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Opinions on Valve cover Oil breather. Come on in

9860 Views 20 Replies 8 Participants Last post by  6speeder
So after I had the porous block/main seal repair work. My dealership questioned the crankcase pressure. I completely discounted that comment by telling them my PCV tubing, intake plenum were completely dry. I also advised them that I had a catch can installed for approximately 2000 miles and collected not a drop of oil. If the leak were associated with increased crank case pressure, I would have oil in the pcv tubes etc. We agreed on that.

I started to research the pros and cons of a valve cover breather and thought I would try one. I know it will not improve performance but if it will help the existing PCV system reduce pressure, it may be a good thing. I found a Metco breather and installed it along with the existing PCV system. I took a spirited after the install drive and there was no cabin odor, or oil mist collecting on the valve covers and no leak.


Here is the product:

Here is the install photo. I opted to install it in the plastic fill tube although it can also be installed directly into the valve cover.

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Wife is also putting me on the treadmill. I told her if she dangled a jegs or summit racing catalog on a string in front of me, I'd run faster.

Yes that is correct. I normally run 100 octane 100% of the time.

I have not used 100 octane the last time I filled (a few days ago cause the snow was deep here and my wife was conatantly complaining about the cost of fuel). It occurred to me that people are not visiting the 100 octane pump regularly in the winter. I think the 100 octane is old or has some water in it. My car had a few hesitations under half throttle the other day. Changed the gas and she is back to normal. I will resume the 100 octane in the spring or sooner.

Can you explain again how it reduces the octane? I didn't quite inderstand that comment.
If there's no blow-by smell, leave it on then. That is the only reason (smell/polution) they got away from these back in the ......60s?

no smell that I could ascertain.
Ok, this is the kind of comments I am looking for. Anyone else care to confirm or dispute?
It is my understanding that

When working properly, fresh air should enter the breather and the intake vacuum should pull fumes and smoke (blow-by) through the PCV and re-burn it in the engine.

Can you PM me with some specifics on what I should or should not do. Also what exactly should I watch for in the wideband readings.

If this is not a good idea for my application. I will remove it and reinstall the oil cap.
Removed valve cover breather until I can figure out what is best to do. The more I read about this the more confused I get. I may just go back to a catch can. Although it will do nothing for crank case pressure. I am not too excited about unmetered air and figure stock configuration is best until I can work through this. I have read tons of threads on LS1 tech and there seems to be alot of variance and opinions on what to do.

I would ideally like to reduce crank case pressure and reduce oil in the intake. It seems people who use the breather in conjunction with stock pcv are getting the unmetered air and running a little leaner as a result. Not willing to remove PCV and vent both banks to a vented catch can. I dunno. I got more reading to do. :(
Thanks 6speeder, let me know if there is any breakthrough or success with your V. I too had the catch can on my V and only got mist, no oil. So I removed it. Seemed to be dead weight. I may put it back on once it gets warmer here. I also am not a fan of oil contamination. Not worth the risk in my opinion.

I saw that revxtreme system on the LS1 board and it seems popular and works.

At this time, I will not worry about the crank case pressure until I actually see something more than mist running through the stock PCV.

Again, thanks for your help. Last thing I want to do is re-invent the wheel.

Right now I have a 42design catch can sitting in the garage, catching nothing but dust.

I would like to ask you if I actually installed it correctly. I ran it off the oem PCV tubing into the bottom inlet
and the top went to the TB. Was this correct?

I know it is not pretty but I bought some of the black netted hose covering from the dealer since this photo was taken.

Here is the can:
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I called the dealership yesterday to ask about a replacement PCV valve and was told by parts that they do not show the V as having one. So, if that is the case. The PCV tube is just a path for the gases
on our car. The attached pic shows the connections for the tubing circled. I bought some more 3/4 inch tubing and plan to play with this a little. Upon teardown I will look closely for a PCV valve. If not, I plan to re-install the catch can. I am not comfortable at this point re-installing breather in oil fill tube.

This time I will remove the OEM hard tubing and replace it with 3/4 inch tubing off the driver and passenger valve covers into a T and then to the catch can inlet on the top. The bottom inlet will begin with 3/4 tubing to one stepdown at the CAI tubing. If I throw a code, I will put the stock setup back.

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