1st Generation 1964 1/2 - 1973 - Questions & general discussions that apply to a specific year > 1968 Mustang
Canadian - 390 GT - PCV and emission systems
Vince22:
Hi everyone,
I have a 390 GT 1968 with a 4-speed transmission, a brake booster and no A/C (8R02S160056 / 63A T 2A 04E B7 7 5).
I would like to install the PCV system and be compliant with the original configuration.
Note: I have a 67 air cleaner.
Today,I have an aftermarket carb (Holley CFM 600 -4776-2) without fuel inlet on the driver side.
I will fix it, buying a FUEL BOWL KIT Holley 134-108 and a Ford Style Trans Line (long) Quick Fuel 34-166QFT.
And today, on the carburettor side:
* The time spark vacuum source is directed connected to the distributor advance (note: it is a single diaphragm distributor.
* Then the Power Brake port is connected to the PCV valve / elbow (on the passenger side)
* And the PCV port is capped
Then the brake booster vacuum line is connected to the PCV intake fitting.
And as you can see on the attached picture, it is not the original configuration
And I do not have:
* the PCV tube and the large rear brass intake fitting (there is only a bolt…).
* the distributor vacuum control valve. In fact I do not have anything on my thermostat housing.
* the thermactor system (but I do not want to re-install it - at least not for now.
So I will buy the PCV valve (C7OZ-6A666-A), the PCV Valve adaptor (C7OZ-6A796-A), the hose and clamps, the PCV tube (C6OZ-6758-A), the PCV intakes fitting (C8OZ-9A474–A, C8OZ-9A474-B, C7AZ-9A474-A).
But I see two outlets on the C8OZ-9A474-B and two outlets on C7AZ-9A474-A.
I imagine that some should be connected to the carburetor (time spark vacuum source, power Brake port and the PCV port) and some to the distributor vacuum control valve.
So my questions are:
* is the distributor vacuum control valve mandatory?
* is a single diaphragm distributor correct for my mustang?
* how should I connect the outlets of the C8OZ-9A474-B and the C7AZ-9A474-A?
Keith Stem:
This is a picture of a 68 390 PVC system from Mansfield Mustang, hope this helps.
RoyceP:
1. is the distributor vacuum control valve mandatory? No but it does provide a way to increase engine idle RPM / fan speed if the engine overheats
2. is a single diaphragm distributor correct for my mustang? No it was originally a dual vacuum advance. You can keep the single advance and just connect it to the ported carburetor vacuum connection to eliminate the thermostatically controlled vacuum valve.
3. how should I connect the outlets of the C8OZ-9A474-B and the C7AZ-9A474-A? The U - tube connects them to one another.
J_Speegle:
First welcome to the site. Hope you find the information and support here helpful in your concourse related endeavours
--- Quote from: Vince22 on May 30, 2020, 05:55:49 AM ---I have a 390 GT 1968 with a 4-speed transmission, a brake booster and no A/C (8R02S160056 : 63A T 2A 04E B7 7 5).
I would like to install the PCV system and be compliant with the original configuration.
Note: I have a 67 air cleaner.............
--- End quote ---
Not even getting into all the different versions of the 67 air cleaner it will obviously look out of place plus may mean that other parts of the emission system will be eliminated or not work as designed depending on the air cleaner base your using
And I do not have:
* the PCV tube and the large rear brass intake fitting (there is only a bolt…).
* the distributor vacuum control valve. In fact I do not have anything on my thermostat housing.
* the thermactor system (but I do not want to re-install it - at least not for now.
--- Quote from: Vince22 on May 30, 2020, 05:55:49 AM ---So my questions are:
* is the distributor vacuum control valve mandatory?
--- End quote ---
Mandatory for what? Given our focus here the answer would be yes since that is the way the car originally was equipped. But will it basically work without one? Many owners have rerouted around them or removed them and the vacuum hoses and had well running cars. In many areas removing and not using is a modification of the emission systems which is against the law if it ever comes up. So in that way it is mandatory
--- Quote from: Vince22 on May 30, 2020, 05:55:49 AM ---So my questions are:
* is a single diaphragm distributor correct for my mustang?
--- End quote ---
If your not going back factory why care? And since your not planning on using a PVS (ported vacuum switch how would you control a dual diaphragm distributor advance? It will work
--- Quote from: Vince22 on May 30, 2020, 05:55:49 AM ---So my questions are:
* how should I connect the outlets of the C8OZ-9A474-B and the C7AZ-9A474-A?
--- End quote ---
You don't have to but by joining out/balancing the vacuum between the two source is a better idea over all. Lots of aftermarket and other engines only use a single source. They can be joined by using rubber hoses and a T or you can use parts used on stock cars but be aware that the preformed pipe is shaped differently depending on application
Left to right. 390 - 428CJ - 428 PI
Moving this over to the lounge area since its more about modifications than originality ;) As has been our practice over the years
Vince22:
--- Quote from: RoyceP on May 30, 2020, 11:09:34 AM ---1. is the distributor vacuum control valve mandatory? No but it does provide a way to increase engine idle RPM / fan speed if the engine overheats
2. is a single diaphragm distributor correct for my mustang? No it was originally a dual vacuum advance. You can keep the single advance and just connect it to the ported carburetor vacuum connection to eliminate the thermostatically controlled vacuum valve.
3. how should I connect the outlets of the C8OZ-9A474-B and the C7AZ-9A474-A? The U - tube connects them to one another.
--- End quote ---
Indeed, today I have a single diaphragm distributor and no PVS and so the distributor is just connected to the ported carburetor vacuum connection.
To be compliant with the original configuration, I will start buying the PCV valve (C7OZ-6A666-A), the PCV Valve adaptor (C7OZ-6A796-A), the hose and clamps, the PCV tube (C6OZ-6758-A), the PCV intakes fitting (C8OZ-9A474–A, C8OZ-9A474-B, C7AZ-9A474-A) and the PVS (C8AZ-12091-A) with the hoses kit.
(note: I will keep the single diaphragm distributor for now and only purchase the Dual Diaphragm Distributor later).
So the question is, how should I connect the hoses between the PVS, the carb, the Single Diaphragm distributor, the PCV intake fittings…
I found the attached diagrams:
* the one for Dual Diaphragm Distributor is the one I should use later, when I will have purchase my Dual Diaphragm Distributor.
* but as I will keep the Singe Diaphragm Distributor for few months, I would like to use the other diagram.But the questions are:
* as I have a 67 - early 68 air cleaner, I can not connect the blue stripe. Should I cap the outlet of the front intake manifold fitting or should I connect the blue strip somewhere else (carb ?)
* the yellow stripe is connected to the carburetor. Which port should be used ? (the time spark vacuum source ? the Power Brake port ? the PCV port ?) And the two other ports of the carb should just be capped ?
* as I do not have (yet) the air bypass valve (needed for the thermactor, I guess), should I just cap the outlet on the rear intake manifold fitting ?
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