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valve cover vent


Silent

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Join Date: Jul 2005

Location: Melbourne

Posts: 452

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I fought with this a while back as well. Noone could tell me what thread it was, and I went to over 6 plumbing stores. In the end I just brought an appropriate tap (1/2 BSPT rings a bell but I couldn't be sure) and tapped it out to a more standard thread.

 

 

Yours is threaded? Mine is just a hose fitting....

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I read that too quickly, I was thinking filter.... my pcv is threaded into the valve cover... one of mine broke, so I had to back it out... what exactly do you want to replace it with? It still acts like a pcv, right? It's not just a straight tube going to a filter, right? I wasn't sure there was an alternative to the old oem pcv valve... let me know if you come up with anything....

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the pcv valve in a perfect world creates a vacuum environment in the valve cover. ive read a writeup on this that i couldnt find (ill post it if i can). objects in a vacuum can move a lot more freely than in atmosphere so you want to vent this thing into either the intake or the exhaust. the latter being the better of the two because at WOT the intake no longer acts as a vacuum. as you will notice though, most stock applications will vent into the intake because its easier. (most of the time). ive seen tons of people just vent it to open air though, but i would vent it to exhaust. if you vent it to intake make sure you install a little catch can. but whatever you do. do NOT plug the vent, your valve gasket will most likely fail.

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zguy36' date='

 

My hose 90 degree hose fitting unscrews.

 

[img']http://ozdat.com/forum/files/turbo-z-bay_209.jpg[/img]

 

Can see the speedflow (-AN) fittings on there.

 

Dave

 

the fitting in the valve cover, exactly in that pic is what im lookin for!

is it an 8 or 10? guess it really doesn't matter what thread it is, since i believe you have to tap it anyways

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The hose is a 15mm CONDUCTIVE rubber hose. -8 will work fine for it if you need it, -10 would be an appropriate size (and technically correct, as well).

 

Tap the hole, it's easier, the thread on it is a very fine obscure metric equivalent like the banjo bolts in Weber Carbs or the water lines on the turbo.... But a nice NPT runs right down there and solves that problem. So does any of the positionable MS-Jamnutted fittings, as well!

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For the record, the pcv valve goes between the intake side of whatever throttle(s) you have to the crank case. The thingie on top is only a vent, it's not acting to draw a vacuum inside the valve cover, which would do nothing for you. A vacuum in the CRANKCASE, however...

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Really? What about that big ol' hole in the front there where the timing chain goes. No pressure gets through that big hole?

 

I agree that the crank vent is the one that should get vacuum if one of them is going to, but to say that the valve cover vent is TOTALLY unrelated is false IMO.

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You don't want too much vacuum in the crank case as it draws air in through the main seals. This is very bad since it brings dirt with it chewing up the seals and contaminating your oil. The stock location for the breather tube works well, which in reality just went into the air inlet tube after the AFM. This is the inlet for the pcv and should be able to draw air in through this hole. To see what I am saying, pop off the hose and put your finger over the hole. You will feel it pull a vacuum....

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