Getting rid or crankcase breather/adapting PCV system

Lamar Wadsworth

Lamar Wadsworth

Senior Member
Ozelle the '55 Ford that my parents bought new has a 272 Y block with the original type crankcase breather and downdraft tube. Would like to get rid of that and adapt a PCV system. I'm sure somebody out there has already done this, so no need to re-invent the wheel if I can see how somebody else did it.
 
1. Remove crankcase vent filter on side of block and install a block off plate.

2. Find later model valley cover that has the road draft tube behind the carburetor.

3. Remove tube and install PCV valve of appropriate size for the engine displacement where the road draft tube exited the valley cover. You may need to construct a baffle for the valve to keep it from sucking oil.

4. Connect the PCV valve to manifold vacuum at the carburetor. You may need an adapter for this if the carb has no provision for manifold vacuum.

5.Bob's your uncle. You might need to enrich the carb slightly to compensate for the controlled vacuum leak the PCV creates.
 
Thanks! Sounds easy enough. Surely somebody has a junk 292 that has the valley cover. I am assuming Ford made a block-off plate for the side of the block instead of redesigning the casting? I can make one if I need to, but if I can find one and just bolt it on, I'll do that.
 
Lamar Wadsworth said:
... I am assuming Ford made a block-off plate for the side of the block instead of redesigning the casting? ...
Click to expand...
I suspect the aftermarket block-off plates made for covering the hole left by removal of the mechanical fuel pump are the same size & shape, or at least close enough to fit well.
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Hill's Thunderbird restoration sells a kit with the adapter plate, hose, and pcv valve.it is rather inexpensive. You would then need to deal with the valley plan and block off plate.
 
With the 2 barrel, I'm thinking just make a spacer out of 1/2 thick aluminum using the gasket for a pattern. Drill into the side of it and tap it for a hose barb to screw into it for the vacuum connection. Not rocket science.
 
To be effective you wouldn't want the diameter of the diy vacuum fitting in the new spacer to be smaller than the diameter of the hose fittings on the PCV valve.
 
I have two valley covers with the hole in he back. Both are original Ford Tbird covers. One is factory stock (black) and the other is modified (green)-has the underneath splash piece removed. The stock one is 45.00, the other 25.00. If interested, PM me with your email and I will send pics. Prices plus shipping. These will take large box to ship.
 
Hi everyone, having had my 54 Customline (312 Y block with 3 speed manual floor change) for just over a month
There is a catch can fitted (taking its feed from the downdraft tube hole!) but I'm going to fit a PCV and blank off the downdraft tube opening.
My question is can I run the output from the PCV via the oil catch can and then into the manifold vacuum (and would there be any benefit)?
 
I’m not sure I understand the question, but what it sounds like is “can I /should I use the catch can as an oil separator”. If the engine is good, no. It’s not necessary. Now if you’re using enough oil in normal driving to foul plugs, then maybe. I’d fit the PCV system the way Ford did on the later truck engines (described above) first.

I’m not sure exactly what you’ve got, but it may not be working properly to begin with. And draft tubes really liked to see over 25-30 mph to work well at all. Pollution wasn’t the only reason PCV’s became universal. So put it in stock and see how you do. Then if required, get a proper baffled separator.

If there’s an oil consumption problem, a warm compression test and a leak down test are the next steps.
 
Thanks miker98038, much appreciated. I'll blank off the draft tube outlet and try the PCV. Appreciate the response.
 
Miker 98038.....oil seperator not needed if engine is good. Every shelby mustang put out has an oil seperator on the PCV, including 2024's. I installed a PCV in place of the road draft on my '60 292. Keeps oil out of intake manifold
 
Can anyone tell me why I can't salvage a splash baffel out of an old Chevy valvecover, and tack weld in in any orientation under the valve cover? I could use a knock-out-punch to put a hole in the valve cover for the gromet. I mean the thing can go anywhere. It could go in the block if the cast iron had a hole in it - theroretically of course. The hose can go into the carb, or the intake.

Ya know, on a model A we'd plumb the exhaust gasses into the exhaust pipe.
 
What you want to watch in a y block is stopping the oil thrown by the distributor gear into the PCV connection. I blew 2 head gaskets in a row from detonation on #8 at 5000 rpm and 5 lbs boost on the dyno. Second time around we really looked, and found the oil in the runner to #8. But we’re talking extended high rpm operations, the headers were running red hot. A baffle welded under the aluminum valley cover solved it. Carefully done, with the vent holes way from that gear. It had a baffle in the grommet to begin with, it just wasn’t adequate.

The guys building y blocks for the engine masters are using windage trays and sometimes crank scrapers to try to control the oil, both for drag and mist. Same deal with race cars.

In those cases an oil separator is a great idea. But Ford probably wrecked more cars driving from the assembly line to the transport lot than ever got built with the Shelby name on them. And Ford didn’t use them on the late y block. All of which were 292’s. The 312’s were before factory PCV.
 
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Here’s a link to that for a Mustang. They’ve been around for a long time, mostly for high mileage or race engines. They’ve more common now, especially for direct injection where you’re not washing the intake with gasoline. Nothing wrong with them.

Heavy load applications (trucks, motorhomes, some marine engines) at higher rpm have a lot of slung oil flying around. In Dad’s motorhome, adding an overdrive and split shifting it to keep the rpm under 4000 on long hills, it cut the oil consumption from a qt in 500 miles in the mountains to a qt in 1000. That’s what it got in the flatlands. So I “assumed” it was frothing from higher rpm. Kind of surprised me. But that’s continuous wide open for 10-15 minutes at a time in places like the Continental divide.

https://www.cjponyparts.com/resourc...aked intake tract,up around the throttle body.
 
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