Great War truck Posted December 6, 2012 Author Share Posted December 6, 2012 This is the coupling for the Magneto – before and after cleaning. We shall have to make a new leather part of the assembly. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted December 11, 2012 Author Share Posted December 11, 2012 One of the next jobs coming up is going to be work on the Governor – the one on the complete engine is very heavily corroded and the castings are broken and it will need some significant attention to bring it back to life! The “Swivels” were cast in aluminium and they certainly have not stood the test of time. These three pictures show the remains of the Governor on the “half engine” – the engine that we obtained many years ago with the cylinder blocks missing. The Governor bits are significantly cleaner but the springs are missing and the “Swivels” were wired together. These castings although not nearly so heavily corroded are cracked or broken. These four pictures show the rear of the Governor assembly from the cleaner “half engine”. We were quite surprised to find that these little Swivel castings were made in aluminium which have not stood the test of time – but we guess that they were never designed to last for nearly 100 years in any case. Quote Link to comment Share on other sites More sharing options...
Great War truck Posted December 11, 2012 Author Share Posted December 11, 2012 The first of these three pictures again shows the front of the Governor assembly on the whole engine with the other two showing the rear of the assembly. The first two pictures here show the back of the cleaner of the two clearly and where the metal failures are. The third picture shows some of the “loose” bits after cleaning. Not quite sure at moment where the Bronze stirrup shape part fits in – it was floating around loose! It will be a fairly straight forward exercise to fabricate the broken aluminium castings in bronze instead of aluminium – assuming that there are no weight issues with this assembly. There are enough of the broken parts available to obtain correct dimensions for the replacements. Quote Link to comment Share on other sites More sharing options...
Redherring Posted December 12, 2012 Share Posted December 12, 2012 Nice wiring job. Does this motor really need a governor? I have heard that governors on early Leylands were more trouble than they were useful??? Quote Link to comment Share on other sites More sharing options...
Asciidv Posted December 12, 2012 Share Posted December 12, 2012 Steve, on early engines like this, what was the function of the governor in every day use? Was it a mechanical 'cruise control' or just a 'rev limiter' if you were to use today's terminology? Also how exactly does it work, where is the closed loop function? Why not remake the parts in aluminium? Far easier to do, more original and I doubt that once restored this lorry will ever be abandoned again to decay away. Barry Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted December 12, 2012 Share Posted December 12, 2012 Well, Steve will certainly want to have his "two-pennyworth" on that one Barry - I don't expect that he has picked up your posting yet! But I can only believe that the governor is designed to keep the engine revolutions down so that it does not self-destruct if a zealous driver tries to over-rev it! I am sure that it is not designed to limit the speed of the lorry on the road! Aluminium might be the correct material for the new bits - but I imagine making them - and bronze for me will be a much easier material for me to deal with as it can be easily brazed or silver soldered! We need to take both sets of the governors right down to have a good look at them to see exactly how they are designed to work, but at this stage, none of us is quite sure! I shall not take that any further until Steve is in Devon some time next week and we can take the governors to bits together. It will interesting now to see if Steve contradicts his father! Tony Quote Link to comment Share on other sites More sharing options...
Old Bill Posted December 12, 2012 Share Posted December 12, 2012 It is my opinion that the governor is simply there as a 'rev limiter' to prevent inexperienced drivers from breaking things. None of the ones I have seen has a fine adjustment for setting vehicle speed precisely. The Dennis is fitted with one and it all functions to the point where you can see the lever on the side of the crank case moving when the throttle is opened. It should operate a butterfly above the carburettor but our inlet manifold has never been machined to take one so we run without. I would like the Thornycroft one to function but I would leave the butterfly out of the manifold so that it has no effect on my driving. I have never driven with a governor but I am told that it is not very pleasant so I don't want to try! As far as I can make out, the Thorny one works by having two bob weights held together with a pair of springs and this assembly rotates with the camshaft. At speed, they begin to move apart under the control of the springs. They are attached to bell cranks which slide a slotted collar along the camshaft behind the timing gear. A bronze yoke engages in a second slot in the collar. As the collar moves, the yoke is brought forward with it rotating a crank which protrudes from the side of the crank case. I think that the weights and cranks are zinc die-castings which is why we managed to break them when knocking out the camshaft. I would like to have a working mechanism and am thinking of replacing them with brazed steel fabrications but I need to have a closer look at the bits before we start on that. Something to do on Christmas morning! One of our friends who has a Hallford lorry fitted with a Dorman engine decided to set up his governor by mounting it in the lathe so he could control the speed and set the springs to match. Unfortunately, he forgot that the camshaft runs at half crank speed so his lorry is now governed to 30mph! Steve Quote Link to comment Share on other sites More sharing options...
David Herbert Posted December 12, 2012 Share Posted December 12, 2012 "30 mph", was he hoping it would do 60 ? :-D David Quote Link to comment Share on other sites More sharing options...
Roy Larkin Posted December 13, 2012 Share Posted December 13, 2012 The subsidy scheme required govenors to be fitted and the army were certainly aware of the mechanical damage that would be caused by over revving. The main priority though seems to have been road speed. Speed limits were set as standing routine orders to protect the road surface as much as the vehicles and govenors were set to prevent speeding. This applied to all vehicles and not just lorries and Daimler ambulances were criticised for not having suitable govenors which made them difficult to drive slow enough for the speed limit. Quote Link to comment Share on other sites More sharing options...
Asciidv Posted December 13, 2012 Share Posted December 13, 2012 "30 mph", was he hoping it would do 60 ? :-D David I did laugh at this!!! Barry. Quote Link to comment Share on other sites More sharing options...
nz2 Posted December 13, 2012 Share Posted December 13, 2012 Aside from the road speed point could the installation of a governor be also more for engines used for other purposes. Not having a carburetter with the correct butterfly for the governor would indicate this. Workshop repair lorries with the engine supplying power direct by belt from the flywheel would need fine governing of speed, as would any use towards generating electrical power. Doug Quote Link to comment Share on other sites More sharing options...
Great War truck Posted December 14, 2012 Author Share Posted December 14, 2012 Tony has stripped out the broken bits of the Governor mechanism today – probably broken or severely cracked before we started to dismantle the engine! These five pictures show the first of the two. This is the other one – enough information on measurements here for a fabrication to be made up as a replacement. Quote Link to comment Share on other sites More sharing options...
racer Posted December 14, 2012 Share Posted December 14, 2012 Evenin gents, what a great piece of engineering to work on, can you tell me how the "roller" looking piece is fitted into the alloy/zinc yoke, I can't see any split or loose shaft, also will you have to get the weight of the new fab the same along with spring tension for the correct governer effect ? Andy 1925 Napier Lion x2 1913 Chalmers Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted December 15, 2012 Share Posted December 15, 2012 Evenin gents, what a great piece of engineering to work on, can you tell me how the "roller" looking piece is fitted into the alloy/zinc yoke, I can't see any split or loose shaft, also will you have to get the weight of the new fab the same along with spring tension for the correct governer effect ? Andy 1925 Napier Lion x2 1913 Chalmers That one is on my mind at the moment, too! The only way that the "Roller" could have been put in is by "springing" the yoke and the material that it is made of certainly does not lend itself to that! Perhaps that is the reason for the cracks in the original? We shall not have that problem with the replacement fabrication as the Roller can be inserted before final brazing of that part. I have also been thinking of the weight of the replacement in operation if it is made of a different material. You may have read that Steve favours "steel" but I was more inclined to go for "bronze" - something for us to discuss when we get together over Christmas! My initial thoughts are that it will make little difference - but we shall see! Tony Quote Link to comment Share on other sites More sharing options...
Stormin Posted December 15, 2012 Share Posted December 15, 2012 Couldn't the steel roller have been set in the mould as a permanent core and cast in? After all the alloy / Zamak is a lot lower melting point than steel. The cooling rate of the alloy may have been controlled to reduce cracking as it shrinks around the end pins of the roller. I suspect a lot of stresses may still hav been present and hence the later failure of the castings. Keep up the great work and excellent reports again. Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted December 15, 2012 Share Posted December 15, 2012 (edited) Couldn't the steel roller have been set in the mould as a permanent core and cast in? After all the alloy / Zamak is a lot lower melting point than steel.The cooling rate of the alloy may have been controlled to reduce cracking as it shrinks around the end pins of the roller. I suspect a lot of stresses may still hav been present and hence the later failure of the castings. Keep up the great work and excellent reports again. Great minds think alike! Steve has just come up with the same conclusion. The Yoke is of zinc and is low temperature stuff - so yes, it was cast in, in situ! As was the other steel part with the "eyes" in it to hold the spring ends! Tony Edited December 15, 2012 by Minesweeper Quote Link to comment Share on other sites More sharing options...
Gordon_M Posted December 15, 2012 Share Posted December 15, 2012 Cor - it might have been cheap but it was rubbish. I don't care how intelligent our ancestors were, you'd have to be mad to do that. :nut: Wonder what the in-service failure rate was? I suspect the new, improved Gosling model will be a bronze yoke, steel roller, and two steel pins, with the inner one retained by grub screws, caps, or even peening. Quote Link to comment Share on other sites More sharing options...
BSM Posted December 17, 2012 Share Posted December 17, 2012 Tim, like many others I have been following the family, Thorny thread with keen interest and having been involved in later Military MT restorations I can well appreciate the effort and cost expended on projects from the WW1 period. Having engineering expertise in the restoration group is a marked advantage and it has been quite educational to read how each problem has been faced and overcome internally or with some welcome outside Forum assistance. Congratulations and may your planned restoration activities over the Xmas break be productive. As it is that time of year I don't suppose a bit of Thornycroft trivia would go astray. As you are aware a number of examples were shipped to Australia before and during the conflict. Attached is a copy of a period sales document for 2 "J" chassis numbers I came across. Rod Quote Link to comment Share on other sites More sharing options...
Great War truck Posted December 18, 2012 Author Share Posted December 18, 2012 Thanks Rod Thats very interesting and a bit of a suprise. Is it possible that they were despatched for the use of companies which were involved in "urgent war work"? On the subject of Thornys i have copied across this picture which appeared on the Landships site taken from Wikimedia Commons who took it from Library of Congress. I have spent quite a lot of time searching on Library of Congress site and keep being suprised by what else turns up. described as a blown up German armoured car it is of course a Thorny AA truck. Lots of useful bits there: Quote Link to comment Share on other sites More sharing options...
Minesweeper Posted December 18, 2012 Share Posted December 18, 2012 The export of the two "Thornys" in the middle of the Great War to Australia really is quite interesting! Australians took a significant part during the conflict - but I always assumed that any motor vehicles supplied to them were probably given to them when they reached "over here". It would seem unlikely that the lorries would be sent to Australia and then brought back here again! So were these two - and only two in this consignment - sent over perhaps for training or familiarisation purposes - so that Australian forces knew what to expect when they reached Europe? The sort of question that Roy Larkin might be able to answer - if the answer is not available from one of our Australian friends! Tony Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted December 18, 2012 Share Posted December 18, 2012 I noticed the shipping destination was Melbourne. The SS Benalla was a busy ship during WW1 bringing troops up from Australia to Europe. Quote Link to comment Share on other sites More sharing options...
nz2 Posted December 18, 2012 Share Posted December 18, 2012 described as a blown up German armoured car it is of course a Thorny AA truck. Lots of useful bits there: Visible behind the front wheel is a stabilizing arm and screw down jack, positioned on a large block of wood. Also the image shows an AA gun that was mounted upon the deck. Parts of the barrel mechanism lies off the deck and pointing towards the camera. Doug Quote Link to comment Share on other sites More sharing options...
Great War truck Posted December 18, 2012 Author Share Posted December 18, 2012 (edited) We knew that the Governor in the “whole” engine was in very poor condition – but took it out today to have a look at what was there. The original body castings had just about crumbled away but both came out very easily. The springs are “finished” but good enough to obtain measurements from them for replacements. Edited December 18, 2012 by Great War truck Quote Link to comment Share on other sites More sharing options...
nz2 Posted December 18, 2012 Share Posted December 18, 2012 Looking again at the photograph of the damaged Thornycroft shows damage to the rear of the vehicle, having received considerable force to demount the gun, yet the remained of the vehicle appears to have survived remarkably well. The size of the plates for mounting the gun are solid and substantial in form, so to destroy them without destroying the rest of the lorry is a mystery to me. If it was a direct hit ( or very close) the ammunition about the gun would produce a greater explosion and with it a greater level of destruction. Doug Quote Link to comment Share on other sites More sharing options...
Great War truck Posted December 18, 2012 Author Share Posted December 18, 2012 It seems likely that it was just a round detonating in the breech. Not too much damage to the chassis but probably didnt do the gun crew any good. Quote Link to comment Share on other sites More sharing options...
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