Vacuum advance setting

[Onne]

Hello all
Just wondering, there is a screw on my distributor housing, which seems to be attached to the vacuum advance. It's now fully tight, so no movement in the vacuum advance thing itself.
Is this how it should be, or is the screw for fine adjustment?

If have also tightened the whole housing, which had been loose for more than a year...
I did wonder why my timing changed every so often. Thought it was the weather.

[Alec]

Hello Onne,

if you are talking about the knurled nut, then that is to fine tune the timing. As it is you have no adjustment one way and all the other. It does not affect the vacuum advance at all as that is internal.
Ideally set the nut to mid way, then set your engine timing and then fine tune with the nut.

Alec

[Willie]

Eleven clicks of that knurled nut equals one degree of timing adjustment.

[Packedup]

I've had a couple of these where the knob has seized up due to corrosion. A bit of grunt with pliers has usually done the trick. Most likely it's at the full end of it's travel though

[Onne]

I will give it a go. My timing is spot on though, now that I have set it using a timing light, so I'll leave it there then!

[Alec]

Hello Onne,

I hope you disconnected the vacuum advance when you timed it then?

Alec

[Onne]

I did. Been down that route before...

[bmcecosse]

The only accurate way to set the timing is with your ear - it should be 'just not' pinking. Static setting is only a starting point - literally - to get the engine started.

[Onne]

I know BMC. I have now got it on the setting where it revs the merriest

[bmcecosse]

Excellent!

[Cam]

In fact the the manual for the series MM it says, set to TDC and road test for optimal setting!

[Onne]

those were the wise people!