Points Gap Setting N1

[spookefoote1956]

Morning everyone. On setting the points on an N1 mag the points start to open and the fag paper falls out. Lovely. No problem with setting that at 1/2" BTDC fully adv. After that at what part of the rotation are the points at their widest or is it just a case of rotate until they are at their widest?

Big love, Chris

[clive]

once the points are open they pretty much stay the same until they start to close again. However I don't understand your question. If you are checking the opening (12 to 15 Thou) you need to do this before setting the timing not afterwards. Or was this simply a theoretical question?

[spookefoote1956]

Just a theoretical question Clive

[Groily]

Usually there'll be a wee bit of variation as the points go through the 'open' phase, whether with a face cam or a ring cam. Often a few thou depending on wear etc etc.
I usually set gaps to 12 thou with the heel of the pushrod (face-cam) or opening point fibre heel just fully on the ramp, ie points just fully open.
That way, you get guaranteed snappy opening, which is good for best strength spark and least chance of arcing.
If, say, the points open a bit wider further round the open part of their rotation and you set the gap at its largest, it could well be a bit small when it's really needed. In no case do you want it less than 10 thou when they've just opened (imho) or more than 15 or 16 absolute max. ('Big' gives them more of a hammering when they close.)
Bear in mind too that a larger gap advances the timing, a smaller one retards it. Which is why a correct gap when setting the timing is important, particularly on motors with a bit of poke. Can't remember what each thou of gap = in timing terms, but it's more than one might think and a few thou 'off' on the gap can build up to quite a big variation in °BTDC.