Announcement

Collapse
No announcement yet.

Nice "lightweight" piston

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Nice "lightweight" piston

    Here's a #4 piston I just pulled from a 99 motor. Nice eh?
    I drove the car about 100 miles and it ran like a top, sold the engine to a friend then it started making noises. I gave him his $ back. I think the piston was deteriorating the whole time. Heat 'exhaustion' perhaps?? Ben, ever see these on #4? The rest of the parts look fine. Cyl walls are good.
    Anyone need a block? Crank? :lol:

    [attachment=136]
    sigpic

  • #2
    RE: Nice "lightweight" piston

    well there's your problem!
    ~Andrew
    Atlanta Region SCCA
    D Prepared Miata

    Comment


    • #3
      RE: Nice "lightweight" piston

      LOL...pretty sure about that??

      Engine had 80k on it so it wasnt from excessive mileage.
      sigpic

      Comment


      • #4
        RE: Nice "lightweight" piston

        Dang. Was that car forced induction?
        DIYAutoTune.com

        | 10AE-T | BEGi S4 | GT2560r | Enthuza | 6UL | MS3Pro PNP|
        | 2001 Track Rat | Enthuza | Jenvey | MS3Pro PNP | Exocet in Progress|
        | 1992 323 | Wrong-wheel-drive Miata Endurance Racecar|

        Comment


        • #5
          RE: Nice "lightweight" piston

          Originally posted by ben91
          Dang. Was that car forced induction?

          Nope. Just a plain old street driven stocker.
          Owned by an older fellow.
          sigpic

          Comment


          • #6
            RE: Nice "lightweight" piston

            are you positive the rod is straight? would not take a whole lot for the skirt to hit the counterweights on the crank.

            gave his money back? good for you man.
            The only thing that oughta be hella flushed is a toilet.
            http://www.miataramblings.blogspot.com

            Comment


            • #7
              RE: Nice "lightweight" piston

              The rod appears straight to the naked eye.
              The rotating mass in the shortblock assy turned nice and free and seemed fine too when assembled.
              Whe running the noise sounded like a wrist pin and indeed, it was related!
              I see a mark or two on the counter weight but nothing real conclusive to my eye.
              Just the skirt pieces dropping off at XXrpm could cause some marks.
              There are a couple marks in the area of another cyl counterweight too.
              sigpic

              Comment


              • #8
                RE: Nice "lightweight" piston

                I would guess just a defective piston...
                The only thing that oughta be hella flushed is a toilet.
                http://www.miataramblings.blogspot.com

                Comment


                • #9
                  RE: Nice "lightweight" piston

                  that's crazy. Had it ever been overheated? I've seen #4 piston problems on miatas before, but never quite like that. It didn't burn, it wasn't smashed, it looks like a clean break. It COULD just be a factory defect...
                  ~Andrew
                  Atlanta Region SCCA
                  D Prepared Miata

                  Comment


                  • #10
                    RE: Nice "lightweight" piston

                    Not knowing all the history of the car I dont know if had ever been overheated or not.
                    The owners had reciepts for various service items done and everything looked normal there.
                    Another tidbit...looking at the top of the piston, the #4 had the least carbon buildup of any, almost none.
                    sigpic

                    Comment


                    • #11
                      RE: Nice "lightweight" piston

                      lack of carbon points towards HG. broken *** piston points to... I dunno
                      DIYAutoTune.com

                      | 10AE-T | BEGi S4 | GT2560r | Enthuza | 6UL | MS3Pro PNP|
                      | 2001 Track Rat | Enthuza | Jenvey | MS3Pro PNP | Exocet in Progress|
                      | 1992 323 | Wrong-wheel-drive Miata Endurance Racecar|

                      Comment


                      • #12
                        RE: Nice "lightweight" piston

                        Exactly... broken HG can lead to over-heating, and at least in the early miatas (I'm not terribly familiar w/ the NB motors), Cylinder #4 was the one most prone to suffer damage from heat, but usually only in F/I applications. Though, if it overheated at some point in its life, I can see that piston being weakened and, though it's a stretch, eventually falling apart.
                        ~Andrew
                        Atlanta Region SCCA
                        D Prepared Miata

                        Comment


                        • #13
                          RE: Nice "lightweight" piston

                          :jawdrop: god damn

                          Comment


                          • #14
                            RE: Nice "lightweight" piston

                            Wow! I'm glad that didn't happen to my piston when rod #1 bent and the piston and counterweight "contacted" each other.

                            Originally posted by miata5620
                            Eric's Garage ... You buy all the parts I tell you to and you will have a killer car... If you want other parts used your car will suck and it will cost you more...

                            Comment


                            • #15
                              RE: Nice "lightweight" piston

                              Originally posted by metalman
                              I gave him his $ back.
                              reason number 596 why to buy parts from metalman...
                              1995 Triple Black Miata

                              Comment

                              Working...
                              X