Fire Risk with Air Cooling?
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I VIEW with considerable trepidation the suggestion, made
in an article published in your issue dated February 6, that air-cooled oil engines may receive more consideration for use in motor vehicles. It seems to me that such power units might present a fire hazard.
In the event of leakage of fuel from either a highor low-pressure pipe, it may seem that conditions for combustion would be almost ideal, for there would be air passing at high speed across cooling fins which might be above " chip-frying " temperature. If combustion did occur there would be a gout of flame from the outlet of the air ducting.
It is true that air-cooled oil engines are approved by the Ministry of Transport for use in ships' lifeboats, but perhaps the fire risk has not been fully considered or investigated. In my view liquid or even steam cooling is still the best and safest method from every point of view. Incidentally, there appears to be a high level of noise from air-cooled oil engines of more than a litre capacity, and this might preclude some of them from serious consideration for road use.
Liverpool, 15. D. F. GILMOUR. [A considerable number ofair-cooled oil engines is in operation, apparently quite successfully, in Germany arid elsewhere, whilst a bus operator in Britain has been highly satisfied with the results obtained with a German model fitted into a British vehicle. So far no news has come to hand as to any of these causing serious fires. Petrol has been used in close proximity to air-cooled engines on motorcycles and certain cars for many years without causing undue perturbation in respect of any fire risk, although it is realized that a spray of fine droplets of oil under high pressure is highly combustible, if a naked flame be encountered by it, but a cylinder fin would have to be very hot to cause it to ignite. ED.]
Can Oil Change Cause Trouble ?
A PARAGRAPH entitled "Change of Oil Not 1-1 Dangerous," which appeared in your issue dated January 23, was of considerable interest to me. I have recently had the opportunity of examining the V-8 petrol engines in three vehicles, which had to be taken off the road because of the failure of main bearings.
These units had been running on a straight oil and. in error, were not thoroughly cleaned when a changeover was made to a popular oil of the additive type. It seems that in each case the addicive material .removed particles of carbon deposit and caused them to become a danger by mixing with the oil, resulting, I am convinced, in the failure of the bearings. A trained engineer, who carried out a detailed inspection of these particular engines, expressed. the same opinion.
I hope that this experience may be of some help to those operators who have recently changed to a special additive oil, or who are contemplating making such a change.
Manchester. R
Bus Services In a Growing Town
THE excellent article by D. R. MacGregor, in your issue I dated February 13, dealing with services operating in Bedford, mentions that the joint express service of Percival Motors (Cambridge), Ltd. and this company, between Cambridge and Oxford, passes through Bedford. In fact, the route of this service is via Luton, Dunstable and Aylesbury, well south of Bedford. We do, however, operate a number of express services from or via Bedford, including
E28 Service 5 between Birmingham and Clacton-on-Sea, Service 34 between Bedford and Lincolnshire and Service 40 between Bedford, King's Lynn and Hunstanton.
That from Huntingdon and St. Neots, referred to by Mr. MacGregor is No. 17, operated by our Huntingdon depot. This route has recently been extended from Godmanchester to Hemingford Grey, near St. Ives.
An application is current for a new express service between Bedford and Cromer, via Huntingdon, Swaffham, Fakenham, Holt and Sheringham, which arises, in part, from the forthcoming closure of the Midland and Great
Northern Railway. E. A. LAINSON,
Cambridge. Managing Director, Premier Travel, Ltd.
Cords Rings for Production Engines
WE were interested to read in your issue dated " February 6, that at the Road Haulage Association's Coventry, Rugby and North Warwickshire Sub-area forum in Coventry recently, the representative of F. Perkins, Ltd., was asked why they fit Cords piston rings in their engines. It seems that the questioner was under the mistaken impression that Cords are only for worn bores.
Although Cords rings are very successful in reducing the rate of wear and improving performance from a worn bore, we also supply many rings for new bores to Perkins and other manufacturers. Due to their special cupped design and the low radial pressure, the rate of wear is much less than with the usual type of ring.
London, N.W.I0. D. H. PIPER, Sales Manager,
Cords Piston Ring Co., Ltd.
Tyres a Delicate Problem
YOUR editorial comment in The Commercial Motor dated February 20 does not give the facts as far as the Tyre Manufacturers' Conference are concerned. The Conference have not tried to place difficulties in your way, but have done everything possible to be co-operative. We appreciate that you made no direct approach to the Conference, and we contacted your Birmingham representative only following suggestions made by several of our members that the request for information could be best handled on an industry basis by providing a unified statement.
It happened that the industry was then giving consideration to tyres in relation to new motorways and it was felt that a statement arising from this could form a better basis for an article than a series of statements from individual manufacturers.
There is no question that a visit to any tyre factory by a member of the Press, or contact between the Press and our members, must be approved by the T.M.C. In their relations with the Press, as in other things, our members are free agents.
We regret that the request to see a draft of your article has been considered as a form of censorship or to imply that the Conference were endeavouring to suppress a free discussion on technical and other subjects. This was certainly not our intention.
London, S.W.I. R. T. BYFORD, Secretary, Tyre Manufacturers' Conference.