Valve cover tube

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toytron
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Valve cover tube

Post by toytron »

I just acquired a 110 engine, T0527RD.
The odd thing is that one of the valve covers has a tube in next to the number 5 cylinder. Is that normal?

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Re: Valve cover tube

Post by Scott V »

if the tube is on the head & not on the valve cover............thats normal for a turbo head.

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Re: Valve cover tube

Post by toytron »

No it is on the valve cover.

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Re: Valve cover tube

Post by bbodie52 »

T0527RD
Image
T = Tonawanda, New York (GM Tonawanda Engine Plant)
http://media.gm.com/media/us/en/gm/comp ... wanda.html
0527 = Engine manufacturing date (month and date). May 27th.
RD = 1965-1967 164 CID 110 HP Manual Transmission (Corvair 500 and Monza)

:chevy:

The only tube on any Corvair model that was ever routed directly into the head in the area of the valve cover was associated with the turbocharged engine from 1962 through 1966. This tube is routed directly into a casting in the right front portion of the cylinder head. It was routed from the turbocharger to the head to serve as an oil return line after the lubricating oil passes through the turbocharger bearing area.

If there is an open tube attached to the sheet-metal valve cover, he was likely a modification installed by a previous owner. All engines have a small percentage of compression gases that leak past the piston and piston rings. These gases enter the crankcase and begin to build up pressure in that area. 1960 – 1962 engines utilized a road draft tube that was routed from the crankcase top cover to an opening just below the bottom sheet-metal, next to the oil pan. This tube allowed crankcase gases to escape into the atmosphere and to some extent were drawn from the crankcase by a pressure differential caused by a moving vehicle, which helped gases to escape from the road draft tube. In 1963 the road draft tube was abandoned and replaced by a Positive Crankcase Ventilation (PCV) system that utilizes engine vacuum to draw the crankcase fumes back into the intake manifold to be re-burned and ejected via the exhaust system.

The PCV system must be cleaned periodically as a part of the normal tuneup procedure. If the system is plugged, or if a worn engine causes excessive blow-by into the crankcase, the sealed crankcase pressures can build excessively. The oil dipstick tube is a common ventilation point where excessive crankcase pressure tries to exit. As it does so crankcase oil can also be ejected from the dipstick tube. Some owners attempt to relieve excessive crankcase pressure by installing a vent of some type to allow this pressure to bleed off. This may be the tube that you are describing.

If the valve cover has been improperly modified it may need to be replaced. The crankcase on the 1963 – 1969 engines is supposed to be sealed with no vents. A properly maintained PCV system should be in place to properly vent the crankcase. You may wish to run a compression test on all six cylinders to check the condition of the piston rings, following the procedure in the shop manual. If engine compression is within normal specifications the PCV system should be adequate to control crankcase pressure buildup. The pictures below show crankcase ventilation and the road draft tube setup for 1960 – 1962 Corvairs. The last picture shows the various PCV systems that are found in later models.
Crankcase Cover and Vent
Crankcase Cover and Vent
PCV Tube Connections
PCV Tube Connections
Corvair Crankcase Ventilation (1960-1962)
Corvair Crankcase Ventilation (1960-1962)
Corvair Crankcase Ventilation (1964-1969) and Turbo 1
Corvair Crankcase Ventilation (1964-1969) and Turbo 1
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Re: Valve cover tube

Post by toytron »

Thanks Scott and Brad, I will look at it again and try and post a picture of it here. I didn't look close enough to see if it looked modified but I will. I might just remove it for further study. I obtained it for parts so it will be interesting to see what this strange thing is.

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Re: Valve cover tube

Post by notched »

Someone might have used it as a turbo engine at some point. I have added tubes to the valve covers as a drain. Works fine if you don't have a turbo head.
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Re: Valve cover tube

Post by toytron »

Ahhh.

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Re: Valve cover tube

Post by Scott V »

if its a turbo head..........it could be that the 110 dropped a seat or trashed the head & it was replaced it w/a turbo head. sounds backwards yea...but lots of people treated vairs like throw away cars & lots of them were butchered repaired w/any spare or junk yard part that was sitting around.

look at the casting numbers on the other head. im guessing its a 110 head.

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Re: Valve cover tube

Post by toytron »

Thanks all, I pulled the cover and discovered that it was fabricated by someone and it is in the location of the oil return tube for a turbo. The head is a 110 the number is a 3883863. The biggest mystery is that it came with two carbs mounted with the linkage and fuel lines to the fuel pump and vacuum line to the distributor. So if it wasn't for a turbo return what was it for. As I said it was fabricated because it ended up being a piece of copper tubing brazed into the cover.

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Re: Valve cover tube

Post by miniman82 »

Crankcase evac? Some people put a vent on the valve cover and connected that to a one way valve in the exhaust collector to draw out fumes, but normally you only see it on race engines.
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