Weber vacuum advance?

[atkinson40]

Truck runs like a rocket on the freeway.  Pulls strong and hard.  Has about 2K on the rebuild.  Electronic dizzy swap.  The Weber is a back ass wards French model. 

 

Problem is it idles a bit rough.  I pulled all the plugs and they look just as they should.  I was going to hook a vacuum gauge up to the vacuum advance port(wrong I know as there's no vacuum there at idle) to see if I could get insight into the idle problem. 

 

Although my brain was broke and I now know I should hook the vacuum gauge up to manifold vacuum, I discovered that the vacuum advance port has no vacuum at high rpms either??

 

I read the debates about if I need vacuum advance and am still confused. Any insight.  If so where do I get it.  Where its hooked up now ain't got nothin'.

 

Thanks Kevin

 

 

 

 

 

 

 

 

[datzenmike]

OK

 

Keep this in mind...

 

At idle the throttle plate is almost completely closed and very little air get in. For argument sake lets say half a cup per cylinder. So there's 50cc in a cylinder that is just short of being capable of 400cc when filled and all these molecules, even when compressed are not very tightly packed in there. When, lit the flame travels farther and slower between molecules across the combustion chamber.

 

At wide open throttle (WOT) there is 400cc's or 8 times as many molecules very tightly packed in there and the flame take a lot less time to burn completely.

 

As far as timing goes, idle or light throttle needs more advance than WOT. As intake vacuum is higher at idle and low speed and lower to almost zero at WOT, it can be used to advance the timing when needed.

 

A race car that is run only at WOT does not need vacuum advance.

 

Any vehicle that is driven at variable throttle positions will run more efficient if the timing is varied to match the throttle. Gas mileage and part throttle performance will increase.

[banzai510(hainz)]

I adjust the timming and the carb mixture for best results.  maybe ck the dizzy for bushin wear

ck the valve lash as its a new motor(but highly unlikely)

 

 

buy some NGK wire(NE64) set to make this look better