0300 Stuck valve today on take off!! Help

0300 Stuck valve today on take off!! Help

I have not long owned a 172B with an 0300 continental engine.
I love it so much and always runs so smooth. I haveread all the bits on here about leaning it etc and do so as much as i can!
Today about 1 min after takeoff, i lost a bit of power and the engine was viabratring.I checked mags/fuel etc but all ok.
Landed back at strip, and seems that one of the cylinders has no compression when i wind the prop over with my hand.
Does this mean i have a stuck valve??
Is it a major??
Ive heard storys of guys putting a piece of rope in the cylinder and turning the prop over and it pushes the valve shut?? Could i do this? will i cause damage and will it just stick again.
Is it a biggy to get the valves sorted so it wont happen again.
Apppreciate any tips??
Will be ringing engineer tomorrow and hopefully hell be able to drive out to the stip and check it out for me.
rwc

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Re: 0300 Stuck valve today on take off!! Help

I just worked on a 172B with a O-300 a couple weeks ago. found two cylinders almost dead. 10/80..The first step I always do is add air like your doing the compression check. with a rubber mallet using common sense tap the valves and see if the compression comes up to specs. if it doesn't step two... with air applied- take a screw driver and lightly apply side pressure at 12,3,6 and 9 o'clock position around the valve spring. if the compression comes up to specs or very close you have a worn guide and theirs nothing to do but repair the cylinder...if this also fails then use the rope trick.. I put yellow rope in the cylinder and removed the valve spring and keepers. removed rope, and pushed the valves in far enough to see the valve face. turn the valve and get a good look at it for wear. I cleaned up the stem and checked the valve seat.. if you put a piece of hose over the stem you can spin it a bit to clean up the face and guide. you can use lapping compound but you must make sure it is cleaned up really good so you dont cause more damage. put the rope back in the cylinder and push the valve all the way closed and put the springs and keepers back on.. I am an IA so the work is not a problem.. your call on what you feel comfortable doing.. it took me 1 1/2 hours to do both.. unfortunately one valve was burnt and it had to be removed due to a bad piston.. a piece of the ring ruined the valve..the other cylinder though came up to 78/80 a borescope is very handy to check the seat..

hope this helps

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Re: 0300 Stuck valve today on take off!! Help

I am having a similar problem with my O-200 that is in my 1966 150F. The problem first showed up at 500 AGL on take off where the engine would run rough, and then eventually clear up. Then the problem began occuring upon initial start-up. The engine runs to about 1000rpm, then drops significantly down to about 300 and then returns to 1000rpm. It sounds really "sick".Upon checking compression on the cylinders, one cylinder will be way below normal psi. however, it hasn't been the same cylinder on both occassions. I've been told various different things to diagnose the problem including valves sticking, carb malfunctioning, and cam being shot. Confusing and frustrating.

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