C1 Crankcase Vent Can
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Drifting
Joined: Oct 2001
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From: Cohasset MN
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C1 Crankcase Vent Can
Going through the Corvette Central catalog, I noticed the crankcase vent can that mounts inside the engine. Where exactly does it mount? I assume it is below the intake manifold. What happens if it is missing?
Melting Slicks
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From: Portlandia Oregon
It mounts in the valley at the rear of the engine under the intake manifold. There is a hole at the rear of the block on 1967 and earlier blocks.
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Army
See pic. This is the 'tomato can' that serves as a baffle separating oil liquid from crankcase vapors. If it is missing you can get pretty severe oil "pullover" and spray the residue out of your road draft tube.
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Correct!
Also, if you have a 63-67 style engine setup with the PCV valve instead of a road draft tube, then you will be sucking LOTS of oil into the intake manifold and severely oil fouling the plugs.
YOU NEED THE CAN (oil seperator)!!!!!!!!!!!!!!!!!!!!!!
Know this, there are TWO, repeat, TWO styles of oil seperators, 55 and 56-67. The one shown above is the 56-67 style. There is NO MISTAKING the 55 can, it is much longer, and will NOT fit under a 56-later 4bl intake manifold.
Tom Parsons
Also, if you have a 63-67 style engine setup with the PCV valve instead of a road draft tube, then you will be sucking LOTS of oil into the intake manifold and severely oil fouling the plugs.
YOU NEED THE CAN (oil seperator)!!!!!!!!!!!!!!!!!!!!!!
Know this, there are TWO, repeat, TWO styles of oil seperators, 55 and 56-67. The one shown above is the 56-67 style. There is NO MISTAKING the 55 can, it is much longer, and will NOT fit under a 56-later 4bl intake manifold.
Tom Parsons
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Drifting
Joined: Oct 2001
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From: Cohasset MN
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Thanks guys! I was just curious. I have never had the intake manifold off of my '61 (avatar) but I did have it off my '57 when I first bought it and I can't remember if it had the can installed. The engine came from a passenger car and was put in by the previous owner. And thanks for the photo, Frankie. That helps a lot.
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Army
Before I had the intake manifold off two years back, I also did not know if the can was installed. If you are pretty flexible you can actually look in the road draft tube hole with a mirror and strong flashlight and see if the can is in there. An articulated finger in that area can feel the mounting flange for the can as well. A piece of coat hanger can also be used but you have to be DARN careful poking around in there.
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ONLY, ONLY 56-67 small blocks have the provision/hole in the rear of the block for the can/road draft tube/PCV adapter. In 1968, this hole for crankcase ventilation was eliminated and crankcase ventilation was accomplished with holes in the valve covers. YUK, what was Chevrolet thinking!!!!!!!!!!!!!!!!!!! 
The wonderful Corvette script valve covers were gone forever! (NO, the 69-later finned valve covers just don't cut it!)
Tom Parsons
The wonderful Corvette script valve covers were gone forever! (NO, the 69-later finned valve covers just don't cut it!)
Tom Parsons
Drifting
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From: california
LOOKS LIKE IT TO ME!!! In the mid 60s GM as I remember put a PCV valve went in there, then elimated the road draft tube in the blocks completely. the PCV was incorperated into the intake.
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Bill
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Army
Quite possibly...(the pic is part of my collection and not any car I own).
Sealing up the road draft tube would be done to make a 'closed' PCV system. That is one that works through valve covers and air cleaner and does not require the road draft hole.
Sealing up the road draft tube would be done to make a 'closed' PCV system. That is one that works through valve covers and air cleaner and does not require the road draft hole.
Drifting
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From: california
Sorry Wmf62. All the early vettes i worked on always had that can and the valley covered by sludge. 'clean' must in your pic must have been an engine never run. Pre PCV and the tube all SBC valleys were NOT clean. That sludge contrubed to flat cams and wasted lifters on early small block cars. It was nothing new, the FE fords and chryslers also suffered from it too. It seemed to me it was obviosly the oil in the pre PCV days.
In those days we factored in flat rate to clean the sludge out.
In those days we factored in flat rate to clean the sludge out.
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From: Greenville, Indiana
Sorry Wmf62. All the early vettes i worked on always had that can and the valley covered by sludge. 'clean' must in your pic must have been an engine never run. Pre PCV and the tube all SBC valleys were NOT clean. That sludge contrubed to flat cams and wasted lifters on early small block cars. It was nothing new, the FE fords and chryslers also suffered from it too. It seemed to me it was obviosly the oil in the pre PCV days.
In those days we factored in flat rate to clean the sludge out.
In those days we factored in flat rate to clean the sludge out.
Oil passages in the block would stop up and wouldn't pump oil up through the rocker stands so the owner would have to run a copper line outside the engine and into the valve cover to get oil to the rockers. Common on Stovebolt sizes and Y block Fords.
I see a plug in the rear block hole also. That's not the first one I've seen.
Drifting
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From: california
In pre-63 engines, before the pcv, those oil separators would sometimes plug with sludge and wouldn't let any vapors out of the engine. Stopped up. I used to pour kerosene in them and then set them afire to burn the sludge out of them. Sometimes the valve covers would be full of sludge with just enough room for the rocker arms to wiggle.
Oil passages in the block would stop up and wouldn't pump oil up through the rocker stands so the owner would have to run a copper line outside the engine and into the valve cover to get oil to the rockers. Common on Stovebolt sizes and Y block Fords.
I see a plug in the rear block hole also. That's not the first one I've seen.
Oil passages in the block would stop up and wouldn't pump oil up through the rocker stands so the owner would have to run a copper line outside the engine and into the valve cover to get oil to the rockers. Common on Stovebolt sizes and Y block Fords.
I see a plug in the rear block hole also. That's not the first one I've seen.
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Army
Well - I care for one...
I used to fill the old steel wool breather oil filler caps with kerosene and light them off to clean the blowby sludge out of them every few thousand miles. It works and keeps you warm in a cold garage in the winter (temporarily)!
I used to fill the old steel wool breather oil filler caps with kerosene and light them off to clean the blowby sludge out of them every few thousand miles. It works and keeps you warm in a cold garage in the winter (temporarily)!
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From: Inverness FL
St. Jude Donor '07
Sorry Wmf62. All the early vettes i worked on always had that can and the valley covered by sludge. 'clean' must in your pic must have been an engine never run. Pre PCV and the tube all SBC valleys were NOT clean. That sludge contrubed to flat cams and wasted lifters on early small block cars. It was nothing new, the FE fords and chryslers also suffered from it too. It seemed to me it was obviosly the oil in the pre PCV days.
In those days we factored in flat rate to clean the sludge out.
In those days we factored in flat rate to clean the sludge out.
Bill
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From: Mustang OK
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