[gonfishin]

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.

My question is: WILL THIS BENEFIT OR HARM MY BUILD?

Here is the product:
http://www.metcomotorsports.com/proddetail.asp?prod=MBR0003


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.

 

[JOEYCTS-V]

Curtis, I dunno. First you vacuumed your car, now this?! I don't think 9's should be a problem this spring.

She looks purty BTW!

 

[gonfishin]

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.

 

[baabootoo]

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?

 

[DrumStix]

You won't really decrease crankcase pressure at all with the breather. Rather, you will just vent it to the atmosphere instead of back into the intake which is a good thing. Like baabootoo said, it was removed in the 60/70's from cars so that we would not be venting these oil fumes and other gases directly into the air. In doing this you will keep some heat out of the intake but better yet, any engine oil from being introduced into the cylinders above the rings. A big issue with introducing oil is that not only does it gum stuff up and interfere with the combustion process of gasoline/ethanol as these engines were designed, it also lowers octane level as oil has a lower rating. See you are a genius.

Did I hear that you run 100 octane 100% of the time?

 

[gonfishin]

Sticky,

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.

 

[gonfishin]

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?

baabootoo,

no smell that I could ascertain.

 

[6speeder]

A crankcase breather is a bad idea under normal driving conditions. When not under boost the blowby and other vapors in the crankcase are removed by the PCV system. It is a closed system. When you put on a breather you are opening that system and depending on how you reroute the PCV system either are introducing a vacuum leak into your intake (through the breather and the crankcase.) Not good. Or you are completely disabling the PCV system which will allow those caustic vapors to accumulate in the oil. Also not good.

 

[gonfishin]

Ok, this is the kind of comments I am looking for. Anyone else care to confirm or dispute?

 

[gonfishin]

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.

 

[6speeder]

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.

If all you do is replace the valve cover oil cap with a breather then you are introducing a vacuum leak into the engine. If you have a scanner or access to a Tech II, monitor your LTFT's, then pull the cap and check them again. You will see the LTFT's spike and probably over time get a check engine light. The PCV system uses engine vacuum to pull out contaminants, but it uses air after the MAF, so it is properly metered. With a breather you are introducing non-metered air, a vacuum leak.

 

[PhxTriode]

If all you do is replace the valve cover oil cap with a breather then you are introducing a vacuum leak into the engine. If you have a scanner or access to a Tech II, monitor your LTFT's, then pull the cap and check them again. You will see the LTFT's spike and probably over time get a check engine light. The PCV system uses engine vacuum to pull out contaminants, but it uses air after the MAF, so it is properly metered. With a breather you are introducing non-metered air, a vacuum leak.

Ummm a vacuum leak from the crank case that builds pressure which is the whole purpose behind a breather ???? Several high boost engines use breathers as the rings do allow for some blowby and this allows it to relieve pressure in the crankcase and not recycle air by pushing it through the intake. I also belive that PCV systems are only effective at a certian level of crankcase pressure and designed for the stock levels.

Some racing programs actually use a vacuum system on the crankcase to cause less pumping effect in the crankcase and allow them to use lower tension rings thereby reducing friction.

The caustic approach may have some validity over very long periods of time.

If he puts a breather on his valve cover to vent the crankcase and caps his hump hose port, I can not see any way for a vacuum leak nor unmetered air. Also LTFT are just that Long Term Fuel Trims which are just a summary of counts of Short Term Fuel Trims which if his tune is dialed will show niether and will never register when in Powre Enrichment.

Just my $.02

P.S. Curtis if your worried about it, just watch your wideband when your in boost.

 

[gonfishin]

PT,

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.

 

[gonfishin]

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.

 

[6speeder]

Good luck. I went through this with my supercharged Lightning engine AND my Z06 Vette. The stock PCV systems just seem to pull oil mist through the intake. The best I have been able to do is greatly reduce the amount by limiting the PCV airflow. I have tried THREE different catch cans on my Vette, two did nothing to stop the oil flow, the one I"m running now, the Revxtreme "seems" to work as my oil consumption is way, way down, and I don't have oil pooling in my intake manifold anymore.

I tried rerouting the PCV and using a breather which eliminated the engine vacuum in the crankcase. It totally eliminated the oil in the intake problem but with no PCV I'm sure the oil was being contaminated much faster and would need to be changed much too often for my tastes (and pocketbook, Mobil1 is NOT CHEAP).

 

[gonfishin]

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: http://www.42draftdesigns.com/categories/products/catchcans.html

 

[Mike 09 V]

The obvious is that the manufacturer would not have installed this system nor suffered the expense if it did nothing worthwhile. So at the very least it likely is contributing to cleaner air. If it didn't do that they would have engineered another system to replace it. Here is some info from a Mustang site that is interesting. http://www.supersixmotorsports.com/pdf/PCVBypass.pdf

 

[Domsz06]

Clifford is running the same Metco u had on that first pic.....

 

[6speeder]

CBLOVEDAY: I'm sorry, I haven't tried a catch can on the V yet, so I don't know the correct install. I do know the outlet side of the catch can should go to the vacuum source.

I inspected the intercooler when I had the supercharger cover off, at 5,000 miles and it did show some oil was flowing in the intake, but not as bad as my old Lightning engine. As long as my oil consumption is low I am not going to fool with the PCV system on the V, it's way more complicated than on the Vette.:hmm:

 

[gonfishin]

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.