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  • Overheated SR20

    I was at ITR Expo this weekend. We got to run Autobahn full course which is pretty cool. Long story short, I overheated the engine. The temps were fine and then all of a sudden they skyrocketed. I immediately started short shifting and grannied it until I could get it off the track. After a ton of troubleshooting, I determined the power steering line got into the fans and stopped them spinning. The problems started to spiral after that.

    As it sits, I tested the engine for compression. 100, 80, 60, 120. The spark plugs were wet but not with all gas. I think some water was in there. 3 out of four coil packs have cracks in them.

    It looks like a head gasket to me. What do you guys think? The gauge read close to 250 for water temps by the time I was able to get it off the track.
    Chicago Region SCCA SM # 688 http://www.scca-chicago.com
    TSSCC SM # 688 http://www.tsscc.org

  • #2
    Sounds like the head gasket to me... from the few times I've done this .
    -Monty

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    • #3
      Originally posted by McCoy View Post
      Sounds like the head gasket to me... from the few times I've done this .
      Ouch! hopefully this is the last for me.
      Chicago Region SCCA SM # 688 http://www.scca-chicago.com
      TSSCC SM # 688 http://www.tsscc.org

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      • #4
        Okay, leak down test was bad. Looks like a rebuild is in the future. I kind of knew it was coming. I was having an oil leak from the timing chain cover area only when under boost. So some pressure had to be slipping past the piston rings.
        Chicago Region SCCA SM # 688 http://www.scca-chicago.com
        TSSCC SM # 688 http://www.tsscc.org

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        • #5
          I don't know what kind of power you might try to make with that motor on its next build, but keep in mind that overheated SR20 blocks that have been rebuilt to make high power sometimes have issues with the cylinder walls having been weakened from the past overheating and are more prone to mushrooming out near the deck under high power. Just an FYI.

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          • #6
            What's "high power?"
            '18 Chevrolet Volt - Electric fun hatch for DD duty!


            DefSport Koni Sleeve and Spring Perch Buy!!!
            http://www.nissanroadracing.com/showthread.php?t=5902

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            • #7
              IIRC, around 500 whp is where that problem shows up. I imagine some detonation with 400 whp would produce similar results. The aluminum gets soft from having been overheated, and is more likely to become malleable and mushroom out at high cylinder pressures. There were some pictures floating around at some point, but I don't recall where they were.

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              • #8
                Sounds about right. Temps over 350 deg F will start to anneal the aluminum, making it weaker.
                '18 Chevrolet Volt - Electric fun hatch for DD duty!


                DefSport Koni Sleeve and Spring Perch Buy!!!
                http://www.nissanroadracing.com/showthread.php?t=5902

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                • #9
                  Thanks for the heads up. It only went up to 250 degrees as far as I could tell. I was at a mild 296 WHP. I am putting in 256/264 cams during the process but I'm still looking at a max of 330 WHP, more realisticly just over 300. The shop seems to think I am better off just having this one rebuilt as opposed to sourcing another engine that could already have problems.
                  Chicago Region SCCA SM # 688 http://www.scca-chicago.com
                  TSSCC SM # 688 http://www.tsscc.org

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