It sure didn't to me, so I'm making this post.

About half an hour ago I went out to replace my K&N filters from cleaning, and something caught my attention that I never noticed before since buying the car in April of '08.

Looking at the PCV system, it is hooked up like this:

There is a breather style cap in the passenger side valve cover (Except it has no holes in the bottom for air so It's not actually a breather), with a hose going to the throttlebody. The cap says Mr. Gasket so obviously this was a PO installed part. On the Driver's side valve cover, there is the PCV valve with a hose connecting it to the intake manifold.

I thought the whole purpose of a PCV system was to create a vacuum on the PCV side that pulls fresh air in via the breather side. How can this be accomplished when BOTH valve covers have a sealed device that is hooked to a vacuum source?


I have in my basement an Edelbrock breather cap. Did I miss something or is it time to rip the passengers side cap off, cap the port on the throttlebody and throw on the breather?

 

Thats what i would do. There are some interesting breather systems where poeple try to accomplish having and vacuum in the crank case instead of positive pressure to help rings seal and gain a few more hp. However in your case just sounds like they had no idea what their doing.

 

No idea?
That's exactly how the stock setup is done.

 

The cap with the hose isn't supposed to have holes like a normal cap. The Hose is the vent. It takes air from the air cleaner like the stock setup, instead of making a big mess all over your valve covers. Its a better setup IMO.

 

HOLD IT! If your passenger side valve cover has a tube that runs to the passenger side of the throttlebody and connects to the upper port, then its correct. Now if you have a PCV with a hose connected and connects to the driverside of the intake manifold, then thats correct too. Yes I agree that it would make a mess inside the plenum and intake manifold, but it is what it is to GM specs. If you decide to make any mods to this setup, you might run the risk of throwing off your emissions and setting off the Check Engine light. click hear to chevkout the vacuum hose diagrams. TPI OWNERS, I need a little help please. Hoses and lines issues.

 

I would prefer to eliminate the PCV system completely. Why? Because when I removed the intake pieces when we were dropping in the new block to clean and port them, the level of gunk buildup inside them was astounding.

What I propose to do, is install a breather cap in the passengers side cover, and have a hose running from the drivers side cover down to the back of the block. This way the air moving under the car will create a vacuum and cause PCV without relying on the engine's vacuum. Not to mention I wouldn't have hot crankcase gasses and blowby entering the combustion chambers. With baffled valve covers AND a baffled breather, I doubt I'll have too many issues regarding sludge.

What would be your opinion on this setup?

 

That's how it used to be done before PCV, they were called draft tubes. It will make a mess of the bottom of your car. Also, your friends with nice driveways might not appreciate the way your car marks it's territory.

 

The gunk may have been from the EGR system. I too have seen this and it is quite .. , well, lets just say 'gross'. Looks like the inside of an exhaust pipe.

On PCV systems that tend to pull oil just install a separator or a catch can. Separators are set up to return the oil back to the engine. In some instances a catch can may be easier to install. However, they may need to be emptied from time to time.

If an engine has a cam with some overlap the fluctuating idle vacuum can actually pump the oil past the stock valve cover baffles. In this case a catch can or separator having volume dampens these pulsations and reduces the volume of oil pulled past the baffles.

So either one helps a lot in reducing the oil pulled through the PCV system.

RBob.

 

Regardless of what approach you are taking, when the engine is at operating temperature, the engine oil begins to vaporize a little, so thats why there is whats called the oil seperator. Other than the oil seperator, youll always get gunk in your intake. thats why there is what is called "intake, throttlebody, and carburator cleaners" in spray form. As for the blow-by gases entering the combustion chamber via hose connected to intake and throttle body, this is intentional by GM so that the ignition of fuel in the cylinder wont be so "hot". You dont want your exaust to be too hot because it will damage your catalytic converter. Thats why GM made the system as we know it. Another reason is because blow-by contains unburnt fumes which will contaminate your engine oil thus rendering it useless. And another reason is because of the emissions. By government, the car manufactures wanted to eliminate as much toxic fumes as possible so they routed all blow-by gases back into the cylinders to burn off the remaining unburnt fumes. Im not to sure if you'll run into problems if you remove the PVC system, I can garantee you that if you get caught with your mods, if you proceed, you will face heavy fines because the emissions deals directly with the Federal Governmnent. It is a Federal crime to play with emissions. Thats why smog inspections stations will not take even a $1,000 dollars to illegally pass a car which would fail only because of the penalties involved. Also if you dont ventilate your block, youll have to change your engine oil sooner than every 3 months or 3,000 miles. Good Luck though.