I need oil catch can/ pcv system help please...
Thread Starter
Drifting
Joined: Feb 2008
Posts: 1,952
Likes: 1
From: Waveland MS
I need oil catch can/ pcv system help please...
I have a 408 stroker iron block lq4, I need to know where I need to relieve crank pressure at and how I need to wire up my oil catch can. I would like to stay away from at breather on the valve cover though. Any diagrams it suggestions guys? As of now my valley cover nipple is rubber vacuum lined into,my manifold and the manifold is moist with oil after a good hit.
Drifting
Joined: Feb 2007
Posts: 1,993
Likes: 7
From: LaPine Oregon
What's different.........
What would be any different plumbing your engine than any other engine? If you have a baffle /oil seperator under the valley pan ( LS6, LS2, ect) that is an area that has crankcase vapor pressure and is removed from splashing oil ( like the valve covers).
Why can't you install the oil catch can between the valley pan baffle outlet port and the manifold inlet port. The port from the valley pan baffled port goes to the top of the catch can ( typically) and the port on the side of the catch can goes back to the intake port. You may want to add a PCV ( 2001-2003 LS6 use a PCV. 2004 LS6 use just a hose).
I would use fuel hose instead of vacuum hose ( at least 3/8" ID). Most any of the oil catch can mfg'ers offer diagrams and pictures of installs on their websites. CCA, MikeNorris, Elite, ect
Why can't you install the oil catch can between the valley pan baffle outlet port and the manifold inlet port. The port from the valley pan baffled port goes to the top of the catch can ( typically) and the port on the side of the catch can goes back to the intake port. You may want to add a PCV ( 2001-2003 LS6 use a PCV. 2004 LS6 use just a hose).
I would use fuel hose instead of vacuum hose ( at least 3/8" ID). Most any of the oil catch can mfg'ers offer diagrams and pictures of installs on their websites. CCA, MikeNorris, Elite, ect
Former Vendor
Joined: Apr 2006
Posts: 2,470
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From: Portland OR
St. Jude Donor '10-'11-'12
The valve cover tube going to the TB is the fesh air return. It should be filtered air as its going into the crank case. You can route that hose to the baffle and install it there.
what happens is under higher rpms the air whipping past that TB opening causes reversion. Its just located in a bad spot, Gm didnt really think about it is my guess.
what happens is under higher rpms the air whipping past that TB opening causes reversion. Its just located in a bad spot, Gm didnt really think about it is my guess.
Drifting
Joined: Feb 2007
Posts: 1,993
Likes: 7
From: LaPine Oregon
PCV system
99blancoss has a point with high rpm . When GM (2005) again modified the PCV system on the GEN 4 LS2, they added an oil seperator to the 'clean' or fresh air side where the air goes into the crankcase and for the 'foul' side they still use the valley pan location but a different , more effective oil seperator. You may want to use the improved LS2 design.
The point with the two oil baffles and high rpm is that at WOT you have high blow-by. WOT and high engine rpm you no longer have vacuum to help pull the air from the crankcase, you also have more blow-by and can exceed the capacity of the 'fouled ' air side ( which is sized normal engine loads).
The extra fresh air oil baffle was installed to make sure that under WOT conditions that crankcase fouled air did not reverse flow back into the intake.
Valve covers could be 'Y' into the catch can or but better another catch can could be added and the return hose going to the airbridge. Depends on how effective the one loop system is. You don't want to vent the valve covers to atmosphere as that will reduce vacuum draw to crankcase.
Last edited by dieseldave56; May 7, 2010 at 06:51 AM.
