PhilbertZ Posted July 23, 2008 Share Posted July 23, 2008 Hey everyone - I'm going to go 2/2 with n00b questions here on the forum... I've noticed this filter on the valve cover of many Z's here. I have a hose where this filter is in this photo - and I HATE it (ugly, PITA for removeing the valve cover, etc). Can someone tell me what this filter's purpose is? I have a N/A motor so I don't know if this is specific to turbos - I just found this photo online. In case you don't know what I'm referring to, it's the K&N style filter just to the left of the "O" in "Turbo" on the valve cover: Thanks in advance for your wisdom Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted July 23, 2008 Share Posted July 23, 2008 It's just a breather, not specific to turbos. You can do it if you want but... The idea behind the hose is to suck blow-by from your valve cover and keep your oil cleaner. Other people say that it's beneficial to have the crankcase in a vacuum... something about rings... you can read up on it if your interested. Short version = pull your hose and put the breather on if you like the look better. Quote Link to comment Share on other sites More sharing options...
PhilbertZ Posted July 23, 2008 Author Share Posted July 23, 2008 wow that was fast! Thanks for the background - I'll look into it. Is the breather filter something most auto stores carry - if not where would I find one? Quote Link to comment Share on other sites More sharing options...
PhilbertZ Posted July 23, 2008 Author Share Posted July 23, 2008 oh, and if it's a vacuum hose, what the best treatment to the spot where that hose plugs in on its other end? Just cap it off? Is there a clean looking way to do that? Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted July 23, 2008 Share Posted July 23, 2008 As far as clean, I dunno. Most just buy the right size plug, works fine. Yup, most auto parts store should carry one. I've stared right at one while checking out at O'reileys. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted July 23, 2008 Share Posted July 23, 2008 dont cap it off.. you need to ventilate the block.. thats what the PCV valve does.. but the valve cover needs to breath. trust me Quote Link to comment Share on other sites More sharing options...
TrumpetRhapsody Posted July 23, 2008 Share Posted July 23, 2008 Sorry, should've been more clear. I think we were both talking about capping off the vacuum hose to the manifold if he puts a breather on the valve cover. Not capping off the valve cover. Quote Link to comment Share on other sites More sharing options...
PhilbertZ Posted July 23, 2008 Author Share Posted July 23, 2008 That's right: I am asking about putting a filter/vent on the valve cover (to let it breathe) and capping off the manifold where it WOULD have connected via the vacuum hose (which would be removed with the filter install). Quote Link to comment Share on other sites More sharing options...
Xander Posted July 23, 2008 Share Posted July 23, 2008 As far as I know the hose should not be connected to a vacuum source but rather filter air from in front of the throttle body. The PCV valve is located on the bottom of the plenum via a one way metering valve. It then goes to the side of the block. The inside of the crankcase is connected to the valve cover via the timing chain opening on the front and a oil drain back opening at the back of the block. From the valve cover it should get clean filtered air. If you are still running the factory AFM then this is a source of unmetered air and could case a slight lean condition. You could plug the PCV hole in the manifold an keep the filter on the valve cover. And maybe put a filter on the side of the block. This would effectively disable the PCV system. Do NOT block the pcv on the valve cover and side of the block. This will not allow the block to vent the blowby gasses from the piston rings and thus put your crankcase under pressure. Can you say oil leak??? Give us a picture of your block so we can see what you got. Quote Link to comment Share on other sites More sharing options...
josh817 Posted July 28, 2008 Share Posted July 28, 2008 As far as I know the hose should not be connected to a vacuum source but rather filter air from in front of the throttle body. The PCV valve is located on the bottom of the plenum via a one way metering valve. It then goes to the side of the block. The inside of the crankcase is connected to the valve cover via the timing chain opening on the front and a oil drain back opening at the back of the block. From the valve cover it should get clean filtered air. If you are still running the factory AFM then this is a source of unmetered air and could case a slight lean condition. You could plug the PCV hole in the manifold an keep the filter on the valve cover. And maybe put a filter on the side of the block. This would effectively disable the PCV system. Do NOT block the pcv on the valve cover and side of the block. This will not allow the block to vent the blowby gasses from the piston rings and thus put your crankcase under pressure. Can you say oil leak??? Give us a picture of your block so we can see what you got. I heard the same thing from my dad but slightly different. I agree with you and not Dad so much because he said if you use the filter you can blow the oil seals due to pressure but I was thinking... its a filter, it can breathe through it... if there was pressure build up it would vent through the filter. So I ask the same thing, is it ok for me to put filters on both the crank case and the valve cover or should I have some sort of vacuum on it to suck it out. I really don't want to tap a hole in my manifold... :[ Quote Link to comment Share on other sites More sharing options...
jtl260z Posted July 28, 2008 Share Posted July 28, 2008 I heard the same thing from my dad but slightly different. I agree with you and not Dad so much because he said if you use the filter you can blow the oil seals due to pressure but I was thinking... its a filter, it can breathe through it... if there was pressure build up it would vent through the filter. So I ask the same thing, is it ok for me to put filters on both the crank case and the valve cover or should I have some sort of vacuum on it to suck it out. I really don't want to tap a hole in my manifold... :[ You can safely run a filter on both...I've been doing it for 10+ years and still running strong. Quote Link to comment Share on other sites More sharing options...
bjhines Posted July 28, 2008 Share Posted July 28, 2008 I went through this on one of my S-30s. Removing the tube and placing a "pop" filter on top may make a mess of your engine. I had quite a bit of blowby that misted everything on top of the engine with oil during track duty. A turbo may make this even worse. I had quite a lot of vacuum flow with the crankcase being evacuated from both the top and bottom. It kept my aircleaner housing clean and my engine external clean. Most of the flow went into the exhaust system. The exhaust evac tubes can be found as weld-in kits by Mr. Gasket and Moroso. They have high flow with limited vacuum pressure. They work well with the PCV system in all conditions. The PCV works most effectively at high manifold vacuum. When the throttle is wide open the exhaust evac tubes work the best. This was a VERY effective system on my car. It was clean enough to eat off of after an entire season of track duty. I ended up running the PCV system and the tank vent system entirely. In addition I installed an exhaust evac tube in the collector and plumbed the top valve-cover-vent to the exhaust tube. Quote Link to comment Share on other sites More sharing options...
PhilbertZ Posted July 29, 2008 Author Share Posted July 29, 2008 As far as I know the hose should not be connected to a vacuum source but rather filter air from in front of the throttle body. The PCV valve is located on the bottom of the plenum via a one way metering valve. It then goes to the side of the block. The inside of the crankcase is connected to the valve cover via the timing chain opening on the front and a oil drain back opening at the back of the block. From the valve cover it should get clean filtered air. If you are still running the factory AFM then this is a source of unmetered air and could case a slight lean condition. You could plug the PCV hole in the manifold an keep the filter on the valve cover. And maybe put a filter on the side of the block. This would effectively disable the PCV system. Do NOT block the pcv on the valve cover and side of the block. This will not allow the block to vent the blowby gasses from the piston rings and thus put your crankcase under pressure. Can you say oil leak??? Give us a picture of your block so we can see what you got. This is the setup I'm dealing with (not my car in this image): So...Sounds like I can do the filter thing as long as I block off the hose where it goes into the intake manifold (the lower right part of the green doodle I made)? Quote Link to comment Share on other sites More sharing options...
Xander Posted July 29, 2008 Share Posted July 29, 2008 So...Sounds like I can do the filter thing as long as I block off the hose where it goes into the intake manifold (the lower right part of the green doodle I made)? not quite. if you put a filter on the valve cover than you will have to block the pipe at the other end. I think it goes into to throttlebody booth. Also you should block the pcv valve on the bottom side of the intake manifold. There is a pipe running from the side of the block to the underside of the manifold. thats the one I'm talking about. you will have source of unmetered air. This air is going into the engine without being metered by the AFM. Quote Link to comment Share on other sites More sharing options...
Xnke Posted July 29, 2008 Share Posted July 29, 2008 Ok. To keep the PCV system active, and remove the hose, here's the scoop: 1. Put filter on valve cover. This is just a breather. 2. Cap the hose barb that you removed the opposite end of the valve cover hose from. This barb is a vacuum port, and if you don't cap it, it'll let unmetered air into the intake. 3. DO NOT remove the hose connecting the side of then engine block near #1 from the manifold. You need to keep this if you don't want to be washing engine oil off from around every seal and gasket. This helps to keep your crankcase in a vacuum condition, lessening the chances of blowing an oil pan or front cover gasket. (Or valve cover gasket, for that matter.) As far as I can tell from the engine diagram, limited personal experience, and hundreds of internet posts, this is the proper way to remove that ugly tube. I could be wrong, but I'm pretty sure this is the right way to do it. Quote Link to comment Share on other sites More sharing options...
Xander Posted July 30, 2008 Share Posted July 30, 2008 Ok. To keep the PCV system active, and remove the hose, here's the scoop: 1. Put filter on valve cover. This is just a breather. 2. Cap the hose barb that you removed the opposite end of the valve cover hose from. This barb is a vacuum port, and if you don't cap it, it'll let unmetered air into the intake. 3. DO NOT remove the hose connecting the side of then engine block near #1 from the manifold. You need to keep this if you don't want to be washing engine oil off from around every seal and gasket. This helps to keep your crankcase in a vacuum condition, lessening the chances of blowing an oil pan or front cover gasket. (Or valve cover gasket, for that matter.) As far as I can tell from the engine diagram, limited personal experience, and hundreds of internet posts, this is the proper way to remove that ugly tube. I could be wrong, but I'm pretty sure this is the right way to do it. Yep. If you want to keep the pcv system this is the way to do it. Quote Link to comment Share on other sites More sharing options...
PhilbertZ Posted July 30, 2008 Author Share Posted July 30, 2008 thanks guys - this is fantastic feedback - very much appreciated! Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted August 1, 2008 Share Posted August 1, 2008 The purpose of the hose it to allow filtered air to enter the crankcase since the PCV takes care of evacuation of said air and blow by but I could swear that the air is also metered in the stock implementations of the system. Quote Link to comment Share on other sites More sharing options...
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