Crank case ventilation question
Thread Starter
Racer
Joined: Jul 2015
Posts: 442
Likes: 103
Crank case ventilation question
So have an ls2 with an ECS system on it. love it. but I feel theres a spot for improvement. in place of the oil cap is a filter that screws in like a factory cap, byt has a small baffle at the base to collect oil particles before venting crank case pressures to atmosphere. I like the design but I believe its slightly faulty. mine, when screwed into the filler neck doesn't actually tighten to a solid, "sealed" feeling and is left with some free play. and ive also noticed on hard pulls that a small fine collection of oil mist can be found on the passenger side front windshield. obviously from that breather. my plan is to replace this breather with a cap that has an -10 AN male fitting on it. it screws in like factory but allows me to run an appropriate sized line from the valve cover to a catch can in a more efficient way to vent the crank case and trap any oil mist. the question: has anyone done this before (I know MM sells a kit doing the exact thing) and is just one side enough? MM claims a -10 is good for applications around 1000hp, but whats the actual flow requirements relative to AN fitting size one should use?i just want to be sure im not choking the PCV system by making this conversion. thanks.
Burning Brakes
Joined: Aug 2008
Posts: 855
Likes: 35
From: Katy/Houston Texas
So have an ls2 with an ECS system on it. love it. but I feel theres a spot for improvement. in place of the oil cap is a filter that screws in like a factory cap, byt has a small baffle at the base to collect oil particles before venting crank case pressures to atmosphere. I like the design but I believe its slightly faulty. mine, when screwed into the filler neck doesn't actually tighten to a solid, "sealed" feeling and is left with some free play. and ive also noticed on hard pulls that a small fine collection of oil mist can be found on the passenger side front windshield. obviously from that breather. my plan is to replace this breather with a cap that has an -10 AN male fitting on it. it screws in like factory but allows me to run an appropriate sized line from the valve cover to a catch can in a more efficient way to vent the crank case and trap any oil mist. the question: has anyone done this before (I know MM sells a kit doing the exact thing) and is just one side enough? MM claims a -10 is good for applications around 1000hp, but whats the actual flow requirements relative to AN fitting size one should use?i just want to be sure im not choking the PCV system by making this conversion. thanks.
Melting Slicks
Joined: Nov 2013
Posts: 2,049
Likes: 316
From: USA
I have a C5 but same principle. I run a -10AN off each valve cover to the intake air filter. I just don't like the smell of breather/VTA systems so this vents back into the intake tract under WOT like the stock setup would, it's just a lot higher flow. It's overkill for my ~700whp level, but the hose and intake tract is also bone dry still.
If you get something welded on the valve cover, make sure to baffle it to prevent oil from splashing directly into it.
If you get something welded on the valve cover, make sure to baffle it to prevent oil from splashing directly into it.
Last edited by aaronc7; Jan 11, 2020 at 11:43 PM.
Team Owner
Joined: Nov 2007
Posts: 24,035
Likes: 2,342
From: Gilbert AZ
Holley/Earl's also has baffled oil caps setup for this. I run a -10 baffled oil cap to catch an mounted down in fender. Second -10 from baffled fitting on valley cover.
Last edited by Unreal; Jan 12, 2020 at 09:34 AM.
Melting Slicks
Joined: Oct 2010
Posts: 2,691
Likes: 165
From: Greenwood Indiana
I have a question for ya
my blower build has no vent/pvc on the valley cover (also using stock intake) i planned to run 2 -10 bungs, 1 from each valve cover to a vented can, then vac line to blower dongle
will this be ok?
Last edited by ~STOLEN~; Jan 15, 2020 at 10:40 AM.
Instructor
Joined: Apr 2017
Posts: 151
Likes: 60
From: Fort Worth, TX
One from each valve cover works fine, that's how I have mine set up. I didn't bother with a vac line though. Just 2 10an lines to a vented can.
Melting Slicks
Joined: Oct 2010
Posts: 2,691
Likes: 165
From: Greenwood Indiana
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