Pioneer 450 chainsaw

Old 09-20-23, 03:43 PM
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Pioneer 450 chainsaw

Hi All , I am restoring a vintage Pioneer chain saw , spec’s call for setting points at 30 degrees BTDC , how do I determine that point? Should I assume the high point on the shaft would be used to set the points should be set.?
Old 09-20-23, 11:49 PM
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I would set them to that gap at the points open-most spot. The highest spot on the points cam lobe.
Old 09-21-23, 05:34 AM
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Unless the plate holding the points can be rotated with respect to the camshaft, the spark timing is fixed by gearing. Follow Cheese's response for setting point gap.
Old 09-21-23, 07:42 AM
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would also just set the gap to specs at the most open point on the lobe could also just eliminate the points if you wanted to convert it over.
Old 09-21-23, 11:46 AM
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If there in no mark or tab on the engine indicating TDC and/or anything indicating degrees (e. g. 10°, 20°, 30°) before TDC then you'll need to pull the spark plug and start measuring.

When the piston is at its highest point in the cylinder, that is TDC (top dead center), and likewise when the piston is at its bottom most point, that is BDC (bottom dead center).

Referencing a circle that has 360 degrees, TDC will be at 0° and BDC will be at 180°. To locate 30° on the circle before TDC rotate the crankshaft to make the piston move to a point that is 30° before TDC.

Imagine the Degree Wheel (image below) attached to the engine's crankshaft that moves the piston. Just by imagination you should be able to get very close to the 30° BTDC location to set the points gap.

Old 09-21-23, 03:59 PM
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Don't make something simple difficult. Set it to the highest point on the lobe then set the gap on the points . I have been doing it that way for 65 years and have had no problems. Have a good one. Geo
Dixie2012 voted this post useful.
Old 09-21-23, 06:38 PM
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All great responses but I like setting the points on the high spot on the shaft, my original thought.

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