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Old 11-10-2012, 02:29 PM
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When you put the cam sprocket on the cam, as you are building the motor, you phase the dot on the cam sprocket at 6PM and the dot on the crank sprocket at 12PM. This sets up cylinder #6 to fire at TDC. After getting the whole mess buttoned up, you must turn the crankshaft one revolution clockwise. This puts the cam sprocket dot at 12pm and the crank sprocket dot at 12PM and sets up cylinder #1 to fire at TDC. I have no idea why the GM engineers set it up that way, but they did. Seems to me that they could just as easily punched the dot on the other side of the cam sprocket and had 6PM/12PM be TDC for #1 instead of #6.
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