PCV/Breather.
Thread Starter
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Tuned
Joined: Sep 2013
Posts: 453
Likes: 20
From: Little Rock, AR
PCV/Breather.
Ok, I have some questions about the PCV. On our carbed 300s (mine is an 83) I have a screw in oil cap, and a PCV valve at the back of the engine. The PCV has two ports, the one on bottom I have plugged into manifold vacuum. The top I had had plugged into the top of my air breather and tee'd into the charcoal canister. I noticed that I could loosen the oil cap and it would hiss loudly as it released pressure. Then my dipstick kept blowing out. I went to Auto Zone this morning and bought a oil breather cap, bent the small tab so it would stay on, then held it down with duct tape. 
. I figured the engine needed to take in air through the oil cap to draw through the engine and out the pcv. Correct, or no? Where else would it pull fresh, filtered air from???
. I figured the engine needed to take in air through the oil cap to draw through the engine and out the pcv. Correct, or no? Where else would it pull fresh, filtered air from???
Lead Driver
Joined: Jul 2009
Posts: 6,477
Likes: 19
From: Sheffield, AL
Many models have a port on the oil fill cap which has a hose [accordion style, originally] that then connects to the air cleaner housing. That way, the vacuum is pulled from the intake manifold [or carburetor base] through the PCV valve and the clean make-up air is taken from the air filter housing.
At some point [1984?], when the valve cover began to have the dip in the middle [in preparation for the F.I. plenum], there was a place for PCV valve and then on the opposite end [near front of truck] there were two openings. One was for the hose going to the air cleaner and the other was not vented and was where oil was added.
At some point [1984?], when the valve cover began to have the dip in the middle [in preparation for the F.I. plenum], there was a place for PCV valve and then on the opposite end [near front of truck] there were two openings. One was for the hose going to the air cleaner and the other was not vented and was where oil was added.
Thread Starter
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Tuned
Joined: Sep 2013
Posts: 453
Likes: 20
From: Little Rock, AR
The only problem is that there is no place for the hose you are talking about. I understand how the system works, except that there is literally no place near the front of the engine to draw filtered air. Pictures of someone else's that had the screw on typeoil filter would be cool, cuz I'm stumped.
Senior User
Joined: May 2014
Posts: 151
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From: Charlotte
I got a rubber grommet and a oil breather filter that you can get at most parts store. You know, one of the small cone filters. The pcv is still operating in the back hole, connected to manifold vacuum off the intake.
Thread Starter
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Tuned
Joined: Sep 2013
Posts: 453
Likes: 20
From: Little Rock, AR
But I digress.
It came with no oil filter breather, and I keep reading about how it used a hose, but that hose would need to be near the front of the engine...soooo. Im confused.
Junior User
Joined: Mar 2010
Posts: 78
Likes: 1
From: Southside, AL
Here is a picture of my oil fill cap. It is original to the truck. It is an 83 F100. Hope it helps.
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Thread Starter
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Tuned
Joined: Sep 2013
Posts: 453
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From: Little Rock, AR
Here is a picture of my oil fill cap. It is original to the truck. It is an 83 F100. Hope it helps.
Attachment 108881
Attachment 108881
Nothing like that at all. That makes sense. Mine doesnt...
OEM style cap as it is on my truck.
Very similar to this engine, except my PCV Valve is at the back, not right by the cap.
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Junior User
Joined: Mar 2010
Posts: 78
Likes: 1
From: Southside, AL
I don't think those kind of caps let much air in there if any. Sounds like the breather you put on there worked pretty good.
The vacuum lines on my truck are barely hanging on, lol! I'm very careful when I have to move them around.
The vacuum lines on my truck are barely hanging on, lol! I'm very careful when I have to move them around.
Thread Starter
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Tuned
Joined: Sep 2013
Posts: 453
Likes: 20
From: Little Rock, AR
They let in NO air. Which is the part I dont understand. It was building pressure and blowing the dipstick out. My teacher said there may buildup more fumes in the engine compartment with how I have it rigged, but if my truck is running its going down the road, anyways. I dont waste gas idling in parking lots. Perks of being 17 and broke all the time..
Senior User
Joined: Sep 2013
Posts: 373
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From: Marlborough, CT
By your description, you have the wrong cap. If there are only two holes in the cover, you need the breathable cap. The engine in the picture shows what I believe to be the PCV in the wrong spot-that valve cover should have a hole/grommet in the back for the PCV, where you see the PCV in the picture should be the breather hose to the air cleaner, then a solid oil cap. The 2 hose PCV should have one hose going to the manifold tee, the smaller hose connects to a solenoid for EVAP canister purge. If you don't have any emissions on your truck, only use one port for PCV vacuum and cap the other. ~Bill
Cargo Master
Joined: Mar 2008
Posts: 2,577
Likes: 211
From: Washington
https://www.ford-trucks.com/forums/1...l#post10260146
https://www.ford-trucks.com/forums/1...l#post10258992
Here is a good photo of the PVC system with a hard cap and 2 more holes in the valve cover.
You can see the PVC valve at the back of the valve cover near the firewall.
I am not sure your valve cover is from an 1983, might be of a newer truck.
Jim
https://www.ford-trucks.com/forums/1...l#post10258992
Here is a good photo of the PVC system with a hard cap and 2 more holes in the valve cover.
You can see the PVC valve at the back of the valve cover near the firewall.
I am not sure your valve cover is from an 1983, might be of a newer truck.
Jim
Cargo Master
Joined: Mar 2008
Posts: 2,577
Likes: 211
From: Washington
Here is a photo of the little piece that attaches to the air cleaner on my truck. It is a twist lock type attachment to the air cleaner and is used on ~85-86 ... maybe more years not sure.
You might have an older air cleaner style and a newer valve cover.
https://www.ford-trucks.com/forums/1...l#post10258992
Carburetor Air Cleaner Hose Adapter E53Z-9E606-A 1985 Ford
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Jim
You might have an older air cleaner style and a newer valve cover.
https://www.ford-trucks.com/forums/1...l#post10258992
Carburetor Air Cleaner Hose Adapter E53Z-9E606-A 1985 Ford
.
Jim
Ford Parts Specialist
Joined: Nov 2006
Posts: 88,826
Likes: 787
From: Simi Valley, CA
Here is a photo of the little piece that attaches to the air cleaner on my truck. It is a twist lock type attachment to the air cleaner and is used on ~85-86 ... maybe more years not sure.
You might have an older air cleaner style and a newer valve cover.
https://www.ford-trucks.com/forums/1...l#post10258992
Carburetor Air Cleaner Hose Adapter E53Z-9E606-A 1985 Ford
1985/89 Ford Tempo/Mercury Topaz 2.3L only!
You might have an older air cleaner style and a newer valve cover.
https://www.ford-trucks.com/forums/1...l#post10258992
Carburetor Air Cleaner Hose Adapter E53Z-9E606-A 1985 Ford
1985/89 Ford Tempo/Mercury Topaz 2.3L only!