Drop Tube

[GunnersWillys]

Question:  My '58 3B has a drop tube versus PCV, meaning it is probably not the original engine.  I offroad this Jeep, and occasionally need to do water crossings.  Nothing too extreme, but probably deep enough at times to have that tube underwater. 

Is this okay if I don't let the engine shut off?  Or can I convert the engine to a PCV or closed loop so I can ford maybe 20" of water.

Appreciate the feedback.  Thanks.

[Rus Curtis]

Old post but my .02 cents worth.

If the engine keeps running, you should be okay.  However, if it stops the engine could take on water.  I think you could also reposition (not much) or add a hose to reroute upwards right before the crossings to help.

I remember Oldtime explaining the closed PCV system was added to address this issue (I want to say M38 time frame) and was definitely standard by the time the 3B's were built.  If you wanted to convert, Harry Sheets may have a complete assembly (tubes and all) where you could either clean and install or use as a pattern to bend your own.

[GunnersWillys]

I hadn't considered a hose.  That might work, as long as I am well sealed at where the tube mounts to the valve cover. 

It's the cutting off in deep enough water that worries me.  Doesn't take much to drown out these vehicles.  Thanks.

[scoutpilot]

Just to put a fine point on this. It's called a "Road Draft Tube" because it relies on air moving past the angle-cut end to create suction at the tip thereby drawing the air inside to the atmosphere. Adding a tube (hose) that will take the end of this device out of the airflow will not work. It is best to convert to the closed PCV system.

[Rus Curtis]

It is best to convert to the closed PCV system.

This.