vacuum advance

[Banana Bonanza]

As I mentioned in another thread, vacuum advance on my Japanese SOHC B6 seemed faulty. Unlike the Festiva advance the B6 advance is single chamber.

I took it apart:



And there was a hole (I stuck screwdriver in the hole to make it show up in pic):



I have an adjustable vacuum advance for an old Chev V8 that I am going to replace it with . Already made a little bracket, need tiny bit welding to put tip off B6 advance onto arm on Chevy one. Needs to be welded, no real way to clamp it. Naturally my house electric isnt working right today so welder isnt working, one leg of the 220V circuit isnt powered so only have 120V at the 220V outlet.

[Banana Bonanza]

Sorry for delay, had to deal with getting welder working again.

Anyway, here is the unmodified Chevy advance on left, B6 advance on right:



Here is the Chevy advance cut and modified:




And here is the modified Chevy advance installed;




No pinging in brief test and engine seems happier. It probably could even stand more static advance, but I'll test it on longer drive uphill, downhill, higher speeds, etc.

[Banana Bonanza]

Took it for fairly long drive today. Having working vac advance helps lot. More power at higher rpms. Its happy now going 55 to 60 (4spd) without constantly correcting it. Before it wanted to sit at 50mph if I didnt watch it all the time and correct. Be a while before i have a gas mileage figure. I'd be surprised if it didnt hit at least 40mpg though.

[Fordverde]

Have you tried to fix the festiva's vacuum advance?

[Banana Bonanza]

The B3 distributor advance is fine on old engine I removed, I tested it. It bolts on identically to the B6 advance, just Festivas had the dual chamber where one side was to retard rather than advance. The advance shown above with hole in diaphram is one that came on the B6 from Japan that i bought and put into my Festiva. Its not repairable.

I could have just swapped advances or complete distributors and just blocked off the retard side. However I chose to adapt the Chevy advance and as I say, it seems to work fine. I have the little adjustment set to advance the ignition as fast as possible (the Chevy advance is adjustable), and still cant make the B6 ping.

To get anymore static advance, I'd have to pull the distributor and reclock it. But frankly cant think why I would bother, its running as good as I could wish for. Just wait until it racks up enough miles to give me some sort of accurate idea of fuel economy. If it tops 40mpg then I'm not going to worry about it unless I find a deal on a 5spd tranny. If its still below 40mpg, then I will reclock distributor so I can give it yet more static advance. I just cant see such giving any great performance gain over way its running now.

[Banana Bonanza]

Very pleased with the Chevy vacuum advance, especially today when I calculated 50 MPG at gas fill up!!!!!!! That was unexpected. One of those "have your cake and eat it too" situations. I simply couldnt ask for any more than that. Now if I find a 5spd......