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Josh@RideTech

Crankcase Ventilation

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I noticed that my engine is pushing some oil out of the rear main seal.  At the moment, I'm not running an external ventilation setup.  I'm thinking about pulling the valve covers and welding some AN fittings onto them and going into a catch can.  If anyone has some pictures of the setups that you're running, I'd like to see some different options.  I want to make it really clean!

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i did the AN fitting route with a catch can but it didn't work for me.  ended up just putting breathers on each valve cover and calling it done.  no problems since doing that.

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Header evacs are designed for open headers or collector mufflers (needs to be a VERY low back pressure exhaust system). With mufflers, the velocity is lacking to achieve crankcase ventilation. I did a LOT of research into crankcase ventilation for my car before I went the vacuum pump route and the header evac was a concept I briefly entertained until finding a lot of people saying it wouldn't work very well on a car with a full exhaust.

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I took the car out for a 20 mile cruise a couple of days ago and spun it up to around 5500-6000 and noticed that I'm seeing oil push out of places it never did before (rear main seal, seals, etc).  I know I'm higher compression than a stock setup but I've never had to run a breather of any sort.  Now I'm just prolonging pulling the valve covers back off....

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I am going to be switching to a mishimoto version now that I got the sponsorship and I have a nice carbon fiber/aluminum can if you want one.  

 

I have always been a little confused what happens to the pcv valve when you run a can?  Never been able to hear one way that everyone seemed to agree with.

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16 hours ago, 95riosnake said:

Header evacs are designed for open headers or collector mufflers (needs to be a VERY low back pressure exhaust system). With mufflers, the velocity is lacking to achieve crankcase ventilation. I did a LOT of research into crankcase ventilation for my car before I went the vacuum pump route and the header evac was a concept I briefly entertained until finding a lot of people saying it wouldn't work very well on a car with a full exhaust.

 

I agree that a vacuum pump would be the best way to go!

 

I forgot he has chambered mufflers on the car.  So yes the header evac wouldn't work very well.  But I have seen were plenty of people have had no problems with straight through mufflers.  The real key is to weld the tube into the header at the proper location and angle to create the low pressure zone. 

 

Though I have not done as extensive research as @95riosnake, so your mileage may vary.

On my Cobra so far I've just thought about running the pcv lines to a vented catch can.

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I put a breather filter in the oil fill neck just to see if it helps, so far so good.  I've never used one but we'll see what happens.  If I still notice oil where it's not supposed to be I'll pull the valve covers and run it to a vented catch can.  

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One tip with the breather to keep oil mist off your engine bay is to get a black wrist warmer and stretch it over the breather, IIRC @prokiller suggested this to me and I plan to do it once I actually drive my car again.

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1 hour ago, Josh@RideTech said:

I put a breather filter in the oil fill neck just to see if it helps, so far so good.  I've never used one but we'll see what happens.  If I still notice oil where it's not supposed to be I'll pull the valve covers and run it to a vented catch can.  

Not sure what you did. ie just added a single breather? Did you cap the pcv? 

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Just now, 95opal said:

Not sure what you did. ie just added a single breather? Did you cap the pcv? 

 

I did.  It was a quick simple thing to try, I had it sitting in my toolbox.  It's not going to be the best route but it's a first step lol.

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7 minutes ago, Josh@RideTech said:

Yeah, no change at all.... The car started running lean last night and I pulled the MAF off and it was covered in oil -___- 

 

The air-oil vent can is on it's way.   

@95opal

Figured it wasnt going to suffice but was worth a shot being a freebie. Make sure to go 12AN on the line and fittings. You can go duel fittings in each cover or single in each cover. Good luck

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Holes are drilled, AN fittings welded in, and catch can/breather setup is ready to go on.  I assume I delete the stock PCV system and just run this one out in the atmosphere?  Cap off the PCV on the back of the lower intake?  @95riosnake @95opal @RedTwilight

 

Edited by Josh@RideTech
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33 minutes ago, 95opal said:

Yes plug the pcv valve. Cap off unused vac sources. Not sure what you mean by run this one to atmosphere? No pic

 

It's basically just a catch can with a breather.  It's not hooked in to the PCV system is what I was meaning by that @95opal

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14 hours ago, Josh@RideTech said:

 

It's basically just a catch can with a breather.  It's not hooked in to the PCV system is what I was meaning by that @95opal

 

 

Then your good....just cap the pcv and unused vac sources as i stated earlier

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just curious - did you check the screen that resides under the PCV valve inside the intake manifold?  mine was SOLID so essentially the PCV was not working at all to reduce crankcase pressure.  it was a 5 dollar fix by adding the new screen.  

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On 4/8/2016 at 0:16 PM, GearGambler said:

just curious - did you check the screen that resides under the PCV valve inside the intake manifold?  mine was SOLID so essentially the PCV was not working at all to reduce crankcase pressure.  it was a 5 dollar fix by adding the new screen.  

 

I did!  Everything is good in there.  I put all new pieces in when I rebuilt the engine (now has 51 miles on it.....) and it all still looks the same as when I put them in.  

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