Working on a 1965 F350 with an FE in it, noticed today doing brake lines, that it has both pcv and road draft tube(hose cut short, vents on top of crossmember). Thinking I need to eliminate the draft tube for the pcv to operate correctly, but not sure. First time I have run into a motor with both, seems to me that neither one will operate correctly. Anyone else ever run into this? Suggestions? Thanks
unique challenge - '65 about start of smog requirements (?) - maybe somewhere along the line someone tried to meet new/updated smog rquirements - maybe did not know of draft tube - yep, just need to block it off and make sure PCV is functioning and from other valve cover return internal air to air cleaner
I eliminated the road draft tube on my '57 Pontiac and installed a PCV valve in its place. Seems to work well. KK
You still need another breather or way to get air back into the crank case with a PCV system. Normally this involves a breather on the opposite valve cover from the PCV valve. Perhaps they were using the road draft tube for that purpose?
What you have will/does work. The trouble is, the road draft tube is now the intake of the system. If there is not some sort of adequate filter in the line, it is susceptible to ingesting whatever passes by. That could end badly. Where is the current PCV valve located?
The motor has a breather style oil fill cap on the fill tube and the valve cover also has a twist in breather cap, sorry did not mention that. And the pcv valve is routed to a port on the intake manifold behind the carb. I am thinking that over the last 50 years a lot of "if it fits" repairs have gone on. I think I am going to plug the road draft tube hole, I was just under the truck a bit ago and I don't think it has done anything for years from the looks of the end of the hose. Thanks
If there is a breather style cap present, and it has some sort of filtering properties, and the PCV valve is present, and plumbed to the manifold, then none of these systems are working as they were designed. Plug the road draft hole. That will "close" the system. Air will then only able to go in through the breather cap, through the engine, and out through the PCV valve. With the road draft tube present and open, air will be pulled into the engine via the path of least resistance, which will likely be the unfiltered road draft tube.
I would't think a "factory" road draft tube would be a rubber hose, it would be metal. That part sounds more like an owner installed piece. Where does the rubber hose attach? Could it have been part of something original that fell away, and an owner concocted another system? Does't sound original anyway. I am Butch/56sedandelivery.
Let's think about this' you have a PCV valve pulling vacuum on the crankcase and a open hose or pipe from the crankcase to one of the dirtiest locations on the car not good.
No it is definitely not a typical metal draft tube, it appears to be a piece of heater hose that goes up to a 90 degree fitting on the back of intake. I am going to remove fitting and install a plug in the location on the fitting. The hose appears to be clogged with debris, so probably little to no air was being drawn through. I do not believe that it anyway a stock setup, my thoughts a home grown repair at some point in my trucks past with whatever was on hand. Thanks
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