Hello all. So I bought something from a forum member purely because it looks cool and was super cheap. I bought a oil cap breather. I probably done a some research first. But hey it was only $30. I have a 02 Z06 with cam, full exhaust and bolt ons with PCV still in place. So this morning I put it on and drove around for abut 10min and drove fine and no oil splashed or leaked out. Is this safe to use for now? Any real benefits on a NA motor like mine? Also will be getting a catch can soon. Thanks for the help. Here are a few pics.

 

Well................. GM Sealed the PCV System and the oil cap on the cover for a reason. The PCV Valve METERS how much air is induced in and out of the engine around the TB and compensates for that in the tune.
The fresh air for the system comes from the throttle body. The small depression in the mouth of the TB is the hole for the filtered air (after the MAF) to enter the crankcase,, You are now allowing air to enter the crankcase that is unmetered.

When you vent the crankcase (with that cap),, you do a couple of things. You change the flow of fresh air in the engine. I do not know how much it hinders the correct flow.

You change the tune by inducing added unmetered air into the engine. How much i don't know off the top of my head.

There is a time to use that rig and thats when you have forced induction.

Looks good, Runs correctly. Pick you poison..

 

What was previously said is 100 % correct. If you still feel the need to have one I got one with a ball check valve in my FI Ls2 at CFM (Central Florida Motorsports). It doesn't mess up your PCV system. Been using mine for a few years now.

 

Actually the PCV meters the amount of fresh air being drawn in via a metered orifice inside the valve. Where the fresh air comes from is irrelevant as long as it is filtered and is sourced before the throttle blade/blades (ie carb). So your valve cover breather is fine and has nothing to do with the tune. You can eliminate the line from the valve cover to the TB if desired as you now have redundant fresh air sources.
Early PVC systems such as came on my '69 Z/28 had no provision for a fresh air supply. It only provided a steady vacuum on the crankcase and evacuated only engine blow-by. The problem with this was as the blow by increased it could overwhelm the PCV valves capability and the contaminated blow-by would create sludge and premature oil contamination. But all that has been overcome by the newer systems. Just one of the reasons modern motors can achieve such high mileage.
So don't worry about your cool looking filter. Just get in an go!

 

I really appreciate everyone's input and help. Catch can will be going on in a week as well. is it ok to run both or is it one or the other?

 

Your still good with the breather.

 

I agree with the above statement except do not remove the valve cover to throttle body vacuum/ pcv setup until you put in the catch can. You need all the positive crankcase ventilation/vacuum you can get. When you do a proper catch can set up you will re-route the throttle body vacuum source through it. Catch cans do not work without a vacuum source,and the lack of under boost is the biggest problem on a forced induction car as we don't want oily air drawn into supercharger impeller blades via the air filter vacuum source as it is the only option bedsides adding a vacuum pump. Under high rpms you can see the cylinder blow by gasses exit your valve cover breather,, on a dyno for example it is quite visible.If the valve cover filter sucks in any air it will be minimal, and the expelled air (cylinder blow by)from WOT will be visible by the oily crap all over the pass. side coil cover. I run mine without the coil covers as my temps stay lower, they just hold the heat in.Elite catch cans work the best for the money. Norris cans are garbage

 

Early C5 PCV systems were below par---that's why on the LS6 GM changed the system completely---And many modded LS1 engine owners converted their LS1 PCV systems to the LS6 PCV system----
If you understand how the PCV system works--an LS6 update is always a good idea
However if your are trying to simply make your LS1 system work better--I have done your exact same mod many many times---I often use an oil cap that has a one way check valve in it that allows fresh air in but none out---Your set up is similar however you may get some oil vapor smell when you shut the engine off as there is no one way check valve--If you don't smell any oil vapor--then you are good and leave it be
My opinion 1st of all is that the LS1 PCV system is marginal so anything you can do to reduce vacuum restriction in the PCV system is good--Atmospheric breathers is one way to increase crankcase vacuum-------I actually will put 2 atmospheric breathers on the engine !!!One on the cap and one on the driver's side rear plug---
Never ever had any oil smell or oil blow by messing up the engine bay---
PS: I even installed 2 atmospheric breathers on my C7 !!! again no blow by--and very little oil in the catch can mostly because of the increased crankcase vacuum makes the PCV system more efficient--

 

I agree with Bill's assessment above. Do what you want but I think it will do more harm than good on a stock engine. Not worth it, IMHO.

 

This 01z with ECS 1500 is new to me and noticed fresh oil around the top of the intake manifold by injectors on both sides. I have an oil cap breather could this be the problem? Or am I looking at something else?

 

Engine is not stock. Its stock cubes but not stock.

 

Not to get too technical but opening up the crankcase to the atmosphere,
ie 2 breathers will not increase vacuum in the crankcase. It will produce just the opposite. The PCV has a metered orifice and regardless of the vacuum created at the TB, which can and will vary, it will only pull a pre-determined number. The reason blower motors need increased scavenging is do to their increased cylinder pressures resulting in increased blow-by. If the blow by doesn't have a path out seals start leaking and other bad things happen. A stock C5 PCV system wasn't designed to handle a blower that's why you see catch cans and valve cover breathers on them. Have you ever seen the giant beer keg sized can located behind the driver on a Top Fuel dragster? It has 2 giant hoses connected to the crankcase. This is a catch can. The cylinder pressures are so high, as is the blow by they create, that without that can they would blow most of the oil in the crankcase onto the track. So in our cars seeing oil smoke out the breather after a dyno pull is an indication of less than optimal cylinder sealing for a blower. Which the stock C5 engines were not designed for. It doesn't hurt anything really, but with better ring seal would increase power somewhat and decrease the blow by. So back to the OP, adding that breather can't hurt and adding a catch can when and if engine wear or adding a blower results in increased blow-by you will stand a better chance of your engine not ingesting it.

 

Without reading your entire post just the 1st sentence--I completely dis agree but you are entitled to your opinion---As a person with a degree in hydraulics and fluids --we were always taught that anything you can do to reduce pressure or vacuum friction loss in a system will make the system work more efficiently--
On a PCV system you basically have 2 sides---the "suction side" that pulls in fresh air from atmosphere---and the vacuum side that pulls the crankcase vapors into the intake manifold----
YES the PCV limits the vacuum "VOLUMNE or FLOW" that can be injested into the manifold---But not the vacuum pressure-- Increasing the vacuum presssure will make the PCV work better---
In hydraulics you deal with Pressure--Velocity-- and Flow
In electricity you deal with Amps --Volts- and Watts
( actually the same principles apply)

Anything you can do to reduce either pressure or vacuum friction loss will always be a benefit by increasing the VACUUM or the PRESSURE
NOT the "FLOW"
Atmospheric breathers will NOT change the FLOW only increase the vacuum pressure---
PS on my 14 C7 when unplugging the air filter vacuum inlet port I could feel almost "0" vacuum pressure because the port is so far away from the engine---- But after removing both stock inlets and putting my finger over the valve cover inlets I could now feel substantial vacuum pressure----telling me that when installing the breathers on the ports the PCV system will work better------