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Home-Built Tools Free Stuck Valves
"When exhaust valves stick on L-head type air or liquid cooled engines, I use a pair of simple low cost tools that I made to lift the valves and lubricate the stems," says Chester Clark, Ewing, Mo. "They let me free stuck valves quickly without costly valve removal, grinding, and readjustment. Works on smaller air-cooled engines such as Briggs & Stratton and Wisconsin, which have valves in the block and not in the head.
"One of the tools is used to lift the valve and the other for rotating. The lifting tool is made from two flat washers about 1/16-in. thick. The lower washer is notched to make room for the valve stem. It slides under the valve head. I welded three 1 1/2-in. long spacers vertically to the edges of the washers - two opposite each other and across from the center line of the hole and the other opposite the notch on the washer - to form a valve head cage assembly. A small slide weight is placed on a 6-in. long bolt, then a nut is threaded on so that a 3/4-in. length of threads is exposed. Then the bolt is inserted into the top washer on the lifter and tightened with another nut.
"The sliding weight is then used to pull the valve.
"The rotating tool is made from a short length of plastic pipe or PVC conduit which is sized to just slip over the outside diameter of the valve head. I cut 6 or 8 equal spaced slots 1 1/2 in. deep into one end of the pipe. I drilled a 3/8-in. dia. hole through both sides about 1 1/2 in. from the other end of the pipe. Then I slipped a radiator hose clamp over the slotted end and tightened it lightly to keep i on the pipe.
"I clean and lubricate the valve stem when the valve is in the maximum lifted po sition. Since it is usually the exhaust valve that's stuck in the Šup' position, I rotate the engine until the piston is just past top dead center on the exhaust stroke for that cylin der. I apply a small amount of lubricant o other loosening agent to the stem. Then I slip the notch of the lifting section of the too under the valve head. The slide hammer ac tion will free the valve and overcome the valve spring tension. The cleaned area on the stem should extend 1/8 in. beyond the nor mal travel range. Remove the lifting tool.
"Again apply a small amount of loosen ing agent to the stem. Slip the rotating too over the valve head and tighten the clamp Insert a bar or screwdriver shank through the holes. Use a repeated 30 degree rotating and lifting action to thoroughly clean the stem Repeat this operation until the spring alway returns the end of the stem back down onto the lifter from the extended travel range. Re peat the previous steps several times on al exposed valves. Rotate the engine crankshaf several times to cycle the valves and check for any sticking.
"This procedure usually requires less than a half hour and restores an engine to its origi nal operating condition."
Contact: FARM SHOW Followup Chester L. Clark, 840 County Road 115 Ewing, Mo. 63440 (ph 573 439-5918).


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1998 - Volume #22, Issue #2