Valve guide sticking

Valve guide sticking

During our annual we discovered very low compression on the number 5 cyclinder.  Further investigation (pulling the valve cover) showed the exhaust valve loose in the guide.  There was some discoloration on the lower part of the spring.  I assume that was the result of heat or lack of heat.  Also, there was some small particles of alumnimum in the cover.

Anyone else experience this?

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Re: Valve guide sticking

Own a C-150G. Flown almost daily. Last winter had to pull #4 cyl. and have it re-worked. Engine would loose 100+ r.p.m. on climb-out at about 1500-2000 ft. a.g.l. This would only happen on the first flight of the day as the engine warmed up. Shop said the valves or guides? were coked. I change the oil and filter every 40hrs. Now I think #3 cyl. has the same problem, but not as bad yet. It is also more noticable right after an oil change, (strange). I guess this is a common problem on O200a"s. I don't know how to prevent this from happining. Does anyone?

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Re: Valve guide sticking

Had the same problem.....was advised to run a little Marvel Mystery oil in the Gasoline.  Told not to put it in the oil though.  Seems to work.  My 2 cents.

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Re: Valve guide sticking

Lycoming has a Service Instruction downloadable from its website at <http://www.lycoming.textron.com/support/publications/maintenancePublications/serviceInstructions/SI1425a.pdf> which describes suggested maintenance procedures to reduce the possibility of valve sticking. The document, SI 1425A, is four pages long and describes the "rope trick" in detail. This technique is applicable to TCM engines as well as Lycomings.

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Re: Valve guide sticking

It has been our experience that any exhaust valve leakage leads to valve failure in as few as ten flight hours.  Sometimes it takes a little longer.  If it were me, I'd fix it.  Nothing is going to improve the geometry short of replacing the guide.  Marvel Mystery Oil does nothing to aid this.  Staking does nothing.  Re-lapping will very temporarily improve things--maybe.

Walter Atkinson
Advanced Pilot Seminars

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Re: Valve guide sticking

Bill; I am surprised that your mechanic did not recomend pulling that cylinder.you are looking at a valve about to be swallowed. In other word, the valve stem will break,and the valve head will fall into the cylinder,and beat thrue the piston causing metal to be ingested in you moving parts then engine teardown,and overhaul. Pull the jug.marvel mystry oil nor relapping will help.Send yor cylinder to an overhaul shop. good luck. P.S. I've been an A/P for fifty years.

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Re: Valve guide sticking

I have a 182P which has burnt 12 exhaust valves in last 500 hours. Our mechanic has been fitting aluminium bronze valve guides to the exhaust side.These are outside spec within 80 hours. Has a bulletin been posted by TCM to specify Ni Bronze guides for the exhaust side? Any other ideas? Thanks

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