superjim's PCV catch can and evacuation system


Active Member
Nov 17, 2003
I embarked on a project to improve my pcv system, get oily vapors out of the engine bay and cabin, and reduce oil leaks. I found the pcv valve and grommet (even the latest aftermarket style) has been a source of problems for a lot of people. Getting an oem style pcv valve installed in the grommet is difficult and even after installed can have a loose fit and be a source of vacuum leaks.

I did something a little different that works. I used a Dorman grommet # 42056 which has a very snug fit around the neck of the pcv valve. As with the OEM grommet, the hole is overly tight for the barbed end of the pcv valve to push through. (yes I know it can be done). The problem with the oem grommet is the hole is large enough to push the barb though but then not tight enough to get a good solid seal on the neck of the valve. So my solution was to cut 4 vertical slices in the bard with a dremel cut-off wheel. That way the barb and compress to get through the hole without excessive force and pushing the grommet into the engine. Then the barb expands back out after the valve is fully inserted. You can feel this happen. I apply a small amount of silicone sealant on the valve to lubricate the installation and give a complete seal when dry.

Next I installed a catch can from Evil Energy and routed the out lines to the throttle body and the intake tube just before the turbo. Installed check valves in both lines. The function is the throttle body pulls vacuum at idle and low rpm then the intake pipe pulls vacuum at high rpm and boost. A check valve in the line to the throttle body prevents pressurized air from going back to the catch can and pcv valve. The check valve in the line to the intake tube prevent air from being drawn into the throttle body a low rpm instead of the pcv valve.

And last was the valve cover vents. In the old days before pcv valve and emission controls, hot rodders would run a hose from the valve covers to the underside of the car. The air passing by underneath would pull a slight vacuum on the hoses and valve covers. I did this on both valve covers. I installed my original K&N valve cover vents on the ends to catch dirt during intake vacuum. I wanted to stall check valves to seal the hosed during engine vacuum to prevent huge vacuum leaks but then open to allow gasses to escape when needed. The problem was check valves required too much opening pressure for this application. So I used two more pcv valves.

I made a mounting bracket out of abs plastic and attached it to the transmission cross brace.

I am very pleased with the outcome and the way it performs.

Pictures attached.



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hello people: How's that doorman grommet working out 4 U. thanks
keep in mind there are several different Dorman grommet #'s with different size holes. If you get one that the bard can go through, it wont give a good seal on the throat of the valve. That's why a tighter hole (pardon that phrase) works if you slice the barb. It was really a poor design from the start.
Test fit the grommet and and the pcv valve prior to installation to get the fit you want. I used a small dremel grinder bit to take a couple thousands off the ID of the grommet so it would take excessive force to install the pcv valve after the grommet was installed.