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Vented Oil Catch Can #4561150
11/01/17 10:49 AM
11/01/17 10:49 AM
Joined: Jul 2017
Posts: 187
Venezuela, South America
Emanuel Offline OP
Emanuel  Offline OP
Joined: Jul 2017
Posts: 187
Venezuela, South America
Does a PCV delete and Vented Oil Catch Can setup worsens or improves the life of the Oil?

Is the vacuum of the Intake Manifold needed for proper extraction of the condensation and contaminats of the oil?

Are there any UOA results that shows improvements with a vented Oil Catch can?

Re: Vented Oil Catch Can [Re: Emanuel] #4561156
11/01/17 10:55 AM
11/01/17 10:55 AM
Joined: Aug 2008
Posts: 21,260
ON, Canada eh?
StevieC Offline
StevieC  Offline
Joined: Aug 2008
Posts: 21,260
ON, Canada eh?
There is a lot of vapor in the crank case and a PCV which forces the combustion gases that slipped past the rings and general vapor out of the crank case to be burn't off is beneficial in that regard.

I have seen a wrench head friend of mine use a 12V Vacuum pump to draw the vapour out of the PCV into his catch can before venting to the atmosphere. That's an option.

Now if an engine was operated only on long trips or extended run times each run I think it might be debateable if the PCV would still be beneficial for vapour in the crankcase.

That said. Catch cans should not be necessary in properly setup PCV systems in standard vehciles. (Racing applications it's a different story because of a multitude of differences that may exist where a catchcan might be beneficial)

Last edited by StevieC; 11/01/17 10:58 AM.

'18 Dodge Grand Caravan GT - AMSOIL SS 5w20
'06 Santa Fe - 535,000km AMSOIL SS 0w30 / ATF
Re: Vented Oil Catch Can [Re: StevieC] #4561165
11/01/17 11:01 AM
11/01/17 11:01 AM
Joined: Jul 2017
Posts: 187
Venezuela, South America
Emanuel Offline OP
Emanuel  Offline OP
Joined: Jul 2017
Posts: 187
Venezuela, South America
Yes, and I have also read that vacuum in the crankcase helps to improve the rings seal

Re: Vented Oil Catch Can [Re: Emanuel] #4561214
11/01/17 11:42 AM
11/01/17 11:42 AM
Joined: May 2012
Posts: 5,663
Fort Lauderdale, FL
DoubleWasp Offline
DoubleWasp  Offline
Joined: May 2012
Posts: 5,663
Fort Lauderdale, FL
Yes. Vaccuum improves ring seal, and also prevents ring flutter due to the rings pressing down on crankcase air while on down stroke. Keeping the crankcase under vacuum also majorly reduces bay-to-bay breathing and turbulence inside of the engine.

Two of my cars have Ford electric emissions pumps made into vacuum pumps that suck air out of the crankcase. They'll do 7-9" of vacuum easily. Vaccuum pumps suck through a catch can first in order to protect the pump from oil. The discharge of the vacuum pump is routed back to the intake air box (pre filter) to prevent stink (a real problem with some oils) and emissions. I have very small, basic breathers in the opposite valve cover to allow a little fresh air to move through the crankcase.

This actually doesn't even make the air filter oily. Any part of the intake tract feels dry as a bone.

Previously had one of them routed to the exhaust, but the pump has an easier life this way.

Using this method, there's no oil in the intake tract, no crankcase gases get to the atmosphere, and the crankcase is under 7-9" of vacuum at all times. Win/win.


07 Lincoln Navigator M1 0w-40/FU
68 Charger R/T / Supercharged 440 VR1/DBL7349
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17 Maserati GranTurismo Cabrio
Re: Vented Oil Catch Can [Re: DoubleWasp] #4562231
11/02/17 03:29 PM
11/02/17 03:29 PM
Joined: Apr 2004
Posts: 441
ON, Canada
yugrus Offline
yugrus  Offline
Joined: Apr 2004
Posts: 441
ON, Canada
Originally Posted By: DoubleWasp

Previously had one of them routed to the exhaust, but the pump has an easier life this way.


Can you please elaborate on that, as I'm contemplating exactly this sort of a set-up? How does this routing makes the electric pump work harder? I assume you've had a sort of venturi valve welded into your exhaust.


'14 Chevrolet Tahoe
'15 Mazda CX-5
Re: Vented Oil Catch Can [Re: Emanuel] #4562648
11/03/17 12:37 AM
11/03/17 12:37 AM
Joined: May 2012
Posts: 5,663
Fort Lauderdale, FL
DoubleWasp Offline
DoubleWasp  Offline
Joined: May 2012
Posts: 5,663
Fort Lauderdale, FL
I didn't have a high performance free flow exhaust to go with it. The pump didn't discharge as well when the engine was really hitting it good. I could hear the air escaping from the bypass in front of the check valve used to prevent backflow.

A good low restriction exhaust would spare all of that, but I can't stand the sound of a loud exhaust. An exhaust that pronounces itself with a really good sound is one thing, but just loud is just annoying to me.

At the end of the day, I feel it was a waste of time. It's a lot easier just to route the hose to the air box than to modify the exhaust.

There's no need for venturi in the exhaust anyway. Use one pump, and you'll get 7-9" on a vented crankcase (has a small air inlet to allow fresh air in). Double up and run two pumps in a series and you'll get 16-18" vacuum.

I wouldn't do that, because too much vacuum in an engine not built for it can cause the wrist pins to run a little dry.....so I've heard.

I first did this because I was dealing with an engine that had enough blow-by to force oil out of pretty much anywhere, including the PCV system. I attached an extended oil filler neck, and stuck a 5/8" nipple through the top of the neck just below the oil cap, to keep it from being an oil vacuum pump. Catch can in between that and the vacuum pump.

Engine runs completely dry to this day. I could replace the seals and what not, but I'm interested to see how long this trend lasts. So far it's gone 27k miles without exposing a drop of oil. I'm liking where this is going.

I've also run these systems with no vent at all, to where you had to struggle to remove the oil cap, and it released with a loud pop.


07 Lincoln Navigator M1 0w-40/FU
68 Charger R/T / Supercharged 440 VR1/DBL7349
07 Ram 3500 4x4 / Cummins 6.7 /DBL7349
17 Maserati GranTurismo Cabrio
Re: Vented Oil Catch Can [Re: Emanuel] #4562795
11/03/17 07:37 AM
11/03/17 07:37 AM
Joined: Jun 2003
Posts: 5,949
Illinois
SHOZ Offline
SHOZ  Offline
Joined: Jun 2003
Posts: 5,949
Illinois
I use to run a catch can on the PCV line and had the crankcase air intake hose on the valve cover plugged. This kept about 7" of vacuum on the crankcase when the intake had vacuum. Worked great but you had some pumping noises at idle.

The catch can had a drain/check valve that the vacuum would pull closed. When I went WOT and lost the vacuum it would open, or when the car was off. This drained the catch can each time.


2008 Hyundai Accent 1.6L 5 sp manual hatchback
2010 Hyundai Genesis Coupe Track 2L Turbo 6sp manual
Re: Vented Oil Catch Can [Re: Emanuel] #4562851
11/03/17 09:07 AM
11/03/17 09:07 AM
Joined: Mar 2011
Posts: 2,198
Indiana
Indydriver Offline
Indydriver  Offline
Joined: Mar 2011
Posts: 2,198
Indiana
Originally Posted By: Emanuel
Does a PCV delete and Vented Oil Catch Can setup worsens or improves the life of the Oil?

Is the vacuum of the Intake Manifold needed for proper extraction of the condensation and contaminats of the oil?

Are there any UOA results that shows improvements with a vented Oil Catch can?

A good catch can condenses out oil in the crankcase blow-by air keeping it from contaminating your fresh air intake tract. The Rx can on my Camaro pulls out about 4oz/1000 miles. It has no effect on the lifecycle of the oil or your OCIs. For those who doubt the efficacy of catch cans, just pull the throttle body of a non-catch can V8 after 30 or 40,000 miles and shine a light into the intake manifold. Good luck cleaning all that effluent out of there. Or pay your dealer about $400 for a “fuel system” cleaning and hope he really gets in there with solvent and brush to clean it out.

Last edited by Indydriver; 11/03/17 09:12 AM.

2014 Camaro 2SS/RS LS3 Vert 14,000 M1
2012 Sienna 79,000 M1
2007 Tahoe 140,000 PP


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