came loose. The balls didn't fall out, but they all moved to one side and allowed the crankshaft to flex and caused a crack. When the ball bearings all moved to one side the engine had a nasty shake that felt like the ignition was failing.
The way I found this was watching outside when someone else ran the engine and I could see the prop hub wobbling.
This failure is what caused me to overhaul my W670 (I did it myself). That was a very long time ago, so check everything I say as my memories may not be very good.
About all you can do from the outside is to adjust the valve clearances at the rocker arms. To change the cam timing you have to pull the engine apart (take off the accessory case). If that is the problem, you might also see contact between the valves and the pistons. Look inside the spark plug holes with a flashlight and inspect the tops of the pistons. The pistons may not be able to touch the valves, but if they did, you'll need to remove the valves to make sure they aren't bent and that the valve guides aren't damaged.
Which propeller do you have? The steel bladed McCauley prop has an RPM range that you have to avoid and that should be placarded in the cockpit. I'm not sure, but the other props may have similar limitations. Also make sure that the pin is in place on the prop shaft spline so that the prop is indexed correctly to the crankshaft. There is a blind spline inside the hub that lines up with the location of that pin.
Check the oil screen for metal parts. My engine began to fail when the cage around the crankshaft ball bearings came loose. The balls didn't fall out, but they all moved to one side and allowed the crankshaft to flex and caused a crack. When the ball bearings all moved to one side the engine had a nasty shake that felt like the ignition was failing.
The way I found this was watching outside when someone else ran the engine and I could see the prop hub wobbling.
This failure is what caused me to overhaul my W670 (I did it myself). That was a very long time ago, so check everything I say as my memories may not be very good.
Re: help needed
Tue Feb 15, 2011 9:40 pm
Brandon,
you rebuilt the engine? I'm glad I never flew in that plane.no deathwish here
you rebuilt the engine? I'm glad I never flew in that plane.no deathwish here
Re: help needed
Tue Feb 15, 2011 10:50 pm
Nobody dead yet... Give it more time!
Re: help needed
Thu Feb 17, 2011 2:13 am
Hi everybody
Yesterday we checked all the engine timing
Ignition is OK on both magnetos
Inlet and exaust valves are OK
We have proceeded a new running
Engine starts easily
After a few minutes,The RPM has been increased to 1800
A few "bang" has been eared but the number is decreasing when temperature of engine oil increases
If we use the mixture command from full rich to lean for only 2 or 3 millimeters, the detonation noise appears
We thank this engine is too lean but after check on the carburator and inlet pipe (in case of additionnal air coming from a deficient seal) we did'nt found something
If somebody have encountered this problem before or have some genial idea, please let me know...
Thanks for helping
Yesterday we checked all the engine timing
Ignition is OK on both magnetos
Inlet and exaust valves are OK
We have proceeded a new running
Engine starts easily
After a few minutes,The RPM has been increased to 1800
A few "bang" has been eared but the number is decreasing when temperature of engine oil increases
If we use the mixture command from full rich to lean for only 2 or 3 millimeters, the detonation noise appears
We thank this engine is too lean but after check on the carburator and inlet pipe (in case of additionnal air coming from a deficient seal) we did'nt found something
If somebody have encountered this problem before or have some genial idea, please let me know...
Thanks for helping
Re: help needed
Fri Feb 18, 2011 12:07 am
Was the carburetor overhauled?
You might check with WIX member "Seafury1"
He was working on a Stearman that had a problem that I think turned out to be the carburetor:
viewtopic.php?f=26&t=37817&p=381518#p381518
You might check with WIX member "Seafury1"
He was working on a Stearman that had a problem that I think turned out to be the carburetor:
viewtopic.php?f=26&t=37817&p=381518#p381518