Petrol Substitutes.
Page 13
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A Mechanic-correspondent Relates His Experiences, Covering a Period of Nearly Twelve Months.
Owing to the difficulty experienced in getting anything apprdaching an adequate supply of Motor spirit, due to the general shortage of supplies last year, I was compelled to experiment with several of the petrol substitutes then being marketed, in order to keep our fleet of seven commercial-motor vehicles on the road, and I have consistently used a mixture of petrol and various substitutes ever since.
Seven Vehicles in Use.
I might here state that the vehicles, owned by a Co-operative Society, are as follow : 3-ton .Signal, American _lorry, 32 h.p., L-headed engine, Stromberg carbuttetter, with no heating device fitted ; 2i-ton Karrier lorry, 30 h.p., T-headed engine, Clandel-Hobson carburetter, with hot water jacket to induction pipe branch; Argyll van, 16 h.p. Aster engine, T-headed, Zenith carburetter, with no heating device whatever ;
Briton van, 14 h.p., L-headed engine, Zenith carburetter, hot air drawn from exhaust muff ;
Briton van, 10 h.p., L-headed engine, Zenith carburetter, hot air drawn from exhaust muff ;
Humber van. 8 h.p., T-headed engine, Zenith carburetter, no heating device ; Humber ear, 15 h.p., T-headed engine, T. and M_ carburetter, with hot water jacket.
140 Gallons of Fuel Per Week.
The petrol used by these vehicles amounted to about 140 gals. per week, but, owing to shortage of supplies, I was unable to obtain more than 90 gals. per week. I obtained three casks, at is. 2d. per gal,, of mineral turps or white spirit, as it is sometimes called. I mixed this with petrol in the proportion'of 2 gals. of petrol to 1 gal. of mineral turps. The onlyalteration I made to the carburetters was the fitting of a small weight to the floats to make the needle valves cut off later, in order to counteract the effects of the heavier fuel. I was surprised at the result ; none of the ears showed any appreciable difference in the power developed, and there was only theA faintest trace of pinking•,when pulling hard on hills. There was no oiling up of plugs or difficulty in starting, once the engine was thoroughly warmed. On cold mornings, of course, petrol injection was necessary in order to get an easy start.
Benz olite Tried.
A little later I tried Benz elite, sold by a northcountry firm, and I obtained very good iesults from the use of this fuel ; its price was Is. 10s. per gal. I was able to use 1 gal. of Berizolite to I gal. of petrol with good results during the summer months, no difficulties being experienced in connection with starting or running, though these good results may have been due to the fact that the hot weather assisted in the vaporization of the heavy fuel. I discontinued the use of this fuel owing to its price being increased.
Then Petrofin and Glico's Mineral Turps.
During the autumn and winter months I used a mixture of either Anglo's Petrofin (1s. 8d. per gal.) or Glico's mineral turps (1s. 10s. per gal.) with petrol in the proportion of three of petrol to one of substitute. No ill-effects have been experienced once the engines are thoroughly warmed up. Even on the exceptionally-frosty mornings which we have had lately, a petrol injection generally suffices to get a, start or, failing that, a cloth laid along the induction pipe, over which a kettleful of boiling water is poured generally does the trick. Care should be taken to
see Athat -no water enters the float chamber via the needle-valve.stem or the overflow hole in the lid of the float chamber.
L Head Engines Better Than T Head.
I have noticed that more substitute can be mixed with the petrol on the vehicles having,the L-headed engines, owing to the fact thatithe,theat(from the exhaust pipe keeps the induction pipe and the car.. buretter constantly warm. Now, in T-headed engines, less substitute can be used, because the carburetter is at the opposite side to the exhaust pipe and, therefore, always cold. I find a tendency for unvaporized paraffin to collect at the rear or low end of the inlet pipe and oil up the plug of the back cylinder. This difficulty was, to some extent, overcome by fitting a small pipe, in. bore, from the exhaust pipe into the inlet pipe above the throttle, thus injecting live exhaust gas in order to heat the new charge. The fan belt can also be slackened a little in order to allow the engine to run a trifle hotter than usual.
The Lubrication Difficulty.
With reference to lubrication, if good oil of standard quality be used, and the piston rings are in good condition, no apprehension need be felt as regards the oil thinning out if it is changed regularly. As a rule, I change all mine after each 1000 miles.
I cannot say that I have noticed any, free paraffin in any of the crankcases. The oil is slightly thinner than when it is put in, and smells slightly of paraffin, but I have had some oil standing in a test-tube for two months after being in use 1500 miles, and I cannot discern that any settlement or stratification has taken place.
How to Mix the Fuels.
I do not recommend pouring the separate fuels direct into the tanks on the vehicles. I always use a
2-gal. measure, graduated into gals. for mixing, keeping one barrel of petrol and one of substitute on tap side by side. I run petrol to the correctequan
tity into the measure and then fill up to the top with substitute, afterwards pouring it into the tank or
into 2-gal. cans for storage. The act of pouring through a funnel into the tank thoroughly mixes the fuels.
No Excessive Carbon Deposit: One Lorry Deliberately Ran for a Long Period Without Attention.
I do not find any excess of carbon deposit in the cylinders as a result of the use of these substitrotes. The 33/4-ton Signal lorry has run about 8000 miles using a mixture of 2/ gals. of petrol to l gals. of mineral turps or Petrofin. On taking the cylinders off last week for the first time in 8000 miles, I found that the carbon deposit was very slight, about 1-32 in. thick, certainly no more than if petrol or benzole had been used alone. The valves were also in good condition, and though they have not been ground in during the 8000 miles, very little grinding was necessary to make them as new. I purposely let the lorry run a long time without taking the engine down in order to observe whether any ill-effects were caused to the machinery by the continued use of petrol substitutes. However, some form of heating of the air • supply to the carburetter is necessary to get the best results, and I find the vehicles pull better if the air supply is cut down a little, though of course this means slightly higher fuel consumption. I certainly recommend all who are not getting sufficient petrol to give these fuels a trial as they are dependable, and, if the above points are noted, safe and economical.