Well, before you invest too much time/money trying to set the point timing, please know that this procedure isn’t a “must do”. Keep in mind that an older engine probably has some slop in the mag plate/crank, so the benefits of performing this exact procedure may be negligible. Also keep in mind that a new set of points should be set to open a little wider than .020″ to account for initial rubbing block wear.
All that being said, you can try this method of timing the points without the tool:
Remove the coils and condensers from the mag plate, leaving only the points in place. Set new points to .022″/.020″ for old points on the high side of the cam. Now, you have room to connect the ohm meter leads up into the mag plate with the flywheel installed and snugged up. Make up two little leads with eyelets that can be attached to both points terminals that will run down and out of the mag plate and be connected to an ohm meter. Connect the other end of one of these leads to one ohm meter lead, the other ohm meter lead should be attached to a decent ground on the bottom of the mag plate. Please make sure you have calibrated your meter beforehand.
With the flywheel installed and snugged up, turn it slowly until the appropriate has mark underneath approaches the two has marks on the mag plate. Make note of where the ohm meter goes from zero ohms to infinity. Ideally, this will happen when the flywheel hash mark is on the first hash mark on the mag plate for new points, or midway between the mag plate hash marks for old points. You can readjust the points to achieve this perfect timing through the opening in the flywheel….
Please note that a JW18 has the cover over the flywheel so the points are accessible with the flywheel on….If your engine is really a 1966 model, it looks like the flywheel does not have this cover, so the points are not accessible with the flywheel in place…D
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