Ventilating the Flat Head!

[19Fordy]

Here's a pictorial of the 8BA crankcase ventillation system using the 8BA style intake manifold. If you install an electric fuel pump you can mount an oil fill tube and a road draft tube that would run down the back of the engine. Air passing beneath the road draft tube would pull air and gasses out of the crankcase. I recall seeing this on early Ford engines. The tube looked like electrical flex conduit but was larger in dia. The photo below shows an oil fill tube with cap I made . It mounts where the fuel pump stand used to be. If needed, a hole could be drilled in the side of the oil fill tube and a road draft tube inserted which would run down along side the bellhousing. The same thing could easily be made out of steel.

 

[Jack E/NJ]

19Fordy>>> a hole could be drilled in the side of the oil fill tube and a road draft tube inserted which would run down along side the bellhousing.>>>

NO, your oil fill tube looks too pretty to drill for a draft tube! Why not use the Chrysler style baffled breather cap and run a draft tube from its tubing vent?

Jack E/NJ

 

[frenchy dehoux]

This is what I have installed on my Lincoln motor. Lincoln V12 did not have a draft tube only rely on the oil cap that is vented.

Frenchy

 

[Jack E/NJ]

Looks like you might've used the existing dipstip hole, Frenchy. Good choice for the draft tube! But what's that funny-looking can sticking out from the tube like a sore thumb? A baffle to catch road rocks?

Jack E/NJ

 

[bbrocksr]

This is what I have installed on my Lincoln motor. Lincoln V12 did not have a draft tube only rely on the oil cap that is vented.

Frenchy

Looks like a crankcase ventilator off a Y block/292/312.
Bill

 

[Walt Dupont--Me.]

Looks good Frenchy, looks like you used the breather from a Y block. Walt

 

[bbrocksr]

Well, Old Henry, some of us figured Old Henry Ford had it all bassackwards and this is the sorta of the way some of us do positive crankcase ventilation now. But I'm not naming names. 8^) Jack E/NJ

Positive crankcase ventilation uses manifold vacuum to pull the gases into the intake manifold, not through the carburetor.
Bill

 

[Brendan]

I'm not sure about 8ba but here is the illustration from the Ford Passenger Car Sales Handbook for the 59A-B showing the path of crankcase ventilation. I would think the 8ba is similar.

i thought that blow-by comes out of the oil filler! LOL,

 

[bbrocksr]

i thought that blow-by comes out of the oil filler! LOL,

If the baffle tube is left out you'll get a lot of blowby out of the oil filler.
Mine was left out and it had lots of blowby I put the tube in and almost stopped it completely. Also with the tube out it defeats the ventilation system. Bill

 

[Old Henry]

i thought that blow-by comes out of the oil filler! LOL,

Wouldn't need the filter on the filler if that were the case.

 

[19Fordy]

19Fordy>>> a hole could be drilled in the side of the oil fill tube and a road draft tube inserted which would run down along side the bellhousing.>>>

NO, your oil fill tube looks too pretty to drill for a draft tube! Why not use the Chrysler style baffled breather cap and run a draft tube from its tubing vent?

Jack E/NJ

Thanks for the kind words. That's why I'm still using the stock road draft tube and a shortened breather tube with a filter on top.

 

[Jack E/NJ]

bbrocksr>>>Positive crankcase ventilation uses manifold vacuum to pull the gases into the intake manifold, not through the carburetor.>>>

There are two types of PCV. The first is on the low vacuum side of the carb into the air cleaner that works mainly at high throttle when blowby is greatest and usually doesn't include a PCV valve. The other is on the high or manifold vacuum side of the carb that works mainly at low throttle and includes a PCV valve that closes at high throttle. Most vehicles in the 60s and later had both types of PCV systems.

Jack E/NJ

 

[Shadetree]

Let's hear from the originator of this thread.

Shadetree

 

[Ronnie]

This shows flow.The line from air cleaner to engine insures filtered air into engine.To replace air removed by pcv.Flow is from air cleaner to engine not engine to air cleaner.

 

[peteyshoes]

there is no road draft tube on my engine. there is a small baffled vent on the front, upper right side of oil pan. probably the predecessor of the draft tube. i know it works, as it will leave a film on pan after a good run.

 

[Jack E/NJ]

Ronnie>>>This shows flow.The line from air cleaner to engine insures filtered air into engine.To replace air removed by pcv.Flow is from air cleaner to engine not engine to air cleaner.>>>

Only at low throttle when the PCV valve is open. At high throttle, the valve closes due to low manifold vacuum at which point the flow is reversed by blowby and/or engines having crankcase venting. If you pull the tube connecting the air cleaner to the sealed PCV filler cap you will almost always see clear evidence of this reversed flow in the form of a milky residue of entrained crankcase moisture and oil that get by the filler cap's baffle material.

Jack E/NJ

 

[bbrocksr]

bbrocksr>>>Positive crankcase ventilation uses manifold vacuum to pull the gases into the intake manifold, not through the carburetor.>>>

There are two types of PCV. The first is on the low vacuum side of the carb into the air cleaner that works mainly at high throttle when blowby is greatest and usually doesn't include a PCV valve. The other is on the high or manifold vacuum side of the carb that works mainly at low throttle and includes a PCV valve that closes at high throttle. Most vehicles in the 60s and later had both types of PCV systems.

Jack E/NJ

Jack, Not True, The PCV valve is hooked to manifold vacuum to suck the gases out of the crankcase and fresh,filtered air enters the crankcase through the line from the air cleaner. A PVC valve does not close in the direction of the vacuum, It meters the gases in that direction. It closes in the opposite direction to prevent a backfire from entering the crankcase.
Check the airflow on Ronnies post.
Bill

 

[Jack E/NJ]

Bill---No argument on PCV valve's backfire prevention or which direction it closes or the flow from the air cleaner when it is open at high manifold vacuum. But consider post #36 in the case where the valve is closed or nearly so and path of least flow resistance at low manifold vacuum.

At any rate, in a vented crankcase like the flathead, the use of a simple unrestricted (no PCV valve) reverse flow PCV system directly into the air cleaner cannister will indeed suck gases and blowby out of the crankcase and into the combustion cycle.


Jack E/NJ

 

[Old Henry]

in a vented crankcase like the flathead, the use of a simple unrestricted (no PCV valve) reverse flow PCV system directly into the air cleaner cannister will indeed suck gases and blowby out of the crankcase and into the combustion cycle.

I would wager that if you could measure the vacuum in the air cleaner canister there would be no measurable vacuum, certainly not enough to suck air backwards into the out vent where the airflow is creating much greater vacuum to suck it that way.

 

[jack orchard]

Is there any general agreement on the best/easiest/cleanest way to put a PCV system on a 8BA? Thanks...jack