The Stovebolt Site Forums The Shop Area Engine Shop road draft tube needed on '59 235 ?

I have a '59 235 and it does not have a "road draft tube" but does have a vented oil fill cap on top. The block has a freeze plug where the tube would go. Do I need to have a vent for the lower crank case or will the top oil cap vent suffice for the engine? The engine is a complete rebuild. Photo attached.
235 engine

Any help is appreciated.

thanks

Hy coralhead, your 235 does not "need" a road draft tube, the road draft tube was designed to draw fumes from the crankcase of the engine while the vehicle was moving down the road. Without the road draft, all the air movement in and out of the engine must take place at whatever vents remain, your vented filler cap may be sufficient, hope that helps.

If you do not have the tube you are likely to smell blow-by fumes in the cab. Most of the time when the tube is removed and the engine is plugged it is because a PCV system is installed to re-burn the blow-by.

Any crankcase vent system needs to draw fresh air in an expell blow - by gasses, a single vent cap won't do very good job. Get a road draft tube at least. Modify to PCV, not that hard and helps keep crankcase dilution way down. Factory PCV was useed on many 261 truck engines as wall as 235s in forward control bodys and optional on others. I cut the downpipe off an old road draft tube & welded a washer to accept a grommet and PCV valve.
BC
Good looking rig you got going!