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rings won't seat?

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  • Engine: rings won't seat?

    I am contemplating buying a car, for the sake of argument and to keep in in the tech section let's say it is a 6 cylinder Lark. (This will apply to Studebakers anyway).

    The current owner had the engine rebuilt about 10,000 miles ago with chrome rings and running dino oil only. It smokes, has low compression, but runs well otherwise. a bit of oil in the cylinders raises the compression, so it sounds like the rings failed to seat.

    Odds are I'll end up tearing the engine down, but until I do, I have nothing to lose. So does anyone have any tricks to seat them first?
    Ron Dame
    '63 Champ

  • #2
    Originally posted by Ron Dame View Post
    I am contemplating buying a car, for the sake of argument and to keep in in the tech section let's say it is a 6 cylinder Lark. (This will apply to Studebakers anyway).

    The current owner had the engine rebuilt about 10,000 miles ago with chrome rings and running dino oil only. It smokes, has low compression, but runs well otherwise. a bit of oil in the cylinders raises the compression, so it sounds like the rings failed to seat.

    Odds are I'll end up tearing the engine down, but until I do, I have nothing to lose. So does anyone have any tricks to seat them first?
    Unfortunately chrome rings usually seat right away (100-200miles) or not at all. The cylinders glaze easily. You might try using a non detergent oil and driving it HARD. Randy

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    • #3
      bon ami powder down the carburetor while its running at high idle...........................don't shoot me its not my idea. Years ago I had a fresh bowtie overhaul that the rings never seated on. I tried this trick and it didn't work. Maybe I didn't use enough, maybe its a stupid idea but it maybe a good last resort. If the rings didn't seat you likely have too much bore taper and you'll need a bore job anyway. I went on to put 150k on this bowtie all the while it used oil. Never smoked but fouled plugs like nobody's business. Anti fouling adapters on the plugs and the cheapest oil money could buy, hey it beat walking :-)

      Originally posted by Ron Dame View Post
      I am contemplating buying a car, for the sake of argument and to keep in in the tech section let's say it is a 6 cylinder Lark. (This will apply to Studebakers anyway).

      The current owner had the engine rebuilt about 10,000 miles ago with chrome rings and running dino oil only. It smokes, has low compression, but runs well otherwise. a bit of oil in the cylinders raises the compression, so it sounds like the rings failed to seat.

      Odds are I'll end up tearing the engine down, but until I do, I have nothing to lose. So does anyone have any tricks to seat them first?

      Russ Shop Foreman \"Rusty Nut Garage\"
      53 2R6 289 5SpdOD (driver)
      57 SH (project)
      60 Lark VIII 2dr sd (driver)

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      • #4
        I've used the Bon Ami trick twice with success. Just remember to change your oil after doing it.

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        • #5
          The only thing that seats rings, is pressure. Pressure that comes from the gas pedal.
          The compression gets behind the rings and forces them out to the cylinders harder than just their spring load. The extra load forces the wear required to mate the rings to the cylinders. If this does not occur within the first 300 to 500 miles, the sharp peaks formed in the cylinder walls during the honing operation are warn down and will no longer be available to wear the rings to match. I guess this is where someone came up with the term "glazing"...though it really doesn't fit the problem..!
          My guess is that the original honing of the cylinders did not have the correct stones used on it for the chrome rings, and the chrome never even had the chance to mate with the cylinders. This is actually fairly common.

          I would "NOT" put any abrasive (Ajax, Bon Ami, etc.) into the fuel system to crutch the ring wear. It will continue to put scratches in the cylinder walls in a vertical pattern which is NOT a good idea down the road a few hundred miles. Oil will continue to flow in these vertical grooves and end up on the wrong side of the rings and out the tail pipe.

          The simplest trial fix would be to get a "ball hone" (about $60) of a fairly rough grit, pull the pistons and rehone the cylinders at home. Clean everything well and put it back together. Your'e not out a big sum of money other than the hone, new gaskets, and a few hours of work.

          Mike

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          • #6
            I have no evidence but, The Bon Ami fix cant be a good thing as anything that gets on the rings is going to get in the ring lands.
            Ring lands are as important to ring seal as the cylinder straightness is.

            I would not do it, even on your motor.

            That is a used car back lot trick. Not for a motor that you would keep.

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            • #7
              Its a PITA re-doing someone else's work.

              The chrome is only in the top compression ring; low compression points to failure of both compression rings. Smoke points to other problems, i.e. oil rings. I doubt the only problem is the chrome rings won't seat, even if someone used a 320, or finer grit hone. (Shoulda used 220.) Its more likely due to a half a--ed, shade tree overhaul.

              I've used chrome rings in several Studes. They all took 2000-3000 miles to seat. The last set I used was in the 62GT's motor, about three years and 33,000 miles ago. Those rings took around 3000 to seat, but then yielded the best oil mileage I have ever gotten in a Stude (5700 miles per quart, per the maintenance log I keep).

              From now on, I plan to use nothing but moly rings, because one of their outstanding features is they seat quickly, and should be honed with a 400 grit hone (less friction/heat during break-in).

              As for the OP, simply trying to seat supposedly failed chrome rings, I agree with Mike: Remove the head, and re-hone with a 220 grit hone (ball type may not be aggressive enough). Bring each piston to bottom, and hone the cylinder as best you can.
              Last edited by JoeHall; 06-06-2015, 10:33 AM.

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              • #8
                My 2 cents, tear it down. hone cylinders with berry hone coarse.as you can buy, if cylinders are worn severly and you are a CASO like myself shop for Hastings rings. they have high unit pressure against the cylinder. once you wear out these rings you will need a re/bore and new pistons. Hastings rings are designed for worn cylinders and the Stude 6 has a wide ring that spreads the ring pressure and Hastings has re-thought this, thus higher than normal cylinder wall pressure is needed. been there done that, 62 OHV 6 .030 over ,turbo from corvair large side draft Bendix Stromberg carb, stick no OD , 373 gears and short wide tires. at 70,000 hard miles engine expired,think wife holed several pistons lugging it! cut huge ridge out replaced pistons in badly worn cylinders, hastings rings saved it for another 50,000 miles! Good Luck Doofus

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                • #9
                  I would not even use moly rings except perhaps in a tight tolerance rebuild.

                  For anything else just use a standard cast iron ring, much more forgiving.
                  Hasting is a fine product but may be hard to find.

                  Don't build it tight and don't baby the break in.

                  Follow your cam break in needs (the Joe Gibbs Break in oil can be a lifesaver)

                  Make sure your tune up is spot on during cam break in.
                  Fix any problems found first. Operating the motor on a bad tune will not be good for it.

                  Then take it out and drive it and romp it good, but not for a long time (you want to make power but control (restrict) heat).

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                  • #10
                    Gas in the oil will cause excessive smoking so if you have a bad tune up or an electric fuel pump that is not switched by oil pressure... Check that!

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                    • #11
                      The last engine I rebuilt. I used Mobil dino 10W30 oil (not Mobil 1). Compression was down 15 psi from what it should have been, and it blew plenty of blue smoke. I ran it hard for maybe 200 miles, no change.

                      So, I changed the oil to Delo 15W40. Compression immediately came up, zero blue smoke, and it uses no oil.

                      Go figure.

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                      • #12
                        The Bon Ami idea scares me, though it might work for a while. For the short term, I'll drive hard, maybe luging without detonation, to bring cyl pressures up an see what happens. Then this winter, pull it down and build it, doing what should have been done, like balancing, stacking and decking, etc.
                        Ron Dame
                        '63 Champ

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                        • #13
                          When I was high school age my cousin and his wife got a new '58 Chevrolet V8 stick. It was not performing as it should, rings possibly being the problem. They lived in the San Francsco area. It was suggested to take the car to Nevada, where at the time there was no speed limit. Take the car to its top speed and keep it there until the temperature started to rise. They did this and the problem was solved. Just a thought.
                          Perry
                          \'50 Business Champ,
                          \'50 Starlight Champ,
                          \'60 Lark Convertible,
                          \'63 GT R1,
                          \'67 Triumph TR4A

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                          • #14
                            From my notes, the Bon Ami story is true, although it was applied to freshly built aircraft engines during WWII. The story was that for a quick break-in, the plane was started and given the cleanser treatment before taxiing and taking off. The test pilot would monitor the engine temperature, which was always high on new builds. When it finally started dropping back to normal, the theory was that the metal to metal was worn smooth and efficiently broken in to allow the temperature to recede.
                            64 GT Hawk (K7)
                            1970 Avanti (R3)

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                            • #15
                              Are the rings not seated, or are they worn out?
                              Back in the 80's I knew a guy that didn't properly clean the cylinders he honed, and in one week the new rings were shot. He tried to blame the rings, so they sere sent back to the factory to be anylized, and the factory determined the cylinders were not cleaned well enough.

                              After honing, I use a rag soaked with gas and wipe out all the cylinders several times. I then use a clean rag with clean oil and give each cylinder a good dose of oil. The next day I reclean the cylinders with a white cloth, and you can see how much grit the oil has lifted. I reoil the cylinders and wipe again until the white cloth doesn't pick up any more grit. Most ring manufacturers tell you to use hot soapy water the clean the cylinders, but I don't like the rust that water leaves behind.

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