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Discussion Starter #1
Where do you guys take the vacuum to the 123 distributor?
Could the outlet in bottom of the europe intake box work?
It was not connected at all when I got it.
 

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But Mad North-Northwest
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Airbox won't work, it needs to be manifold vacuum (downstream of the throttle plates).

If you've got carbs with individual intake runners there's really no place to hook it up: just leave it disconnected. You'll lose a little fuel economy at cruise but that's it.
 

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In my opinion, there is no reason not to run your car as efficiently, economical and environmentally friendly as it can be. Especially when it can be achieved as easily as it is in this case.

Edit:
Unless it's a racecar of course, then power at wide open throttle is the only thing that matters, and vacuum advance has no place.
 

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In my opinion, there is no reason not to run your car as efficiently, economical and environmentally friendly as it can be. Especially when it can be achieved as easily as it is in this case.
What would you propose for a SPICA setup? I wouldn't mind running a vacuum line if it was easy enough...
 

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You might tap into the 5th hose that runs from the idle air distributor on top of the intake. Then you wouldn't need the pulse reduction valve as there should be relatively pulse free vacuum there.

It is also possible to tap a hole in the runner for cylinder no. 1 and fit a takeoff adapter there.
 

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Discussion Starter #8
Thanks guys, I am looking now, and was thinking of connecting it with a T-connector to the hose that comes from intake manifold frontside and attaches to the breather connection on the head cover. Would that work?
And yes it has Dellorto 40s and I would like to use the vacuum, its a daily runner setup with standard cams etc.
 

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There should be ports on your Dellortos that will provide vacuum for the 123. ('8' in the diagram). The adapter I mentioned earlier will fit one of these.
It might be a better/cleaner source than t-ing the crankcase ventilation.
 

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shoudnt be better to take the vacuum from the front niple of the inlet manifold? just thinkig loud
I'd rather not use a port that is already in use for the crankcase ventilation because it's bound to be an amount of oil in the hose, and you will risk clogging up the anti pulse valve.
 

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I'd rather not use a port that is already in use for the crankcase ventilation because it's bound to be an amount of oil in the hose, and you will risk clogging up the anti pulse valve.
all the oil comes from the head case nipple, if you block that and use the front nipple of the intake manifold for your 123 (this all in case you dont have a vacuum nipple on your carbs), its just vacuum in the port, how can you cloge it if its just sucking air all the time?
 

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There will be vacuum takeoff ports on each barrel of the carbs on an Alfa Romeo 105 with factory dual-carb setup. Dellorto, Solex or Weber. They ony differ in the type of thread used in the ports.

Why would you want to block the connection to the crankcase venting when it's not necessary? It's there for a reason.

And if you do not block it, but 'T' it instead, you will eventually have to stop the engine, and leave the distributor as the lowest point of a hose that will contain oil and no vacuum to hold it back.
 

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Depending on the type of carburettor or injection system you run, there will be vacuum takeoff ports for each barrel. I've had vacuum advance connected (and working) with my Dellortos using a take-off adapter on barrel no.1 and an anti pulse valve.

Hello PerO, I've just found this thread, and this post of yours is interesting for me.
I have a 1750 GTV with Dellortos and a non-vacuum distributor (original Bosch 045 type).
To improve fuel economy, I would like to try using a Bosch 229 distributor with vac advance, from an 1800 Alfetta.
I have found the vacuum take-off ports on my Dellortos as you have described in your diagram, so my only other question is about the possible difference between ported and non-ported vacuum sources......
Do you know if these Dellorto ports are ported or manifold vacuum, and whether the levels of vacuum at high-speed light-throttle cruise would be different between ported and non? (I know they are different at idle.)
I'm just wondering if this particular source of vacuum will be strong enough to drive the distributor capsule on the Alfetta distributor, because I don't know for sure where this 229 distributor was designed to have been driven from, in the original Alfetta installation.

PerO, I wonder which type of vacuum-advance distributor you have used? Was it a good one for performance driving? The 229 that I have on hand may be good for economy but maybe not for performance.....

Many thanks,
Graham H,
NZ (1750 GTV, Alfasud x3, Alfa 156)
 

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PerO, I wonder which type of vacuum-advance distributor you have used? Was it a good one for performance driving? The 229 that I have on hand may be good for economy but maybe not for performance.....
I have run 123 distributors. Being programmable, they easily allow for an incremental approach to tuning and reduce the risk of detonation and other problems when setting up timing and advance. 123s are for daily drivable cars and if set up with a good coil should be sufficient for a classic engine tuned for the street. If ultimate performance is the goal I'd go with a module-based system.
 

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OK, thanks PerO. The 123 is a good system to have, but it's probably more than I need to spend for my car at the moment - it is one of 5 Alfas so we don't drive it very many miles each year! I'm doing some other upgrades to it at the moment (brakes, cams), so perhaps a more-expensive ignition will come later.
In the meantime, I've got this spare 229 Bosch (from an old Alfetta) in the spares-box, so I can try that for no cost.
Best regards,
Graham H
 

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1626612

I assume the initial poster figured it out since 2014 but I was asking myself a similar question having purchased a vacuum distributor. My Euro manifold has the vacuum port referenced above. Makes for an easy connection.
 

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I used the small vacuum pipe normally connected to the breather I don't want oil vapour sucked into cylinder 1 so happily disconnected it at the cam cover, I used a pulse damper and used the vacuum signal to retard the ignition this stopped the car popping when engine breaking
It worked for me but I'm running big cams and larger Venturi so perhaps not needed on a fully standard car
 

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But Mad North-Northwest
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I used the small vacuum pipe normally connected to the breather I don't want oil vapour sucked into cylinder 1 so happily disconnected it at the cam cover, I used a pulse damper and used the vacuum signal to retard the ignition this stopped the car popping when engine breaking
That's really not how you want to use the vacuum advance. The vacuum advance should ... well ... advance the timing when it senses intake vacuum. This advances the timing at part throttle and cruise and gives you better economy and a bit more responsive throttle.

If you're using that port to retard ignition when there's vacuum you're just retarding the ignition at idle and under cruise. That is not at all what you want.

Anyway, since I posted in this thread back in 2014, I've gotten a GTV with Dellortos and a Euro intake that has the green-circled vacuum port above (my Giulia with Webers has no provision for vacuum advance.) I have that hooked up to the 123 and it's working very well. I haven't seen any need to use a pulse damper: the 123 appears to have smoothing circuitry and the advance does not show any unsteadiness from the pulsing of a single cylinder.

The vacuum advance curve I used is cloned from the stock mechanical advance on the Bosch 018 distributor that was on the car when I got it.

1626882
1626881
 

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Let me check back at how I set it up but it definitely cured the poping and hesitation on trailing throttle, it did no other function
 
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