adding a 34 ADF, vacuum question

[danaspider]

I am replacing the carb on my 79 spider. On the new 34 ADF carb there is a connection point for a hose. Located near the accelerator pump. What is this connection for? Where should the vacuum advance for the distributor come from? The manifold? I am adding the 1800 manifold.

[stefhahn]

the connection you found is the vac port - originally put to the aircleaner, I use it for the distributor vac advance.
I can send you a picture if you need that.

ciao,
Stefan

[danaspider]

Cool, send a pic if you have it

Thanks

[stefhahn]

PM me your email adress, plz.
ciao,
Stefan

[danaspider]

Send it to spinks.dana@gmail.com

Thanks Stefhan

[Danno]

Danaspider, sorry I didn't see this post when I posted in your manifold thread.....

I do not have a 34ADF, never had, can't say I'm an expert, but I thought I've read before that the adf doesn't have a vacuum advance port and that's the difference between it and the adfa.... guess I'll have to go do some more reading up on this. maybe check some diagrams provided by Brad Artigue.....

[danaspider]

The ADF has a single vacuum type connection near the base of the carb. Stefhan feels it can be uded for the vacume advance.

I can do an imaage if someone can give an update on how to paste it into the editor

[dlbj]

Hey Dan, I've got pix on my site that shows all of my connections for my 34 ADF install.

http://members.cox.net/dlbj/fiat_34ADF.htm

Hope this helps (more importantly hope I labeled it correctly).

- D.J.

[stefhahn]

@Dana, you should have received the pic yesterday

[TJC]

Hey Dan, I've got pix on my site that shows all of my connections for my 34 ADF install.

http://members.cox.net/dlbj/fiat_34ADF.htm

Hope this helps (more importantly hope I labeled it correctly).

- D.J.

I agree with Danno's statement above about the ADF including the facts that I never owned one and am not an expert, but in the link above, I don't think the port labeled in the pic named "Right Side Connections" is a vac advance port. Dizzy vac advance signals must come from a "ported" vacuum conneciton on the carb, i.e., it's must come from slightly ABOVE the throttle plate (not on the intake manifold as depicted). This ensures that there's no vac signal to the distributor when the vehicle is at idle.

[dlbj]

TJC, I'm going to make the switch like you suggested to mine and take it for a little run. But just to be clear I'm including a picture to make sure that I have the change correct. The other thing I will need to do is to move the fitting on the intake manifold so that it is closer to the evaporator box. BTW what is the purpose of the evaporator box?

[dlbj]

Also, the right side hookups picture is labeled incorrectly for the fitting that I said was connected to the bottom of the evaporator box. It actually goes to the brake master cylinder. The picture with the front side hookups was labeled as I have it hooked up (which will switch as soon as I make my vacuum changed for the advance). Thanks again for your input.

[TJC]

TJC, I'm going to make the switch like you suggested to mine and take it for a little run. But just to be clear I'm including a picture to make sure that I have the change correct. The other thing I will need to do is to move the fitting on the intake manifold so that it is closer to the evaporator box. BTW what is the purpose of the evaporator box?
http://members.cox.net/dlbj/switchVacuum.jpg

Hi dlbj,
I think you misunderstood me. I meant that I agree with Danno that the ADF is probably not equipped with a ported vac at all. I believe it's the ADFA that is (I believe the "A" denotes an emissions carb). In other words, just because the port may look like it's coming from above the throttle plate, doesn't necessarily mean it is. However, taking it from the intake manifold is definitely NOT ported and, therefore, cannot be used for a dizzy vac advance (or for EGR for that matter). I kind of made this discovery upon reading posts on Mira (and probably here, too) and after inspecting the DMSA carb that I was about to install. Here are some links to pics I took back then that depict what I'm describing should be a ported vac signal:
http://i2.photobucket.com/albums/y12/tj ... /DMS02.jpg
http://i2.photobucket.com/albums/y12/tj ... /DMS06.jpg
http://i2.photobucket.com/albums/y12/tj ... /DMS07.jpg

As far as your "evaporator box" question, are you referring to the charcoal canister on the passenger side of the engine compartment? If so, that's for storing and releasing vent gasses from the tank. I believe that connection is indeed supposed to be on the intake manifold itself, but make sure the connection on the manifold is the one with the restrictor (or has a sufficiently small ID) or it will act as a vac leak and cause poor idling (believe me, I found out the hard way).

[So Cal Mark]

the port under the accel pump should be used for the crankcase breather tee. And in some circumstances, using manifold vacuum to the advance diaphragm can be beneficial.

[mdrburchette]

the port under the accel pump should be used for the crankcase breather tee. And in some circumstances, using manifold vacuum to the advance diaphragm can be beneficial.

Can you explain this Mark? I'm under the impression that at idle the dist doesn't want vacuum, thus the reason for ported vacuum. I've been trying to decide whether to buy a new diaphragm for my 71 or just lock the plate like on my 72.