PareosWC Posted June 26, 2020 Report Share Posted June 26, 2020 Hello, gents- on my Dodge 230 motor, the draft tube was beat up and bent near the end, so I cut the bent portion off, but am now wondering... How much tube is 'adequate' to vent those crankcase gasses? I have leaks at the fuel pump gasket, the dipstick, and the valve covers. Not an issue, but I wonder if I'm over-pressurizing the motor with only a 6 inch tube? Quote Link to comment Share on other sites More sharing options...
plymouthcranbrook Posted June 27, 2020 Report Share Posted June 27, 2020 (edited) This is just my thought but I expect the tube needs to be long enough to extend down into the airflow beneath the car. That way the passing air will creat a negative pressure at the tip of the tube and cause the crankcase fumes to be drawn out. I don’t think six inches would be long enough if your tube attaches at the same point my 217 does. Although after studying your picture it does not seem to be the same. Mine attaches near the back of the motor on the right side and I have an open vented cap at the oil filler. Still I would think it needs to be in the slipstream unless a pvc system has been installed. Edited June 27, 2020 by plymouthcranbrook Quote Link to comment Share on other sites More sharing options...
Merle Coggins Posted June 27, 2020 Report Share Posted June 27, 2020 Since your truck is a military vehicle, and seeing the air filter at the oil fill pipe, I would suspect your engine would have had a a PCV setup instead of a draft tube. but if you want to use a draft tube it would have to be long enough to hang down in the air stream below the engine so that it can pull the gases out, as mentioned earlier. The also have a diagonal cut at the end with the long side towards the front. 1 Quote Link to comment Share on other sites More sharing options...
PareosWC Posted June 27, 2020 Author Report Share Posted June 27, 2020 OK, thanks for the clarification, guys. I'll set up a PVC system, as I'm not sure that I can get some fresh air in there when I'm running less than 35 mph... Quote Link to comment Share on other sites More sharing options...
greg g Posted June 27, 2020 Report Share Posted June 27, 2020 What you have pictured isn't the road draft tube it is the oil fill tube and the air in for the crank case. The road draft tube is on the manifold side and is the exit for the crankcase. The draft tube operates on creating a low air pressure zone (partial vacuum) at the bottom end of the tube. The vehicle must be in motion for the draft to be created. The pcv system was developed for military vehicles to increase their stream fording capability, by making it harder for water to enter the crankcase when crossing streams or looded roads or off road situations. 1 Quote Link to comment Share on other sites More sharing options...
JBNeal Posted June 27, 2020 Report Share Posted June 27, 2020 additional information - draft tube replacement for PCV system Quote Link to comment Share on other sites More sharing options...
PareosWC Posted June 27, 2020 Author Report Share Posted June 27, 2020 Thanks, Greg. I just wanted to show the 230 motor, and I know we all like pics... I'm familiar with the difference of a road draft tube and breather assembly ? Quote Link to comment Share on other sites More sharing options...
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