Announcement

Collapse
No announcement yet.

Replacing head gasket.

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

  • Replacing head gasket.

    I'll start off that this is about RB20DET, 1989 GTS-T 4 door.
    I am having a problem with my number 4 cyl, it's not I guess firing?

    This problem arose while I was just driving back from a party, I wasn't going fast, or driving hard and I rarely did, but when I parked my car to get some pizza with a buddy and got back in to drive home it started to run really rough, when at a light I could feel the entire car shake and rumble.

    I didn't think much about it, and I didn't really notice much of a power loss since I was just driving casually.
    When I dropped my buddy off I got out and listend for any knocking, nothing, sounded normal. Turned off the car, turned it back on and bam it worked fine, I drove it home thinking it was just maybe a wire got loose, or a hose blew off.

    In the morning I drove it to the store and it went back to the way it was, and it made a really loud rumble out the exhaust, I knew something was up.

    So I took it to my mechanic and he said the engine sounds fine, no knocking, and other than it shaking the car it runs smooth. He thought it was an electrical problem. So we did a strew of tests...

    First I replaced the ignition module, nothing.
    Second I replaced the wiring harness, nothing.
    Third I switched out a 'working' spark plug, put it in there and put the 'dead' spark plug into a 'working' cyl, still nothing.

    Did the same with the coil, nothing.

    I checked if there was a spark going to that plug, and yes there is.

    We were kinda baffled on what it could be, and he suggested a compression test. When he told me to do the test, I had just begun to get really busy with life and just put the car on hold, I parked it, and just forgot about it, went off to school and didn't touch it till about a month ago.

    There is no white smoke blowing out the back, and the car still runs like it did when this problem first occured.

    And here I am now. I was out waxing my baby and my uncle came over to see how I was doin with the car, he told me how the rings around the piston could be loose or broken, and told me that I can find this out by doing a compression test, if it's not the normal compression, then try either changing the oil or put a little down in the cyl. and then trying it again. I have yet to do this.

    But he suspects that the head gasket might be on it's last legs, whitch might make sense, after driving it around hte block or what ever, I notice I have a small oil leak, and my oil is really black now. I was planning on replacing the head gasket either way this summer. So my question really is this.

    If I were to replace the head gasket and the piston rings if needed, would I need to replace all my other gaskets? As the top of the engine will be alot more tight seal and fit, casuing the compression to be percise and more I guess tight, I am afraid the bottom will blow out if I get a brand new head gasket and neglect the bottom.
    Oakville Skyline owner, of 1989 GTS-T 4 Door.

  • #2
    yeah get a engine gasket kit from somewhere and change them all if your going thru the trouble of pulling the head. also make sure that the head isnt warpped when you take it off. it will probably have to be decked by a machine shop anyways. but as for replacing the piston rings, if your going that far upgrade to forgies otherwise that money and time will pretty much be wasted just replacing with stock. if stock is what your price range is then i would recommend looking for a replacement engine and just swapping.

    Comment


    • #3
      when a coil pack starts to short it is really intermittent, usually starts after it get warmer but depends.

      you can switch the coil pack to a different cylinder and check that way? but money is on a coil pack. the oil can be really dirty and have a fuel smell to it since the fuel would just wash past the ring on #4

      Comment


      • #4
        Originally posted by love_boost View Post
        when a coil pack starts to short it is really intermittent, usually starts after it get warmer but depends.

        you can switch the coil pack to a different cylinder and check that way? but money is on a coil pack. the oil can be really dirty and have a fuel smell to it since the fuel would just wash past the ring on #4
        I competely agree with love boost, don't go taking your head apart just yet, try changing out the coilpack with someone elses, if its miss-firing then and dropping fuel into your manifold your going to get a rough run feeling from that alone, not to mention the coilpack not firing... swap coil packs and take it for a testy. ALSO check for possible boost leaks, that can **** with the MAF/ECU making in run REALLY rich, do you smell fuel at all?

        Comment


        • #5
          I've always smelled fuel while driving, but never had a problem like this before. I thought it was just maybe the exhaust.
          It's just that one cyl, I am planning on changing my oil, draining everything and flushing it, then just taking out all my plugs and letting it dry for a night.

          I have swapped my coils, and I know there is spark going through that coil, they are brand new Yellow jackets and the wiring harness is brand new as well, the plugs are NISMO and only have about 8000kms on them, and my engine has never been raced, driven hard from me.
          Oakville Skyline owner, of 1989 GTS-T 4 Door.

          Comment


          • #6
            driveability concern

            your best bet to confirm no burnt valves or bad rings is a compression test and a leakage test, if your still weary about an ignition problem then if yo have access to a 4 or 2 channel oscilliscope the you can watch the wave form pattern for 2 coils and see if the signals screw up as well as the Kv going to each plug

            Comment

            Working...
            X