No Vacuum Lines

[jeremywatco]

Good evening,

So I am working on tuning the motor of my '73 302. Starts and idles fine but just wanted to check the mixture and everything. Also the timing. Trying to figure things out and everything I've read so far is to measure vacuum for the mixture and to block off the vacuum advance for the timing....

Well...

Maybe I am blind but i have no vacuum lines on my motor.

The card has two ports on it. Once is capped off and the other is right below the air filter and its just open, no cap or anything.

The distributor is electronic and has no vacuum port and I cannot find any vacuum lines anywhere on this engine.

So that being said, whats the best way to set the mixture and then to set the timing?

 

[73azbronco]

Good evening,

So I am working on tuning the motor of my '73 302. Starts and idles fine but just wanted to check the mixture and everything. Also the timing. Trying to figure things out and everything I've read so far is to measure vacuum for the mixture and to block off the vacuum advance for the timing....

Well...

Maybe I am blind but i have no vacuum lines on my motor.

The card has two ports on it. Once is capped off and the other is right below the air filter and its just open, no cap or anything.

The distributor is electronic and has no vacuum port and I cannot find any vacuum lines anywhere on this engine.

So that being said, whats the best way to set the mixture and then to set the timing?

whats your carb make model and dizzy make model/

Engine probably has a drilled and tapped but plugged hole on the intake usually in front of carb. Depending on carb some will have ports for ported reference either metered or full open to intake vacuum.Need more info for timing of dizzy, what is it?

 

[B RON CO]

Hi, if you have PVC system, power brakes, C4, or a carburetor, and original emmisions on a 73 you have vacuum ports.
As mentioned, they may have been eliminated.
Post a picture of the engine. Ford put a few vacuum ports on the back of the intake manifold.
Also the original distributor used a vacuum advance.
You will get some answers if you post a couple of pics.
Good luck

 

[jeremywatco]

Here are some pics of the carb and dizzy

Sent from my Pixel 3 using Tapatalk

 

[B RON CO]

Hi, the red cap is the ported vacuum for the original Ford distributor vacuum advance. The replacement Mallory distributor has mechanical advance only.
I think I see a large vacuum line off of the bottom of the carb for the pcv, and a vacuum hose off of the intake manifold, snaking around and going into a metal tube.
Good luck

 

[pcf_mark]

The distributor, Mallory Unilite, is electronic which is nice because you no longer have points. But it does not have a vacuum advance which is good for economy and light throttle performance. You can change that at any time but let's work with what you have.

As noted you have several vacuum hoses and it would be good if you checked that they are connected and leak free before doing anything else. You have two big ones on the back side - one off the base of the carb and one one a brass fitting screwed into an intake runner. The one on the base of the carb could be PCV but we a pic from the drivers side. The one in the runner looks like it just sort of stops. Check that out.

Assuming these are ok then can just put your timing light in the truck with the engine warmed up and at idle. Just make sure you put the timing light pick up on the number 1 spark plug wire and try to read the balancer. You should have 6-12 degrees of timing. I like 10-12. If you can't read your timing tab or your balancer clean them first before warming the truck up it is much easier. If your timing is not correct simply loosen the bolt holding the distributor down slightly (do not make it really loose!) and turn the distributor while watching the timing light. Tighten the bolt. Now with the timing light still on rev the engine up to 2500 rpm for a second and watch the timing mark. Does it go up under the water pump? This is the advance in the distributor working.

Let us know how that goes. The carb is super simple.

 

[B RON CO]

Hi, I took another look and I see you are missing the choke stove tube. The choke will never fully open without that. Also the small port in the back of the air cleaner should be plugged since you are not using it. If you have a C4 tranny that vacuum tube should go tho the modulator down on the tranny. Good luck

 

[jeremywatco]

Thanks for all the help.

I did notice that my choke never fully opens. This doesnt appear to be the carb that came with the motor. There is an abandoned choke cable coming out of the firewall.

How do I plumb a choke stove tube? Does it go the that port blocked off with the black cap? Does the metal tubing just go down and clamp to the exhaust right after the header? I see NAPA carries a universal kit.

To answer the other questions. Both those big hoses do go to things. The one that comes out the back of the carb goes into the head. The other one comes out and goes down to the tranny.

 

[jeremywatco]

I think I understand the setup on the stove tube. Looks like on the top of the header there is a small hole that I just push the tube into and then screw to the carb