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zero compression in 5 out of 6 cylinders

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  • zero compression in 5 out of 6 cylinders

    A gentleman in California gave me a '64 Commander 4 door with a six and a automatic.He told me his brother had just rebuilt the car when it had 200 mies on it and "developed a flex plate knock" after 200 miles. The brother refused to dial indicate the new bell housing. The car was parked for years. I got it home and tried to start it. Good fuel, spark, nothing worked. I just did a compression test. first cylinder = 120 lbs. All the rest of the five others = zero to 5 lbs. I see the piston tops. they aren't broken. The rockers go up and down, with about 26 thousands play at the rocker. The engine is very clean, found an old fel-pro gasket set box in the trunk. Empty. Any thoughts?

    Kelly J. Marion

  • #2
    Did the valves move with teh rockers? It sounds sort of like stuck valves.

    Ron Dame
    '63 Champ
    Ron Dame
    '63 Champ

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    • #3
      First, are you sure you haven't got a problem with your compression tester, i.e. leaking release valve, etc? If that's not the case, maybe you've got valves gummed/not seating due to rotten fuel (hard to imagine on 5 cyls, though). A leakdown test would confirm any suspicions you may have. LH

      Straight from the horse's mouth
      Whirling dervish of misinformation.

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      • #4
        Maybe the valves aren't seating or the rings have yet to properly score the cylinders.

        I'd perform a leak down test and see what happens.

        http://community.webshots.com/user/s...host=community

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        • #5
          Worse case scenario, the 5 pistons are stuck in the up position as the connecting rods came loose from the crankshaft, thus making a 'knock' at 200 miles. [:0]


          1949 2R17
          R is for Rusty

          In the middle of Minnesota
          sigpic
          In the middle of MinneSTUDEa.

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          • #6
            watched the valve stems come up and down and contact the rockers., can't say the valves are seating properly on their seat, though. Watched the pistons go up and down in the cylinders while all the plugs were out doing the compression test. Bad head gasket? cylinder bolts not torqued down? cracked head??????

            Kelly J. Marion

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            • #7
              No pistons?

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              • #8
                Stick your thumb in the spark plug hole and see if the pressure can push past your thumb. If it can, you're good to go. If you can't feel any pressure; and at five pounds, you hardly would, I would take a pair of channel locks and spin the valves while they're closed. They probably have rust on them. That would account for the extreme clearance as well.

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                • #9
                  It's hard to imagine 5 of 6 being that low. Could the knock have come from a bad timing gear? It would seem that the cam timing would have to be off if you can see the valves and pistons moving yet have no compression at all on 5 cylinders. Bring the engine around to the timing mark. Then check to see that the distributor rotor is pointing to the #1 cap position, or 180 degrees out.

                  Jim Bradley
                  Lewistown PA
                  '78 Avanti II
                  Jim Bradley
                  Lake Monticello, VA
                  '78 Avanti II
                  sigpic

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                  • #10
                    Did the car run when they parked it?
                    Is it possible to have the valve timing way off but yet have compression on one cylinder?



                    1949 2R17
                    R is for Rusty

                    In the middle of Minnesota
                    sigpic
                    In the middle of MinneSTUDEa.

                    Comment


                    • #11
                      The man gave me the car, but his story is murky. Brother rebuilt it. Brother drove it 200 miles with an ever worsening knock. The man who gave it to me said it was a flex plate and he works on, and owns many Studes. I paid zero (except for the 9i+*27t^*n9 California speeding ticket going over 55 with a trailer, another story). He had no incentive to fib. First time I tried to start it, nothing, nada. Yesterday we ran a compression test 120, 5, 0, 0 5, 0. The cylinder with "0", no pressure out of the spark plug hole. Loose cylinder head? broken/stripped cam gear? Never seen this before. Any ideas? Tear the head off? How to check the cam gear on a "6"? I've seen valves stick after sitting, but five cylinders out os six?

                      Kelly J. Marion

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                      • #12
                        If everything is in time, then the cylinder with compression should fire. Being that it is not firing, it leads me to believe the camshaft is out of time.


                        1949 2R17
                        R is for Rusty

                        In the middle of Minnesota
                        sigpic
                        In the middle of MinneSTUDEa.

                        Comment


                        • #13
                          Doesn't really matter what MAY...be the problem..!
                          With numbers like that, it requires at least a head removal for head and block inspection.

                          You (others) can guess till a herd of cows walk Hollywood Blvd., you need to actually find the problem, the head is the first place to look.

                          Mike

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                          • #14
                            Guessing? I dont physically have the car in front of me so what choice do I have? [8D] If everything is in time, the pistons go up and down as do all the valves, then you should get at least some compression. Right? Just a guess....


                            1949 2R17
                            R is for Rusty

                            In the middle of Minnesota
                            sigpic
                            In the middle of MinneSTUDEa.

                            Comment


                            • #15
                              Interesting problem. I've never seen anything like this. The head comes off tomorrow (after I check to see that the head bolts are tight. Just thought I was missing something. I'll let you know, if interested.

                              Kelly J. Marion

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