• Welcome to the new SAOCA website. Already a member? Simply click Log In/Sign Up up and to the right and use your same username and password from the old site. If you've forgotten your password, please send an email to membership@sunbeamalpine.org for assistance.

    If you're new here, click Log In/Sign Up and enter your information. We'll approve your account as quickly as possible, typically in about 24 hours. If it takes longer, you were probably caught in our spam/scam filter.

    Enjoy.

Vaccum Advance

Scotty

Scotty

Silver Level Sponsor
How important is it to run mechanical Vaccum Advance? My SIV 1725 is running ok but I noticed the advance on the dizzy is turned all the way in. Timing is set by the book.

Is there anything I should be concerned about with this?

I do have a servo and have the line for that plugged into the Weber. The mechanical advance line is plugged in as well.

Beyond the Weber running a little rich (using Autolite 64 plugs to compensate) the car runs solid.

Thanks in… advance :)
 
puff4

puff4

Platinum Level Sponsor
That knurled knob on the distributor's vacuum advance module doesn't actually change the amount of advance. It changes the engine's overall timing when rotated, but the mechanical and vacuum advance amounts are unchanged. The knob was there to allow for varying quality fuel, back in the day... sometimes you'd get decent octanes, sometimes you'd get crap fuel... and that knob allowed you to easily change the timing to adjust for this. Ideally, before setting the timing you should set this to a centered position (half way through the adjustment path), and then set your timing by rotating the distributor the requisite amount. This would then allow an equal amount of advance and retard to be dialed in when needed. But it's somewhat academic these days when fuel is pretty uniform... so changing it to be 'correct' doesn't really matter a lot if you're never going to use it.
 
B

beamdream

Gold Level Sponsor
Not wanting to steal the OP' s thunder, but using a vac guage takes a lot of guesswork out of timing.

Plumbing a vac guage into the inlet manifold (I use a temporary fitting in the manifold drain port) allows you to tune both mixture and ignition (in my case) a steady 22" of vacuum at idle, this gives me best combination of power,economy and smooth idle/running.

I'm using a S1 1600 with the original WIA Zeniths running on 95 RON, obviously every car is different but aiming for 22" of vacuum at idle is a good starting point. You could also temporarily use the brake booster port (if fitted ) as a vac source.
 
You must log in or register to reply here.
Top