Which Vendor wants to jump on making these..., 022115542 Options

[JamesM]

What would it take to get one of our vendors to make these?

022115542 - crank case valve

Surprisingly critical part for proper operation on 72-74 djet cars, not just for crank case venting but has a large impact on idle control and how d-jet runs. Supposed to be a regular maintenance/replacement item as well yet they haven't been available for close to 20 years. Struggling to find any that don't result in some sort of idle control issue these days.

Less critical is the associated nut 022115544

@Mikey914 @UROpartsman or anyone else want to bite?

[Mikey914]

Happy to take a look at these this next week. I'm pretty sure I have one laying around.
Can't see these tings being too expensive.

[JamesM]

Happy to take a look at these this next week. I'm pretty sure I have one laying around.
Can't see these tings being too expensive.

Last time Porsche had these they were around ~$10. Biggest issue I see is probably figuring out the proper spring pressure.

https://members.rennlist.com/pbanders/PCV.htm


Used on some VWs as well so may be a larger market? IDK? I suspect a lot of people don't realize how badly worn ones can mess with how d-jet cars run as people don't really associated them with the injection system, but in addition to causing air leaks/idle speed issues worn ones can cause erratic manifold pressure under driving conditions, which can result in change to the MPS output that messes with the FI mixture and can cause missfires/the mystery "d-jet" bucking that no one can ever track down because no one ever gives the crank case vent valve a 2nd thought unless they have failed completely.

[JamesM]

Was gone over in depth long ago on STF but for some reason doesn't ever seem to be brought up here.

https://shoptalkforums.com/viewtopic.php?t=34350

[Not_A_Six]

Was gone over in depth long ago on STF but for some reason doesn't ever seem to be brought up here.

https://shoptalkforums.com/viewtopic.php?t=34350

That was a very interesting discussion. Thanks.

There was a lot of really bad information being bandied about until Brad Anders stepped in.

IMO, Brad Anders has it exactly right for the particular part you are looking for. It has two modes -- fixed metered and shut. Contrast this with a modern valve that varies its metering based on the differential pressure across the valve. For that 022115542 part, correctly plumbed to the plenum (with crankcase replacement air provided via the anti-flashback valve), it's going to be "open" just about any time the engine is running. It should only close under backfire, start up, and *possibly* under WOT.

Under WOT with a lot of blow-by, crankcase pressure should be limited to very slightly above atmospheric pressure by back-venting through the anti-flashback valve. At the same time, the manifold vacuum is less than 1 In-Hg because the throttle butterfly is fully open. So the differential pressure across the PCV valve is likely less than 2-3 In-Hg or so. Somebody would need to characterize the valve to see how it's supposed to behave at that pressure. But, I suspect under these conditions, the majority of the gasses are vented to the airbox through the anti-flash valve rather than through the PCV valve, even if it's open at WOT.