Vacuum lines confusion

[ermie571]

Hi all.....2.1 running log and carb. I have a vacuum line from dizzy to carb. The other vacuum line at carb is blocked off. But I have another vacuum connection at the dizzy. It's on the big disc attached to the dizzy and faces towards the back of the bus
Where should this go?

There is one that goes to the left hand side connector as you look at it behind the carb from the back of the dizzy. Is that right?

Not sure if there should be an unconnected vacuum line at the dizzy?


There's another vacuum connector on the black plastic air intake stuff...but have been told don't need that.

Any pointers?
Thanks folks

Em x

[Aidan]

Emma twin vacuum disi is 2.1 disi, the second line would be plumped into the plenum chamber and fuel regulator but that stuff is no longer there - I think you would be best with a 1.9 single vacuum disi, but others with 2.1 running carb may say otherwise, I don't run carb so not sure with this 2.1 as carb set up
the second outlet on the carb is for the air intake gubbins which is blanked off

[ermie571]

Thanks Asian. Went to 2.1 dizzy at recommendation of club for correct advance curve lol x

Should I block second vacuum outlet?

[ghost123uk]

Thanks Asian

Went to 2.1 dizzy at recommendation of club for correct advance curve lol x

Ah but it won't be the correct curve without the second vac pipe, and you can't just add it (tis a bit more complicated).

Should I block second vacuum outlet?

Not necessary to do so as it is doing nothing at present.

Background = the disk you refer to is the advance/retard diaphragm, One of the pipes, when it has a vacuum on it (from the inlet manifold) "sucks" on the diaphragm and advances the timing (of the spark) to improve engine efficiency. The other one (now not in use on yours) does the opposite and counters the advance under certain circumstances (full engine load) to both prevent pinking and also to improve the emissions from the exhaust. As said by "Asian" , that is an "injection" thing though (mind you, the old DF's use a twin vac dizzy Next time I see one I must note how the second vac pipe is configured)



Aside(ish) - I wonder how much the timing curve differs on a 2.1 compared to a 1.9 ? Then we have the different compression ratios of the various WBX motors from 8.5:1 to 10.5:1 ummmm.

[ermie571]

fat fingers..so sorry...could have been worse...Aslan from CS Lewis' Narnia is pretty close too!

Apologies Aidan - it was early and on my phone (autocorrect needs to be introduced to the 80-90 user list....lol)

ok....will leave alone then. Its been like that for years

and as for how much it differs.....we put a 2.1 dizzy on the other engine I believe when we upgraded from the 1.9...I didn't notice any difference at all...

thanks for the info ghost on my advance/retard unit. At least I know what it is called now...and if its not sucking air that can harm the running of the engine, all is good.


Em
xx