2020-B2-2

Author Topic: Breathers and PCV combinations?  (Read 213 times)

brdzword

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Breathers and PCV combinations?
« on: January 29, 2020, 04:00:47 PM »
I have been using an oil cap on Driver side and oil breather on passenger side.  My FiTech throttle body is covered by aftermarket open Air filter.  My PCV is on the valley pan as original and is connected to the manifold fitting at the rear of the FiTech throttle body valve plate.  I am also using a Morroso oil catch can in line with the PCV.  I would like to try a second breather in place of the driver side oil cap.  Would I be defeating the purpose of the PCV valve?  Could it help in any way as far as crankcase pressure?  Thanks.  My engine is not stock.

Bluebandit

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Re: Breathers and PCV combinations?
« Reply #1 on: January 29, 2020, 06:17:55 PM »
It could. Remember the lower the vacuum the less effective the pcv valve operates. If you are experiencing high crankcase pressure due to blowby the extra breather can help relieve it.

NOT A TA

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Re: Breathers and PCV combinations?
« Reply #2 on: January 29, 2020, 10:50:48 PM »
It could. Remember the lower the vacuum the less effective the pcv valve operates. If you are experiencing high crankcase pressure due to blowby the extra breather can help relieve it.

^^^
John Paige
Lab-14.com

81Blackbird

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Re: Breathers and PCV combinations?
« Reply #3 on: January 30, 2020, 06:41:25 AM »
I don't think two PCV valves is a good idea.  You need a vent somewhere in the system and if your pulling from two sources without a vent your just vacuuming down the crank case.  Unless there is a lot of blow by which may be enough to accomplish what your looking for.  Since you have one PCV valve now, is there residual oil around the breather?   If so, there may not be enough vacuum to pull the fumes into the intake for re-burning.  Then a stronger vacuum source(?) or a second PCV valve may help with the excess blow by.  As you know some weld a vacuum source on each of the headers to pull crank case fumes directly into the exhaust system for burning.
« Last Edit: January 30, 2020, 06:44:10 AM by 81Blackbird »

Formula8

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Re: Breathers and PCV combinations?
« Reply #4 on: February 13, 2020, 10:30:09 AM »
I was running a PCV in the driver's cover and a breather in the passenger.  I would get oil in the line going to the PCV and my dipstick would pop up once in a while.  I changed the PCV back to the valley pan and that reduced the oil in the line but the dipstick would still blow occaisionally.  I then put a breather on the drivers valve cover in addition to the passenger side breather, while keeping the PCV in the valley pan and all is good so far.  I think that is the set up you are talking about.  If so, yes, it works.
71 Formula 433, 4 bolt splayed cap 400 block, 4" stroke Scat forged crank, 6.8 Eagle rods, custom Autotec pistons. SD 295 KRE D ports, Old faithful hybrid roller, factory intake, "Shaker tuned" Holley 800DP, Tribal Tubes, TKO 600, 3.73 Eaton posi. http://www.factcheck.org/

NOT A TA

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Re: Breathers and PCV combinations?
« Reply #5 on: February 13, 2020, 11:48:37 AM »
I was running a PCV in the driver's cover and a breather in the passenger.  I would get oil in the line going to the PCV and my dipstick would pop up once in a while.  I changed the PCV back to the valley pan and that reduced the oil in the line but the dipstick would still blow occaisionally.  I then put a breather on the drivers valve cover in addition to the passenger side breather, while keeping the PCV in the valley pan and all is good so far.  I think that is the set up you are talking about.  If so, yes, it works.

I had that problem occur on road race tracks with the dipstick pop up, had to wire the dipstick down. I'd gotten black flagged a couple times because corner marshal's thought I'd blow the engine or something when a little oil got on the exhaust. Took a bit to figure out what was happening because there was no oily mess.
John Paige
Lab-14.com

Ryoko

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Re: Breathers and PCV combinations?
« Reply #6 on: February 13, 2020, 01:39:52 PM »
I was wondering how everyone deals with port injection and PCV valves since there's no carb spray to wash the intake runners clean.

Formula8

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Re: Breathers and PCV combinations?
« Reply #7 on: February 14, 2020, 11:03:47 AM »
I was wondering how everyone deals with port injection and PCV valves since there's no carb spray to wash the intake runners clean.

Catch can just like a modern car.
71 Formula 433, 4 bolt splayed cap 400 block, 4" stroke Scat forged crank, 6.8 Eagle rods, custom Autotec pistons. SD 295 KRE D ports, Old faithful hybrid roller, factory intake, "Shaker tuned" Holley 800DP, Tribal Tubes, TKO 600, 3.73 Eaton posi. http://www.factcheck.org/

Re: Breathers and PCV combinations?
« Reply #7 on: February 14, 2020, 11:03:47 AM »
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