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New web page on D-Jet PCV valve

http://members.rennlist.com/pbanders/PCV.htm

Photos of the internal components and a description of how it operates, along with a comparison to modern PCV valves and maintentance suggestions.
Old 04-11-2003, 09:19 AM
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I thought that anytime there is high manifold vacuum, the valve should be fully open. There isn't vacuum in the crankcase so wouldn't the valve be pulled open towards the manifold side and allow maximum ventilation, even at idle?
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Old 04-11-2003, 10:05 AM
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Quote:
Originally posted by jkeyzer
I thought that anytime there is high manifold vacuum, the valve should be fully open. There isn't vacuum in the crankcase so wouldn't the valve be pulled open towards the manifold side and allow maximum ventilation, even at idle?
What you say is the "common knowledge", but it's not true. When the pressure differential across the valve is high, where the low pressure side is on the manifold port, the disk is sucked up against the seat on the manifold side of the valve, and the only flow through the valve is through the metering slots. You can prove this to yourself with a new PCV valve, just abruptly suck hard on the manfold port, and the disk snaps up on the metered seat and you get a low flow. That was the first thing I did yesterday when I got two new valves from the dealer.

Considering that you can only generate a few inches of mercury of vacuum by sucking with your mouth, and that at idle you have well over 10 inches, it's clear that the valve is in the metering position at idle. If it were open, you'd have a large vacuum leak and it would be impossible to set the idle properly.
Old 04-11-2003, 10:29 AM
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Thanks for the link...

I just order 2 PCV valves from the dealer for $8.00. I am amazed the Porsche dealer has anything for $8.00???

Kerry
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Old 04-11-2003, 11:29 AM
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Brad,
As always thanks again. I'm getting my engine ready for the transplant into the new chasis (now being painted signal orange Poly + Clearcoat). Last year I posted something about the PCV valve and researched this a bit myself and found almost nothing. So a BIG thank you.

I replaced my PCV valve with a 4mm outlet (tire valve drilled to 4mm) and the problems continued. Biggest problem that I have had with my old PCV is oil getting sucked into the air distribution box. I guess that you could make this the start of a PCV problems topic.

Thanks Again

Joe C.
Old 04-11-2003, 11:48 AM
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Joe, how much oil were you getting? A small amount of oil (couple of tablespoons or so) is normal.
Old 04-11-2003, 01:20 PM
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Paul,
I woul say one to two tablespoons would be correct. My entire air box is coated inside and out with POR15 so the amount is both hard to see and easy to clean up. The original engine had almost 200,000 miles on it and I imagine that the PCV valve had about the same amount of miles. I always thought that the valve was way too easy to move with a screwdriver because the spring was so loose. But for @ $10.00, I can have it dialed in right. MPS is a rebuild and of course the distributor is my rebuild.

Joe C.

Last edited by retro74; 04-11-2003 at 05:06 PM..
Old 04-11-2003, 05:01 PM
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