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Old 16th August 2014, 11:28 AM   #21 (permalink)
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Matt , that is a sick engine bay!

Border1, when I disconnect the actual tube that connects to the PCV and rev the engine, there is a hell of a lot of suction. I've checked the Venturi port is facing the right way.

This comes back to my original question though; when sucking hard on the PCV, it shuts. So surely having more suction will just keep it shut?

Pictures in 2 minutes!
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Old 16th August 2014, 11:31 AM   #22 (permalink)
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One way valve en-route to venturi



Close up of PCV connection



Overall view



Just FYI, I'm in the middle of two jobs right now, took the rocker cover off earlier, just popped it back on when I saw the e-mail
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Old 16th August 2014, 11:32 AM   #23 (permalink)
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So just to confirm, if you remove the hose in the foreground of picture 2 and rev the engine, so you get a lot of suction?
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Old 16th August 2014, 11:34 AM   #24 (permalink)
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Woo, can also see my bodge of the home made det cans fed into the top that I use for tuning it!
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Old 16th August 2014, 11:36 AM   #25 (permalink)
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border1, yes, a lot! even at idle there is a constant suction going on. Revving it hard creates a strong suction.

I'm still thinking that it will just shut the PCV though
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Old 16th August 2014, 12:01 PM   #26 (permalink)
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When you say PCV, do you mean the black and white check valve coming off the cam cover on the exhaust side of the head with the arrow on it?
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Old 16th August 2014, 12:03 PM   #27 (permalink)
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The check valve is in the right way round.

This looks to be similar to what yours is trying to achieve...

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Old 16th August 2014, 12:13 PM   #28 (permalink)
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Border1, no, I believe that is just a standard one way valve. I believe the PCV is the valve shown in image 2 in the middle of the valve cover.

Matt, I'm not sure that's what mine looks like at all. My PCV doesn't go to the intake does it? It just goes to the exhaust, there is no catch can, just from PCV to the rocker cover cam breathers then to the exhaust.
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Old 16th August 2014, 12:50 PM   #29 (permalink)
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It's hard to tell on my phone but is there a vac line to the PCV valve?
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Old 16th August 2014, 12:59 PM   #30 (permalink)
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No, it's just the valve sticking out from the centre of valve which connects to the exhaust. There's no where for a vacuum line to go.
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Old 16th August 2014, 01:53 PM   #31 (permalink)
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Just to make things more clear, I took the PCV out from the centre where it was located in image 2.

See: -





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Old 16th August 2014, 01:56 PM   #32 (permalink)
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Looks like a standard inline check valve.
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Old 16th August 2014, 02:02 PM   #33 (permalink)
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Maybe, although I did a quick google to confirm: -

'RB26 PCV' ->

Genuine Nissan Rb26dett PCV Valve- Nissan - Genuine Nissan - OEM - Manufacturers
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Old 16th August 2014, 03:04 PM   #34 (permalink)
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Troubleshooting PCV Valve Problems
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Old 16th August 2014, 03:10 PM   #35 (permalink)
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I'm really just interested in how this is working at the moment, not troubleshooting.

As posted in my original post, I'm just not sure I understand how if there is suction from the exhaust, which causes the valve to shut, the crankcase ever gets pressure release.

If the crankcase is in vacuum, the valve is open.. this just doesn't make sense.
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Old 16th August 2014, 03:19 PM   #36 (permalink)
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OK, edited: the way you have it installed won't work having taken a look at the plumbing.
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Old 16th August 2014, 03:26 PM   #37 (permalink)
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Yes, border1 checked this earlier and I confirmed.

Definitely strong suction on the PCV which is causing it to SHUT - which is pointless? Am I missing something here? The suction that is meant to suck out the crankcase gases is causing the valve to shut? Surely that's not correct operation :/
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Old 16th August 2014, 03:29 PM   #38 (permalink)
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Quote:
Originally Posted by edizio View Post
Surely that's not correct operation :/
Exactly.
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Old 16th August 2014, 03:36 PM   #39 (permalink)
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Hm, very strange; would this cause a vacuum/boost leak? I can't immediately see how because it goes through the crank case and not to the intake but when placing my finger over the valve at idle, the tone of the engine changes significantly enough to hear.
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Old 16th August 2014, 03:37 PM   #40 (permalink)
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Yep, looks like your PCV check valve is either faulty or has been replaced with the wrong one. Not sure why anybody would replace it with the opposite sort so maybe it's just broken!
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