PCV valve installation

[57_100_6]

Don't have my tech talk book handy and was wondering if anyone had a picture or description for installing PCV valve to keep the crankcase pressure in check. Will any PCV valve work?
Thanks
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[Keoke]

Don't have my tech talk book handy and was wondering if anyone had a picture or description for installing PCV valve to keep the crankcase pressure in check. Will any PCV valve work?--------NO!
Thanks
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I have tried many different valves with out much success. The problem I experienced is the valve would work at low speeds but fail at speed actually building crankcase pressure.--Fwiw---Keoke

 

[Lin]

Ed Driver has a little piece on his web site about the subject:

https://www.vintage-sportscar-touring.ca/technical/PCV.html

also the Nock's at British Car Specialist sell a PCV kit (valve and hose)

Lin
1960 BT7 in restoration
1959 Bugeye

 

[Johnny]

Doesn't the tube running from the block up to the valve cover then on to the carbs serve that purpose?

 

[Keoke]

Doesn't the tube running from the block up to the valve cover then on to the carbs serve that purpose?

Well almost Johnny, but it can be improved on.

Lin, I used that same PCV that Kock sells and the reference also cited would not work for me. Except at low speeds---Keoke-??

 

[Lin]

Keoke,
Since my engine is yet to be installed I cannot say anything about how the PCV might or might not work. I will let you know late summer or early fall if all oes well! I do have the valve to try.
Cheers

Lin

 

[Hangtown Healey]

I put a PCV system on my BJ8 as described in a 1970's Healey Highlights club magazine. It seems to work. I did it in the 70's. I don't remember if I really tried testing it. I do shake the valve once in awhile to verify the little ball is still loose. The valve is for an old Chevy straight six. To test a PCV system, one can put a pice of paper over the oil filler hole in the valve cover and observe if it blows out or in.

 

[57_100_6]

Thanks for all of the input on this subject. I am going to give it a try seeing it won’t hurt anything and I have heard of good results from various other older cars using this method.
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[tahoe healey]

Please explain to me why you would want a PCV valve. I took one off my MGB (as many of us did in the 70's)'cause of several failures.

 

[Keoke]

Please explain to me why you would want a PCV valve. I took one off my MGB (as many of us did in the 70's)'cause of several failures.

Hi TH, It is easier than installing a rear engine oil seal if you can get it to work. Theoretically it will invert the pressure in the crank case. The failures you allude to were the result of owners failing to service the valve hence they would stick shut.--Fwiw--Keoke

 

[Dave Russell]

The PCV is quite helpful on an engine that is designed for it. Although it's original intent was to keep blow by fumes from escaping to the atmosphere, the PCV maintains a slight vacuum on the crankcase. This vacuum instead of pressure in the crankcase helps reduce the oil leaks.

The type "A" valve is closed at idle, open at cruising power, & partially closed at full power. The valve flow rate, calibration, & air intake vent for the crankcase must be sized to the particular engine. Mid range jetting/fuel flow might need to be increased to compensate for the extra air going into the manifold at cruising power.

Some folks get it to work on Healeys, some don't. I haven't bothered to try, but if I had one that was working, I wouldn't remove it.

I think the Nock recommended connection method for the Sixes (connecting both bottom & top vents to the PCV) does not allow for air intake to the crankcase. A better method would be to connect the PCV to the crankcase vent only & leave the valve cover vent open to atmosphere as it is presently connected to the air filter. Maybe with a properly sized restrictor. A type "A" PCV from a similar sized engine should match up pretty well.

This would allow for controlled air circulation in through the valve cover, through the engine, & out through the lower crankcase vent & PCV to the intake manifold.
D