Should? I waist my time and step in and explain, all that needs to be explained here?
Or should I sit back and listen to bad information?
Under no circumstance should oil or even oil mist be introduced to the intake track.
This could be a very big post. You EXPERTS OUT THERE BETTER KNOW WHAT YOUR TALKING ABOUT.

 

Pasta,

Please tell all. What's the deal with the oil catch can. I'd rather spend the monies and not have to worry about any potential issues/problems.

 

this is intresting..more information please. it think.

 

I agree that oil ingestion is never a good thing, but in the age of PCV systems, it's nearly inevitable. However in my opinion, the amount that gets ingested by the VQ is harmless. I removed my VQ30's intake manifold on numerous occasions and I found oil in the resonance chamber. It was basically the same amount that G/Z owners are finding in their lower intake manifold. My VQ30 never burned oil in 115K miles of hard use and my VQ35 doesn't seem to be either.

At part throttle and full throttle load, this residual oil isn't going to be sucked into the engine in the form of droplets. The incoming air simply doesn't have the velocity to lift such small amounts of oil directly into the intake ports. What ends up happening is the oil gets rolled along the inside manifold and smeared. Some residue will eventually get pushed combustion chamber, but I don't think it's anything to worry about seeing that oil is already covering the piston sleeve, etc.

 

I've removed the upper collector from more than 25 VQ35DE engines and all had oil inside the lower collector. Most had an oil film on the upper and lower collector surfaces. Some had oil pooled in the lower collector troughs. All had oil in the oil gallery under the cad plated steel cover. There are six holes in the gallery that allow the oil to be drawn from the PVC valve through the oil gallery and then into the intake runners. Oil in the combustion process lowers the gasoline's octane and causes pinging. An oil catch can should be installed between the PVC valve and the lower collector's steel tube at the front of the lower collector. Most people install it between the drivers side valve cover and the intake tube. Check out the attached pictures. I'm hoping to have a G35 specific oil catch can built complete with condensing coils and all the plumbing. The setup IM working on will have a vacuum at all rpm ranges and will not pull any oil into the intake charge. Controlling crank case pressure is my main goal with the benefits of no oil in the intake track. Understanding that owe PVC valve only works at high vacuum levels and does nothing at "WOT" is the biggest challenge. Oil passed by the valve seals and controlling oil pushed by the oil rings by high crankcase pressures will produce horse power gains at higher rpm's. I may not believe that the simple catch can design is the best, but it sure beats the hell out of the stock PVC setup. This project is in the works right now and will be dyno proven on some other cars besides mine. Results will produce HP.

 

Gee,

Good post.

My Maxima's intake manifold would collect well over a tea spoon of oil with low areas containing standing oil. Every Maxima with this particular intake manifold showed the same thing. My Maxima never pinged unless I intentionally lugged it at a really low rpm. My G has never pinged once.

For those that have oil catch cans, do you accumulate anything? I know lots of Maxima guys use to run then until they started noticing they were collecting nothing. I know my friend's with Contour SVTs, Hondas, and LS1s, typically see about 1/4 pint every two to four weeks. All these cars use to burn oil and now they don't. They're also auto-xed.

 

I am not going to get into the discussion about if you need a catch can or not, but here is a picture of my greddy catch can. If you change the OEM intake you should be able to put it in the same place.

 

ALOT of great info going back and forth here, guys. This is what i like about this forum in comparison to others.

As i understand it, the general concensus is that an oil catch can inserted between the PCV and lower collector will not GREATLY benefit, but can generally help to prevent issues and maintain the engine. Do i have that roughly correct?

As far as the pictures go, thanks for the various input and suggestions. Gman, it looks like you have alot going on under there! I see you also relocated some of your resevoirs. In having the catch can over by the intake, did you run into issues running the hose, or are you running the lines someplace else?

 

Good info Pasta. I can always count on you for posting the correct info!

I am considering one of these myself since I did find a good handful of oil in my intake area. I do autox though so this could be a cause. I never see my oil life go down though.

Now to decide which can to get.

 

Yeah I have the greddy kit which replaces the factory resevoir. As far running the hoses there is no problem. I am not mechanically incline so I don't know where that black hose on the left goes, but the clear hose on the right of the catch can goes straight down into my front bumper and ends up by the inside of the wheel well. The clear hose spits out any oil blow back.

 

The real question is if any of you catch users are actually collecting oil or not and if so, how much?

 

I can see a little oil residue in the clear hose, but it is not excessive. I have only had the catch can for 6000 miles. I am not mechanically inclined so I won't dare to open the can to take a peek.

 

Hey Pasta,

Here's one more lower collector to add too the list.


DaveO

 

I installed my MD spacer last Saturday and there was no oil to be found in the manifold. Was expecting at least a drop here or there. Mileage is currently at 32K.