The International Cessna 170 Association

We are driving the 100 miles to Athens after work to test for a:) stuck valves, b:) carb ice - obviously gone now, c:) vapor lock from burning car gas with winter mixture on a hot humid day at high power settings. The plan is to pull the prop thru and feel for a soft cylinder. Also, going to pull the dipstick and check for metal first.

Thanks again to all who posted suggestions, will keep you posted on the outcome.

Joe, good luck ! I hope it's a simple and inexpensive fix !
Rudy

Hey, Joe! You need any help? Who's included in the "we"?

Joe, Always and I mean !always! expect ice![size=24][/size]

You may have dodged the bullet this time but carb ice can kill you. Deana(better half) was doing pattern work during her pilot training and the Lycoming O-290 engine, which was supposed to be immune to carb ice, died while she was on final! Thank God that she had enough altitude to make it dead stick to the runway in the "glide like a rock" Piper Tri-Pacer she was flying. Needless to say, after that little incident she religiously applied carb heat in all conditons.

After reading your description of events I suspect that it was ice that caused your throttle to "stick" or not to close. Apparently you were in an atmospheric condition that was very condusive to carb icing. I hope for your sake that it was icing and not a sticking valve.Do keep us posted and let me know if there is anything that I can do to help. PS. SORRY YOU MISSED MY COOKING! GARY

Stuck Valve or maybe Valves! The rope trick unstuck the valve and the bird is back in the hanger at Grand Prairie. Maybe I had carb ice also, but more than likely I came in hot and high and ate the runway length up, I do not know for sure. Learned alot over this. I will fly thinking the engine is going to quit and where am I going to put her down at, much more than I use to. In an emergency landing, I will try to make it as normal of a situation as possible ( very informative phone conversation with George before Robert and I took off for Athens. Stu also provided me with very helpful info to get the job done. Robert was not going to let the 170 sit out in this Texas weather even if it meant pulling the wings and trailering it! ) I learned from these conversations and our community here on our site that carb ice can happen at cruise RPM and at any time, so from now on that will be the first thing I try. Thanks everyone, what a wonderful group we have - I certainly hope everyone's situations turn out as well as this one did for me and George. His slow B get's to wait a little longer before we have the race.HA

Who you callin' SLOW, Joe? Like Brother Dave Gardner once said, "I may be slow (not really-gh) , but I'm ahead of YOU!!"

Hey Joe great news! You might try running with Marvel in the gas. Used to use it all the time in the Jacobs engine and it really helped there.

Dave

For some marvelous reason, I had quit using Marvel when I switched to car gas a few months ago!!!!
George, how in the world do you figure you are ahead of me? I went to several TX fly-ins looking for you, and the only one you have showed up at was the one I did not make!

N1478D wrote:For some marvelous reason, I had quit using Marvel when I switched to car gas a few months ago!!!!
George, how in the world do you figure you are ahead of me? I went to several TX fly-ins looking for you, and the only one you have showed up at was the one I did not make!

Yes, Everyone noticed that you failed to show at the one that would make you eat your words! Aren't you a little-bit ?

My worry about flight safety has been addressed by the fact that the valve guides can be checked and maintained, George mentions this in his reply to the Rope Trick in The Hanger. There is a bulletin from Lycoming stating the need to check for reduced sized guides per so many hours. Not sure if Cont. has issued a bulletin or not. But, the fact that a mechanic can check/fix the guides on a regular basis, especially during the later hours of cylinder life greatly eases my worries of in flight engine problems.

flyguy wrote:Ron Massicot just finished 'reverse'* reaming the guides in two of his cylinders. His time spent removing the carbon from the back of the valve stem and (reverse) running a 'new' 7/16 hand reamer thorough the guides resulted in smoothing out the roughness he had experienced. He did not remove the cylinders to do this work.

*'Reverse' reaming means he turned the reamer backward to the way the flutes meant to cut. This has a burnishing effect without removing excess metal from the guide itself.

My personal opinion is that if the guide has excess material in the form of carbon or a slightly constricted guide body it would not hurt a thing to go ahead and ream it out. The tolerance of the inside diameter is such that ('foreward') reaming with a hand reamer would not go out of tolerance. Even if it did it is no big thing to have the guide inside diameter .002" over the diameter of the valve stem.

Good luck. Maybe we will see you soon. Gary

It's seems like this would be valuable information to move over to the hanger maybe under the rope trick, or an engine maint. heading.
George, is this something that we can do, or is it taken care of behind the scenes?
Gary, thanks again for this last weekends invitation. I was really excited and looking forward to all of the fun and the good cooking and beverages. Looking forward to when it works out in the near future. Take Care, and thanks again.

Done! Good , Joe! You can make such suggestiions to me also in a PM (private msg).
This is really great Software that lets us do this sort of operations, and have a much more useful Discussion Forum. Thanks, Dale! You make me look good! (A real feat!)

So I got carted off to the "HANGAR". Ifn i had wanted to be in that dark spooky place I wud have dun it maself! Iz'at lak gettin put in the corner at skool?

Neat trick GAY-O-HORN.

Now this message might ought to be in "Learn How to Land in EMERGENCY SITYUATIONS"! dU WE HAVE A CUBBY HOLE FER THAT IN YER fAMOUS hANGER?

Seriously Joe I am going to post a message over there about a technique taught to me in approach to land with a dead or dying engine.

There was the 40 minute flight bringing it home, and I have flown it twice more since the stuck valve. Every thing seems back to normal. Planning on doing a differential compression test fairly soon, and flying airport to airport and also will avoid flying over unfriendly terrain for a while. But it looks like it was a lead or carbon deposit that is gone now and she is ready to go

What is it with aircraft engines & stuck valves? I don't think I've ever heard of car engines sticking valves. Motorcycles have air cooled engines (real ones,that is,the kind that say Harley-Davidson on them!) & I never hear about them sticking vales either.
I assume the valves stick in the guide--is this due to carbon,lead ,or what? Seems like we have trouble with loose guides as well as tight guides,judging by the number of cylinders removed for guide replacement after failing the compression check at annual.

Eric