Announcement

Collapse
No announcement yet.

look what I found lurking in my 3rd stage head (MCH5)

Collapse
This topic is closed.
X
This is a sticky topic.
X
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Re: look what I found lurking in my 3rd stage head (MCH5)

    Originally posted by cowboy View Post
    I don't know if I agree with you on that flatracker this being a coltri they are used for breathing air so I am sure that in the air application the blowby is not run to the intake as that would end up having to be removed before it would be breathing quality air.
    There IS actually a tube that runs from the sump to the intake of the first stage so that it can suck up the oil mist. This is called top lubing and is what will get some oil to the top ring or two on the piston. That bit of oil is moved to the second stage for top lubricating there and then to a separator to remove the excess. The air then goes to the third stage where oil is "splashed" into the lubricating area and there is a drain like to allow excess to flow off and back to the sump. Oily, wet air is then sent to a coalescer where it it is battered around and most of the condensate is removed. From there it goes to a chemical tower where the remaining oil and water is processed/removed.
    Ray Contreras
    CompressorStuff.com

    Comment


    • Re: look what I found lurking in my 3rd stage head (MCH5)

      ok I stand corrected. I have not fooled with many coltris and not any for breathing air

      Comment


      • Re: look what I found lurking in my 3rd stage head (MCH5)

        Originally posted by cowboy View Post
        ok I stand corrected. I have not fooled with many coltris and not any for breathing air
        One of the reasons most breathing air compressors call for synthetic oil, this oil mist especially when nitrox blending is involved can form a combustible mixture.

        Comment


        • Re: look what I found lurking in my 3rd stage head (MCH5)

          Got more spare parts... 3x crankshaft bearing, 3x crankshaft bearing spacers, 6x 1st/2nd/3rd stage wrist pin bearings, 4x main shaft bearings (front and rear),2x rear main oil seals ...265$

          20150421_114907.jpg
          Last edited by trdscfjc; 04-21-2015, 12:59 PM.

          Comment


          • Re: look what I found lurking in my 3rd stage head (MCH5)

            Originally posted by flatracker View Post
            One of the reasons most breathing air compressors call for synthetic oil, this oil mist especially when nitrox blending is involved can form a combustible mixture.
            During the 70s, 80s and 90s dive shop owners became intimately familiar with their compressors because of natural mineral oils and the fouling it caused. Carboning up was a big problem and valve changes were a routine thing. Synthetic oil really cut that to a minimum.
            Ray Contreras
            CompressorStuff.com

            Comment


            • Re: look what I found lurking in my 3rd stage head (MCH5)

              Originally posted by rcontrera View Post
              During the 70s, 80s and 90s dive shop owners became intimately familiar with their compressors because of natural mineral oils and the fouling it caused. Carboning up was a big problem and valve changes were a routine thing. Synthetic oil really cut that to a minimum.
              The group III hydrotreated mineral oils they have now are as heat resistant as all but the high end synthetics but everyone is fully on the synthetic band wagon now. That said brits compressor had to be seeing some very high temperatures to form carbon in that valve in a non oxygen enviroment.

              Comment


              • Re: look what I found lurking in my 3rd stage head (MCH5)

                Originally posted by trdscfjc View Post
                Got more spare parts... 3x crankshaft bearing, 3x crankshaft bearing spacers, 6x 1st/2nd/3rd stage wrist pin bearings, 4x main shaft bearings (front and rear),2x rear main oil seals ...265$

                [ATTACH=CONFIG]4953[/ATTACH]
                was the bottom end shot? or are you just changing everything?

                Comment


                • Re: look what I found lurking in my 3rd stage head (MCH5)

                  Just figured since I got it out gona change everything...

                  Also found this in a box on my porch...

                  20150422_003511.jpg

                  Comment


                  • Re: look what I found lurking in my 3rd stage head (MCH5

                    Just a quick but important note about the crankshaft bearings...

                    These are no longer produced by INA or FAG as far as the shop was able to find, the only company making this bearing is IKO out of Japan (very high quality)

                    The main hub for my bearing supplier did have them in stock so not really a issue for me but they did have to do some digging to find out what it was as there was no part numbers on the oem bearings, these IKO's are marked RNAF354716

                    Comment


                    • Re: look what I found lurking in my 3rd stage head (MCH5

                      I haven't examined either one of your or Brits machine but from what I can glean it seems to be a worn third stage causing the reduced pumping and the 2nd stage rod bearing problem is a wear issue of its own

                      Comment


                      • Re: look what I found lurking in my 3rd stage head (MCH5

                        I do know if the third stage pressure backs up in to the second it will wipe out the rod. this is what happened to daves compressor.

                        Comment


                        • Re: look what I found lurking in my 3rd stage head (MCH5


                          I do know if the third stage pressure backs up in to the second it will wipe out the rod. this is what happened to daves compressor.
                          I had it that over pressure would throw the pressure switch but clealry not.

                          Believe me on this but i never thought I would utter these words "Red-or-Dead, but I too am about to put my Red head on. Only my 'ghast is blabbered'. One of the 6mm Allen/Hex bolts is stuck fast. As i write this I see a rounded off hex, a 3/8" allen fails to turn in the 6mm hex too. A 7mm hex hammered in has jsut started to move it. I'm not sure how this came to be but one bolt was torqued down good and proper. I was taking my head off a factory-new pump? Hey-ho, anyway it is off.

                          So flatracker, you have two of us to test your theory out on. And I suspect you're be right...

                          Thank you for the bearing information. We really should start a thread on what fits what, namely which Bauer parts are OK, what LF parts fit Coltri etc etc. I can't do one yet because whilst I have tried everything none of it worked!
                          Last edited by BritCNGUser; 04-23-2015, 06:58 AM.

                          Comment


                          • Re: look what I found lurking in my 3rd stage head (MCH5

                            Brit,
                            I encourage you to get some good readings off your blowby flowmeter prior to installing the new third stage redhead. On my coltri I take readings with less than 100 psi in the discharge hose to get a first stage blowby reading, I let it rise up to 700 psi and take another reading (from which I subtract the first stage blowby reading) to get the second stage blowby and I take a final reading above 3500 psi to get the third stage blowby (by subtracting the blowby recorded at 700psi).
                            In my case I get blowby of approximately 10 cu ft/hr per stage for a total of 25 to 30 cu ft hr but mine is an MCH 13 so yours should have different readings.

                            Comment


                            • Re: look what I found lurking in my 3rd stage head (MCH5

                              I encourage you to get some good readings off your blowby flowmeter prior to installing the new third stage redhead.
                              Against my better judgement waiting for one last fitting to arrive I ignored my own advice and yours and fitted my Red-Head. And now idiot that I am, I am paying the price.

                              I remind you at 200 bar I would see 3 and 28 bar respectively at 1st and 2nd stage and a pressure-up time of 3mins 15 with 2 x Maxifilter + a Omnitek 175 with my car disconnected. Fitted the red-head and saw an immeidate 50bar and climbing at my 2nd stage. This frightened me so I knocked it off. Ran again and thsi time the 2nd stage went to 40 bar and then in a second dropped to 28bar. I thought nothing does that except valves?

                              RedHeadMCH13.jpg

                              Stripped down my brand new valve assy. I was right. 1.10 & 1.11 (exhaust side) the star-plate etc were actually corroded and I'm far from sure why. I suspect remnant moisture from factory testing.
                              1.12 the inlet washer also fairly tarnished. Cleaned everythign up and this improved things. My 2nd stage sits at 35 bar, my 1st at 3.5 so runs to spec but my PU time is now way up at nearly 5 mins and I am not sure why. I thought the new barrel and rings (and valves) might need bedding in but 4 hours running and my PU time is still 5 mins. I will have another go at cleaning parts 1.10 & 1.12 and see what then. At the moment I was better off with my old head.

                              I have to say my red-head does not get instantly hot like the old type head used to, but my second stage does and runs hotter than the 3rd. I think I have inlet valve blowby on the 3rd but I'm guessing agian. I did notice a 'clonk' at 10-15 secs after start up but assumed thsi was the new 3rd stage piston (small bore) sliding-down and thumping the 3rd stg (large bore) pusher piston. At least I hope that is waht I was hearing, I have never heard that noise before? . I am going to run my inlet valve washer & exhaust star-plate over a carborundum stone I have. I worry about that clonk? Another strip-down then...

                              You'd have thought by now that doing this analytically would have sunk in as the way to go? Apparently not. I will NOW fit my flowmeter!!!!

                              I am losing the will to live here. I soldier on...

                              PS: Just checked my attachment. This board down-sizes the image so not as clear as I uplaoded. Readable... just, if you look at it a bit cock-eyed.
                              Last edited by BritCNGUser; 04-26-2015, 08:06 AM.

                              Comment


                              • Re: look what I found lurking in my 3rd stage head (MCH5

                                Ah dear. Spent a good 2-3 hours messing. Flowmeter lashed in for now although I intend to have it permanently fitted via some valves.

                                I got fair blowby.

                                Karl you say you see: 10 cu ft/hr per stage for a total of 25 to 30 cu ft hr??
                                Mine showed 21-22cu ft/hr at low pressure. Numbers hardly increased as pressure topped out to 28-30 cu ft /h so my blowby is coming mostly for the first stage. However my PU time has increased. Now at 4 mins 30 secs. Now it is the 3rd stage head getting hot whilst 2nd stage keeps relatively cool.
                                3 & 28 bar 1st & 2nd stage repsectively but a longer PU time. I now know I have fair bit of 1st stage blowby, and suspect the 3rd stage exhaust valve.

                                I spent a good hour with fine automotive type valve-grinding/ decoke paste polishing the 3rd stg exhaust valve seat and star washer which arrived corroded. It helped but still hasn't solved the issue. PU time now 4 mins, so still worse than the old type head. I am running ti now to see if the valves will seat with more running.
                                Last edited by BritCNGUser; 04-30-2015, 07:23 AM.

                                Comment

                                Working...
                                X