Vaccume Line Help
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Vaccume Line Help
I have a 1975 360 and half of the vaccume lines are plugged. Is there a diagram of vaccume lines for this motor? Also, there are 2 valve cover breathers, and not PCV valve (I'm not sure if that's what it's called or not). I'm pretty sure that there should be one on either of the valve covers.
It's all messed up, any advice is extremely helpful! Thanks
It's all messed up, any advice is extremely helpful! Thanks
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Joined: Jun 2007
Posts: 103
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On those years Ford had the PCV valve in the oil filler cap.
I am sure that there are vacuum diagrams for your engine, but there may be several different schematics for the same engine. Is sounds to me like someone thought that removing all the smog devices would make the engine run better, or that the fuel economy would improve. You can probably hook one of the breathers up to the air cleaner via a hose with a PCV valve in it. The end of the hose that goes into the air cleaner has a small air filter to help stop the flow of oil into the carb's venturi.
What you really need in the way of vacuum in those years is:
1. Distributor vacuum advance...ported vacuum...located at the bottom of the carb. No vacuum until the throttle is cracked.
2. Power brake booster if it is vacuum operated. Hint: Most all power brake boosters in those days used vacuum, unless it was a diesel. This vacuum is connected directly to the intake manifold or to the vacuum tree mounted on the intake or on the firewall.
3. Transmission modulator valve, if it is an automatic...This vacuum line is connected directly to the intake via the vacuum tree mounted either on the manifold or on the firewall.
4. Heater/AC air distribution doors. This is also connected to the vacuum tree and probably has a vacuum cannister inline with a one/way check valve to maintain momentary vacuum losses that normally happen in different driving conditions (vacuum can get to the system via the engine, but it is checked from leaving the system by the one-way check valve).
Those are the primary vacuum demands on the engine. There may be more, and of course if you don't have power brakes or an auto trans, then you won't need vacuum for them either.
I would, however, hook up some way of incorporating a PCV into one of the breather caps, as it will help to draw out engine killing moisture from the crankcase...that is what PCV stands for, by the way. Positive Crankcase Ventilation.
Hope that helps and good luck.
Dan Harriman 84 F150
Orange, Texas
I am sure that there are vacuum diagrams for your engine, but there may be several different schematics for the same engine. Is sounds to me like someone thought that removing all the smog devices would make the engine run better, or that the fuel economy would improve. You can probably hook one of the breathers up to the air cleaner via a hose with a PCV valve in it. The end of the hose that goes into the air cleaner has a small air filter to help stop the flow of oil into the carb's venturi.
What you really need in the way of vacuum in those years is:
1. Distributor vacuum advance...ported vacuum...located at the bottom of the carb. No vacuum until the throttle is cracked.
2. Power brake booster if it is vacuum operated. Hint: Most all power brake boosters in those days used vacuum, unless it was a diesel. This vacuum is connected directly to the intake manifold or to the vacuum tree mounted on the intake or on the firewall.
3. Transmission modulator valve, if it is an automatic...This vacuum line is connected directly to the intake via the vacuum tree mounted either on the manifold or on the firewall.
4. Heater/AC air distribution doors. This is also connected to the vacuum tree and probably has a vacuum cannister inline with a one/way check valve to maintain momentary vacuum losses that normally happen in different driving conditions (vacuum can get to the system via the engine, but it is checked from leaving the system by the one-way check valve).
Those are the primary vacuum demands on the engine. There may be more, and of course if you don't have power brakes or an auto trans, then you won't need vacuum for them either.
I would, however, hook up some way of incorporating a PCV into one of the breather caps, as it will help to draw out engine killing moisture from the crankcase...that is what PCV stands for, by the way. Positive Crankcase Ventilation.
Hope that helps and good luck.
Dan Harriman 84 F150
Orange, Texas
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