Inline positive action check valve

Smokin-6 · 05-11-2008, 09:46 PM

I just put in the ATR positive action check valve with a AC Delco PCV. I wanted to cut down on the blow by through the drivers side breather, it seemed to work. My car seems to have a little lower bL on the Scanmaster, they used to be 124 with Int of 128. Now with the check valve installed the bL is 118 and Int of 127. I have not put that many miles on it so maybe thats why. I heard these check valves could cause rough idles, although I can blow through it one way very easy, and the other way can't (boost path). Anyone experience this?

Steve Wood · 05-12-2008, 09:55 AM

If you put it in, then you should know if you have rough idle, or not....

It may well affect your A/F ratio slightly as the factory set up was not calibrated with a check valve in place. I would think the ECM would compensate for the difference.

Orlando_87GN · 05-12-2008, 11:17 AM

I've got one of those check valves on each car. It was just a viton seal, brass bodied check valve painted black available from McMastercar. The idea was pick up where the PCV valve leaves off. The PCV valve has a simple ball inside that is supposed to allow evacuation of the crank case. It probably works great in a normally aspirated application but not in a boosted car. The PCV was never designed to block high pressure boost going in the other direction, essentially filling the crankcase with pressure. I never noticed a change in BLM's maybe the change you are seeing is from something else. Or you may want to hook a MityVac vacuum pump/gauge up to the top of the PCV and check valve to test the whole contraption. I supposed if it takes more vacuum to pull through the PCV and check valve than your engine makes; that could cause a problem similar to plugging the PCV completely.

05-11-2008, 09:46 PM	#1 (permalink)
Smokin-6 87 Turbo T Join Date: Jul 2007 Location: Seneca, MD Posts: 119	Inline positive action check valve I just put in the ATR positive action check valve with a AC Delco PCV. I wanted to cut down on the blow by through the drivers side breather, it seemed to work. My car seems to have a little lower bL on the Scanmaster, they used to be 124 with Int of 128. Now with the check valve installed the bL is 118 and Int of 127. I have not put that many miles on it so maybe thats why. I heard these check valves could cause rough idles, although I can blow through it one way very easy, and the other way can't (boost path). Anyone experience this? __________________ 2 1/2 Magnaflow exhaust, 9 inch filter, stock turbo/ ported compressor, 60's & TT chip, Scanmaster, RJC Power Plate, ported throttle body, stock block, 3 inch DP with no CAT, adjustable FPR, high flow fuel pump/ hot wire kit, new valve springs & timing chain. Original owner!

05-12-2008, 09:55 AM	#2 (permalink)
Steve Wood An American American Join Date: Sep 2000 Location: East of Eden, Texas Posts: 37,175	If you put it in, then you should know if you have rough idle, or not.... It may well affect your A/F ratio slightly as the factory set up was not calibrated with a check valve in place. I would think the ECM would compensate for the difference. __________________ ------------------ 'A government that is big enough to give you everything you want, is also big enough to take away everything you have.' - Thomas Jefferson I think one should worry more when people are lining up to get out of a country rather than into it. If they're sneaking in, we must be doing something right. The Chronicles of Zap, from the early 21st century www.vortexbuicks-etc.com

05-12-2008, 11:17 AM	#3 (permalink)
Orlando_87GN Resident Idiot Join Date: Sep 2000 Location: Orlando, FL USA Posts: 10,458	I've got one of those check valves on each car. It was just a viton seal, brass bodied check valve painted black available from McMastercar. The idea was pick up where the PCV valve leaves off. The PCV valve has a simple ball inside that is supposed to allow evacuation of the crank case. It probably works great in a normally aspirated application but not in a boosted car. The PCV was never designed to block high pressure boost going in the other direction, essentially filling the crankcase with pressure. I never noticed a change in BLM's maybe the change you are seeing is from something else. Or you may want to hook a MityVac vacuum pump/gauge up to the top of the PCV and check valve to test the whole contraption. I supposed if it takes more vacuum to pull through the PCV and check valve than your engine makes; that could cause a problem similar to plugging the PCV completely. __________________ Check Out MikesStuff4Sale.com to view my used parts! ------------------------------------------------ 1987 Buick Grand National Budget 4.1, 204/214 cam, TA-49 Turbo, Stockish Heads, V4, MSD50's, TH DP, JayJackson 62mm TB, Translator plus Extender powered. 3680# with pilot ------------------------------------------------ 1993 Mazda RX-7 4.1 Buick Powered 11.20 @ 128mph (2.4 60')!

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