Announcement

Collapse
No announcement yet.

Gas tank for hit and miss engine

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Gas tank for hit and miss engine

    Recently developed an interest in gasoline fueled hit and miss engines and within the next week or so will be getting my first one. Sadly it is lacking a gas tank. So have decided to make one out of two 105mm shell casings. Some of the period pics do show some with cylindrical brass fuel tanks. To get the years of grunge out will be using naval jelly and some coarse steel wool or emery paper with proper chemical resistant gloves to protect my skin. Most likely will be using the brass fittings and 1/4" copper tubing for the fuel lines. And a short section of brass 1" pipe with a machined cap for the fill opening. Here is where I run into one nagging problem. Easy way to attach the fittings would be to just drill the tank for the different fittings and solder them in place. It would work and like I said is the easy way out. The second way would be to make bushings for each fitting and then carefully solder them in place, thread them and then screw in the various fittings. That would look more like a professional job. problem is I have no idea on how to contour the bushings to fit the outside diameter of the shell casing. The casing does have a slight taper from front to back but it is the od that I am concerned about. And why may you ask make the tank out of shell casings??. Bought a bunch of these some years back and made them clean inside and shiney outside as a gift for some vets I know and one for my modest casing collection. These two were the ones that didn't make the cut. One has a crack in its side which will be the cap for the open end of the tank. These things do take a lot of time to clean up. Have to raise the dents on a scrap hunk of round aluminum in the vise and a dead blow hammer, sand with different grades of silicon carbide paper, and polishing on the wheel with different polishing compounds. On average about 6-8 hours. So would appreciate any suggestions and or comments. Sorry to be so long winded. Thanks,Frank

  • #2
    Protip: Take flat bushing, place on curved tank. Hit lightly with hammer. Tank will now be flat around your bushing.

    Also consider that NPT tapping takes a TON of torque. Tap the bushing *before* you solder it to the tank or you'll likely deform the tank trying to tap it. Tap the bushing in the lathe before cutoff.
    Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

    Comment


    • #3
      I agree with Black Moons. Alternatively, before you close the end of the tank, get a carpenters C clamp and use that to form a localised flat area where the fitting is to go.

      Richard
      'It may not always be the best policy to do what is best technically, but those responsible for policy can never form a right judgement without knowledge of what is right technically' - 'Dutch' Kindelberger

      Comment


      • #4
        Why not unscrew the igniter assembly and work with that? The "inner cage," that held the black powder, will unscrew and then drill through the primer pocket, bore to size, thread for a compression fitting, and thread the fuel line through and turn it down to almost the low point. thighten the fitting and you have a neat, leack-proof fuel line with no messy soldering.
        The igniter assy is a bugger to unscrew, by the way, as they used a thread locker of some type to act as waterproofing.
        the filler cap is still your problem; I would contour it to the smaller diameter and then "file to fit." silver solder would be A LOT neater and stronger.
        Forgot to add that you would be well advised to anneal the shell casing befor much work. They DO work harden from firing, hence the occasional stress crack.
        Last edited by Duffy; 06-04-2014, 09:37 AM.
        Duffy, Gatineau, Quebec

        Comment


        • #5
          Frank,

          The citric acid cleaner used on brass would be a lot easier. About 2 tablespoons to a gallon of warm water. Soak two hours to twenty four and you have dull shiny brass. Considering the vibration silver solder would be better choice. Think a broken fitting spraying gas on a hot running engine.

          Bob

          Comment


          • #6
            Brass is easy to file. A few minutes of work with a half-round file will shape the part to the curve of the shell. And a +1 on Duffy's suggestion to use silver solder.

            Comment


            • #7
              Does the H&M engine have a carb with a float and bowl or does it draw the fuel directly up from the tank? This will have an influence on tank design.
              Jim

              Comment


              • #8
                The engine is a Detroit/Sandow vertical cylinder with flywheel on one end of the crankshaft and a cylindrical piese of metal on the other but from the pics the crank shaft is partially hollow. With the pully on and a suitable belt you can actually run something like a grist mill. I have seen one set up with a short section of prop shaft held in place with 4 large screws. Engine rotation can be reversed by grasping the handle and physically breaking the connection and moving the handle in the opposite direction you wish to go. And this engine is two cycle in that you mix the oil and gas. And it is watercooled as well. You have a 20 gallon galvanized tank on a stand full of water works by thermobaric hot water rises and cold sinks. Supposedly you could inject water into the piston if you wanted to scavenge more power. But that leads to nasty problems of locking up the engine at low rpm's. Haven't gotten any of the bushings yet so will be making a visit to the local lowes to see what goodies I can pickup. Actually the gas tank will see no pressure, there will be a small valve installed on the top of the tank to act as a vacuum breaker. Probably only 4 fittings will have to be installed. Gas fill on the top, vacuum breaker and on the bottom feed ling to carb or mixer and a drain. I have some old strips of silphos silver solder would that serve for silver solder?. The tank height is of course piped to the carb which uses a piece of round cork which will have to be covered with a dope solution like they do on plane models. Think that is about it as far as the description of the engine. Keep the comments and suggestions coming in they are much appreciated. Frank
                Last edited by Frank46; 06-05-2014, 03:13 AM.

                Comment


                • #9
                  Black-moons. What I had planned on doing was drill the holes for the bushings into each of the fittings would screw into. There is just about enough room to get a medium mapp gas tourch inside for the soldering. Kinda like your idea of silversoldering though. Much stronger than solder. The bad case will have its head cut off and will be the end cap for the tank. Tank has some dents that will be pounded out with a dead blow hammer on an aluminum (4"round) mandrel. Like i said it isn't the case taper I really worried as that isn't enough to cause problems, it's the outside diameter that has to be dealt with. Thanks for your help. Frank

                  Comment


                  • #10
                    Isn't Naval Jelly for removing rust? Is there something better for cleaning brass?

                    Comment


                    • #11
                      Duffy, I managed to get the ignitor tube which is about 12" long, roughly 1/2" in diameter and has a bunch of holes to spread the ignition flame to the main charge. And yes it is threaded on to the primer by fine threads. Unfortunately the last 3/8" of it is still stuck to the primer. If I did get the primer out I could stand this upright and use the primer hole as the feed line and eliminate a lot of work. Just thread the primer hole, and run the feed line and use the other shell as an end cap after it is cut down and use that primer hole suitably enlarged to take a 1" piece of brass pipe as the filler. Haven't received the engine yet. Waiting to hear on that soon.
                      Jim, yes there is a round cork float inside the carb. But due to the 10% ethanol in todays gas it is strongly suggested on one web site devoted to detroit engines that the float be coated with model air plane dope to seal the cork float so it won't degrade. If that isn't done I'll be shopping for some cork to make a new float. I saw one video on a running detroit engine somewhat similar to what I have and it's fairly level to the carb. So obviously some feeding to the carb is done by how much gas is in the tank.
                      Elf, years back I bought some 40mm bofors shell casings and made up a few that would hole some candles as a gift for my mom. The naval jelly did a good job of removing the powder residue, green corrosion and other funk from inside the shells. It was a simple matter then to sand the interior to a mirror shine to hold the candles. I have the bottom of a brass 5"54 caliber shell casing that came from one of the gun mounts on my ship USS Franklin D Roosevelt CVA42. A buddy in the machine shop cut it down for me and I spent countless hours while on watch sanding away the gunk inside it. Funny thing while talking about shell casings. My day found two 105mm cases that had been done up as trench art. Unfortunately one of my scuzzy horse track neighbor bought them and the two candle stick holders. I hope that whatever money he got and bet on the horses lost. Serves him right. Thanks for the help and it's greatly appreciated. Frank

                      Comment


                      • #12
                        I wouldn't worry too much about silver hard verus silver soft solder. Its a bulkhead fitting on thin walled tank, as long as the fitting has a decent bit of lap surface area over the tank metal, it should deform the hell outta the tank before it gives way.

                        IMO the only advantage of the silver hard solder (1100c melting point) for this project is how nicely it will flow into the tiniest of gaps with no skill whatsoever. No need to pre-tin anything, just flux it up nicely (with proper hard silver solder flux) and the solder will suck into the joint so easily you'll assume its disappearing somewhere till the perfect fillet forms instantly all around the bulkhead. Won't have the slightest worry about it leaking if you get the gap between the bulkhead and tank as small as you can. That said, with a brass tank you will be getting close to the melting point with silver hard solder and regular soft silver solder should stick to brass very nicely.
                        Play Brutal Nature, Black Moons free to play highly realistic voxel sandbox game.

                        Comment


                        • #13
                          Was surfing through the various hit and miss engine site the other day. And wouldn't you know it there was a pic of one with a large brass fuel tank. I've seen other ones with smaller tanks made of brass and even one of copper that basically used a large piece of copper pipe and two end caps. I hate to think that at today's prices for copper what that one cost. Got word from the seller and my engine should ship sometime this week. So I did manage to get to Lowe's and get some brass pipe bushings in 1/8" and 1/4" pipe along with some other goodies so will wait until the engine is here to get an idea just how big or small size wise the tank has to be. Thanks for all your suggestions and comments. As always they are greatly appreciated. Frank

                          Comment

                          Working...
                          X