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

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

    Brit..when you hook up your new compressor it would be nice to know the readings of fill time, pressures at the stages, blowby, etc. This info would be nice to know.Thanks

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

      Agreed, I would like to know too. Problem, I have my Coelescing filter before my MaxiTower, and it is plumbed in rigid. So my PU times will be meaningless to you and all. There is solution, swap me your times with and without you Parker fitted. Thus we establish what the Parker adds, then I know what times to give you after subtraction of Parker etc. Thus we get like-for-like. I remind you I have 2 x Maxi + 1 x Parker (actaully Omnitek 175 but smae body) but I can omit the 2nd Maxi for times. I have a flowmeter comign next week. See...

      http://www.cngchat.com/forum/showthr...escing-filters
      Last edited by BritCNGUser; 04-07-2015, 06:40 AM.

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

        so did either one of you get your compressors repaired or just living with slow fills till it dies?

        Comment


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

          I am not convinced that installing a filter on the compressor outlet will have any effect on the output. Regardless of the filtration you install you should be able to pump at the same volume that you do just prior to shutdown at 3000 or 3600 psi.
          I mentioned the idea of a priority/backpressure valve in an earlier message as a means to keep the compressor running at the optimal pressure for balancing the load on each cylinder.. A highly restrictive filter is in effect doing the same thing as a priority valve just in a less precise manner.
          Since adding an inlet flowmeter and a blowby flowmeter to my coltri I do notice an increase in blowby cfm as the pressure rises above 1000 psi. I am getting approx 8cfh of blowby per stage. I have less than 20 cfh blowby below 1000psi and it increases to the mid to high 20's cfh as the pressure rises to 3000 psi.

          I can well imagine an inlet dryer/filter reducing the compressor output as it will struggle to intake adequate volume if the filter presents any restriction.

          I get the impression that your gas supply was adequate based on the manometer test you did. Personally I would put more faith in a pressure reading at the point of use to eliminate the possibility that the length of pipe between the gas supply and the compressor could be creating friction/drag/restriction.
          Cowboy has me sold on the concept of a pulse tank to ease the pressure pulses on the regulator. I can measure my pressure at my pulse tank without significant variation.

          Comment


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

            Originally posted by karl View Post
            I am not convinced that installing a filter on the compressor outlet will have any effect on the output. Regardless of the filtration you install you should be able to pump at the same volume that you do just prior to shutdown at 3000 or 3600 psi.
            I mentioned the idea of a priority/backpressure valve in an earlier message as a means to keep the compressor running at the optimal pressure for balancing the load on each cylinder.. A highly restrictive filter is in effect doing the same thing as a priority valve just in a less precise manner.
            Since adding an inlet flowmeter and a blowby flowmeter to my coltri I do notice an increase in blowby cfm as the pressure rises above 1000 psi. I am getting approx 8cfh of blowby per stage. I have less than 20 cfh blowby below 1000psi and it increases to the mid to high 20's cfh as the pressure rises to 3000 psi.

            I can well imagine an inlet dryer/filter reducing the compressor output as it will struggle to intake adequate volume if the filter presents any restriction.

            I get the impression that your gas supply was adequate based on the manometer test you did. Personally I would put more faith in a pressure reading at the point of use to eliminate the possibility that the length of pipe between the gas supply and the compressor could be creating friction/drag/restriction.
            Cowboy has me sold on the concept of a pulse tank to ease the pressure pulses on the regulator. I can measure my pressure at my pulse tank without significant variation.
            karl they seem unwilling to address the problem at hand which is severely reduced pumping rate of their compressor, they seem unwilling or unable to go back to basics and tear down the compressor, check clearances, replace the worn parts and get back to normal performance. throwing parts at the problem hoping for a miracle cure has resulted in the usual result.

            Comment


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

              Originally posted by flatracker View Post
              karl they seem unwilling to address the problem at hand which is severely reduced pumping rate of their compressor, they seem unwilling or unable to go back to basics and tear down the compressor, check clearances, replace the worn parts and get back to normal performance. throwing parts at the problem hoping for a miracle cure has resulted in the usual result.

              really? you must not of seen the pictures that i posted , i am tearing down my compressor, checking clearances and replacing worn parts....

              Comment


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

                Take a look at post #233 in this thread.

                Comment


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

                  Really? What is your piston to cylinder clearance, what is your ring gap, what did your third stage plunger mike at? Maybe you checked all these things and more and just didn't post them , if so I jumped to an erroneous conclusion.

                  Comment


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

                    An high pressure compressor is a very simple but precise piece of equipment. Visual inspection of parts as to go or no go specs is like looking at a CNG tank and trying to guess how much pressure is in it.

                    Comment


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

                      flatracker you are right.It is very hard to look a tank and guess how much gas is in it as I rode around in my van for a week or two with the transducer down. and even with filling up everyday I ran out twice.LOL

                      Comment


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

                        Karl: I can't see how adding 'filterage' will change anything either, perahsp I was not clear, all I was talking about was the order for better filtering and the added pressure-up times these give. I use pressure-up times as a quiclk way of diagnosing improvement/ decline. At the moemtn I have 2 x Coltri Towers + OmniTek 175 + PM/priority valve + long hose so we can't compare like-for-like with PU times.

                        Update: Having spent days on this previously I have not had time to really go into this anymore and flattracker is highly likely to be right. It needs stripping-down and looking at properly. I have just fitted a MCH 13 type priority valve purely becasue I'm committed to CNG and it seems like such a sensible idea even if a bit 'rearranging deckchairs on the Titanic'. I found a cheap used Dwyer 40- 400 scfh flowmeter on Ebay this week, these are cheap stateside but here go for crazy prices so I compromised on the 40- 400 scfh range a little, but it was cheap. With the amount of blowby I am getting I suspect it'll show-up on even with scale not below 40scfh. [Karl your comments on the 40- 400 scfh range please] I use 80ml of oil every 7-8 hours use, draining from my Parker/OmniTek, and the main advantage of having it before the Max filter, but for the moment I 'll live with it.

                        I have held off putting my complete new pump for several reasons:
                        1. Laziness.
                        2. It limps on so it made sense to forgive the oil consumption and slow fill, grind my old pump into the ground before running the new.
                        3. Originally it seemed sensible to be robbing bits off it to fault-find my old pump, this was meant to find which part at issue and "Bob's your second cousins' mother" I would be done. Then replace only said part on the new pump to be put into store.
                        4. Having done 3, and robbed bits from my new pump until now I had no option anway. New pump incomplete and no new parts to put back to run the thing as new anyway. I was waiting for these.

                        Now my plan is to get the new pump back with new parts and finally run it. Get datum pressures, times, temperatures etc etc. Then.... and here I'm not sure if I am being clever, take bits off the old pump and see when the fault returns.

                        But before I do all that I want to get my flowmeter on and see what I get so that:
                        a. I get more clues
                        b. I have an idea of pressures, flows, times, temperatures etc etc compared to my new pump when I fit the thing, and can compare liek-for-like.
                        Otherwise I will still be in the dark. i suspect my second stage because when I last did the rings and piston I was able to rock the con-rod on its big-end bearing slightly. But it was very slight. (er, do you have big ends in Ameriacan?) The gudgeon (wrist??) pin wear was minimal unlike trdsfc's.

                        I still can't grasp how my last go at this with now new barrel and rings for both the first and second stages robbed off my new pump does not solve the issue. Makes no sense to me. I had it as a supply problem but no. Unless I have more severe bottom end wear thatn I think.

                        When I finally find the issue the plan is still to fix it, and then run it into the ground, with my then hardly used new pump in store , but that is a lot of swapping about over what appeared to be my first simple solution of robbing bits until it worked.

                        At present I have 3 and 28 bar on the 1st and 2nd stages respectively using more oil than i should. From empty used to be 3hrs 45mins to fill my 98L tank, now 4hrs 35mins which really si not that bad even now so I think I will live but I WILL crack this!

                        Attached some internet filth for trdsfc. First stage gaskets and you need two are pricey. I have just got some sheet gasket and gaskets punch/stamps for next time. Cheaper than gaskets and I can a make a dozen.
                        Attached Files
                        Last edited by BritCNGUser; 08-01-2015, 04:32 PM.

                        Comment


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

                          Depends on how bad you need to pump CNG. If it were me, I would put the new pump in and take my time to dismantle the old pump...and learn as much as I can on how the pump works. Sort of cool to have a completely rebuilt spare.

                          Comment


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

                            Originally posted by BritCNGUser View Post
                            Karl: I can't see how adding 'filterage' will change anything either, perahsp I was not clear, all I was talking about was the order for better filtering and the added pressure-up times these give. I use pressure-up times as a quiclk way of diagnosing improvement/ decline. At the moemtn I have 2 x Coltri Towers + OmniTek 175 + PM/priority valve + long hose so we can't compare like-for-like with PU times.

                            Update: Having spent days on this previously I have not had time to really go into this anymore and flattracker is highly likely to be right. It needs stripping-down and looking at properly. I have just fitted a MCH 13 type priority valve purely becasue I'm committed to CNG and it seems like such a sensible idea even if a bit 'rearranging deckchairs on the Titanic'. I found a cheap used Dwyer 40- 400 scfh flowmeter on Ebay this week, these are cheap stateside but here go for crazy prices so I compromised on the 40- 400 scfh range a little, but it was cheap. With the amount of blowby I am getting I suspect it'll show-up on even with scale not below 40scfh. [Karl your comments on the 40- 400 scfh range please] I use 80ml of oil every 7-8 hours use, draining from my Parker/OmniTek, and the main advantage of having it before the Max filter, but for the moment I 'll live with it.

                            I have held off putting my complete new pump for several reasons:
                            1. Laziness.
                            2. It limps on so it made sense to forgive the oil consumption and slow fill, grind my old pump into the ground before running the new.
                            3. Originally it seemed sensible to be robbing bits off it to fault-find my old pump, this was meant to find which part at issue and "Bob's your second cousins' mother" I would be done. Then replace only said part on the new pump to be put into store.
                            4. Having done 3, and robbed bits from my new pump until now I had no option anway. New pump incomplete and no new parts to put back to run the thing as new anyway. I was waiting for these.

                            Now my plan is to get the new pump back with new parts and finally run it. Get datum pressures, times, temperatures etc etc. Then.... and here I'm not sure if I am being clever, take bits off the old pump and see when the fault returns.

                            But before I do all that I want to get my flowmeter on and see what I get so that:
                            a. I get more clues
                            b. I have an idea of pressures, flows, times, temperatures etc etc compared to my new pump when I fit the thing, and can compare liek-for-like.
                            Otherwise I will still be in the dark. i suspect my second stage because when I last did the rings and piston I was able to rock the con-rod on its big-end bearing slightly. But it was very slight. (er, do you have big ends in Ameriacan?) The gudgeon (wrist??) pin wear was minimal unlike trdsfc's.

                            I still can't grasp how my last go at this with now new barrel and rings for both the first and second stages robbed off my new pump does not solve the issue. Makes no sense to me. I had it as a supply problem but no. Unless I have more severe bottom end wear thatn I think.

                            When I finally find the issue the plan is still to fix it, and then run it into the ground, with my then hardly used new pump in store , but that is a lot of swapping about over what appeared to be my first simple solution of robbing bits until it worked.

                            At present I have 3 and 28 bar on the 1st and 2nd stages respectively using more oil than i should. From empty used to be 3hrs 45mins to fill my 98L tank, now 4hrs 35mins which really si not that bad even now so I think I will live but I WILL crack this!

                            Attached some internet filth for trdsfc. First stage gaskets and you need two are pricey. I have just got some sheet gasket and gaskets punch/stamps for next time. Cheaper than gaskets and I can a make a dozen.
                            hope you fiqure it out brit. They must do things different on your side of the pond, over here if they warranteed your pump they would insist on the defective unit back.

                            Comment


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

                              Coltri have been very good to me. They have good product and I worry that those reading this will go off with a contrary view. Be clear here, my bitch in the scheme of things is laughable. I used to fill my 98L (is that about 8.5GGE??) tank in 3hrs 45mins, now boohoo it takes 4hrs 35mins. Oh come off it! If you'd done and paid for two Fuelmakers you'd be struggling to match my 'slow' figures. So I'll not cry too much. A Coltri to date is the best pump in the world for the price. Only wish I'd gone for a MCH10 and had done with it.

                              Now I'll wait for my flowgauge to arrive and cry in my beer...
                              Last edited by BritCNGUser; 04-15-2015, 01:31 AM.

                              Comment


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

                                Originally posted by BritCNGUser View Post
                                Coltri have been very good to me. They have good product and I worry that those reading this will go off with a contrary view. Be clear here, my bitch in the scheme of things is laughable. I used to fill my 98L (is that about 8.5GGE??) tank in 3hrs 45mins, now boohoo it takes 4hrs 35mins. Oh come off it! If you'd done and paid for two Fuelmakers you'd be struggling to match my 'slow' figures. So I'll not cry too much. A Coltri to date is the best pump in the world for the price. Only wish I'd gone for a MCH10 and had done with it.

                                Now I'll wait for my flowgauge to arrive and cry in my beer...
                                brit an 98l tank will hold about 7gge at 3000 psi if you let it cool down after filling and top it up. The propblem with operating at your reduced fill rate is the recycled heat on an already heat stressed unit will quickly turn into carbon buildup and serious damage much as trdscfjc has.

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