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Re: Checking oil pump
Here are pics. I have removed the end caps. Inside is the worm gear driven by the crank. This turns a 90 deg. shaft that turns a hollow tube on top of it. The base of the shaft has two lobes on it, that raises the tube position depending upon the rotation of the variable ratio shaft below it. These operate much like a camshaft, providing variable lift during it's rotation. If the throttle is in the idle position, and the variable shaft is not in contact with the 90 deg shaft, then the tube remains down during it's rotation. If the throttle is opened, the variable shaft rotates, pushing the 90 deg shaft up at two points during each revolution, causing the tube to raise up and down twice during each revolution.
The tube is fed with oil from the tank, which fills it from the bottom. There are various holes drilled through it, that correspond to receiving holes in the pump body surrounding it, going to the feed lines to the engine. When the tube is in the full down position, the oil system is primarily going off gravity feed, with very low flow out the side holes. However when the 'cam' is on, and the tube is raised twice during each revolution, the oil is trapped in the center as the tube is coming on it's down stroke, slightly pressuring it. When the holes line up during rotation is is released under that pressure pumping more oil during each revolution to the block.
Below are pics then movies.
Failures of the actual pump are relatively rare, but do happen. The Worm gear to 90 deg shaft can strip or get damaged teeth. The worm gear drive can be broken by forcing the crank mesh during assembly. The spring between the tube and 90 deg shaft holding it, can break or weaken. The variable shaft can bend or break.
None of these parts are gauranteed interchangeable with other models of pump, nor are internal parts available for purchase from anywhere.
Here are pics. I have removed the end caps. Inside is the worm gear driven by the crank. This turns a 90 deg. shaft that turns a hollow tube on top of it. The base of the shaft has two lobes on it, that raises the tube position depending upon the rotation of the variable ratio shaft below it. These operate much like a camshaft, providing variable lift during it's rotation. If the throttle is in the idle position, and the variable shaft is not in contact with the 90 deg shaft, then the tube remains down during it's rotation. If the throttle is opened, the variable shaft rotates, pushing the 90 deg shaft up at two points during each revolution, causing the tube to raise up and down twice during each revolution.
The tube is fed with oil from the tank, which fills it from the bottom. There are various holes drilled through it, that correspond to receiving holes in the pump body surrounding it, going to the feed lines to the engine. When the tube is in the full down position, the oil system is primarily going off gravity feed, with very low flow out the side holes. However when the 'cam' is on, and the tube is raised twice during each revolution, the oil is trapped in the center as the tube is coming on it's down stroke, slightly pressuring it. When the holes line up during rotation is is released under that pressure pumping more oil during each revolution to the block.
Below are pics then movies.
Failures of the actual pump are relatively rare, but do happen. The Worm gear to 90 deg shaft can strip or get damaged teeth. The worm gear drive can be broken by forcing the crank mesh during assembly. The spring between the tube and 90 deg shaft holding it, can break or weaken. The variable shaft can bend or break.
None of these parts are gauranteed interchangeable with other models of pump, nor are internal parts available for purchase from anywhere.
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