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What part is this on my 170 Inline 6???

Prest72

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Hey Guys, my first question on the new Bronco. What is this on the 170 CI? Looks like vacuum hoses coming from Fuel pump, and distributer? Do I need it? I am going to change the Distributer out to a DUI and wanted to just connect vacuum to it and be good, but can I remove this part? What does it do? Pic below circled in red.
IMG_3826.jpg
 

doran4x

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Your vacuum wipers connect to that. Follow the hoses.


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DirtDonk

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Actually I’ll take a different tack on that. It looks like the vacuum modulator for the distributor.

The V8’s had the exact same part starting in about 1969 or 70 and going through 72 or 73. It was used with the dual diaphragm distributors only. Not necessarily aCA only part, but could have started out that way.
Not used with the single diaphragm distributors.

So definitely follow the tubes. If they go to the distributor, or if they go to the wipers, you’ll know what that was used for.
 

m_m70

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I'm guessing (by no means an expert here) the wipers as well. looks like your fuel pump is connected to it and that's where the wipers get their vacuum from.
 

DirtDonk

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Now we need to find a good vacuum diagram to see what is what.
It might be used as a manifold to distribute vacuum to each wiper, but I admit I’ve never seen one used in this fashion. Didn’t think there was any need for some fancy spring loaded differential valve thingy in the wiper system.
Unless it’s been gutted perhaps?
 

okie4570

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Vacuum wiper hose leaves the top of the fuel pump and head straight to the driver's side windshield frame and to the wipers. Not sure what that apparatus is, never seen one before.
 

DirtDonk

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Looks like at least one of the others runs to the vacuum advance canister. As said, the vacuum should run from the pump to the wipers.
Are vacuum wipers still being used on this Bronco?
If not either someone was thinking the pump was the vacuum source for the ignition advance, they had used up all the other vacuum ports for other functions, or they were simply looking for a place to plug in an unused hose to keep it from becoming a vacuum leak.

If anyone can pull up an image of the top of the intake behind the carburetor on a V8 of '70-'72 vintage still running original equipment, you'll see that device.

Paul
 
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Prest72

Prest72

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Okay, so after more investigation the following:

3 hoses connected to it

one hose coming from fuel pump to it that says "wiper" on top of fuel pump
one hose from manifold goes to it
one hose from distributer goes to it.

I assume its a vacuum collector of sort for the wipers????

Nice to know I stumped you guys.
 

jamesroney

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Okay, so after more investigation the following:

3 hoses connected to it

one hose coming from fuel pump to it that says "wiper" on top of fuel pump
one hose from manifold goes to it
one hose from distributer goes to it.

I assume its a vacuum collector of sort for the wipers????

Nice to know I stumped you guys.
I'll try to help. Paul was mostly right. Are you asking:

"What is the distributor spark control valve?" or "Is my distributor valve connected properly?"

The distributor vacuum control valve compares the vacuum signal between the intake manifold and the spark port, and allows manifold vacuum to override spark port vacuum to the distributor vacuum advance thru the temperature activated vacuum valve. (TAV) It is often called the deceleration valve, because it will primarily come into effect during deceleration and gives a small advance to assist in burning fuel.

The root part number of the valve is -12A111 and it is found in a large number of Ford vehicles from 1968-1977+. You can find good examples for a 6 cylinder as a C8AZ-12A111-A. The Bronco piece will have a special part number because the part is acutally a "valve and bracket." You should be able to find the engineering number stamped on the bracket.

It has absolutely nothing to do with the wipers, and should not be connected to the wiper system. It needs to see manifold vacuum. NOT wiper vacuum.

Here's a diagram that shows what it is, and how it is plumbed.
 

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1970 Palmer

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Well, it looks like we have many different opinions. Let me say first, I'm not exactly sure either. The canister in question was used on many different Ford engines during the 1970's. It's part of the emission package for that particular engine. It has nothing to do with the vacuum wipers. It's just connected incorrectly. If you pop the blue plastic cap off the end, you will find a spring and a diaphragm. My guess is it's a temperature controlled valve to control when the manifold vacuum is directed to the "retard side" of the distributor vacuum advance.

If you do not have to have the vehicle emission tested to register, I would leave it bolted in place and plug the retard side of the manifold vacuum hose. Then just set the ignition timing like normal.
 
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Prest72

Prest72

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Thank you guys. I will be installing a DUI distributor w normal vacuum advance here soon. I wanted to just connect it straight to the manifold vacuum and cap all this other stuff including basically all ports of this blue "collector". Thoughts?
 

DirtDonk

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Don’t hesitate to try both full manifold vacuum and ported vacuum from the carburetor on your new distributor. Full vacuum can work, but most of us find the ported vacuum signal easier to tune with and better running in some cases.

Since you will have a single port vacuum advance canister on the new distributor, the old multi port valve is absolutely useless, Unneeded, unwanted and would be a distraction at the very least.
Remove it and put it in the parts box.
 

Oldtimer

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And as a side note, (as stated above) the vacuum line from fuel pump goes straight to vacuum wipers.
The fuel pump vacuum assist was to assist manifold vacuum to wipers under full throttle.
It never did much good.
On long upgrades in Sierra's I would have to back off throttle every now and again to get wipers to clear wet snow.


Image from 68 Bronco service manual:
2022-04-29_172427.jpg
 
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1970 Palmer

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Thank you guys. I will be installing a DUI distributor w normal vacuum advance here soon. I wanted to just connect it straight to the manifold vacuum and cap all this other stuff including basically all ports of this blue "collector". Thoughts?
Thoughts........sure mine are cheap, LOL. Run a "existing" vacuum hose from the ported vacuum port on your carb, to the outside port of the double distributor advance. That is exactly like any other "non emission" (49 state) engine was routed. Leave the manifold vacuum line connected to the back (retard port) on the distributor, exactly like it was originally connected. Here's what makes a difference. Take a #6 oval head Philips screw about a 1/4" long and using a #1 Philips screwdriver push the oval head screw into the end of the manifold vacuum hose ( a shot of silicone spray helps) to form a plug and slip it back on the rear retard post (the one closest to the distributor. No need to change the factory distributor. The diagrams posted by James Roney answer your question exactly. My suggested modification only eliminates the smog era retarded timing. Set the timing at 8 to 10 BTDC degrees at idle, after you have plugged the retard line.
 
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