To work on the engine I needed to remove the generator assembly. Four bolts and the stator housing came right off. However, the rotor was stuck on the crankshaft. Those of you who have worked on generators know that there's nothing holding the rotor onto the shaft once the one long bolt is removed. It's just a tapered fit between the two pieces. However, about fifty years of being together means they didn't want to come apart. They were bound together very, very tightly. I did some poking around on other web sites and ran across a good way to separate the two parts. Unfortunately when I read how to do it there were no good pictures to illustrate the method. So I decided to fill-in the blanks. Special thanks go to Dave Iwuc of RUC Enterprises for guidance in this process.
Here we go...
Here's the rotor currently jammed in place.
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Here are the bolts related to the removal. The one on the left is the one that actually held the rotor in place. It isn't part of the removal process and is shown here only for reference. I bought the other two bolts in the picture and a length of solid metal rod.
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I cut the head off of the new 5/16 bolt and used a Dremel tool to grind a slot into the top of it so that I could use a screwdriver to tighten it into position.
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This bolt was too short to reach from the crankshaft all the way too the top of the rotor shaft. That's not necessarily a bad thing. This is where the 5/16 rod comes into play. I cut the appropriate length of rod and placed it between the homemade "screw" and the soon to be added extractor bolt. This would give me the convenience of getting just the length I needed and also prevented the screwdriver slot from getting mashed and distorted when the extractor bolt was tightened against it.
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The rotor needed a little modification now. The inside of the shaft was totally smooth since nothing screws into it. The long bolt passes through the hollow shaft and into the engine crankshaft. To get the "gear puller effect" I had to add threads to the inside of this shaft. I tapped it using a 3/8"-24 tap. It doesn't show too well in this picture but there are nice new threads in that blurry area.
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Now comes the easy part. I dropped the headless 5/16 bolt into the rotor shaft and screwed it into the crankshaft with a long thin screwdriver. Then I dropped the dummy 1-1/2" long piece of rod on top of it. Then I screwed the 3/8" bolt into the newly tapped threads inside the rotor shaft. As the bolt is tightened it pushes against the dummy rod which in turn pushes against the bolt that is screwed into the engine crankshaft. Since the bolt cannot go down the rotor must come up!
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As I tightened the bolt I could feel the whole assembly torquing up. Then with a loud pop the two pieces separated. I unscrewed the 3/8 bolt with my fingers and lifted the rotor off with my hand. There was NO WAY it would've come apart otherwise. (Note the homemade screw still in position in the crankshaft.) I'm certainly keeping my homemade parts for the next time I need to work on a generator.
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