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Building Tips and technical articles. => 1/2 A building. => Topic started by: Dennis Saydak on November 27, 2012, 06:13:33 PM
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Guys, I'm helping a newbie get started in C/L and I can't figure out how to remove the muffler from this engine. I'm thinking that the cylinder needs to be taken off to remove the muffler but there is no flat fin areas that will assist with appling a Cox wrench. Any help in this regard would be greatly appreciated. This engine will be used to teach some basic maneuvers such as loops & inverted flight.
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Hello Dennis, without the flats on the top of the head this does make removal a bit problematic. For starters, a heat gun would certainly help. I would tighten the glow plug pretty snug first. I would then put on some gloves and heat the case at the point where the cylinders threads into the case. I would rotate the engine during heating to assure even heat. While holding the engine with one hand and a glow plug wrench on the head see if the entire cylinder screws off without loosening the head. If the head comes loose, your going to need make a jig from two pieces of wood with two semi-circles cut out of them. Clamp the cylinder between the two blocks in a vise and try and unthread. DON'T use pliers. Ken
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I have used a peice of heavy rubber between the cylinder fins and a pair of pliers. Don't have to grip too hard to loosen.
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I drill a block of wood to match the cylinder diameter, cut the block in half and clamp the whole thing in a vice. Plenty of control and friction, no damage to the fins!
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At the risk of branding myself as a redneck hick of some sort, I've used pliers in the past. The cylinders in question are all marked up, but work just fine.
Do those of you that use wood use something especially hard, or does regular old fir do?
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Thanks guys, I'm going to try the split wood block trick after soaking the cylinder/muffler area with penetrating oil overnight. Nothing ventured, nothing gained.
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If you feel like you're squeezing the wood too hard, take Kennith's advise and heat the crankcase. It'll help you three ways: aluminum expands more than steel with heat, the crank case will be hotter than the cylinder, and if there's any gummed-up castor in the threads, enough heat will soften it. So with heat, everything should be lots looser and easier to take apart.
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It came apart easy using Larry's method. I probably didn't need to use the penetrating oil.