I know that some corvettes had the pcv valve in the filler tube. would a regular pcv valve work in a horizontal position? Carlg
'67 Impalas with a 283 (and probably some others in '67) had the filler tube with a sealed cap with a PCV valve that threaded into a bung on the back side of the filler tube. They breathed back to front with a tube coming up from the back of the block to a filter on the air filter. Clean air from the air filter went back to the back of the block, then through the crankcase and then up through the filler tube, then through the PCV valve to a fitting at the base of the carb. Soon after that they went to a side to side setup.
It won't work correctly. The valves are made internally to reduce the flow in high vacuum conditions like cruising and actually increase the flow to maximum under low vacuum (pedal to the metal) conditions. A vertical one on it's side won't modulate as the vacuum changes during operation. Another function is to prevent a crankcase explosion in the case of a backfire. A backfire might close the valve but then again it might not....
Would any PCV valve with pipe threads on one end be designed to work in the horizontal position? Did the valve with the threads ever get mounted vertical?
I checked and there is a pcv for a 63 Corvette that screw into a fitting that screws in the back of the base of the carb. Fram fv100. It wouldn't work screwed into a fitting on the fill tube though. It would have a tube running to the back of the engine. If you engine originally had a draft tube there should still be pcv conversion kits available that just require pulling out the draft tube and putting in the replacement piece and hooking it up. That was pretty standard practice in the mid 60's
They're repopping the L79 filler tube with the PCV bung and the corresponding valves are available again. Check with Year One, etc.
Probably but check the flow direction first. I blow through it to make sure. The Chevrolet one that screws into the filler tube has the threads on the crankcase end with the hose connection going to the vacuum source. I'm using one that screws into a Rochester carb base (vacuum source) with the hose end going to the crankcase or breather tube. You can't tell the direction by looking at the outside. It would be easy to install it backwards.
Can you run a pcv in the oil tube and vent it with a breather in the top? So you can run closed valve covers?
It won't ventilate the crankcase this way, it will simply pull air in the breather. I'm sure it's been done though, and I expect someone will chime in saying they've done it. But a proper pcv system will pull air in through a breather (or from the air cleaner) into one side of the engine, and then through the pcv valve on the other side of the engine into the intake system, so the crankcase is ventilated, and oil vapors and moisture from condensation will be evacuated.
This is the way to go. This is known as a "Closed PCV" system. This type of system will keep your engine much cleaner because the system is NOT vented to the open air. More info --> The closed PCV system RustyBolts describes was standard in California. The open PCV system was standard for 49-state cars in 1967. This was the PCV attahed to a tube from the back of the block to the carb and the oil filler tube just had a vented cap.
either or. I have nothing but a motor . I need to make a system for my motor. diagram would also help along with part numbers. Thanks for your help.
I only ask this because there have been A Bunch of these threads here with people willing to help, with many of us taking a stab at what we think you have in mind only to find out that the OP's components won't support the plan. Systems can be designed with all aftermarket parts, OEM ( or reproduction) or a combination. Blocks, intake manifolds (with/without oil fill tube), carbs, air cleaners, valve covers and the hardware relating to open/closed system design all play a roll in the plan. Like I said, we need at least some of your thoughts and/or budget limitations, if any because some of my examples can involve more money than just going down to Pep Boys.
I tried running without a PCV using the front fill tube with breather and a Moon breather on the back of my drivers side valve cover. I had oil seepage issues so I blocked off the top of the Moon breather, tapped it for a fitting, and ran a PCV valve (NAPA 2-9336) that looks like the one used by mtgstumby. That solved my oil issues.
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