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Olly Monk on
Winter Projects
No racing now until May 2012 but plenty to do in the workshop. The 2.5cc car needs a couple of button heads making to sort out the volume and the squish clearances. The 10cc car needs a service and modifications to the chassis and a new tether arm to get the new Picco engine in. After the Swedish events I came away with the thoughts of a Dooling replica car with the right engine in, not the modern 20 year old, ex novice hydro, Rossi 40 engine. I had bought a couple of 2.5cc diesel twin shaft Russian engines at the right price during the Euro Champs.
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The picture shows the bottom half of a Slabang chassis being faced off. Shortly after this picture was taken, I tried the engine in and it is too wide across the lugs. After studying the pictures of a finished car it needs a crankcase with no lugs and a different mounting system. That was the end of the project for the time being. Now long term:- I had managed to buy a Gary Barnes gearbox off eBay a few years ago, and have bought the rest of the kit to build a replica Dooling Arrow. |
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No drawings come with the kit, but Gary supplied a set of pictures to work from when I built the first replica car. They are a standard chassis with a variety of different tops available. The first job is to remove excess material from the pan so that you can get the gearbox in. From the picture you will see that the pan near the axle cut outs is black. This is soot from a simple wick burner with a smoky flame, black up the area you are trying to fit the part into, fit the part and where it's shiny is where it’s touching. (below) |
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In the right hand picture the top of the pan has been faced off. The next operation is to machine the pan out wide enough to fit the engine in, removing equal amounts of metal from each side. |
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The engine and gearbox are in position at this stage. Everything can be moved about in the pan until you are happy it will all fit. Not much room left for the tank and shut off! |
The first picture below shows the gearbox in place. Make sure its square to the centre line of the pan. The engine mounting holes have been spotted through with a drill and centre punched using an optical punch tool, really good as it magnifies the mark and you get it right. The gearbox is held in place with M4 cap heads and the engine with 6-32 cap heads these have a much coarser thread and are more suited to aluminium as they will be in an out a lot during the lifetime of the car.
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Next up is the front suspension. It’s based on aluminium "T" section, a rubber grommet and a couple of collars.
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The front axle assembly is shown above. Just ensure both axles are parallel when fixing in position.
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A change of material next, fitting the top on. Mark all positions for cut outs in the body on the pan and transfer onto the body. Very difficult to measure as most of the outside is curves. |
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Most of the cut outs have been done using my Aldi 'Dremell'. Best cheap tool I have ever bought, along with a couple of boxes of assorted cutters to suit it. Horrible, itchy stuff GRP. Cold water and soap is supposed to be the best for washing the dust off, closes the pores in your skin and it doesn’t get rubbed in when washing your hands etc.
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Picture on the far right shows another of my better machinery purchases, a Digital Read Out for the milling machine. Don’t know how I managed without it. Made light work of drilling out the body holding on straps and the exhaust flange. Now the top and the pan can be fettled up so the top and bottom meet up. Then on with the tank. Right: Body strap. Far right: Exhaust flange. |
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Space was a bit tight in the front of the pan so I have milled material out of the front, right up to the suspension. In the background you can see one of the body holding down straps and the exhaust flange in place.
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A mock up tank is made in wood to ensure that the body will fit over it and it can be used as a former to build part of the tank.
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Finished tank in place. Unfortunately the vent pipe fouled the front suspension and had to be moved, see patch on tank prior to refitting vent. After a trawl of the internet and a visit to Stuart’s to have a look at his Dooling car, I have sorted out a way of making and fitting a simple cut out to the car. It's basically a brass body with a piston that closes off the fuel flow to the engine. I have yet to sort out the spark ignition circuit and how to switch it off. |
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The cut out being fabricated mixture of silver solder to fit the mounting bracket and soft solder for the pipes. The second picture shows it in position and piped, the steel rod is the piston that shuts the fuel off.
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The Dooling car so far, still some more to do. I have got my modern cars back from David Giles who had them as exhibits for his presentation on tether cars to the Bristol Model Engineers Society.
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Thanks to Olly Monk for all his work in putting together this article and photographing the stages of construction.
©copyrightOllyMonk2012
