1956 Mercury 312, the draft tube is blocked off with a plate and I’m trying to identify where the PCV valve was placed. After reading a lot of threads on here, I looked at the back of the intake manifold and valley plate. Is the part I circled on red maybe the PCV valve? It goes into the intake and has vacuum attached Thank you for any help
On some y block’s PVC valves were inline.A hose came from a tower on the valley cover to the valve then another hose went to the intake. On others the PCV were screwed into a fitting on the intake and a hose came from the tower on the valley cover. Yours is hard to tell. You say the 90* fitting is attached to the intake and the PCV is screwed into it. Is the aluminum tube on the end of the hose going anywhere? It needs to attached to the engine somewhere to **** the vapors out of the engine. If you have a standard oil fill at the front of the valley cover remove the breather an put a piece of paper over the hole. If it stays there the system is working. If is not the PCV maybe incorrect. A V100 valve works in the correct direction if I think I’m seeing correctly. Many have said where yours is located is not a good idea as most of the vapors go to the rear cylinders. Most factory systems go into or under the carb. A 55-56 engine would have a breather on the left side of the engine block buy the fuel pump and a vent on the oil fill cap. On the yblocksforever.com page, PVC systems have been discussed at length.
Well it is a PCV valve connected to a cobbled together batch of fittings. Those PCV valves usually have a number on the body. Most likely the equivalent of a standard Motor products V100 that fit a lot of 64 and later Fords and a number of other cars. if you are having issues with the PCV system make sure that the one you have flows in the right direction, meaning the air should flow towards the intake and the check valve should restrict it from flowing towards the crank case.
Just the latest post on PCV on yblocksforever. How to baffle the pan (if you go that way) on various valley pans. Includes a test procedure for vacuum and a part number for another valve by Ted Eaton. http://forums.y-blocksforever.com/Topic164478-1.aspx
That is a lot closer to the Y block pcv conversions I have seen in the past. I knew a couple of of guys who did them in the 60's not so much for emissions but it got embarrasing when you pulled up beside a hot gal in your Y block and a cloud of blowby drifted out from under the car.
Thank you guys for all the replies. The other end of that aluminum hose looks like it taps into the valley pan, I’ve included some more pics to help. I can’t see any numbers on the PCV valve while it’s still on, so I’ll need to remove it and match it up. I did the paper test on the oil fill, there doesn’t seem to be any suction there. I’ve included pics of the oil fill cap and the fuel pump side of the engine, I don’t see a breather there like Jimmy Six mentioned
I have the same PCV into the valley pan on my 62 Studebaker 259. There is a breather on the oil fill tube. The PCV was connected to a fitting in the back of the intake. It drew well but all the vapors went to cylinder #7. This eventually caused a major breakdown a long way from home. I rerouted the hose to the carb where it distributes the vapors evenly. Car runs much better. Can't remember where I got the PCV valve from the last time, but they are out there. Warren
Thank you for that info, I’ve read about routing it to the carb but I’m confused on some details. I have a new Holley 4bbl and on the back I have a vacuum port that goes to my distributor. Would I tap into that or do I need one of those spacers I’ve read about with it’s own port.
General consensus is PCV at the valley pan and a hose vented oil fill cap to inside the air cleaner is ok. Most modern V8’s are valve cover to valves cover which is apparently better circulation. Baffles always required and a spacer or a carb fitting for PCV strongly preferred. You can use the stock filler cap, but you’ll get a bit of oil smell parked in the garage. If you care. There should be a larger fitting on the Holley designed for the PCV connection.
Is it just me, or is that valve installed backwards? Ford used those threaded PCV valves on the early '60s motors but IIRC the non-threaded end was where the vacuum connected. The intake IS the vacuum source....
I just pulled the PCV valve, the arrows are pointing towards the threads, which was pointing towards the intake which is the vacuum source, so must have been backwards right?
So I can leave the valley pan side connected, take the intake side off and plug the hole. Run the intake side to the carb with the PCV valve, install a hose vented fill cap and route it to the air cleaner. Does PCV valve arrow go towards carb or valley pan? And yes I already have a oil smell in the garage[/QUOTE
PCV valves are one-way valves, allowing vacuum to pull vapors out of the crankcase but preventing a vacuum IN the crankcase from drawing air-fuel mixture out of the intake manifold. A vacuum in the crankcase can exist at certain RPMs. You should be able to blow through the valve with your mouth one way but not the other way if the valve is in good condition. The flow direction has to be towards the intake vacuum connection.
You can **** from the valley cover if there is a baffle welded in. The 62 up y-blocks had the baffle stock and so did the 55-57 Thunderbirds. If your PCV hose is plugged into a “teapot” looking device with a screw in the center it’s correct. I would move the PCV valve to the center of the intake if possible. Ford pickups used one in the center of the hose with no threads. The side breather I was talking about is on the side of the block under the #2 Cylinder spark plug but you said the was a plate there. There are many ways to install one and they are all correct and work to keep vapor from going to free air and smelling. If you have the correct valley cover already some have removed the “teapot” device, added a grommet that accepts a PCV valve similar to the rocker cover style and run the hose to the supplied line from many carburetors. Ted Eaton does this and has shown photos on yblocksforever.com site. To run it as a closed system you can buy a sealed oil fill cap with a 1/2” hose bib and run it to the air cleaner inside the air cleaner media so it’s ****ing clean air thru you engine. It the way the factory has done it for years..
It definitely has the tea pot into the valley just like you described. For now I temporarily put the PCV valve in between two lengths of 1/2” hose with clamps. One end to tube from valley cover baffle, the other to the back of the carb. The distributor advance vacuum line to another smaller vacuum port on the carb. Ordered a new oil fill cap and will breath it into the air cleaner. Tested it and it seems to run smoother as of now. I’m learning that old cars are a love hate relationship. Earlier today I got my brakes done, wheels painted, polished and looking real Nice. Then I got stuck around the corner from my house for an hour. Still more love than hate though Thank you all for your patience and knowledge. I’ve also joined y blocks forever for questions more specific to the y block.
Technical is great but so is the “Street” section. I’m DryLakesRacer over there. The help I’ve received on that site in 11 years is impossible to count. The contributors have had everything you could think of happen and fixed with a lot of help.
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