Part built Allchin 1.5 inch

Advert

Part built Allchin 1.5 inch

Home Forums Traction engines Part built Allchin 1.5 inch

Viewing 25 posts - 376 through 400 (of 548 total)
  • Author
    Posts
  • #429799
    derek blake
    Participant
      @derekblake72550

      So I had a quick go with the foot pump tonight, and yes of course it leaked.

      air seemed to just get pumped straight up the blast pipe, maybe regulator not seated? And my safety valve leaked badly also.

      i will do a better sealing job Sunday and try again, I’m not really worried about seeing engine work I’d like to just my mind at rest that the cylinder is sealed.

      any advice on why air goes straight up the chimney and why the safety valve leaks would be greatly received.

      regards,

      Derek

      Advert
      #429801
      JasonB
      Moderator
        @jasonb

        I'd be looking at the valve if it is going right through the engine and out the blast pipe.

        One problem with a foot pump is that it won't give much initial pressure that is needed to hold the regulator puck and valve against the port faces, if you have a small compressor that would be better.

        #429802
        SillyOldDuffer
        Moderator
          @sillyoldduffer
          Posted by derek blake on 20/09/2019 19:50:20:

          So I had a quick go with the foot pump tonight, and yes of course it leaked.

          any advice on why air goes straight up the chimney and why the safety valve leaks would be greatly received.

          regards,

          Derek

          A car tyre foot-pump isn't ideal for testing engines because they produce low-volume bursts of air at high-pressure when the engine wants a steady flow at moderate pressure. The pressure may be enough to lift the safety while the bursts fail to seat the valve properly.

          Try making a couple of pipes to fit in the cap of a 2 litre lemonade bottle. Connect one to the pump and the other to the engine so the bottle acts as a reservoir. The bottle has the effect of reducing pressure and increasing flow to match the pump to the engine better.

          Dave

          #429803
          derek blake
          Participant
            @derekblake72550

            Right OK, thanks Jason.

            i will do a bit more work before trying again and look to see if you can buy a quiet air compressor.

            #429804
            derek blake
            Participant
              @derekblake72550

              Thank you Dave that’s very interesting info, I will see if I can find a cheap small compressor.

              #429809
              Meunier
              Participant
                @meunier

                Derek,

                a low cost alternative for testing purposes – if you can lay your hands on a car wheel and tyre, bodge-up a screw that will fit tightly in the end of a plastic aquarium-type tube, flatten two sides of the head to allow air to pass and position the head of the screw to depress the pin on the Schrader valve when the tube is pushed on. You can adjust the tyre pressure to suit. Good for a few attempts to run/seal whilst you wait for a compressor.
                DaveD

                Edited By Meunier on 20/09/2019 20:49:04

                #429812
                derek blake
                Participant
                  @derekblake72550

                  Many thanks for the suggestions, I shall have a mess around this weekend for sure.

                  #430047
                  derek blake
                  Participant
                    @derekblake72550

                    Evening all,

                    so I had another go with the foot pump, the valve was so tight it couldn’t seal and my engine came alive!

                    exciting for sure, unfortunately there are some issues and that’s leaks, to be expected of course but I have leaks from the 4 bronze studs under the nuts.

                    the other studs so far seem fine, slightly annoying but maybe I could put some copper washer under the nuts?

                    i also have another leak which I hope is from the valve chest cover and not the valve chest itself!

                    have any of you ever had leaks from the studs? I can’t remove the studs as I’m sure you will all know from my previous posts.

                    #430054
                    derek blake
                    Participant
                      @derekblake72550

                      I give up on the old tinternet, have spent 2 hours trying to find 4BA copper crush washers..I’m not sure of any other way to seal the threads.

                      #430066
                      Paul Kemp
                      Participant
                        @paulkemp46892

                        Derek,

                        Try twisting some PTFE tape (plumbers use it!) into a string and then wind that round the stud (clockwise) then screw the nut down on it, any that extrudes out past the profile of the nut you can trim off with a craft knife. It's a relatively low pressure so should do the trick.

                        Paul.

                        #430102
                        derek blake
                        Participant
                          @derekblake72550

                          Right OK thanks Paul, there’s not a lot of stud sticking out so I will have to use very small amount but we’ll worth a try.

                          thank you

                          #430118
                          derek blake
                          Participant
                            @derekblake72550

                            Can you use fibre washers with steam?

                            #430329
                            derek blake
                            Participant
                              @derekblake72550

                              Not a lot of progress, steal trying to seal leaks.

                              air escaping from valve chest cover at the moment, no matter what gasket i use.

                              i haven’t seen any leaks from the valve chest joins yet which is critical, as I can’t remove the cylinder again.

                              #430345
                              Jeff Dayman
                              Participant
                                @jeffdayman43397

                                Hi Derek, did you use some silicone sealer or other gap-filler at the screw heads shown in the pic below with the red arrows? If not air may be getting by the heads or the screw slots out the side, under the gasket. You could add some sealant by removing only the valve chest cover. Some socket head capscrews or philips head machine screws would be better here than slot heads, because with those there is no leak path across the head. There may still be a gap above the head though, needing extra gasket or some sealant, or both.

                                dereks-steam-chest.jpg

                                #430347
                                derek blake
                                Participant
                                  @derekblake72550

                                  Thank you Jeff, on these screw head I actually added some JB weld as the counterbore had made a gap under the chest cover and I filed off level.

                                  is it actually possible that air could be creeping up the fixing studs then, I assumed as they were under the plate it would be sealed.

                                  i haven’t tried sealant yet, but that’s only because the valve isn’t fully set yet.

                                  a leaking valve cover isn’t an issue that can’t be fixed from your suggestions, I was trying the air route to put my mind at rest about the valve chest itself wasn’t leaking and worse still the cylinder saddle as both can’t be removed now.

                                  as the sealant can be easy cleaned off I will try a thin layer tomorrow and see if it’s a fix, I did add some washing up liquid around the area and it does seem to be out the top where valve chest cover fits.

                                  #430348
                                  derek blake
                                  Participant
                                    @derekblake72550

                                    I will add a layer of sealant under the gasket tomorrow as this can still help before fixing sealant on all surfaces when the valve is set.

                                    #430350
                                    derek blake
                                    Participant
                                      @derekblake72550

                                      Looking at your suggestions Jeff, I didn’t add JB to the top fixing screw for some reason and that’s where it leaks so I shall do the same to that one tomorrow and try again. I think you may have just hit on the reason for the leak! 🙏

                                      #430357
                                      Jeff Dayman
                                      Participant
                                        @jeffdayman43397

                                        My fingers are crossed here! Good luck tomorrow.

                                        #430608
                                        derek blake
                                        Participant
                                          @derekblake72550

                                          Small amount of work done, screw heads sealed and new gasket added and valve chest leak seems sorted but still small amount of others to do but looks like none on cylinder saddle or valve chest itself yet but only running on around 20psi presently.

                                          short but noisy video added to YouTube if your interested in viewing, listed under “Allchin first air test”

                                          Edited By JasonB on 26/09/2019 20:45:29

                                          #430612
                                          JasonB
                                          Moderator
                                            @jasonb

                                            Looking good

                                            #430614
                                            derek blake
                                            Participant
                                              @derekblake72550

                                              Many thanks Jason, that means a lot.

                                              #430628
                                              derek blake
                                              Participant
                                                @derekblake72550

                                                Many thanks for adding the video Jason.

                                                #430652
                                                Jeff Dayman
                                                Participant
                                                  @jeffdayman43397

                                                  Well done Derek! Like a Swiss watch!

                                                  #430826
                                                  Paul Kemp
                                                  Participant
                                                    @paulkemp46892

                                                    Derek,

                                                    Not much wrong with that! Nice and regular impulse on the crank. Well done. Little challange for you, see how slow you can get it to run on your 20psi, good slow running is harder to achieve than having it whizzing round and a very good indication of how good your valve timing is. I reckon you will get that just creeping round!

                                                    Paul.

                                                    #430840
                                                    derek blake
                                                    Participant
                                                      @derekblake72550

                                                      Thank Paul, for some reason the regulator not working yet.

                                                      i suspect the leaks etc are not allowing the pressure to hold it against the face so the speed is the speed at the moment.

                                                      but hopefully as I work through the leaks I will have more and more control, even to see the engine come alive after a year is a good feeling as I was concerned it wouldn’t work.

                                                    Viewing 25 posts - 376 through 400 (of 548 total)
                                                    • Please log in to reply to this topic. Registering is free and easy using the links on the menu at the top of this page.

                                                    Advert

                                                    Latest Replies

                                                    Home Forums Traction engines Topics

                                                    Viewing 25 topics - 1 through 25 (of 25 total)
                                                    Viewing 25 topics - 1 through 25 (of 25 total)

                                                    View full reply list.

                                                    Advert

                                                    Newsletter Sign-up