Quote:
Originally Posted by three4rd
Gary - yeah, you heard me right. I've rolled the flywheel over and over to make sure. That's what I mean when I say that something seems way off. My piston is at the top long before the S appears in the window. And yet it appears that the points start closing right as the power stroke begins - so the points must be staying open a long time as I mentioned. The thing is, I didn't do anything that would change the relationship between when the points open with respect to the rest of the engine. So if the timing is way off, it must have been that way for a long time. No way to be sure until I use a test light I suppose. Right now I have a .020 gap set where the points are open at their widest. I paid more attention to that then where the points were with respect to the flywheel marks. This all feels like a puzzle for which I don't seem to have all the pieces, though in my case I suppose I have them all but aren't sure where they all go...and now please no jokes about my not having all my marbles LOL  |
Yes, the points stay open most of the flywheel rotation. They only close and open again very quickly to send a burst of current through the coil, which at that instant amplifies the current to give the burst of spark across the plug electrodes. That's why it is important that the points close exactly on the "S" mark so that the spark occurs just slightly before the piston reaches TDC (which is the "T" mark). The spark occurs before TDC because the high speed of the engine rotation puts the piston just past TDC by the time the spark ignites the fuel.
The .020 setting is really more of a ballpark setting. You may find that after you get your test light and finally get everything set just right on the "S" that the points may measure more or less than .020.