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first stage rings? mch 5

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  • first stage rings? mch 5

    Im' replacing the first stage rings. My question is the piston had 3 rings and the package I got has 4. 2 with holes and 2 without. The piston has a place that I could put the 4th ring below wrist pin.

  • #2
    one of the rings is a oil control ring (double ring with grooves)

    this ring is to be installed in only 1 direction, if you install it the wrong way and the oil wipe angle is the wrong way it will wipe the oil up into the compression chamber


    The wiper should be installed so the oil is wiped from the cylinder walls down to the crank case.

    Also note, the bottom of the standard rings has a groove on the bottom, this also acts as a oil wiper

    Skip ahead to 2:20

    https://www.youtube.com/watch?v=PkpppbZL8gQ




    Skip to 3:50 for the ring orientation (your rings may or may not have the white paint, if they do, the painted side faces up towards the valve)

    https://www.youtube.com/watch?v=VygSVXrse2M
    Last edited by trdscfjc; 06-07-2017, 12:34 AM.

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    • #3
      So looking at the rings through a loop I can see one side is straight and the other has a small bevel. So should the straight side go down?

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      • #4
        Also looking for the orientation of the first stage valve. There is an S on one side with 4 positions available. Intake side or outgoing? facing the piston or the head?

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        • #5
          Played this game twice with my first stage. I strongly recommend a Flexhone tool down the bore too. I have a permanent flowmeter installed off by crankcase, and it would fill with oil until I did. Likely the bore will be shinier than a new pin so the rings won't seat well. Had awful oil consumption with new rings even when fitted correctly. (Must have got it easy, my rings were marked TOP). Until I honed the bore oil use and pressure-up times did not improve. Proper Flexhones are best but as a minimum one those spring-loaded Tripod jobbies will do. Do it now or do it again! By the time I worked out the issue, I'd had a set of new rings in there for 50 odd hours, which weren't seating so I had to hone and put another set in. This was both a waste of time and a decent set of rings.

          See piccy for honing tool but money no object you want a set 3 x Flexhone for all three stages:

          BC 2 3/8” 60mm 240g S/C
          BC 1 1/2” 38mm 240g S/C
          BC14mm 240g S/C



          Rings1stStageColtriMCH5.png

          Hone.png
          Last edited by BritCNGUser; 06-08-2017, 11:06 AM.

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          • #6
            Ok I got my compressor running again but still have all the oil going into the 3rd stage filter. All the pictures I see of the rings show the 3rd one down as having 1 side shorter than the other and the ring set I got does not have that. The rings for the 3rd and 4th slot are the same with one side of the ring square and the other side with a slight bevel. I installed them with the bevel side up. Is this wrong? Does the hone tool come with instructions? If not I would most likely mess the machine up worst. This was my first time changing the rings on the first stage and it only had 3 rings not 4.

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            • #7
              image_5866.jpg Bevel down, sorry for the crappy drawing thus is how the oil control ring is to be installed.
              Last edited by trdscfjc; 06-10-2017, 10:50 AM.

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              • #8
                Btw, you can rent the hone tool for free at any autozone

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                • #9
                  I can assure you mine has 4 x rings. Can't tell you if part of yur problem is incorrectly installed rings, but as I said, happened with me, if those rings aren't seating you get a copper-bottomed guarantee you will dump a heap of oil in the filter regardless of how the rings are fitted. Using a honing tool of either description isn't a challenge. If the bore looks more like you've had it chrome-plated, and I suspect it does, it must be done. Blowby will be massive. If you have a flowmeter on the sump, you'll see it.
                  Honing: You can't horse it up provided you keep the tool moving to and fro. This to get the desired helical scratching effect you're after. The only way to 'Make a right Mons of it' is to not clean it properly afterwards and/or make the scratching non-helical. Non-helical could break rings, so keep briskly moving in and out with your tool (how fast depends on how you like your filth) . Hence you avoid parallel honing. Clean the thing with hot soapy water and a pot-brush, dry it quick. Oil it again even quicker before corrosion grabs the honing. Then you'll be dandy.

                  (I'd better translate - Mons was a British military disaster in the trenches of WW1)

                  I've banged on about htsi before, yet this is a classic example of how working on these units requires gauges on every stage and a flowmeter off the sump. Without these in combination, you're simply blind to what is happening when, or why. With a flowmeter on your sump, you'll know for certain which stage is producing that blowby and thus that oil. Whilst there is strong suspicion your first stage is the culprit, you'll never actually know. 'cos we've been before you, you're find yourself forever waving your willy at the wind trying parts until any logic goes out the window. Believe me, and trdscfjc will verify, we've been there!

                  Your next problem is likley to be that even when you've got it right, you won't know it for a tad, whereas a flowmeter will tell you right now where the issue is, and what is it is straight after your fix.
                  Else like me in the past, you could actually be working on the wrong stage, or find that stage only part of the issue. I've done this for certain.
                  Last edited by BritCNGUser; 06-09-2017, 09:57 AM.

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                  • #10
                    Prepared to be corrected, but I'm pretty sure bevel goes up. Gandini piston site has bevel-up and because second stage is definitely bevel-up, I reckon bevel-up on first stage too. Will check.

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                    • #11
                      interesting, i called the ring manufacturer here in the states and this was the orientation they gave me

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                      • #12
                        Got these images from Gandini's site. 1st & 2nd - Bevel-up. Bevel function is to aid quicker bedding-down, My understanding is that bevel-up acts as a pressure-relief until the ring seats and 'beds-down'. Hence by the time the bevel is worn away, the pressure-relief function is no longer needed. I think on a petrol/deseasel(sic) you would install bevel-down, for clearance of sludge. But I've been reading Wiki pages, so who really knows?

                        Coltri documentation has got much better, it was forever full of omissions and every contradiction, and the Gandini pages talk of different stages to those relevant here, yet my money is on bevel-up. BTW: Those rings that I have came marked as bevel-up.

                        https://www.gandini-industria.it/cat...i-sub/P366-000

                        https://www.gandini-industria.it/cat...-sub/P6075-000

                        But don't take that as the definitive answer either.

                        Depending on which end of the Coltri manual you read, and which version, rings are good for 250 or 500 hours and oil is good for 100, 250 or 500. And the rings have no orientation anyway. And whatever the latest parts books says, rings won't necessarily come marked, so by that logic, it matters not.

                        But me? I'm a ring-orientation whore. I'll go with anyone. Whenever it's a Tuesday.... I'm with you, bevel-down.

                        My latest ring-set are not marked.

                        This floozy will do more digging.
                        Attached Files
                        Last edited by BritCNGUser; 06-16-2017, 05:21 AM.

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                        • #13
                          im still looking into this as well

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                          • #14
                            OK, I have installed bevel up, bevel down, Honed the bore and still getting about an ounce an hour of oil in the filter.

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                            • #15
                              Originally posted by alpacafarmer View Post
                              OK, I have installed bevel up, bevel down, Honed the bore and still getting about an ounce an hour of oil in the filter.
                              About the only thing left in question is the cylinder wall finish. Brit is suggesting a 240 grit hone. That may be too coarse. Those three finger cylinder hones from the auto parts store are even coarser than that. Flex hones are available from about 120 grit on up to very fine 1200 grit. I would have used a 400 grit flex hone. What does the manufacturer recommend?
                              Last edited by hypermilinggx; 06-19-2017, 02:37 PM.

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