PCV Systems
Posted: Sat Jun 30, 2012 3:22 pm
This is a good discussion of PCV Systems, including how to test for correct operation. http://www.aa1car.com/library/pcv.htm
When the vacuum characteristics are changed by engine mods, e.g., cam or forced induction, the OE PCV valve could be mismatched and cause problems, esp idle problems or passing too much vapor/oil mist when decelerating. Think I may have that issue with the 347. I just looked for one with the correct dimensions. Didn't know the selection of the PCV valve was so important. When its not too hot out I'll check the closed off crank case vacuum at idle. I expect its too high.
BP, did you do anything with the PCV system when you supercharged the S10? I think pressurizing the intake would close the valve (like in a backfire condition). No idea what issues that might cause in an EFI setup.
When the vacuum characteristics are changed by engine mods, e.g., cam or forced induction, the OE PCV valve could be mismatched and cause problems, esp idle problems or passing too much vapor/oil mist when decelerating. Think I may have that issue with the 347. I just looked for one with the correct dimensions. Didn't know the selection of the PCV valve was so important. When its not too hot out I'll check the closed off crank case vacuum at idle. I expect its too high.
BP, did you do anything with the PCV system when you supercharged the S10? I think pressurizing the intake would close the valve (like in a backfire condition). No idea what issues that might cause in an EFI setup.
Is it common practice to remove the PCV valve when adding forced induction? Seems like a good idea.