Small filter on oil cap?
Tech Contributor
Joined: Jan 2007
Posts: 19,564
Likes: 1,207
From: Dyer, IN
fwiw my engine builder(schwanke short blocks) told me that the ls engines are designed to be vented on the driver side valve cover. so by venting the passenger side cover like i see so many people do (due to the ease of replacing the oil filler cap with a breather) i would have to say that this is not proper for functionality purposes especially if you are still using a pcv system as it allows unmetered air into the manifold.
just an observation so please dont "jump" me if this is not correct, but inform me in a civilized way
just an observation so please dont "jump" me if this is not correct, but inform me in a civilized way
Tech Contributor
Joined: Jan 2007
Posts: 19,564
Likes: 1,207
From: Dyer, IN
It's in the service manual....under"Engine Controls/Description and Operation/Crankcase Ventilation System"
Yes, there is an orifice on the drivers side valve cover(rear), which is plumbed to a 3 way fitting behind the intake, connecting it to the passenger side valve cover(rear), and the PCV valve. Fresh air is introduced at the front of the passenger side valve cover. So no, as designed, the system is not ventilated at the drivers side only, rather, it is taken from both sides simultaneously. Installing a breather at the passenger side, and leaving the balance of the system connected, just allows a more generous path for flow under WOT......which some of us need.
Yes, there is an orifice on the drivers side valve cover(rear), which is plumbed to a 3 way fitting behind the intake, connecting it to the passenger side valve cover(rear), and the PCV valve. Fresh air is introduced at the front of the passenger side valve cover. So no, as designed, the system is not ventilated at the drivers side only, rather, it is taken from both sides simultaneously. Installing a breather at the passenger side, and leaving the balance of the system connected, just allows a more generous path for flow under WOT......which some of us need.
Instructor
Joined: Dec 2010
Posts: 238
Likes: 0
From: Anoka MN
sorry for being unclear. what i meant was if you use a breather on a otherwise "sealed" pcv system wouldnt you be introducing unmetered air(when a vacuum is present in the intake manifold) into the engine since it is after the MAF which could cause tuning issues? and also wouldn't it be more effective to use a breather on the driver side valve cover instead seeing as how the windage of the engine is designed to vent out of the driver side more than the passenger side(just going off of what my engine builder said)?
thanks for the info.
i currently dont run a pcv on my car, just a -12 hose from the driver side valve cover to a catch can with a breather on it with all previous pcv fittings sealed (as recommended by my engine builder).
thanks for the info.
i currently dont run a pcv on my car, just a -12 hose from the driver side valve cover to a catch can with a breather on it with all previous pcv fittings sealed (as recommended by my engine builder).
Last edited by Z0600; Jan 15, 2011 at 08:56 PM.
Tech Contributor
Joined: Jan 2007
Posts: 19,564
Likes: 1,207
From: Dyer, IN
sorry for being unclear. what i meant was if you use a breather on a otherwise "sealed" pcv system wouldnt you be introducing unmetered air(when a vacuum is present in the intake manifold) into the engine since it is after the MAF which could cause tuning issues? and also wouldn't it be more effective to use a breather on the driver side valve cover instead seeing as how the windage of the engine is designed to vent out of the driver side more than the passenger side(just going off of what my engine builder said)?
Instructor
Joined: Dec 2010
Posts: 238
Likes: 0
From: Anoka MN
So in other words you just don't want to or can't explain the answer to what I am asking? I am not only asking for my personal gain of knowledge, but also for the reason why these forums exist... So everyone can learn things that they didn't know before.
If you don't want to explain any further I understand so don't think I am offended at all. I'm sure if someone else can give their 2 cents they will. Again thanks for what you have already contributed
If you don't want to explain any further I understand so don't think I am offended at all. I'm sure if someone else can give their 2 cents they will. Again thanks for what you have already contributed
Instructor
Joined: Sep 2010
Posts: 242
Likes: 0
From: Topeka Kansas
Need more info
If you look at my picture in the previous post you will see I have a fully functional PCV system with PCV valve in line going to my catch can. The original system ran from the passenger side to a y fitting behind the intake and then to the passenger side valve cover with a pcv valve before going into the intake manifold. The only modification I did was changing the hard tubing out from the passenger side with hose and replacing the y fitting with a T. I added the Oil Filter Vent to see if it would help with the oil vapor being pulled into the catch can. If you are running only a hose to a catch can and no pcv valve into the intake manifold, then you are running un metered air. Did your builder install a catch can with some kind of PCV valve internal to the catch can? Have you ever checked your catch can? Please take a picture and post it.
Last edited by bucketlist1957; Jan 16, 2011 at 01:46 AM.
Instructor
Joined: Dec 2010
Posts: 238
Likes: 0
From: Anoka MN
i have no pcv sytem at all. i capped all of the original pcv system off so i have no unmetered air going into the intake manifold. by doing it the way that i did i still have more than adequite crank case ventilation and none of the downsides of a pcv system (no oil vapors/oil build-up in or on any of the intake, runners, valves or throttle body blade) so i can rev it to high rpms for long periods of time. i agree that a pcv system has its place in a well designed factory application and even some hi-perf applications. but after seeing what can happen with some of them(oil standing in the intake manifold) i prefered to take an alternate route. my catch can usualy sees about a half a quart every 3,000 daily driven miles. that is with a 415ci engine that i drive pretty aggresive while shifting at 7000rpms regularly.
i would take a pic but i just removed the engine/trans for more ugrades
i would take a pic but i just removed the engine/trans for more ugrades
Last edited by Z0600; Jan 16, 2011 at 08:20 AM.
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Instructor
Joined: Dec 2010
Posts: 238
Likes: 0
From: Anoka MN
I had fume issues so I ran the breather from the top of the catchcan to my Haltech engine air filter. I very rarely smell oil and only after a lot of high rpms when coming to a stop and it doesnt last long. What oil leaks do you suspect I would have? I have the engine out and there is no external leaks that I have found yet.
Instructor
Joined: Sep 2010
Posts: 242
Likes: 0
From: Topeka Kansas
Pcv
The reason for the fumes were because you weren't pulling any air flow by just running with vent filter. That is why the PCV system is hooked up to the Intake Manifold. You are doing basicly the same thing by going to the air filter. The reason I mentioned oil leaks is I thought you may not be actually neutralizing the pressure in the crankcase with your venting only. One of the original reasons for the PCV system were to help with blowing seals and leaks. I am not saying I don't believe you I was suprised it is sufficient for a moded engine like you have. Most modified motors wind up needing an additional vaccum pump to do the job.
Instructor
Joined: Dec 2010
Posts: 238
Likes: 0
From: Anoka MN
I agree with the cause for the fumes which i knew would happen going into doing it the way I did. The biggest reason I did it this way was so I have no oil or moisture vapors going through the intake side of the engine. By having a baffled catch can it traps the majority of the larger oil and moisture vapors so there is a minimal amount of fine vapors that can escape and get to the air filter so I felt ok with doing it that way. I have yet to find any traces of oil accumulating anywhere after 10,000 miles. I got the idea from my engine builder because he mainly builds sprint car engines which as you know are wot for there entire life and the majority of them run the same set up that I have now with no issues. More than anything it is nice to see how much water the catch can collects. I would say roughly a quart or two every 5,000 miles.
