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  • Let's talk vacuum port on valve cover......

    I am ih the final stages of completing the Autronic install with the modified valve cover an need to make a decision on the vacuum port on the valve cover. Can I just block it off? Can I just block off the hose that used to go to the other valve cover? I need some pros and cons.........

    I have a tracck event next weekend and need to fire this puppy up this weekend.

    T

  • #2
    Re: Let's talk vacuum port on valve cover......

    Originally posted by HANDBLT
    I am ih the final stages of completing the Autronic install with the modified valve cover an need to make a decision on the vacuum port on the valve cover. Can I just block it off? Can I just block off the hose that used to go to the other valve cover? I need some pros and cons.........

    I have a tracck event next weekend and need to fire this puppy up this weekend.

    T
    I vote for not blocking it off, but venting it to a catch tank.

    Gustave

    Comment


    • #3
      Re: Re: Let's talk vacuum port on valve cover......

      Originally posted by Gustave
      I vote for not blocking it off, but venting it to a catch tank.

      Gustave
      What about where the hose connects down low? Does this just get blocked off? What are the effects if all the ports are just blocked off?

      T

      Comment


      • #4
        Ok I'll take a crack at this as it seems the vacuum plumbing on the S14 presents alot of mystery to alot of people.
        Its pretty straight forward.

        The system is really no different than the system on a similar year say Chevy small block V8.
        In any stock US engine setup, (for pretty much anything post 1973) the tree huggers dont want any raw crankcase or raw fuel tank vapors venting to atmosphere. So to prevent that they have ducted all this crap back into your engine.
        See the charcoal canister feeding into the plenum as well as the vent from your oil separator.

        The S14s oil separator is nothing more than a German version of a PCV valve.
        It separates liquid oil back to the sump, and ducts the oil vapors, blowby, etc back to the plenum (bad).
        Ever notice that oily film inside your plenum, thats blowby and crankcase vapor. Bad, bad, bad for octane. Nothing lowers gasolines octane like oil vapor (or oil),,,, but the treehuggers dont want that nasty unburned stuff in our atmosphere so they think its better for you to try and burn it (again) in your nice clean engine.
        Now that we have basic evaporative management covered...

        The line that comes off the valve cover plumbs that liquid oil from the cambox and any crankcase vapors down to the oil separator which does its job very well.
        It ducts the vapors UP, and the liquid oil back to the sump.

        What I have done, and suggest for everyone,,, is take the line off the bottom of the plenum and put a small K&N filter on it venting it to atmosphere. I retain the oil sep, and let it do its job of taking the overflow oil back to the sump.
        I see no benefit in just routing to a catch tank, in fact I have done away with the classic Grp A catch tank on my Touring Car and actually added a stock oil separator to that motor. Its working flawlessley.

        All my cars have all evaporative controls severed from the plenum. All that gets in the engine is clean filtered air. Everything else is venting to atmosphere as God intended back in the '60s.

        Just remember on the stock type AFM system, if you do this anytime you sever a link to the evap systems you need to cap that inlet on the plenum or you have just created a vacuum leak.

        Hope that helps,,, its really all a form of the classic PCV system found on pretty much every engine made sinsce the middle '70s.
        None of it is necessary for the S14 to run, but I think you want your crancase vented somehow.

        I think you would see pumping losses with a sealed crancase and I'm betting oil leaks at various seals and gaskets soon afterwards from crankcase pressurisation resulting from blowby.
        You could concievably make a baffled breather and just put it on that valve cover port with no line,,, but then all drainback from the cambox must flow back to the front of the cambox. This way its got an escape path fore & aft.

        Cheers
        jimmy p.
        jimmy p.
        87 E30 M3 Prodrive British Touring Car
        88 E30 M3 Zinnoberot - Street
        88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
        92 E30 M Technic Cabrio - S14 POWERED!
        98 318Ti M44, Base - Morea Green
        04 Ford F350 - V10

        Comment


        • #5
          Don't block either the crankcase vent or the top vent.

          A month ago I had a bottom end knock after some enthusiastic track time .
          I was using a Ford Zetec powered se7en.
          This engine has a similar dual upper and lower ventillation system and is a DOHC 16v unit like the S14.
          The engine gradually lost power and vented oil until the knock began.

          Post mortem showed bearing damage from oil starvation of the bottom end despite there being 4.5 quarts of oil in the engine.

          What caused the problem was a pinched lower vent hose.
          This resulted in high crankcase pressure which kept all the oil up in the head. this would then vent out the upper hose.
          Obviously, the lower CCV was essential for oil circulation as it creates a lower pressure chamber to facilitate oil drain back to the sump.

          The moral of the story is ... Don't second guess the factory engineers.

          m

          Comment


          • #6
            [i]
            All my cars have all evaporative controls severed from the plenum. All that gets in the engine is clean filtered air. Everything else is venting to atmosphere as God intended back in the '60s.

            Cheers
            jimmy p. [/B]
            I am not a treehugger, neither do I agree with some environmental policies, but don't you think that's a bit of a one way route?
            Where will our children get all the clean air from for their engines if we keep blowing all the crap in the atmosphere? (or your engine?)

            I know it's only a very very small percentage of "racing" cars doing this, but would it be such a loss in performance????


            Goodbye M3, you served me well.

            Comment


            • #7
              Originally posted by jimmy p.
              Ok I'll take a crack at this as it seems the vacuum plumbing on the S14 presents alot of mystery to alot of people.
              Its pretty straight forward.

              The system is really no different than the system on a similar year say Chevy small block V8.
              In any stock US engine setup, (for pretty much anything post 1973) the tree huggers dont want any raw crankcase or raw fuel tank vapors venting to atmosphere. So to prevent that they have ducted all this crap back into your engine.
              See the charcoal canister feeding into the plenum as well as the vent from your oil separator.

              The S14s oil separator is nothing more than a German version of a PCV valve.
              It separates liquid oil back to the sump, and ducts the oil vapors, blowby, etc back to the plenum (bad).
              Ever notice that oily film inside your plenum, thats blowby and crankcase vapor. Bad, bad, bad for octane. Nothing lowers gasolines octane like oil vapor (or oil),,,, but the treehuggers dont want that nasty unburned stuff in our atmosphere so they think its better for you to try and burn it (again) in your nice clean engine.
              Now that we have basic evaporative management covered...

              The line that comes off the valve cover plumbs that liquid oil from the cambox and any crankcase vapors down to the oil separator which does its job very well.
              It ducts the vapors UP, and the liquid oil back to the sump.

              What I have done, and suggest for everyone,,, is take the line off the bottom of the plenum and put a small K&N filter on it venting it to atmosphere. I retain the oil sep, and let it do its job of taking the overflow oil back to the sump.
              I see no benefit in just routing to a catch tank, in fact I have done away with the classic Grp A catch tank on my Touring Car and actually added a stock oil separator to that motor. Its working flawlessley.

              All my cars have all evaporative controls severed from the plenum. All that gets in the engine is clean filtered air. Everything else is venting to atmosphere as God intended back in the '60s.

              Just remember on the stock type AFM system, if you do this anytime you sever a link to the evap systems you need to cap that inlet on the plenum or you have just created a vacuum leak.

              Hope that helps,,, its really all a form of the classic PCV system found on pretty much every engine made sinsce the middle '70s.
              None of it is necessary for the S14 to run, but I think you want your crancase vented somehow.

              I think you would see pumping losses with a sealed crancase and I'm betting oil leaks at various seals and gaskets soon afterwards from crankcase pressurisation resulting from blowby.
              You could concievably make a baffled breather and just put it on that valve cover port with no line,,, but then all drainback from the cambox must flow back to the front of the cambox. This way its got an escape path fore & aft.

              Cheers
              jimmy p.
              Thanks Jimmy.

              I guess I'll just figure out a way to put one of those little filters on both ports. I already have one of those little filters on the port off of the ICV. Sounds like my engine is going to look like a FnF engine.

              T:sosad:

              Comment


              • #8
                Anyhone have pics of where this filter would go?

                Comment


                • #9
                  Originally posted by HANDBLT
                  Thanks Jimmy.

                  I guess I'll just figure out a way to put one of those little filters on both ports. I already have one of those little filters on the port off of the ICV. Sounds like my engine is going to look like a FnF engine.

                  T:sosad:
                  Hey Tony,
                  Glad to help, I'm not sure if I understood where you were going to put the filter, but just keep in mind that if you put a filter on the "upper" one directly on the valve cover you are going to need to baffle it somehow as that cam box oil is going to be looking for somewhere to drain back to the sump under acceleration.

                  I'd personally consider leaving the oil separator on there and adding a bung to the valve cover if it does not have one plumbing from the rear of your new valve cover to it,,, then put the filter on the vapor side of the oil sep.

                  FWIW, I did away with my ICV too....

                  Let me know if I can be any more help.

                  I have a photo of how I did mine, (utilising the old bracket for the ICV as a matter of fact. Its perfectly located) but dont have it posted up anywhere.

                  Cheers
                  jimmy
                  jimmy p.
                  87 E30 M3 Prodrive British Touring Car
                  88 E30 M3 Zinnoberot - Street
                  88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
                  92 E30 M Technic Cabrio - S14 POWERED!
                  98 318Ti M44, Base - Morea Green
                  04 Ford F350 - V10

                  Comment


                  • #10
                    Originally posted by jimmy p.
                    Hey Tony,
                    Glad to help, I'm not sure if I understood where you were going to put the filter, but just keep in mind that if you put a filter on the "upper" one directly on the valve cover you are going to need to baffle it somehow as that cam box oil is going to be looking for somewhere to drain back to the sump under acceleration.

                    I'd personally consider leaving the oil separator on there and adding a bung to the valve cover if it does not have one plumbing from the rear of your new valve cover to it,,, then put the filter on the vapor side of the oil sep.

                    FWIW, I did away with my ICV too....

                    Let me know if I can be any more help.

                    I have a photo of how I did mine, (utilising the old bracket for the ICV as a matter of fact. Its perfectly located) but dont have it posted up anywhere.

                    Cheers
                    jimmy
                    I going to just plumb from the new port over to the existing hose that went to the old valve cover. When I get more time I'll reroute the line to make it look perty..........

                    T

                    Comment


                    • #11
                      Here is what I have come up with for now:





                      Here is the ICV filter:



                      Here is the port from the seperator that I'll prolly put a filter on instead of porting it back into the intake.



                      Is it the return of the vapors that cause the inside of the TB's to get tlike this?





                      Any ideas would be great, thanks.

                      T

                      Comment


                      • #12
                        <<< Is it the return of the vapors that cause the inside of the TB's to get tlike this? >>>
                        Yes

                        Ever since I did that mine are dead clean, no oily residue.

                        FYI - You will find if you replace the stock vapor line with a piece of standard 3/4" (I think,,, might be 5/8") line there is a K&N filter that is a pop in.
                        The way that stock line enlarges for the stock plenum there are none of the small K&Ns that are a pop in.

                        Cheers
                        jimmy
                        jimmy p.
                        87 E30 M3 Prodrive British Touring Car
                        88 E30 M3 Zinnoberot - Street
                        88 E30 M3 Lachsilber - Race (#98 SCCA SPU)
                        92 E30 M Technic Cabrio - S14 POWERED!
                        98 318Ti M44, Base - Morea Green
                        04 Ford F350 - V10

                        Comment


                        • #13
                          I just pulled my bellows hose (large diameter ridged hose to the throttlebodies on stock motor) and I see the residue you are referring to. When I saw it I was wondering what it was and this thread has been very informative. Thanks...

                          I really like the idea of disconnecting this to the bellows and adding a filter...

                          Then you could just clean your filter periodically.
                          Petro

                          Comment


                          • #14
                            Sorry for the pics not showing up anymore, roadfly sucks.

                            T

                            Comment


                            • #15
                              I understand what to do with the hose going to the bottom of the plenum (put a filter on it) and to leave the valve cover hose alone...but what about the hose on the front of the plenum with the 90 degree elbow. It looks like it goes to the ICV. Where can you get this filter, btw?

                              Secondly, what are all the pros and cons of removing the ICV. Is it OK for a car with A/C? Can someone writeup how it's done? Is there an electrical trick you need to do for the DME? I remember german John saying something about how the ICV can help on down shifts or something like that.
                              "It is needless to say that self-propelling vehicles, like other machines, will never do as much for one who does not understand them as for one who does."

                              Comment

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