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TR6 PVC vacum

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airlifter

Jedi Hopeful
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How much vacuum should there be at the PVC valve? My 69 TR6 does not have any vacuum with either the hose to the valve cover or the one to the air cleaner off. There's 18 inches of vacuum measured directly at the port on the PVC valve.

I saw a photo of a car with an after market air cleaner and it had only one hose from the valve cover to the PVC valve. Can I do this or will it create too much vacuum?

thanks
 
I can speak for the TR4A which PCV valve connects directly to the intake manifold and then to the valve cover. Ideal vacuum at the intake manifold at idle should be 17"-21". The PCV valve should modulate this down to 8"-10" of vacuum on the valve cover/crankcase.

Bob
 
I installed a new PVC valve. I checked the diaphragm and cleaned everything yesterday. It seems to me that 19" is a bit high at PVC intake.

I guess that when both hoses are hooked up there should be enough vacuum to clear the valve cover.
 
It doesn't require much pressure differential to relieve crankcase pressure. For instance , the evacuation ports on the 70-76 carbs draw a vacuum equal to about 1/10 of the manifold vacuum when the engine is idling.
 
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