GasWorksGarage

what exaclly is this called?

Recommended Posts

Looks to be a draft tube, but I have never seen one with the canister on it.

Share this post


Link to post
Share on other sites

If it is leaking it may mean that your engine has too much blowby and the crankcase is being pressurized.  Your oil filler cap could also be plugged.

  • Like 1

Share this post


Link to post
Share on other sites

X 2 on the draft tube.

Does it disassemble ?

Looks like a rolled and crimped joint, which could be soldered or brazed.

Not a big deal, if you don't need to take it apart.

Need a picture of the top, or how it mounts to the block.

 

Mike in Colorado

Share this post


Link to post
Share on other sites
20 hours ago, keiser31 said:

Looks to be a draft tube, but I have never seen one with the canister on it.

Pontiac used a road draft tube on all their flat head sixes and straight eights and used a filter ( NOT CANISTER) near the end of the tube. When the car is turned off that filter is used to keep any roadside dust and dirt from entering the road draft tube/engine. The engine below is a Pontiac straight eight. 

Related image

 

 

This next picture below shows where the air enters the engine on a flathead Pontiac. It's right in front of the ignition coil. This breather has a scoop to channel the air from the radiator fan forcing the air into the engine. I see many of people who have  supposedly restored cars with the breather on backwards even though there is a groove that indexes the breather to the proper location. This one is correct.

Related image

 

 

 

Pontiac used a road draft tube on it's V-8's up to 1962. 1955-1960 models used the filter near the end of the tube. This filter ( NOT a Canister ) was used to keep any dust kicked up by wind or cars passing by going in the reverse flow of the road draft tube when the engine was shut off. They are supposed to be cleaned every oil change along with the breathers/filters up top on the engine. Air Flow goes threw the breathers, circulates around the top end of the head, then into the valley pan down into the crankcase and up again to the valley in Pontiac's case and into the tube threw the filter and out the tube under the car. The tube is cut at a angle to create a low pressure area when the car is under way to suck the gasses out of the engine.

Image result for pontiac V8 road draft tube assy image

This is what it looks like on the Pontiac V-8. the tube and filter are just behind the oil filter Canister housing rt. rear side of the engine. By the coil and ignition wires you can see the tube curving around and changing directions to go the valley pan. On both valve covers you can see where the air enters, which is the breathers/filters. All the filters must be soaked and cleaned rinsed  in mineral spirits or kerosene. once they are clean they are filled with 10W oil they are turned over to let the oil out and allowed to drip dry. The oil clings to the wire mesh inside the breathers and traps dirt as it passes by.

 Image result for 1955 Pontiac V-8 image

 

Now, the clean air entering the engine is filtered by the top end breathers picks up oil vapor, unburned fuel vapor, spent fuel vapor ( exhaust vapor ) water from the combustion process. all of this vapor combined is a caustic corrosive acidic concoction and needs to be vented from the engine out the road draft tube.

 

ALL engines brand new and  to the point of death produce blow by gasses. A new engine much much less than a old worn out one.

 ALL road draft tubes exhibit some dripping of the oil vapor concoction, especially after a high speed run when the draft tube is really working. The amount and the amount of gasses you can see coming out depends on where the engine is in it's life cycle. As said before breathers are to be cleaned and oiled with EVERY 3,000 mile oil change.   

Edited by Pfeil (see edit history)

Share this post


Link to post
Share on other sites

On some cars there is no filter. On air cooled VW's and early air cooled Porsches the road draft system does not have a breather filter to pass through.

 

This is a partial view of a VW engine. Image result for image of 1200 cc VW engine breather/ separator

 

In a early Porsche and all VW air cooled engines fresh air enters at the crankshaft pulley. The end of the crankshaft pulley ( #16 ) has a reverse screw on it's outer snout which fits over the end of the crankshaft end. This reverse screw pulls air into the crankcase and circulates around the engine and finally drawn up the hollow generator stand ( #6 ).   On the side of the generator stand is a place where the OIL Separator ( # 25 ) goes into the generator stand and also connected to the separator is the road draft tube # 26. The oil separator also has a cap on it ( #22 )  and that is where you add oil to the engine from.

 

 BTW this is a image of the crankshaft pully. On the  outside diameter you can see the reverse threads which pulls outside air into  the engine>>>>>>>>>Image result for image of 1200cc VW engine crankshaft pulley

The Pontiac's don't have a oil separator because the tube is bent like a J and oil ( being splashed around ) which is NOT in vapor can't climb the pipe and go out the draft tube. So the only thing that goes out is blowby gasses and oil vapor mixture.

 

So we have two types of devises for a road draft system. The Oil separator type like the VW / Porsche  and the other type used by Pontiac.

Edited by Pfeil (see edit history)

Share this post


Link to post
Share on other sites

Ford Y-block. . . . . 

The can is original and it is filled with the copper, scrub pad, mesh type material. It acts as a condensation point for the oil vapors so they can run back into the oil pan. 

Remove it, (the can unbolts from the tube part). Clean the mesh, reinstall and then expect it to drip again later when the mesh becomes re-saturated. 

Disassembly and cleaning was considered regular maintenance. 

 

Road draft systems are commonly misunderstood. As described above, the idea is that air is drawn in (fan forced?) at the top (generally the oil filler) it flows through the engine and then THE OIL SATURATED FUMES exit at the bottom. The cut angle on the exit tube is not done to be pretty. It faces to the rear so that as the exit tube is flying through the wind stream at highway speeds, there is a 'low pressure area' that acts like a tiny vacuum to remove the oil fumes. 

 

Why are there oil fumes in your engine?

You have hot oil that is being sprayed onto hot metal (250+ degrees) It lubricates, but it also smokes. Imagine a pan of oil bubbling on the stove. Smoke is normal for hot oil. The road draft system was never efficient at removing the vapors. 

 

After about 1962 there was a direct connection made between the crankcase and the intake manifold such that intake vacuum could suck the vapors into the engine to be burned rather than becoming sludge in your engine and forming acidic compounds and being smelly. 

 

If you are not into exact originality removing the valley pan and the few other parts from a 1962+ Y-Block will give you all the original factory set up to convert to a  Positive Crankcase Ventilation system. Not a bad idea to make things better inside your engine and reduce the oil smells. 

Share this post


Link to post
Share on other sites
12 hours ago, m-mman said:

Ford Y-block. . . . . 

The can is original and it is filled with the copper, scrub pad, mesh type material. It acts as a condensation point for the oil vapors so they can run back into the oil pan. 

Remove it, (the can unbolts from the tube part). Clean the mesh, reinstall and then expect it to drip again later when the mesh becomes re-saturated. 

Disassembly and cleaning was considered regular maintenance. 

 

Road draft systems are commonly misunderstood. As described above, the idea is that air is drawn in (fan forced?) at the top (generally the oil filler) it flows through the engine and then THE OIL SATURATED FUMES exit at the bottom. The cut angle on the exit tube is not done to be pretty. It faces to the rear so that as the exit tube is flying through the wind stream at highway speeds, there is a 'low pressure area' that acts like a tiny vacuum to remove the oil fumes. 

 

Why are there oil fumes in your engine?

You have hot oil that is being sprayed onto hot metal (250+ degrees) It lubricates, but it also smokes. Imagine a pan of oil bubbling on the stove. Smoke is normal for hot oil. The road draft system was never efficient at removing the vapors. 

 

After about 1962 there was a direct connection made between the crankcase and the intake manifold such that intake vacuum could suck the vapors into the engine to be burned rather than becoming sludge in your engine and forming acidic compounds and being smelly. 

 

If you are not into exact originality removing the valley pan and the few other parts from a 1962+ Y-Block will give you all the original factory set up to convert to a  Positive Crankcase Ventilation system. Not a bad idea to make things better inside your engine and reduce the oil smells. 

There is a matter of opinion wither or not you can ventilate the crankcase with a road draft system properly. With a system properly maintained the crankcase system does quite well. Most guys at the old gas stations never cleaned, much less oiled and drip dry the breathers at all those canister filters on Pontiac's sometimes because they were never cleaned plugged up. The Porsche/VW system with it's reverse screw actually pumps air into the crankcase. I know both the Pontiac type and the VW Porsche type are called " pressure suction " systems, by the VW Porsche system really forces the air through.

 

 

Now the PCV system. Some vent to the air cleaner, most to the base of the carburetor or intake manifold.

Have you ever considered what burned hydrocarbons, water and corrosive acids effects are on the combustion chamber, cylinder walls and valves and seats. Talk about eating ones own excrement! And that exactly what the PVC system does. 

Edited by Pfeil (see edit history)

Share this post


Link to post
Share on other sites
6 minutes ago, Pfeil said:

the VW Porsche system really forces the air through.

 

Which means that it really is not a "road draft" system . . . . Sounds like more of a 'positive' flow type system. . . . ??

 

I think 41 Buick was the first with a positive flow (intake vacuum) crankcase ventilation. . . . ?

 

The Ford system relied ONLY on the suction that resulted from moving forward. Hardly any suction at road speeds, and nothing when stopped. And with out a consistent flow of ventilating air, the 'excrement' vapors are condensing inside the cooler parts of the engine (valve covers, lifter area) becoming solid carbon particles. 

 

As I remember the Pontiac flat eight never used an oil filter??  There was something about the design of the oil pick up in the pan that acted as an oil cleaner??

Remember that Oil filters were an optional accessory on engines for many years. If you can add one to a car today, I would advise it. 

Share this post


Link to post
Share on other sites
11 hours ago, m-mman said:

 

Which means that it really is not a "road draft" system . . . . Sounds like more of a 'positive' flow type system. . . . ??

 

I think 41 Buick was the first with a positive flow (intake vacuum) crankcase ventilation. . . . ?

 

The Ford system relied ONLY on the suction that resulted from moving forward. Hardly any suction at road speeds, and nothing when stopped. And with out a consistent flow of ventilating air, the 'excrement' vapors are condensing inside the cooler parts of the engine (valve covers, lifter area) becoming solid carbon particles. 

 

As I remember the Pontiac flat eight never used an oil filter??  There was something about the design of the oil pick up in the pan that acted as an oil cleaner??

Remember that Oil filters were an optional accessory on engines for many years. If you can add one to a car today, I would advise it. 

 

 

The Pontiac system, common to all GM cars of the era and the VW Porsche separator type with a road draft tube are both considered the " Pressure Suction Type"

 

 

The VW Porsche type in the beginning and until the crankcase smog laws did vent to the draft tube, later the road draft tube was plugged with a rubber plug that had a slit in it. when the separator above it separated  water the water would run down the road draft tube and the slit would open letting the water and it's contaminates out.  A nipple was provided so a hose could connect the separator to the air cleaner for the vapors. This way only crankcase vapors would enter the intake system and water from the crankcase wouldn't.

 

The Pontiac straight six and eight used a form of a filter in the oil sump.  Exclusive to Pontiac was the “oil cleaner” device on the suction side of the pump and mounted within the pan. This device forced oil to make a 180-degree turn above a sediment bowl of one-quart capacity, which caught any debris large enough to cause engine damage. A fairly large thing. It was thought to only being cleaned at time of a overhaul.

The optional oil filters were not a full flow system, just a partial flow system.  

Edited by Pfeil (see edit history)

Share this post


Link to post
Share on other sites

My Pontiac crankcase vent system (1936) has a scoop right up in the air stream from the fan. It moves air through the engine even at ldle, and probably does better when the car is moving and the draft tube is actually in a draft. I have the heavy duty filters (optional), so there is a copper mesh breather filter on the inlet side. The draft tube (outlet) is in the valve cover (aka side cover) of the flathead 6.

 

The important thing is that you never suck dirty air in. The heavy duty option on the Pontiac has copper mesh at the intake end (and probably a simple oil separator at the draft tube end (the details escape me right now).

 

I had a Ford FE engine that had a copper or steel mesh at the draft tube end. It was packed under a plate in the bottom of the intake manifold, and the draft tube connected at one end. There must have been a breather cap at the intake end. On Small Block Chevys, they had a breather at the inlet, and an oil separator can (no mesh) under the intake manifold that drained the oil off before the air and vapors went out the draft tube.

 

There is a hard limit to how much air a PCV system can move. There is only so much crankcase vapor and air you can mix with the incoming air/fuel charge to the engine and still have the carburetor work right, and the engine idle and run acceptably.  All PCV systems blow backward part of the time because they cannot keep up. As the engine gets worn, and has more blowby, the situation only gets worse.

 

The advantage is that PCV always moves SOME air, even at idle, and many draft systems do not.

 

And as for the Pontiac system, it is pretty astounding how well it works, and how much air it moves. I really can't imagine PCV being any better, even idling in traffic.

 

1 hour ago, Pfeil said:

Most guys at the old gas stations never cleaned, much less oiled and drip dry the breathers at all those canister filters on Pontiac's sometimes because they were never cleaned plugged up.

 

Yes. Here is mine when bought. It was still breathing like this. Don't ask me how. There must have been a hole in the sludge somewhere.

 

iSLa252.jpg

 

What's actually in there:

 

O5MzA94.jpg

 

 

Edited by Bloo (see edit history)

Share this post


Link to post
Share on other sites
13 hours ago, Pfeil said:

Now the PCV system. Some vent to the air cleaner, most to the base of the carburetor or intake manifold.

 

The vent to the air cleaner is  to filter air going INTO the engine. This is a "closed" PCV system. From the engine, crankcase vapors go into the intake manifold (base of carburetor, etc., some source of vacuum).

Share this post


Link to post
Share on other sites
3 hours ago, Frank DuVal said:

 

The vent to the air cleaner is  to filter air going INTO the engine. This is a "closed" PCV system. From the engine, crankcase vapors go into the intake manifold (base of carburetor, etc., some source of vacuum).

 Yes you are correct in some instances. For instance my 69 Pontiac has a closed CCS system. There is a tube that goes from the air cleaner to the valve cover. In the air cleaner there is a small filter that filters the air down the tube to the valve cover and that clean air enters the engine and mixes with gasses and finally comes out at the engine valley pan where the PCV valve is pushed onto. On the other end of the PCV a hose connects it to the intake manifold.

 

Below you can see the tube coming out of the air cleaner going to the valve cover. The flow direction is completely reversed from VW Porsche! ;

Related image

 

 

 

As I said some vent to the air cleaner. In the pictures below are the VW engine and the early Porsche engine. There is a hose from the top of the oil separator to the air cleaner where the exposed gasses are led. Remember my previous thread's picture of the reverse screw on the crankshaft pully? that where the fresh air enters on those engines.

Image result for image of 1200 VW engine see the tube going from the oil separator/ oil filler to the air cleaner on a VW

 

Porsche engine:Image result for image of 1963 porsche 356 engine  The oil separator/ oil filler is larger than the VW, but you can see the hose leading to the rt. side carburetor air cleaner.

There is no mistake in the father of these two engines; Good old Franz Reimspiess

 

Edited by Pfeil (see edit history)

Share this post


Link to post
Share on other sites

the bolt on the top allows for replacing the filter there is a gasket(?) on the tube portion.the oil filler cap is a problem if not cleaned if you are in a dusty area and drive a lot.the cap allows are into engine and the tube allows it out .if filler is dirty you will get the problem you have.blowby is another cause easy  to clean cap by soaking in varsol or similar type solvent then blow dry or let sit in upright position till dry.the filter was (is)a horse hair type material held in place with a mesh

Share this post


Link to post
Share on other sites
24 minutes ago, 54vicky said:

the bolt on the top allows for replacing the filter there is a gasket(?) on the tube portion.the oil filler cap is a problem if not cleaned if you are in a dusty area and drive a lot.the cap allows are into engine and the tube allows it out .if filler is dirty you will get the problem you have.blowby is another cause easy  to clean cap by soaking in varsol or similar type solvent then blow dry or let sit in upright position till dry.the filter was (is)a horse hair type material held in place with a mesh

Yes and a new filter element assy. has the gasket;

Image result for fram oil bypass filter for vw porsche images

Share this post


Link to post
Share on other sites
56 minutes ago, John_Mereness said:

crankcase breather ?

He's referring to the bypass oil filter like the type on the Porsche engine above and the filter element and gasket also above. This is not related to the topic though.

Share this post


Link to post
Share on other sites
On 10/10/2019 at 1:00 PM, Pfeil said:

 Yes you are correct in some instances. For instance my 69 Pontiac has a closed CCS system. There is a tube that goes from the air cleaner to the valve cover. In the air cleaner there is a small filter that filters the air down the tube to the valve cover and that clean air enters the engine and mixes with gasses and finally comes out at the engine valley pan where the PCV valve is pushed onto. On the other end of the PCV a hose connects it to the intake manifold.

 

Below you can see the tube coming out of the air cleaner going to the valve cover. The flow direction is completely reversed from VW Porsche! ;

Related image

 

 

 

As I said some vent to the air cleaner. In the pictures below are the VW engine and the early Porsche engine. There is a hose from the top of the oil separator to the air cleaner where the exposed gasses are led. Remember my previous thread's picture of the reverse screw on the crankshaft pully? that where the fresh air enters on those engines.

Image result for image of 1200 VW engine see the tube going from the oil separator/ oil filler to the air cleaner on a VW

 

Porsche engine:Image result for image of 1963 porsche 356 engine  The oil separator/ oil filler is larger than the VW, but you can see the hose leading to the rt. side carburetor air cleaner.

There is no mistake in the father of these two engines; Good old Franz Reimspiess

 

 

 

Frank DuVal

  • Junior Member
  •  
  • Frank DuVal
  • Members
  • 532
  • 1,171 posts
  • Location: Fredericksburg, VA
On 10/9/2019 at 8:17 PM, Pfeil said:

Now the PCV system. Some vent to the air cleaner, most to the base of the carburetor or intake manifold.

 

The vent to the air cleaner is  to filter air going INTO the engine. This is a "closed" PCV system. From the engine, crankcase vapors go into the intake manifold (base of carburetor, etc., some source of vacuum).

 

 

 

 

 

 

Frank, I found another engine that the crankcase vapors vent into the air cleaner like VW and Porsche. The Buicks with compound carburetion do as well;

Compound carburetion introduced on all Super, Century, and Roadmaster models as standard equipment and available as an option on all Specials.  This year 10 mm spark plugs were also used and the forerunner of a PVC (positive crankcase ventilation) system was pioneered which vented the oil vapors to the carburetor through a small tube from the top of the valve cover to the air cleaner.  Compound carburetion continued through the limited 1942 production, but was discontinued after World War II.

Image result for 1941 Buick compound carburetion image

 

Share this post


Link to post
Share on other sites

Yes, I just read about this PVC system in General Discussion under Cadillac Top Speed.......😉

 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now