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Have to tear the motor down for rebuild..

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  • Have to tear the motor down for rebuild..

    I've lost ~30psi compression (some worse, some less) across all six... still acceptable compression, but in the little bit of mileage I've put on this motor between tests, not acceptable.

    It's getting lots of blow-by. Smoke coming out of the valve-covers and blowing the dipstick out. I can feel the engine pulsing through the covers as well.

    Burns oil as soon as you start it as well... fouling out the plugs too.

    And it's also developed a rod-knock. pretty badly too.

    All of this is pointing at something in the oiling system, to me.


    so, 15k miles on this engine, and it's down for a rebuild.
    vg33et -blew some chunks outta it, then gave it all away.
    2009 370z touring/nav/sports

  • #2
    OUCH!!! That's awfully depressing.. I didn't replace the oil pump in the vg30 when i built it -- hope it doesn't bite me in the ass. I would have replaced it but my poor buddy who owns the car was expecting to spend much much less than he has so far.
    8.5 custom arias pistons (.020 over)
    eagle rods
    t70 turbo (man was that a squeeze)
    38 mm external wastegate
    mild port/polish
    3 angle valve job
    custom intercooler piping
    twin external intakes with z32 maf
    rad moved back
    3" exhaust with only a resonator
    romulator
    420cc injectors
    custom body work, homemade oil lines and fittings..
    walbro 255lph in-line fuel pump.... and lots of headaches... lol

    Comment


    • #3
      how was oil pressure? aside from oiling problems like sludge or blocked passages, was everything cleaned/flushed before?

      there's first of all no way 15k should wear out rings so much to have blowby.... but having excessive blowby does cause a bit of oil cooking, especially where there isn't that much

      also I'd really like to know if you you were running hot/lean

      Comment


      • #4
        I put a HP/HV pump in it when we built it.

        Oh, I'm adding it up, and I'm going to have another 2-3k in it by the time that I'm done.
        vg33et -blew some chunks outta it, then gave it all away.
        2009 370z touring/nav/sports

        Comment


        • #5
          G-E wrote: how was oil pressure? aside from oiling problems like sludge or blocked passages, was everything cleaned/flushed before?

          there's first of all no way 15k should wear out rings so much to have blowby.... but having excessive blowby does cause a bit of oil cooking, especially where there isn't that much

          also I'd really like to know if you you were running hot/lean
          not running hot/lean at all. Only 4-6psi of boost w/ a walbro. shouldn't have been a problem, plus I was watching the LM-1.

          Oil pressure, is still well above FSM specs.

          the whole engine was pretty much new.. but yeah, we tore it down and had it cleaned.

          *edit* as an addition.. the compression tester was coming back with good amount of oil on it from some cylinders.
          vg33et -blew some chunks outta it, then gave it all away.
          2009 370z touring/nav/sports

          Comment


          • #6
            rings may not have seated right...
            BLOZ UP.com
            It is not recommended to confirm proper installation by driving into walls or other barriers as this could cause personal injury or damage to the vehicle.

            Comment


            • #7
              BLOZ UP wrote: rings may not have seated right...
              unfortunatly, sounds like it

              Terrible idea putting those wheels on...

              Comment


              • #8
                motor was perfect until the upgraded turbo. Hell, during that whole ordeal, I tested compression, averaged ~181psi
                vg33et -blew some chunks outta it, then gave it all away.
                2009 370z touring/nav/sports

                Comment


                • #9
                  try nissan rings this time? heh

                  Comment


                  • #10
                    heh, they were nissan rings.
                    vg33et -blew some chunks outta it, then gave it all away.
                    2009 370z touring/nav/sports

                    Comment


                    • #11
                      then all I can think is you didn't break it in properly

                      Comment


                      • #12
                        I've got some spare Total seal rings laying around here for sale... Didn't use them cuz file to fit was just tooooo much of a PITA.
                        It's RWD in reverse.

                        Comment


                        • #13
                          it's not that difficult.. i just use a ring file... takes about an hour to do all the rings perfectly. Less time if you've done it before... took me an hour to file fit and assemble the bottom end of a 4g63.
                          8.5 custom arias pistons (.020 over)
                          eagle rods
                          t70 turbo (man was that a squeeze)
                          38 mm external wastegate
                          mild port/polish
                          3 angle valve job
                          custom intercooler piping
                          twin external intakes with z32 maf
                          rad moved back
                          3" exhaust with only a resonator
                          romulator
                          420cc injectors
                          custom body work, homemade oil lines and fittings..
                          walbro 255lph in-line fuel pump.... and lots of headaches... lol

                          Comment


                          • #14
                            G-E wrote: then all I can think is you didn't break it in properly
                            I'd say ~15k miles is broken in.

                            I've got some spare Total seal rings laying around here for sale... Didn't use them cuz file to fit was just tooooo much of a PITA.
                            Thanks, but I'll get them with the pistons.
                            vg33et -blew some chunks outta it, then gave it all away.
                            2009 370z touring/nav/sports

                            Comment


                            • #15
                              If you call Beeri at Arias he's already got a set of +0.5mm VG33ET 8.5:1 compression forged pistons designed. They use the 21mm stock rod pin diameter too, which is nice. The pins is tool steel, and narrowed for weight.

                              On my set, there's never any piston clatter. Also, clearly, I had them coated at Swain, which isn't included in his price.






                              It's RWD in reverse.

                              Comment

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