mattinker Posted January 11, 2013 Share Posted January 11, 2013 We are just returning our attention to the Water Pump so that we can get that finished – the attached photos of an “onion” is in fact a shroud designed to cover the drive pulley and drive belt for the pump – and it also contains a bearing to support the end of the water pump drive shaft. It was cast in aluminium and is very much showing signs of wear and age with a great deal of its flange broken or rotted away. We had hoped that it might be possible to remove the remainder of the broken flange – make a new flange and weld that to the main part of the “onion” – but a test weld on a part of the flange that would be removed in any case reveals that the original aluminium is very contaminated – and probably was not very pure when the item was made some 95 years ago - so it will not weld. A disappointment as it now means more pattern making so that a completely new “onion” can be cast. Tim Use the onion built up with body filler! By the colour and the crystalline structure it looks to me as though there's a lot of zinc in there. A Za 12 alloy will be 11parts by weight Al 1 part Cu and the remaining82 parts are Zn. This looks like more of a zinc weld than an aluminium on. I haven't done it myself, but I have been told that a good TIG welder can weld this stuff using strips of zinc as filler rod. I cast the ZA 12 alloys myself, they have similar damping characteristics to cast iron. The biggest problem is people try to cut corners wit them making things wit too thin sections. Keep them oiled or well primed and painted and they don't oxidise. Regards, Matthew Quote Link to comment Share on other sites More sharing options...
edinmass Posted January 15, 2013 Share Posted January 15, 2013 Piston manufactures in the USA 1 Egge 2 Ross 3 Aries I have had poor luck with the first company. The other two are good, and now I usually use number 2. They all have web sites, just google their names and the word piston. They also provide rings and pins. We always order modern ring packages as they burn less oil and crank over easier. Ed Quote Link to comment Share on other sites More sharing options...
Old Bill Posted January 15, 2013 Share Posted January 15, 2013 I wouldn't give up on that pump casting without trying Alutight/Technoweld. Many of us have successfully repaired parts that would otherwise have been scrap. Hi Phil. Thanks for the tip. I have no experience of 'Technoweld'. Is it a welding process or some sort of special solder? How have you used it? It would certainly be another useful process to have in the tool kit. Cheers! Steve Quote Link to comment Share on other sites More sharing options...
Old Bill Posted January 15, 2013 Share Posted January 15, 2013 Piston manufactures in the USA 1 Egge 2 Ross 3 Aries I have had poor luck with the first company. The other two are good, and now I usually use number 2. They all have web sites, just google their names and the word piston. They also provide rings and pins. We always order modern ring packages as they burn less oil and crank over easier. Ed Thanks for the recommendation, Ed. It is always nice to hear of personal experience. Cheers! Steve :-) Quote Link to comment Share on other sites More sharing options...
Asciidv Posted January 16, 2013 Share Posted January 16, 2013 Steve, There are many low temperature aluminium 'welding' rods available under different names such as Technoweld, Lumiweld and HTS. In effect it is just like aluminium brazing or perhaps soldering. If you watch this video, http://www.aluminiumrepair.com/video_new.php you would think it is the most magic thing on earth and wonder how you could have possibly done without it. In reality it is never that good. Due to its low viscosity it tends to run away, so if you are trying to fill a crack in a casting on a non-planar face as soon as you move away from the level it runs out from the area that you have just completed. Barry. Quote Link to comment Share on other sites More sharing options...
Barney Posted January 16, 2013 Share Posted January 16, 2013 The video link above is from AET Systems Ltd in Daventry, Northamptonshire so perhaps it might be worth while taking the ‘onion’ to them to see if they are prepared to carry out the repairs. A satisfactory repair would be useful to you and a good recommendation for them if you were to promote them on the HMVF site (might even get the job done for free) so a win, win situation for both of you. Best regards. John Quote Link to comment Share on other sites More sharing options...
philb Posted January 16, 2013 Share Posted January 16, 2013 Hi Phil. Thanks for the tip. I have no experience of 'Technoweld'. Is it a welding process or some sort of special solder? How have you used it? It would certainly be another useful process to have in the tool kit. Cheers! Steve Steve, a timely question; I've just this evening repaired the little bracket in the picture . The slotted plate had broken so I cut a new one and welded it to the rest of the extrusion. It's a bit agricultural (for a greenhouse door actually) but was easy to do. I agree with Asciidv in that the melt is a bit runny but I've managed to contain it in the few jobs I have done. there's thread on here where I, Clive Elliot and a few others described what we had fixed with it. Like most other things, it takes a bit of practice. I believe the "magic" material is a eutectic alloy, which melts at a much lower temperature than the work-piece and then combines with some of the work-piece to make that region a eutectic alloy also - so the whole thing doesn't melt, just the region to be repaired. I've used a natural draught Propane torch for my repairs and that is plenty hot enough. It would be interesting to learn from an expert how the typical properties of the welded material compare with those of the less stratified base materials. Anyone? Phil Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 19, 2013 Author Share Posted January 19, 2013 In a previous posting, we reported that we would be faced with making a new Governor – of the two that we had, the cleaner of the two was broken in several places whilst the second one was heavily corroded. Initially, we could not decided how the originals were made but eventually we decided that they had been die-cast in zinc and that in no way could they be repaired. A new one was required which would have to be fabricated. The broken parts were recovered and all the necessary dimensions were obtained from these. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 19, 2013 Author Share Posted January 19, 2013 We eventually decided that the new Governor would be made out of steel – bronze was considered but steel is readily available and is much cheaper! These four pictures are all quite self-explanatory and show some of the parts of the body being shaped and the method. The parts will be inter-locking as far as possible, just to ensure that silver-soldered joints do not have to take all the strain. The original “Rollers” are used again but this time, they would run in bronze bushes. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 19, 2013 Author Share Posted January 19, 2013 Webs were cut from 1/8” steel to go between the arms, and an 1/8” slot was milled in the steel cylinder holding the pivot pin to take and hold the base of the web firmly in its place and to provide further inter-locking. A similar 1/8” slot was milled at the same time at 90 degrees to the other slot to take a similar web to hold and locate the web that will be inserted later between the pivot cylinder and the weight. The first part of the assembly was silver soldered together at this stage – just then leaving the second web and weight to be soldered in later. The bottom web was then cut out and firstly silver soldered to the weight in which a another 1/8” slot had been milled to take it. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 19, 2013 Author Share Posted January 19, 2013 The final job then was to silver solder the weight with its attached web to the pivot cylinder to complete it. And then of course, the completed items had to be offered up to the cam shaft to see if they fit! They proved to be just a little firm and will want some gentle easing in! Quote Link to comment Share on other sites More sharing options...
snort Posted January 19, 2013 Share Posted January 19, 2013 fantastic engineering,very impressive! Quote Link to comment Share on other sites More sharing options...
Chris Suslowicz Posted January 19, 2013 Share Posted January 19, 2013 I'm concerned that you may have to fit much more powerful springs due to the whole assembly now being made of steel rather than steel weights on a lightweight (Mazak or similar) frame. (Not that I have any suggestion as to how it could be re-made in Mazak, of course, though "lost wax' casting might be an option.) On the other hand, this project is still a brilliant example of the machinist's Art. Chris Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted January 19, 2013 Share Posted January 19, 2013 I'm concerned that you may have to fit much more powerful springs due to the whole assembly now being made of steel rather than steel weights on a lightweight (Mazak or similar) frame. (Not that I have any suggestion as to how it could be re-made in Mazak, of course, though "lost wax' casting might be an option.) On the other hand, this project is still a brilliant example of the machinist's Art. Chris Yes - we have thought of that one and Steve has been doing some calculations to take that into account. I am not sure how far he has reached with it and no doubt he will come into comment! Tony Quote Link to comment Share on other sites More sharing options...
Old Bill Posted January 19, 2013 Share Posted January 19, 2013 (edited) Hi Chris. Yes, I did think of that one. I measured up the survivng springs and calculated their spring rate. I multiplied by 1.1 to allow for the relative densities of zinc and steel (7140kg/m³ and 7850kg/m³) and came up with a rate of 0.44N/mm. The original springs have a free length of 3 3/16" and an unknown pre-tension. I have been able to find an off-the-shelf spring with a rate of 0.45N/mm and an initial tension of 6.23N but a free length of 3 1/2". I am hoping to be able to reduce the free length by bending the eyes a little tighter as this free length has more effect than the spring rate. Now that Father has made up the weights, he can measure the closed and open lengths of the spring eyes and I can check what the forces will be. Of course, this is all a bit academic as we don't intend to fit a butterfly in the manifold! It would be nice to see it work though. Steve :-) Edited January 19, 2013 by Old Bill Quote Link to comment Share on other sites More sharing options...
Asciidv Posted January 19, 2013 Share Posted January 19, 2013 Yes - we have thought of that one and Steve has been doing some calculations to take that into account. I am not sure how far he has reached with it and no doubt he will come into comment! Tony I read this and "m omega squared r", flashed past me and I thought that Steve was going to be brave and put his maths and mechanics to the test, only to be a little disappointed that it was going to be spring rate modification calculation! He ought to let off though, because the bits are beautifully made and I am sure that they will work too. He gave an example of his friend testing out a similar governor in a lathe, it would be nice to see some photographs or better still a video of this one operating. Barry. Quote Link to comment Share on other sites More sharing options...
Old Bill Posted January 20, 2013 Share Posted January 20, 2013 Hi Barry. Yes, I could have worked it out from first principles but there is quite a lot of friction in there so I thought it better to go from a known baseline. That does assume that it worked properly in the first place! I am surprised that there is no adjustment in there so the speed setting must be quite variable between vehicles. If it is just to prevent engine overspeed then I guess they could live with that. The lorry governed to 30mph (!) is a Hallford and was rebuilt a good twenty years ago. Again, the governor is buried inside the timing case so you can't see it operating and the owner didn't take pictures like we do. You can see the lever arm on the Dennis move as the engine is accelerated but the engine has no butterfly or provision for one so there is no actual effect. I have ordered the springs now so we shall have to wait and see. Cheers! Steve :-) Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 20, 2013 Author Share Posted January 20, 2013 The Governor parts are now fitted and are moving and sliding easily. The first two pictures show them at each extent of their range – whilst the third picture shows the reverse side . Quote Link to comment Share on other sites More sharing options...
Chris Suslowicz Posted January 20, 2013 Share Posted January 20, 2013 Thinking about it, the governor is fitted to prevent engine overspeed conditions, which may have been more of a concern for stationary engines (e.g. the water pump that ended up in your splendid Dennis) if the load was suddenly removed. That might well explain why there is no butterfly fitted to the truck. (Or not, I suppose.) :-D Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 25, 2013 Author Share Posted January 25, 2013 Something that we have not been able to get to for a while was the clutch side of the fly wheel – as the flywheel has been standing on the ground with the crank shaft still attached to it. Now that assembly is back in the crank case, it has given us access to the front of the fly wheel to do some work on it. It was still quite heavily rusted as it has not been touched since we have had it – but a good wire brushing has cleaned it up quite nicely. The original main studs to take the clutch were heavily rusted and bent and replacements for those were made up some time ago during some spare minutes and these can now be fitted. Cleaning up has also revealed the broken off remains of the two 3/8” studs which are there to stabilise the clamps for the clutch springs. These were just a simple peg with a screw driver top and are simple to replace – once the remains of the two old ones were removed! The first two of these pictures show one of the main studs before and after fitting to the flywheel. The third picture shows one of the 3/8” pegs whilst the fourth picture shows the whole item. Quote Link to comment Share on other sites More sharing options...
mattinker Posted January 26, 2013 Share Posted January 26, 2013 Thinking about it, the governor is fitted to prevent engine overspeed conditions, which may have been more of a concern for stationary engines (e.g. the water pump that ended up in your splendid Dennis) if the load was suddenly removed. That might well explain why there is no butterfly fitted to the truck. (Or not, I suppose.) :-D I was wondering if the governor wasn't used in convoys? I am assuming that these are governors that can be set to a specific engine speed, not only over-speed. Did these vehicles have power take-offs? I used to own an old Fordson Major tractor, the accelerator set a given speed and after that it would try to maintain that speed. I have a feeling that the Thornycroft would be more like a tractor than a lorry! Regards, Matthew Quote Link to comment Share on other sites More sharing options...
Old Bill Posted January 26, 2013 Share Posted January 26, 2013 Hi Matt. There is no governor adjustment at all so I think it must just have been to protect the engine from inexperienced drivers. There is a story of a convoy of FWDs moving up from the port and the last one taking six hours more to arrive than the rest. This was due to the driver not realising that he had more than one gear and doing the whole trip in first! With that level of competence, I can imagine him opening the throttle wide in order to try to keep up. I'm making a new governor throttle actuating arm today. More pictures later. Cheers! Steve Quote Link to comment Share on other sites More sharing options...
mattinker Posted January 27, 2013 Share Posted January 27, 2013 Hi Matt. There is no governor adjustment at all so I think it must just have been to protect the engine from inexperienced drivers. More pictures later. :-) Great, I always look forward to new pictures! Regards, Matthew Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 27, 2013 Author Share Posted January 27, 2013 A few weeks ago, Steve used his press to remove the bearings from the magneto drive shaft as our puller was not big enough. They eventually came off with a bang and the shaft was pressed through. After a good clean up of the shaft, he has now fitted the replacements, followed by the oil return bushes which are secured with a taper pin. The press really made the job easy and no damage or bruises resulted. The shaft is now bagged up ready to refit once the camshafts are in. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted January 29, 2013 Author Share Posted January 29, 2013 Whilst Father has been making up new governor weights, Steve has been working on the the other end of the mechanism. The governor shaft is in the bottom left of the picture, below the inlet camshaft position. As you can see, it is pretty rough and the two zinc arms which connect with the governor sleeve on the camshaft have broken off with only their bases remaining. Steve measured what remained and then, after a look at the photo in the parts book, made up some replacements. These were a simple brazing and filing exercise. The half engine yielded a governor shaft with a corroded but measurable lever on the end. After sketching it up, Steve brazed up a blank from which to make a replacement. Interestingly, the lever is fixed to the shaft using a tapered cotter pin so two intersecting holes were required. Once the first had been drilled, Steve pressed a pin into the hole to support the drill whilst the second was done. This worked well and the blank was roughed out. Some effort with a file to make the arm look like the original forging and that part was done. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.