A. H. McDonald & Co.~ Industrial Pioneers ~'Imperial Engine Works' - Melbourne, Australia VAPORISERS & HOUSINGS |
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| The McDonalds built their first
engine in 1903 in their home workshop. Commercial engine production dates from July 1st,
1904 when they moved into the Hawthorn premises, although large scale production did not
commence until 1905. McDonalds first produced a range of horsepower ratings and including single and multiple cylinder petrol/kerosene, marine and gas suction engines of their own design between 1903 and 1922. These were primarily intended to be used to power their tractors and road rollers and as stationary engines. From 1918, McDonalds switched production to diesel engines, either using the Hvid (pronounced 'VEED'. Hvid was a Dutch licensor.) fuel vapourising system or hot bulb ignition. Both 2 cycle and four cycle engines were built as well as a number of experimental/developmental engines. McDonalds copied the St Mary's H.O 'Super-Diesel' engine (USA) for their original C and F type engines, with a complete range of engines eventually being added from 2 - 15HP. Interestingly, K.N. McDonald recalls that the system was always referred to as 'Hvid' and not the more common 'Brons' in the factory. The St Mary's used the Hvid fuel vapouriser system and McDonalds continued to use this, with their own improvements, until 1948-49 when Bosch fuel injection was introduced. Many manufacturers around the world initially used this technology, but only for a relatively short period of time. The last HVID engines were made about 1929 in the USA. McDonalds and Brons seem to have been the longest as many found it to be inferior to advanced made in the 1920s. Cummins engines in the USA were one such manufacturer who suffered losses with their 'Thermoil' Hvid engines, despite making many design improvements. The advantage of the Hvid system was that it could use any heavy 'distillate' as fuel, including kerosene to crude oil. McDonalds maintained this was cheaper and easier for the farmer and argued that the system did not require specialist mechanical skills as it was simple and easy to repair. In practice, the system requires minute and careful calibration and can be quite difficult to set correctly. These engines are started on kerosene and then switched over to diesel. Each engine seems to be unique and following the standard factory Instruction Manual exactly as printed does not always guarantee success! However, once set, the engines run successfully. McDonald Imperial Super-Diesel engines have a distinct exhaust note both at idle and under load but observers are advised not to stand too close to the larger engines when working - a fair bit of oil residue can be known to leave the exhaust!
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C/F/J Type | SD/CD/FD Type | SE/CE Type Vapourisers |
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Click on small images to see a larger view |
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FUEL VALVE. (Same Instructions for both C/F/J and SD/CD/FD Types)
This clearance is essential, so as to ensure the needle valve shutting off the supply of fuel to the Engine when the speed becomes excessive. Fuel Valve Adjustment. - Occasionally the lock nut and adjusting screw of the double offset lever (921) may shake loose. This will cause the fuel valve (863) to remain open for too short or too long a period. (It will, of course, depend on which way the screw turns after it gets loose.) If the screw turns downwards, it will keep the valve open for too long a period and allow too much fuel to enter the fuel cup (possibly producing a black coloured exhaust, or the Engine will blow fuel out of the air hole and konk). On the other hand, if the screw slackens upwards, not enough fuel will be allowed to enter the Engine; consequently it will lose power. It is very seldom that any adjustment to this part is required, the correct position being that at which only the minimum amount of fuel is taken into the cylinder to do the work required by the Engine. This position can easily be ascertained by testing the setscrew in various different positions while the Engine is working. In each case, however, it is important that the lock nuts should be securely locked in position, otherwise the adjustment will vary and cause the Engine to work irregularly. To ensure best results, the fuel valve should seat on its outer extreme bottom edge only and not for the full depth of the seating. The copper-asbestos washer makes the joint between the bottom flange of the fuel cup and the machine facing in the cavity of the cylinder head. Vapourising Housing. - The fuel valve (863) is mechanically operated, and it is of the utmost importance that this valve should he kept tight and not allowed to leak. If it leaks, it will be indicated by the fuel vapour being blown out of the small air hole. If this leakage he allowed to continue for any length of time, it will cause
The usual cause for this valve leaking is by dirt getting under the sent; hence the necessity of using clean, thoroughly strained fuel. The glass bowl of the fuel strainer should, therefore, be cleaned frequently. Or it may be due to the set screw on the double offset lever (921) holding the valve (863) open too long a period. Remedy for Leaky Fuel Valve. - If a leak should occur, turn the fuel valve (863) a few times on its seating. This can be done while the Engine is working, or alternatively press the valve open momentarily while the Engine is working, and the probabilities are the grit will be dislodged from the valve seat. If either of these remedies fails to overcome the difficulty, it will be advisable to stop the Engine at the first opportunity, and then proceed as follows -
The fuel cup (862) sometimes remains in the cylinder head after the vapourising housing has been withdrawn. Should this occur, replace the housing, screw both of the 1/2 in. nuts about half way down, turn the Engine round against the compression, and the air pressure inside the cylinder will then lift the fuel cup off the C/A washer, enabling it to be lifted out in the usual manner. Occasionally the fuel cup (862) remains tightly fixed on the lower end of the vapourising housing (860). To remove the cup, hold the housing in one hand and gently hit the side of the fuel cup with a wooden hammer; it will then drop out easily without being marked, distorted, or damaged in any way. Having now removed the complete housing and fuel cup, dissemble it (carefully noting the relation of the various parts), wash thoroughly in kerosene, remove all traces of carbon, also making sure that the small jet holes and passages are thoroughly clean and unobstructed. If necessary, lightly grind the valve with ordinary knife polish - being very careful to thoroughly remove all traces of the emery before replacing the parts together. The fuel cup makes a gas-tight joint to the housing by means of a tapered joint. This joint may occasionally require to be reground. Having all the parts thoroughly cleaned, assemble carefully, making sure the marks on the housing and fuel cup come together, and the small holes in the fuel cup point towards the piston. The copper-asbestos washer (875) makes the joint between the bottom flange of the fuel cup (862) and the machined facing in the cavity of the cylinder head. It is most important, that the flat seatings in the cylinder head, fuel cup, and the vapourising housing are thoroughly level, clean and free from burrs. When replacing the vapourising housing, screw and tighten both nuts evenly.
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TO ADJUST THE CONNECTION SCREW.
POINTS TO WATCH FOR BEST RESULTS.
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| Taken from the A.H. McDonald & Co Pty Ltd Instruction Manuals for Imperial Super-Diesel Engines | |
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