Distributor Vacuum Advance

[DZP]

Hi,
My distributor vacuum advance is not working.
I tested the vacuum advance unit disconnected from the distributor base plate, but I have to suck as hard as I possibly can, just to move the diaphragm a small amount.
It does hold vacuum if I block the pipe with my tongue.
So, how easily should the vacuum unit operate please?
Thanks,
Den

[022Dave]

Hello Den,

I have a handheld vacuum pump similar to this, which I use. The vacuum required is quite substantial, and this jobbie holds the pull to see if it’s leaking.

https://www.ebay.co.uk/itm/184633328443?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=3eWoxo2sSX6&sssrc=2349624&ssuid=xs4D-CjjQqS&var=&widget_ver=artemis&media=COPY

Dave

[DMT]

A simple way is to use a timing light to see if the timing changes when the vacuum is connected / disconnected.

[Lingen]

Den.
As you have found it really. It needs a greater vacuum than you can create "Orally" ( ) but if it holds one it must be working. A strobe light on the crankshaft pulley would verify that.
Mike.

[jbuckl]

Your level of suck & seal is not easy to calibrate… measure the ignition effect as already suggested.
graphs are in the r.o.m.

[richardthestag]

two types of distributor were fitted to Stag, single point and twin point

the 1973 rom doesn't have the settings for the twin point iirc. the reprint however does.

sucking on the vacuum pipe should make the baseplate twitch but I doubt anything more than that

If in doubt, remove it and send it to Martin at Distributor Doctor

[dasadrew]

no good for any calibration purposes, but if you have a disposable plastic syringe you can create a pretty good vacuum. I'm not a junkie, but I have them in all sizes in a box to measure, for example, hardener for 2 component paint and similar stuff, also for topping up dashpot oil etc.