Distributor vacuum unit/dyno test
 

I have been searching for a distributor vacuum unit on the internet for my 1980 sc without luck, because mine is not working, i found out on the dyno. I have also been looking on this site, and it seems that bosch don't make them anymore.
Does it have to be the one with the retard like i have now, or can i go with one with only one vacuum connection.
http://forums.pelicanparts.com/uploa...1535223018.JPG

Could they be hooked up backwards? If you unplug them one at a time does the idle speed change?

It should retard at idle and advance under load.

I have testet the vacuum unit it with a vacuum pistol and it is not holding vacuum, not even for a second, but the retarded is working, so i need a new one, just dont now where to get it. I also now the lines are mountet correct.

An option, particularly if you live in an area without emissions testing where they check the timing, is to ignore the idle settings, and set the timing so full advance is where you want it and let the idle timing end up wherever it lands.

Stock for 80-83 is 5º ±2º BTDC@ 950 RPM, vacuum hose disconnected, with max advance 21º ±2º BTDC @6000rpm, vacuum hose disconnected. Vac advance only does about 5º under load if I remember correctly, so an option would be to use an adjustable timing light, set the full advance with both hoses hooked up to around 26º to be pretty close to the stock full advance setting.

For best performance, some folks advocate leaving everything hooked up and setting it so full advance is 35º, If it pings, back if off a couple degrees. Only do this if you use good gas, 91 or better. If you go this route, I would advise working up to it.

I live in Denmark so no problem with emissions. I run shell vpower 99 fuel.
Thanks for the advice how to set the timing i will go for that. But i still need a new vacuum unit, can i just go for one with one vacuum connection without the retard? and where do i find a new one?

What I was suggesting is that you don't bother replacing it. Set the full advance where you want it with both lines hooked up, and provided you can set the idle where it needs to be, don't worry about it.