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BenHawkins

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BenHawkins last won the day on March 4

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  • Location
    Birmingham
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    Engineer

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  1. I had to work in America last week so didn't have time to make anything. However, a couple of evenings in a hotel room with nothing to do meant I could sketch up the carburettor lever and air admittance disc (which allows the mixture to be leaned off by allowing air into the throttle chamber through the spindle). Now I just need to make it.
  2. I have been cleaning the carburettor. The inlet trumpet was very dented but was relatively easy to tidy up using a hammer and the bick of the anvil There is also a carburettor heater that gets plumbed into the cooling water circuit. A nice bronze casting that cleaned up really well. I didn't go overboard with the cleaning of the float. The inlet pipe was cracked so I made a new one and soldered the original fitting back on. The White and Poppe carburettor has a variable jet, as the throttle is opened the jet size increases. That is achieved by having this cap over the jet which rotates with the throttle barrel. The orifice had become worn so I cleaned only the wear area and soldered it before scraping the solder back. I don't think this really makes any difference to performance. This picture shows the fixed jet in the carburettor body. The top is shiny because I have put some brass polish between the fixed jet and the cover and lapped them together as scratches in this area prevent the correct control of fuel flow. This is the throttle barrel before it was fitted to the carburettor body. I am missing the lever that fits the throttle spindle so need to sketch that up and get on with making it.
  3. I have been trying to get a Bosch D4 magneto rewound for several years. It has been to a couple of people who eventually reject it; not because there is anything intrinsically wrong with it but because everything is so much bigger than a magneto from a few years later and does not fit their tooling. Obviously I could fit a later magneto but it would look quite different. The current magneto specialist was keen to work with me so when he stated the points insulator and distributor end cap (made from fragile ebonite) were not serviceable I took the dimensions from my donor magneto turned up new ones in black acetal. I had the straps for securing the magneto but several parts were missing that I have had to make. The first was the coupling, a relatively simple turning and milling job, especially as I had the engine side and a drawing for the part that fits the magneto, so it was only the length of the intermediate piece that was guesswork. Then came the dovetail packer underneath, this is a 5" wide aluminium plate, 17/32" thick to make up the centre height of the magneto. The magneto fits on the centre line, the final part being the clamp than has two 30 degree chamfers to pull the plate down onto the crankcase. A washer and 3/8 Whitworth castellated nut finish off that job. Just have to hope the D4 magneto will eventually come back working!
  4. Although this van probably only had magneto ignition, trembler coil (secondary) ignition was an option. The engine I am fitting started life with Liverpool Salvage Corps and had the remains of a distributor, so I decided to make the missing parts (mostly informed guesswork as it is not a type I have drawings or photos for). The base of the distributor and vulcanite commutator came with the engine but nothing else. I have been collecting scraps for the last few years and had enough to build it. I counterbored a bit of brass plate. I then silver soldered a scrap bar end into the counterbore. And then put that part back on the lathe for machining. I made the brush carriers out of bar ends of brass with the insulators from black acetal. The brushes themselves are WW10001 magneto earth brushes.
  5. The engine fits between the chassis rails with no adjustment, so having had shims cut in the last batch of laser cutting we lifted the crankcase out again. The lifting beam we installed in the garage last year to get a heavy boring machine out of the trailer was far better for this job than the engine crane we used to put the crankcase in last time. The fit has to be fairly tight to prevent putting the aluminium casting in tension, a mallet was required to get the crankcase into position. Once the crankcase was in place, new 1/2" Whitworth bolts and castellated nuts were fitted through the existing holes.
  6. We finished and fitted the new bronze wheel bearing towards the end of last year, but then abandoned part of a boring machine in the garage making it awkward to get the lorry out. I failed to take a photo of the finished bearing so this part machined one will have to do! The rest of the boring machine arrived at the end of May and we were able to shuffle things around again and prepare for last weekends Dennis event at the Rural Life Museum in Farnham.
  7. Thanks for that fantastic photo, it appears to be identical to the generating set I have. We have not found that much information on them, but amongst other things they appear to have been used as search light generators. The 6' long cast iron base is really heavy, if mine had come with the dynamo, the 1 ton payload trailer would certainly have been over weight. I have not confirmed the capacity of the engine yet but it would appear to be at least 3" bore and 4" stroke. The T4 engine fitted to my vehicle originally was 3-1/2" bore and 5-1/2" stroke. Both engines were compact as a result of using only 2 main bearings so the cylinders can be close together. The T4 cylinder block was only around 16" long, the Simplex is 15-1/2". The bonnet is fairly short on the BT chassis so there isn't enough space for a larger engine. The axle ratio is about 7.75:1, so combined with the 32" OD tyres (when new) it should be OK even if the engine turns out to be a little smaller than the T45.
  8. I have finished adjusting and painting horn guides for the back axle. The bolts are all cross drilled but I ran out of split pins.
  9. No sharpening or rework required. Only issue we had was that if tin shavings built up in the die it would bind up on the punch and lift it out of the holder. From that point on I kept it clean and swapped the grub screw for a cap head so I could apply a little more torque. No problems from that point, think it will probably be able to make the next radiator as well. Thanks for the help.
  10. We picked up a coil of tinplate for the radiator gills in the summer but decided to put the job off for the dark evenings. For about a month we spent 30 minutes each night (by which time we were cold), punching out another 12,000 gills (making 14,000 in total). I have not machined the tube plates yet; I will get that job completed before threading the gills onto the 78 copper tubes. I have given the crankshaft and main bearings a bit more of a clean and reassembled with plastigauge to get an idea of clearances. They are between 2.5 and 4 thou which seems reasonable for this type of engine. So, I think we will be mounting it in the lathe and polishing the journals with 400 grit emery cloth and then proceeding with reassembly.
  11. On the engine front, I have been struggling to strip things down without damaging anything. It took me several weeks to remove the timing gears; they are fitted to the camshafts with a shallow taper and woodruff key. After using the puller, heat, malleting, penetrating oil, cussing etc. they finally gave in and I don't think I have damaged anything. There are five bearings per camshaft, so far I have only managed to remove the front on on the inlet camshaft. The remaining bearings and carriers are all proving stubborn to remove. As the engine has been open for many years I am keen to strip it was fair as possible to make sure I can remove all the foreign objects.
  12. Sorry for the lack of updates, I have been juggling a few too many projects. Since the last post I have cut 78 tubes to the correct length for the radiator core. The coil beneath them is the tinplate we need for the 12000 remaining radiator gills; that should keep us busy in the dark winter evenings. When this chassis was converted to trailer use, the locomotive style horn guides were discarded. The drawings for the standard 3-ton model survive but the special Carter Paterson model were different to accommodate the wider chassis with underslung springs. Anyway I sketched up what I believe to be correct and had pieces laser cut; this is a trial fitment of the first one. The cast iron slipper block can be seen on top of the tyre and was made previously. The fence posts bolted to the chassis are just to help with my scaling of the body design. There is a brace between the fore and aft guides; I fabricated these previously. After welding I dressed the welds with an angle grinder. Three of these have been grit blasted and primed. They need mounting up on the milling machine to carry out the final machining operations. I have purchased this photo of one of the earlier batches of Dennis vans at the Carter Paterson Kingston depot.
  13. I have been busy taking other vehicles to shows recently but decided to make the terminals for the Bosch D4 magneto. To fit below the inlet manifold White and Poppe chose to supply angled versions (probably just to make my life difficult 114 years later). The first task was to make myself a sketch. Then I started to machine the brass parts. This shows a slitting saw on the milling machine. For the screw thread I decided it would be easier to machine the heads off brass wood screws and silver solder them in. I milled two vee grooves into a piece of steel to hold the angle for the second silver soldering operation (no, it is not a six cylinder engine - I made two extra so I could select the best four). They all cleaned up nicely. The insulators were turned/milled from black acetal. Another small task ticked off the list, plenty still to do.
  14. When I wiped down the crankshaft there is some corrosion to the journals, this is probably the worst area. Unfortunately that almost certainly means a regrind and therefore re-metalling of all the bearings. I really should have removed the camshafts by now but I have been getting distracted by events for the other vehicles. I have taken the clutch cone off the shelf and scraped the worst of the grease and grime off it. The leather clutch lining is quite hard and dry but hopefully a few more applications of neatsfoot oil will sort it out.
  15. Last weekend we took the the lorry to the classic commercial show at Gaydon. We had a slightly newer Dennis for company. We had it transported there so only did a few miles of driving the Dennis. I briefly considered setting off at 4am to be there for 10am but decided that could wait until I have completed a few more shorter trips. Whilst preparing for the event I noticed the oil coming from the nearside front hub had some bronze dust in it so we removed the wheel one evening this week. I remember the mandrel used when machining the tyres had scored the bore of the wheel and it looks like this was the cause.
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