The vacuum tower on top of the thermostat housing.
What is it supposed to do? How do I test it to see if it's working?
On a manual shift car, it's my understanding that 1) when cold it is completely closed 2) the engine vacuum goes to the bottom port 3) vacuum advance to the middle port 4) top port to timed vacuum on the carb?
Is it supposed to re-route vacuum depending on engine temp?
I Believe that it blocks vacuum until operating temperature is reached.
I presumed that but I have one on the bench and am trying to make it work there. So far, no good.
I've never seen engineering data specifically stating that it opens at a specific temperature.
Operating temperature could vary depending on thermostats.
Checked the Ford shop manual?
In Ford training and in state/national emission training manuals didn't find anything that specified an exact temperature range. Can offer the following description as to how it works (in some applications the lower port is just a filter)
(http://www.concoursmustang.com/forum/gallery/14/6-290620162533.jpeg)
And Ford's testing process for service personal from the period
(http://www.concoursmustang.com/forum/gallery/14/6-290620162602.jpeg)
Hope this helps
Quote from: CharlesTurner on June 29, 2020, 04:11:28 PM
Checked the Ford shop manual?
What I see in the Shop manual is just the vacuum hose diagram. I see no reference to what temp it opens or begins to open at.
I am presuming that the Ford reference "to carburetor" means to the timed vacuum port and not to manifold vacuum at the carburetor?
Perhaps termanology has changed since then but this is a little oonfusing.
Again, there is no mention of NORMAL operating temperatures? Considering the location being on the radiator side of the thermostat housing I think it will open as the thermostat opens but if it is set to work with a 192 thermostat, how will it work with a 160?
Quote from: shelbydoug on June 29, 2020, 05:08:36 PM
I am presuming that the Ford reference "to carburetor" means to the timed vacuum port and not to manifold vacuum at the carburetor?
The diagram Ford showed in the description identifies (both manifold and carburetor) the port connections based on the application they choose for this publication. Connections for other applications would differ. The full engine vacuum diagrams would answer that question for your given application.
I have them but they DON'T differentiate on "carburetor vacuum.
However, thank you for attempting to help here. I do appreciate it. ;)
The test is watching idle speed to increase and for the temperature light to get lit. :o
That would be one way but now have two of them and can't make either open using a heat gun on the workbench.
I'll eventually get to the bottom of this. I was just trying to take a faster route to the solution and answers.
I should also point out that the shop manual shows four different hose routings depending on on BB, SB, auto or manual trans. On the surface the differences make no sense since there is contradiction in function under different routing.
I don't doubt their acuracy. I doubt my ability to understand the application of English language terms.
I often cut the technicians some slack and leeway in their attempts to explain technical details. It often strikes me as Einstein trying to write Shakespear. Both geniuses of their own just needing another genius to interpret WTF they just said and that ain't me? ::)
Quote from: shelbydoug on June 30, 2020, 08:57:13 AM
That would be one way but now have two of them and can't make either open using a heat gun on the workbench.
I'll eventually get to the bottom of this. I was just trying to take a faster route to the solution and answers.
I should also point out that the shop manual shows four different hose routings depending on on BB, SB, auto or manual trans. On the surface the differences make no sense since there is contradiction in function under different routing.
I don't doubt their acuracy. I doubt my ability to understand the application of English language terms.
I often cut the technicians some slack and leeway in their attempts to explain technical details. It often strikes me as Einstein trying to write Shakespear. Both geniuses of their own just needing another genius to interpret WTF they just said and that ain't me? ::)
Have you tried suspending the vacuum switch in a pot of water on a stove top? Have your vacuum lines attached out of the water to check air flow from. The water temp can more easily be monitored compared to a heat gun. Just a thought .
Yes this is the right way to test both the vacuum valves and thermostats. It also is a great way to test temp sender units.
Bear in mind Ford had to meet federal emission standards in '67 and '68 depending on where the car was going to be sold. So the installation hook up does vary by application. You may find that it performs better in one of the other methods of hookup now that the car doesn't need to meet any specific specs.
Quote from: Bob Gaines on June 30, 2020, 10:36:39 AM
Quote from: shelbydoug on June 30, 2020, 08:57:13 AM
That would be one way but now have two of them and can't make either open using a heat gun on the workbench.
I'll eventually get to the bottom of this. I was just trying to take a faster route to the solution and answers.
I should also point out that the shop manual shows four different hose routings depending on on BB, SB, auto or manual trans. On the surface the differences make no sense since there is contradiction in function under different routing.
I don't doubt their acuracy. I doubt my ability to understand the application of English language terms.
I often cut the technicians some slack and leeway in their attempts to explain technical details. It often strikes me as Einstein trying to write Shakespear. Both geniuses of their own just needing another genius to interpret WTF they just said and that ain't me? ::)
Have you tried suspending the vacuum switch in a pot of water on a stove top? Have your vacuum lines attached out of the water to check air flow from. The water temp can more easily be monitored compared to a heat gun. Just a thought .
No boiling water yet!
If it works the way I think it is supposed to, I actually like the idea of it closing the vacuum to the vacuum advance at idle.
It gives me tuning options.
Also I THINK that it switches at some point from engine vacuum to timed port vacuum. That's really what the question initially was getting at.
Either way, I'm ok with it. I probably will need to do the hot water thing to determine at what temp it opens and if it is simgle stage or dual.
I like the idea that it is still installed in the original thermostat housing. It is appropriate for a '68.
Now if I can only find a yellow plastic overlay for the ignition coil, like the battery top idea, I'd be happier.
Unfortunately, although looking great, the Marti Autolite spark plug wires crapped out already. Too bad. They looked great in the AUTOLITE cap.
I haven't thought about the original spark plug wires in 45 years. I was innocent then. I never realized how FREAKIN' BAD the original wire engineering was back then? ::)
Quote from: Royce Peterson on June 30, 2020, 12:08:12 PM
.........Bear in mind Ford had to meet federal emission standards in '67 and '68 depending on where the car was going to be sold. So the installation hook up does vary by application. You may find that it performs better in one of the other methods of hookup now that the car doesn't need to meet any specific specs.
Keep in mind that this depends on your local/state agencies and their law. Here in Calif the requirements are still there
But that doesn't have any affect of figuring out Doug's challenge
Not just at idle. Any time the throttle is closed the vacuum signal to the distributor drops to a lower value, regardless of RPM. Decelleration for example. The only time the distributor vacuum advance would see manifold vacuum is during an overheat situation if it is all working properly.
Quote from: shelbydoug on June 30, 2020, 12:32:50 PM
No boiling water yet!
If it works the way I think it is supposed to, I actually like the idea of it closing the vacuum to the vacuum advance at idle.
It gives me tuning options.
Also I THINK that it switches at some point from engine vacuum to timed port vacuum. That's really what the question initially was getting at.
Either way, I'm ok with it. I probably will need to do the hot water thing to determine at what temp it opens and if it is simgle stage or dual.
I like the idea that it is still installed in the original thermostat housing. It is appropriate for a '68.
Now if I can only find a yellow plastic overlay for the ignition coil, like the battery top idea, I'd be happier.
Unfortunately, although looking great, the Marti Autolite spark plug wires crapped out already. Too bad. They looked great in the AUTOLITE cap.
I haven't thought about the original spark plug wires in 45 years. I was innocent then. I never realized how FREAKIN' BAD the original wire engineering was back then? ::)
Quote from: Royce Peterson on June 30, 2020, 02:23:19 PM
Not just at idle. Any time the throttle is closed the vacuum signal to the distributor drops to a lower value, regardless of RPM. Decelleration for example. The only time the distributor vacuum advance would see manifold vacuum is during an overheat situation if it is all working properly.
Quote from: shelbydoug on June 30, 2020, 12:32:50 PM
No boiling water yet!
If it works the way I think it is supposed to, I actually like the idea of it closing the vacuum to the vacuum advance at idle.
It gives me tuning options.
Also I THINK that it switches at some point from engine vacuum to timed port vacuum. That's really what the question initially was getting at.
Either way, I'm ok with it. I probably will need to do the hot water thing to determine at what temp it opens and if it is simgle stage or dual.
I like the idea that it is still installed in the original thermostat housing. It is appropriate for a '68.
Now if I can only find a yellow plastic overlay for the ignition coil, like the battery top idea, I'd be happier.
Unfortunately, although looking great, the Marti Autolite spark plug wires crapped out already. Too bad. They looked great in the AUTOLITE cap.
I haven't thought about the original spark plug wires in 45 years. I was innocent then. I never realized how FREAKIN' BAD the original wire engineering was back then? ::)
That's ok with me. I don't see any disadvantage to that function.
This has been a very interesting and informative thread. I have a related question. If you have electronic ignition does the vacuum advance still function? I understand having it all hooked up to look correct but was wondering if it is actually doing anything?
Corey
Electronic ignition (Pertronix etc) replaces the ignition points as a method of charging and discharging the coil. It has no effect on anything controlled by vacuum.
Quote from: Corey Bowcutt on July 01, 2020, 08:32:06 AM
This has been a very interesting and informative thread. I have a related question. If you have electronic ignition does the vacuum advance still function? I understand having it all hooked up to look correct but was wondering if it is actually doing anything?
Corey
Quote from: Royce Peterson on July 01, 2020, 08:41:33 AM
Electronic ignition (Pertronix etc) replaces the ignition points as a method of charging and discharging the coil. It has no effect on anything controlled by vacuum.
Quote from: Corey Bowcutt on July 01, 2020, 08:32:06 AM
This has been a very interesting and informative thread. I have a related question. If you have electronic ignition does the vacuum advance still function? I understand having it all hooked up to look correct but was wondering if it is actually doing anything?
Corey
+1.
There are several hook up diagrams in the 68 Shop Manual.
By trial and error, I have determined that the engine vacuum goes on the bottom, the line to the carb "timed vacuum" is in the middle and the distributor vacuum advance goes on top.
If you put the distributor vacuum advance in the middle as the engine gets hot it will advance the distributor and raise the idle rpm about 400 rpms.
For me that doesn't work.
The tree seems to open at around 160 water temp. Apperently it is two stage? I don't know at what temp the valve distributes vacuum to the vacuum advance. I haven't gotten hot enough yet.
Just found that The March 1967 Shop Tips has a page on these. It references the 1967 valves which have a different design, but they should operate the same. It says the thermal valve opens at approximately 230 degrees to switch from the carb vacuum to the intake vacuum. Mike
Quote from: mr68shelby on February 26, 2021, 07:46:41 PM
Just found that The March 1967 Shop Tips has a page on these. It references the 1967 valves which have a different design, but they should operate the same. It says the thermal valve opens at approximately 230 degrees to switch from the carb vacuum to the intake vacuum. Mike
Is there a '67 version of the vacuum tree? I'm pretty sure the switch over temp on mine is much lower then that?
Quote from: shelbydoug on February 26, 2021, 08:03:35 PM
Is there a '67 version of the vacuum tree? I'm pretty sure the switch over temp on mine is much lower then that?
For non-HipPo 289 applications. Its integrated with heater hose intake manifold connection. There has been one for sale for over a year on Ebay
(http://www.concoursmustang.com/forum/gallery/15/6-260221201838.jpeg)
Since its not factory might as well swap out the thermostat housing and use one from a different year it you choose to go that route
Quote from: J_Speegle on February 26, 2021, 08:15:52 PM
Quote from: shelbydoug on February 26, 2021, 08:03:35 PM
Is there a '67 version of the vacuum tree? I'm pretty sure the switch over temp on mine is much lower then that?
For non-HipPo 289 applications. Its integrated with heater hose intake manifold connection. There has been one for sale for over a year on Ebay
(http://www.concoursmustang.com/forum/gallery/15/6-260221201838.jpeg)
Since its not factory might as well swap out the thermostat housing and use one from a different year it you choose to go that route
I presume that they are very rare and as such the price of them is excessive?
I actually like the way that mine works on my 68.