Stovebolt.com Forums The Shop Area The Engine Shop 235 strange draft tube

I believe bartamos is correct, early military truck, part of the fording system which includes a PCV valve connected to the intake and other components of a closed system.
Likely doesn't belong on that engine. Looks cool though.
Fred

Is there a hose on the carburetor side of the valve cover going to the intake manifold? If so, it may be the intake side of a PVC system. Inside the can with the clips may be an air filter, more than likely an oil bath type.

This is from a GMC truck. It should have a PCV to make it work correctly. The housing has a paper pleated filter inside, top cap is for the oil fill.

Joe

The PCV valve should be located in line with a hose that connects from the valve cover to the intake manifold where the vacuum advance is attached.

Here is a positive crankcase ventilator photo.

This is how the system is setup on the inside, sems like it lets pressurised air out thro the filter at a set pressure. The cap seal is dry, so it lets it out all the time now. No pcv system is attatched now, the valve cover has a npt plug in it. What pvc valve should it have? Installing it so it connects the valvecover to the plug in the intake below the carb?

For now the engine smokes like a steamroller thro the vent. It has been sitting for a long time i guess, hope that the rings will lossen up a bit while driven more. Trying to sort out everything from item to item. It runs now, but has a little rattle from time to time. So i think the lifters should need to be run a litle more too. Just waiting for a new radiator so i can run it a litle longer.

Thanks very mutch for al the input!

There was another recent post that showed a similar PVC design. That shows the suction line and PCV valve, from the valve cover to the intake manifold. [LINK]

1947-1954 Factory Assembly Manual
Engine Positive (Crankcase) Ventilation Instruction
R.P.O. 217 Section 0, Sheet 4.00
Two types:
Series: 5000
and
Series: 3000, 4000, 6000

The reason why the engine smokes could be because the crankcase is not ventilating.
To solve the smoke problem you could take the oil fill cap off and see if the smoking goes away or reduces.

In your photo, the pipe plug in the valve cover is where your suction hose for the PCV system will go. The other end will go to the intake manifold where the vacuum wipers attach. Finding original parts will be nearly impossible. The good news is you can find parts that you can use to make it work. The two ends are simply NPT pipe nipples with a hose connecting them. You’ll need to install a Y connector at the intake manifold to adapt the new PCV system into. The PCV valve could be installed in either end providing the direction of flow is followed. The tricky part is finding a PCV valve in the correct direction of flow (toward the manifold), that meters the proper flow of air so you don’t lose too much vacuum and enough so the system works. They make valves that flow in both directions. They are usually marked with an arrow as to direction of flow.

You must run a filter in that housing or every bit of dust that the PCV system draws in will be circulated thru your engine. Finding a replacement filter may be an issue. From your picture, I see holes in the bottom of the canister. I surmise the air would get drawn into those holes and then thru a filter, then thru the holes in the cap that gets clipped on top. If that is the case then a paper folded filter would not work. I suspect that it would be a more like the filter found in the original air filters where they use a media similar to course steel wool. After cleaning in kerosene, you would soak it in 30 weight oil, allow it to drip dry, them reinstall. Copper Or stainless steel scrubbing pads may be a suitable replacement.

You may consider changing to a conventional road draft system until you get all the parts needed to make your unique PVC system work. That way all you need is the road draft tube (Which is readily available on eBay) and a filtered oil fill cap on the valve cover, which you can find at you local auto parts store.

One more thing. Engines when you first start them up for the first time in years tend to smoke for awhile. You may find that the smoke dissipates a bit after being run for awhile.