1998 V70 XC Intake manifold to PTC nipple check valve?

[98v70xc206]

Hello, I'm dealing with a car with excessive crankcase pressure, and am servicing/upgrading the PCV system. I'm going to go with 5/8" fuel line for the oil trap to the PTC nipple, and 5/16" fuel vapor hose from the intake manifold to the small port on the PTC. I have also drilled out the larger copper orifice of the PTC. I have two questions regarding the PCV/PTC.

1. Would adding a vacuum check valve on the 5/16" line be a good idea to reduce pressure in the PTC while under boost?

2. In the smaller port of the PTC there is a second much smaller copper orifice(the port the 5/16" hose will go on) that I am hoping to drill out in order to closer match the size of the hose to help build more vacuum at idle. Will the modification(enlarging) of this orifice through off the IAC?

I do fully understand what the PTC was designed to do, and don't care about messing with the heater function of it. I just don't want to mess up the idle speed. I'm considering going to the local pick and pull to get one for experimentation. Any thoughts on this matter would be greatly appreciated. Thanks!

[Ozark Lee]

I don't know about drilling the orifices since part of what makes the PTC valve work is the venturi effect. Altering the diameters will necessarily alter the vacuum that is created.

We had a post in the last couple of weeks where, I think it was Ben850, chopped a PTC in half and showed how it was made. That post, if I can find it, can at least give you an idea of where not to drill.

EDIT: It was jreed that made the post. Here is a link.

https://www.matthewsvolvosite.com/forums ... er#p360439

...Lee

[98v70xc206]

Thanks Lee, that what was helpful!

Brent