LQ4 w/ ls3 top end PCV routing?
12-06-2015, 02:35 PM
#1
Teching In
Thread Starter
Join Date: Jan 2015
Location: Slinger, WI
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
LQ4 w/ ls3 top end PCV routing? Hey guys,
I ended up finally getting my ls swap completed on my foxbody near the end of this fall, and I blew the rear main seal out most likely from incorrectly routing my PCV system. I plan on purchasing a single catch can from Mighty Mouse, but how are you guys routing the system? For my valve covers there is 1 port on the rear of the driver's side and 1 port on the front of the passenger side. I'm running a nick williams cable driven TB with an ls3 intake manifold and there is a single vacuum port on the passenger side of the TB. The engine has just the standard lq4 valley cover, so there is no PCV port coming off the front of the engine under the intake manifold. Lastly there is a vacuum port on each side of the ls3 intake manifold just before the throttle body. The car is also running a standard oil cap (not vented).
Any help or suggestions would be greatly appreciated. Thanks guys!
I ended up finally getting my ls swap completed on my foxbody near the end of this fall, and I blew the rear main seal out most likely from incorrectly routing my PCV system. I plan on purchasing a single catch can from Mighty Mouse, but how are you guys routing the system? For my valve covers there is 1 port on the rear of the driver's side and 1 port on the front of the passenger side. I'm running a nick williams cable driven TB with an ls3 intake manifold and there is a single vacuum port on the passenger side of the TB. The engine has just the standard lq4 valley cover, so there is no PCV port coming off the front of the engine under the intake manifold. Lastly there is a vacuum port on each side of the ls3 intake manifold just before the throttle body. The car is also running a standard oil cap (not vented).
Any help or suggestions would be greatly appreciated. Thanks guys!
12-06-2015, 03:19 PM
#2
Drivers valve cover port to the intake port on the pass side of the TB neck
Pass VC port to upper pass TB port
Left side TB neck port is evap so cap it
Do not vent the PCV or oil caps
If you install a catch can, put it inline from the drivers VC to the intake. There is no reason to put a catch can on the short line from TB to pass VC as this is metered air into the engine. Its clean air in, there will be no oil in it
Pass VC port to upper pass TB port
Left side TB neck port is evap so cap it
Do not vent the PCV or oil caps
If you install a catch can, put it inline from the drivers VC to the intake. There is no reason to put a catch can on the short line from TB to pass VC as this is metered air into the engine. Its clean air in, there will be no oil in it
12-06-2015, 03:25 PM
#3
Teching In
Thread Starter
Join Date: Jan 2015
Location: Slinger, WI
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
Awesome thanks man! Which of those lines needs to have the oem pcv valve in it? And what are your opinions on even running a catch can? Is it even necessary to run one on a street driven setup like mine?
12-07-2015, 06:07 AM
#4
LS3 valve covers have a baffle built into the drivers VC. No extra PCV is needed. If you're using older VCs with the baffles removed to clear the taller LS3/92 rockers then you'll run a generic PCV in the slip on port
Im not a fan of catch cans. Dont run one on any of my setups, NA or supercharged. The minuscule amount of oil consumed doesnt affect anything. On the other hand you do need a properly working PCV system. Key word: properly
I do think they're needed on some setups where the rings are over gapped for more boost. More gap means more blow by means more windage, so the PCV system needs to work extra hard. An external vacuum pump is often a good idea in those cases
Im not a fan of catch cans. Dont run one on any of my setups, NA or supercharged. The minuscule amount of oil consumed doesnt affect anything. On the other hand you do need a properly working PCV system. Key word: properly
I do think they're needed on some setups where the rings are over gapped for more boost. More gap means more blow by means more windage, so the PCV system needs to work extra hard. An external vacuum pump is often a good idea in those cases
