Rb25det oil catch can / venting quesiton - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

EnemyS15 · 11-23-2012, 07:54 PM

I have a S2 rb25

Valve cover has 2x welded -8 an male ends and the pcv welded shut (purchased off of another Zilvian)

Oil catch can is a greddy, similar to the pic

I am wondering if it would be possible to replace the drain plug on the bottom of the catch can with an -An fitting/line, run the line to an -AN "Y" fitting connecting the oil drain from top mount turbo to block, and the oil catch to the block as well (creating a constant circulation of whatever blow by oil is collected). Would this set up form a sufficient vent for crank case pressure?

Pic of a Y I would use (not exact size)

If this is not a good idea, any other ideas would be appreciated. Just remember PCV is welded shut on the cover.

*fliprayzin240sx* · 11-24-2012, 07:36 AM

Why would you want the sludge back into your engine? The whole point of a catch can is to keep that same oil out of the engine since its usually contaminated with gas.

bullfrogg0 · 11-24-2012, 07:40 AM

I know that's how sr20's are set up from the factory....

EnemyS15 · 11-24-2012, 09:25 AM

Quote:

Originally Posted by fliprayzin240sx

Why would you want the sludge back into your engine? The whole point of a catch can is to keep that same oil out of the engine since its usually contaminated with gas.

Just throwing out an idea before I just go back to running a line to the intake.

EnemyS15 · 11-24-2012, 11:26 AM

Ok forget the draining part. Would routing the line to the y be sufficient source to relieve crank case pressure?

*fliprayzin240sx* · 11-25-2012, 12:38 PM

Did you look thru this? I'm still learning about the Rb so I'm not sure 100% how the crankcase is relieved. SRs has a line that goes from the crankcase to the valve cover to relieve the pressure. Not sure if the Rb has the same setup.

RB20 RB25 Catch Can PCV Breather Guide

PrimeDirective · 11-25-2012, 01:17 PM

With the pcv plugged use the Y to connect the two top valve cover ports to one line and attach it to the catch can. Then from the other port in the catch can connect it to a vacuum only source, that never sees boost, so either your exhaust or your intake pipe after the Maf and before the turbo.

This will release the pressure but also put a vacuum on the crack case to help seal your rings.

11-23-2012, 07:54 PM	#1
EnemyS15 Nissanaholic! Join Date: Jul 2006 Location: Tampa, Florida Posts: 1,677 Trader Rating: (14) Feedback Score: 14 reviews	Rb25det oil catch can / venting quesiton I have a S2 rb25 Valve cover has 2x welded -8 an male ends and the pcv welded shut (purchased off of another Zilvian) Oil catch can is a greddy, similar to the pic I am wondering if it would be possible to replace the drain plug on the bottom of the catch can with an -An fitting/line, run the line to an -AN "Y" fitting connecting the oil drain from top mount turbo to block, and the oil catch to the block as well (creating a constant circulation of whatever blow by oil is collected). Would this set up form a sufficient vent for crank case pressure? Pic of a Y I would use (not exact size) If this is not a good idea, any other ideas would be appreciated. Just remember PCV is welded shut on the cover.

11-24-2012, 07:36 AM	#2
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	Why would you want the sludge back into your engine? The whole point of a catch can is to keep that same oil out of the engine since its usually contaminated with gas. __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

11-25-2012, 12:38 PM	#6
fliprayzin240sx Man w/ CTSV & a Car Seat Join Date: Aug 2002 Location: Tampa Posts: 17,998 Trader Rating: (19) Rides Gallery: fliprayzin240sx Feedback Score: 19 reviews	Did you look thru this? I'm still learning about the Rb so I'm not sure 100% how the crankcase is relieved. SRs has a line that goes from the crankcase to the valve cover to relieve the pressure. Not sure if the Rb has the same setup. RB20 RB25 Catch Can PCV Breather Guide __________________ If you think Zilvia has too many assholes... CLICK HERE!!!

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

11-24-2012, 07:40 AM	#3
bullfrogg0 Zilvia Member Join Date: Jul 2009 Location: Baytown, Tx Age: 35 Posts: 201 Trader Rating: (3) Feedback Score: 3 reviews	I know that's how sr20's are set up from the factory....

11-24-2012, 11:26 AM	#5
EnemyS15 Nissanaholic! Join Date: Jul 2006 Location: Tampa, Florida Posts: 1,677 Trader Rating: (14) Feedback Score: 14 reviews	Ok forget the draining part. Would routing the line to the y be sufficient source to relieve crank case pressure?

11-25-2012, 01:17 PM	#7
PrimeDirective Zilvia Member Join Date: Jan 2012 Location: Olympia WA Age: 33 Posts: 266 Trader Rating: (3) Feedback Score: 3 reviews	With the pcv plugged use the Y to connect the two top valve cover ports to one line and attach it to the catch can. Then from the other port in the catch can connect it to a vacuum only source, that never sees boost, so either your exhaust or your intake pipe after the Maf and before the turbo. This will release the pressure but also put a vacuum on the crack case to help seal your rings.