The way to find the cylinder with the stuck valve is to feel your cylinders after running the engine briefly, it will be the cold cylinder. Colder than the others.
The rope trick has been performed several times on my Ercoupe C-85. It saves time and money if it works. I have seen no harmful effects from doing the rope trick such as particles from the rope. From time to time I have just removed the rocker box cover and "spiked" the valve. With the rocker box cover removed, you can tell which one it is because the valve stays open and the rocker arm can be rocked back and forth loosely with your fingers. To spike it means to push the valve in and hopefully it will spring back out all the way. Please don't do the rope trick or spiking while learning but involve a mechanic who has done this before. Once a very good old time mechanic dropped my exhaust (the offending) valve into the cylinder and fished the stem out the lower spark plug hole, without removing the cylinder. If memory serves me, he used a string tied to the valve stem to accomplish all this. He then dressed the offending stem with emory cloth and somehow fished the valve stem back through the valve guide and reinstalled the spring and keepers. DON'T TRY THIS ONE AT HOME ! Also, I have had stuck valves that eventually cleared up (on the ground) just by my running the engine for a while until it became unstuck. Works for me most of the time, but when it doesn't, it just doesn't. Marvel Mystery Oil in the Sump probably is a better prophylactic than putting in in the fuel where it goes into the combustion chamber and is burned. Marvel Mystery Oil is a solvent, petroleum distillate, in a very light oil. It will reach the valve guides via the engine oil in the sump. Air cooled engines have looser tolerances than do water cooled engines. Therefore in aircraft engines, one may be able to use less MMO percentage wise in the sump than is recommended on the can for cars. Too much solvent, MMO or any other kind, may wash down your cylinder walls and lessen the lubrication qualities of the aviation grade oil in your sump. Putting it in the fuel cuts the octane, that's ok, and may not do much for the valves. On the other hand, it may reach the exhaust valve stems and guides when added to the fuel. It is all a Mystery. That's why they call it Marvel "MYSTERY" Oil. One caveat to remember is this, MMO is not an approved aviation product, although many people have used it for many years. I and several of my aquaintences have used it. I have stopped adding MMO to my sump (and my fuel) because I think it is better to do frequent oil changes keeping your aviation grade engine oil in very good condition as a preventative measure for stuck valves. Disclaimer: I am neither recommending for or against any of the things written about here. If there are differing opinions, before criticizing me, these are my personal experiences and conclusions regarding stuck valves and MMO. If you have a different opinion or experience, I am interested. Skipper Barfield Ercoupe 99398 ________________________________________________________________ YOU'RE PAYING TOO MUCH FOR THE INTERNET! Juno now offers FREE Internet Access! Try it today - there's no risk! For your FREE software, visit: http://dl.www.juno.com/get/tagj. __________________________________________________________________________ ______ To unsubscribe from this list please send mail to [EMAIL PROTECTED] _____________________________________________________________ Get your favorite topic delivered daily. http://www.topica.com/t/11
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