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On my 292 ford y block there is a canister on the side of the block on the driver side. I have read this is a type of pcv valve. If this is a type of pcv valve can I route this to the back of the carb? Any suggestions?
On my 292 ford y block there is a canister on the side of the block on the driver side. I have read this is a type of pcv valve. If this is a type of pcv valve can I route this to the back of the carb? Any suggestions?
Thanks
Jerry
That would be the road draft tube. Not a PCV but uses road draft (Air movement) to pull the combustion by products from the crankcase.
That is actually a CV valve as in crankcase ventilation. Commonly known as a breather tube. As opposed to a PCV valve Positive Crankcase Ventilation valve. You could try connecting it to the carb and see if it works. It might just be a vacuum leaking source as a PCV valve has a little slider inside like a mini exhaust valve that limits the fume flow.
It's not a valve at all. As Matthewq4b said, it's a road draft tube. The miter cut at the end of the tube creates a natural venturi effect when the vehicle is in forward motion and draws crankcase vapors and blow-by from the engine. The wire gauze filter acts as an air cleaner and vapor condenser that collects oil and returns it to the crankcase and keeps dust from reentering the engine. A PCV valve incorporates a check valve and orifice to prevent crankcase explosions from backfires, and uses manifold vacuum to draw crankcase vapors into the intake manifold. So, yes, in theory you could run a hose from the road draft tube to the air cleaner on the carburetor, but not to the intake manifold without a cumbersome check valve, and in doing so would need some type of orifice so you would maintain normal engine vacuum.
@jerryst , a lot of Y-Blockers are blocking the road draft tube off with a plate, and finding a valley pan from latter 60"s model Y-block and installing a PVC valve. Ford in the 60's installed PVC valves from the factory. I too blocked off the draft tube and installed a valley pan from the 60s. You can sometimes find a valley pan on Ebay, and the plate to block off the road draft tube.
Just to avoid confusion (but we all knew what you meant), "PVC (polyvinyl chloride), is the world's third-most widely produced synthetic plastic polymer, after polyethylene and polypropylene. PVC comes in two basic forms: rigid and flexible."
Thank you all for the quick responses. Going by pictures it is a road draft tube. The reason I was asking if I could connect it to the back of the carb I thought it was a pcv valve. After running my y block i notice it drips oil. Maybe the filter inside is clogged? Does anyone know if I can replace this filter? Or gasket?
Those "Vacuum Crankcase Ventilation Device" can be disassembled and cleaned. Usually when the road draft tube starts dripping oil it indicates a worn engine and lots of blowby. This is the same road draft tube that I remember spewing oil and blowing oil smoke onto the pavement when the vehicle was climbing a hill. The crankcase would build pressure from blowby and the oil and oil fumes would blow out onto the road. Any lightly colored road of old always had black marks in the center of the lane where this oil would be deposited.
Mixer man's explanation of how the road draft tube works should explain why I call it what I do.
Yes, there have been lots of engines converted to incorporate some kind of PVC system.
Thank you all for the quick responses. Going by pictures it is a road draft tube. The reason I was asking if I could connect it to the back of the carb I thought it was a pcv valve. After running my y block i notice it drips oil. Maybe the filter inside is clogged? Does anyone know if I can replace this filter? Or gasket?
Thanks
Jerry
This is a regular maintenance item. I think it needs to be serviced at every oil change, not sure about that (I forgot). The filter just needs to be cleaned, and if it's dripping oil then most likely the little oil return tube is plugged from lack of maintenance, or the unit is overwhelmed by an oil burning engine. The assembly will have to be removed from the engine and thoroughly cleaned.
This is a regular maintenance item. I think it needs to be serviced at every oil change, not sure about that (I forgot). The filter just needs to be cleaned, and if it's dripping oil then most likely the little oil return tube is plugged from lack of maintenance, or the unit is overwhelmed by an oil burning engine. The assembly will have to be removed from the engine and thoroughly cleaned.
Yup Bob got it, it should be cleaned at each oil change. And check the drain if it has never been serviced chances are the bottom of it is full of sludge and not draining back to the crankcase like it should.
Thank you all for the quick responses. Going by pictures it is a road draft tube. The reason I was asking if I could connect it to the back of the carb I thought it was a pcv valve. After running my y block i notice it drips oil. Maybe the filter inside is clogged? Does anyone know if I can replace this filter? Or gasket?
When I acquired my ‘56 which has a 292 Y-block, someone had cut a hole into the canister and routed a crude plastic tube to a screened, AC, oil fill cap. Then they plugged the vent tube with a rubber plug like one you might have used in a chemistry class. When I changed oil in the engine it seemed really dirty and full of sludge. So, I unplugged the draft tube, took off the line from the canister to the fill cap, fixed the hole in the canister with small bolt, rubber and metal washers and a nut, and I fitted a new mesh filter for the canister. To quote the POTUS, . . . . DISASTER!
I tried to drive to a nearby town, 40 miles, and in that distance it chucked a quart and a half of oil. The smoke cloud behind me was enough that I thought the EPA would issue an alert. Made a mess of the engine bay and the left bank exhaust.
Solution: Removed draft tube and canister, with tin snips I made a blanking plate from some thin metal, made a gasket and plugged off where the canister and draft tube had been. Went to NAPA and bought a PCV (positive crankcase ventilation valve), a rubber grommet and some hose. I drilled the chrome valve cover on the left hand of the engine and inserted grommet & valve into valve cover and routed it with hose and fitting into a capped port on the back side of the stock two barrel carburetor. - It was a complete fix. No oil leakage, no smoke from exhaust, no fouling of plugs, and no excessive oil consumption.
Initially, I had routed the PCV line to a capped fitting on the intake manifold. This worked, but after a consult with an engine rebuilder/ specialist, he recommended routing to the back of the carburetor. He said this would provide better atomization of the captured gasses (smoke) from the crankcase for a more complete burn of the crankcase smoke and gas. This is applying the same fix to my 1956 Y-block engine that Ford applied to the same engine in later years. - Three years on from my fix and there have been no problems at all, but I have probably driven less than 5,000 miles in that time. Have changed oil a couple of times, but drained oil appears reasonably clean.
. Otherwise we are just guessing.
