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What an Engine Costs

11th August 1950, Page 46
11th August 1950
Page 46
Page 49
Page 46, 11th August 1950 — What an Engine Costs
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Which of the following most accurately describes the problem?

in Upkeep

The Cost Amounts of Minor Engine Attentions Add Up to a Swill Greater Per Mile Than Expenditure on Major Repairs IN the previous article I showed how common it is for operating costs to differ from the averages as set down in " The Commercial Motor " Tables of Operating Costs. I dealt with each of the headings in the Tables, with the exception of maintenance which, as I pointed out, is a special case deserving separate treatment. Actually, of all of these items of operating cost, maintenance is the most difficult to assess.

Whenever the opportunity presents itself, I obtain actual figures of cost from my haulier friends. In nearly every case, the amount debited against maintenance is, according to my standards, insufficient. On the: rare occasions when the amount debited is what I would regard as ample for the purpose, there is an apologetic murmur from the operator that such and such a lorry had been overhauled that week and that I should not regard the figure as truly representative. .

Such an observation at once indicates that the operator concerned does not realize what is meant by the term "maintenance," which is intended to cover overhauls as well as minor attentions to the cliassis and bodywork of the vehicle. The•caast of maintenance, apart from the expensive items such as major overhauls, is made up of small amounts. I can demonstrate by a simple example that the small amounts often mean more in cost per mile than the large ones. .

Take the case of a vehicle on which the sum of 15s. per week is spent on washing, oiling.-greasing and so on. The • mileage is 240 per week, so that the cost per mile is id. When the mileage has covered a total of 48,000, the vehicle is subjected to an engine pverhaul and a certain amount of chassis repair, costing, say, £80. That is 0.4d. per mile.

Every penny spent-on the vehicle which cannot fairly be debited against any of the other nine, items of operating cost is almost certainly spent on maintenance, and if every penny be properly recolded, the totalformaintenance in 99 eases out of 100 will be found to be niuch greater than the operator fondly imagined.

Neglect or Omissions

The sort of thing that exasperates me is a letter to a vehicle manufacturer from an operator stating that his vehicle has run a colossal mileage and has cost only a few shillings on maintenance. That cannot possibly be true. The vehicle must begin to involve the operator in expenditure on maintenance as soon as it is put into service. If there be no such debit, the vehicle is being neglected and although the amount spent on maintenance is not necessarily an indication of the efficiency of that work, I should, when the amount is small, expect to find that one of two things is happening.. Either the operator has omitted to enter all that is spent on it, or he is neglecting the vehicle. In the majority of cases I think it is a deficiency in accounting. The reason why many maintenance costs records are faulty is that operators have the work done by drivers, or in their own repair shops, the cost being debited against overheads. All such operators, of course, are of the opinion that my figures are excessive. They overlook the fact that they are probably paying as much, or more than I say in the maintenance, costs, and are not debiting their expenditure as they should. I: will }kelp at this juncture to refer to the current issue of the Tables dated 1948. In that, as I have done for many years, I have split maintenance costs into two A36

portions: one called "maintenance (c1)," the other " maintenance (e)."

The expenditure on maintenance td) is intended to cover routine maintenance operations carried out on a time basis irrespective of mileage. Such operations are washing, greasing, repainting and varnishing.

It is difficult, using averages, to cover all 'possible variations which may occur in expenditure under this head. At the one extreme, there is the type of operator who may wash his vehicles once a month, and who never has them repainted or varnished from the time he puts them into service until he disposes Of them. On the other hand, there is the operator who has his vehicles washed daily, revarnished twice a year, and lepainted and lettered in alternate years.

Maintenance (e) refers to expenditure on repairs and overhauls, operations which are necessary not at intervals measured by time but by mileage.

If the frequency of a maintenance operation is determined by time, then, as maintenance costs are assessed per mile, they must increase in inverse proportion to the annual mileage. If the cost per week be 10s. andthe weekly mileage 240, the cost per mile is id., but if the weekly mileage be 480, that cost is reduced to id. per mile.

So far as the average operator of 3-5-ton vehicles is concerned, it is improbable that any improvement in costing methods is likely to take place. So far as the average haulier is concerned, he will be wise, even if he does keep reasonably accurate cost records, to rely upon the Tables as a basis to calculate his charges, using his own figures as an annual or six-monthly check.

Wide Variations Expected

My purpose in this and the previous article is to show that it is reasonable to expect wide variations in maintenance costs even when cost records are as accurate as they may fairly be expected to be. -As an example, I will confine myself to the cost of maintenance of the engine, taking a typical example and showing how, as the result of the application of different methods, the cost per mile may be expected to be either above or below average.

I propose to measure the cost by two methods: first, on the assumption that the operator has the work executed by the local agent and, secondly, that he has some of it carried out by the driver, and some of it in his workshops. The operations needed, their sequence, the intervals between them and their repetition, I am taking from an instruction book.

At each 1,000 miles, according to those instructions, the following work should be done: Drain crankcase and replenish with fresh oil; clean two oil filters and one fuel filter, clean overhead-valve gear."

Assume that the total time necessary to do the work from start to finish is 2 hrs. The cost, carried out by a motor agent, would be I4s. If the work be done in the operator's own workshop at a rate of wages of 2s. 6d. per hr. plus Is. 6d. per hr. for overheads, the net cost is 8s. Those are labour costs; there is no allowance for materials, as the oil used should be debited to another item of operating costs, namely, lubricants.

Every 2,000 miles it is recommended that, in addition to the above, the ventilation pipes be removed and cleaned, the strainer in the crankcase sump removed and cleaned and one or two other items attended to. The additional time needed for this work I estimate at 1 man-hours. The cost .s thus 10s. 6d. for the work done professionally and 6s. if it be carried out on the operator's premises. Materials are debited elsewhere. (I shall, at the end, debit something for cleaning stuffs, jointing paste, etc.) At 5,000 miles, the following work is to be done in addition to that already specified to be carried out every 1,000 miles:—" Clean second fuel filter, clean and replenish air cleaner; check the tappet clearances (note that the cylinder-head cover is already off for the purpose of cleaning the overhead-valve gear); examine injectors," This work will, in all probability, take a couple of hours. It will take less if the tappets do not need adjustment and if the injectors be in perfect order, but it will take longer if there be much to be done to these components. Two hours is, therefore, a fair average time. The cost is thus 14s. if the work be done at a garage and 8s. if it be carried out in the operator's own repair shops. This time there must be a debit of Is. 6d. for materials—paraffin for cleaning the filter, oil for the air cleaner, as well as new copper washers for the injectors. The total cost is thus either 15s. 6d. or 9s. 6d. respectively.

At 15,000 miles a more thorough inspection of the engine is required. The engine sump should be removed and cleaned, the oil pipes cleaned and so on. A period of approximately three man-hours, is necessary for this work, costing either 21s. or 12s. according to the method employed. Materials required will include some new gaskets, paraffin for cleaning, probably some new nuts and washers, split pins and sundries of that kind, costing in all about 10s., so that the total cost is either £1 Ils. or £1 2s.

Material Costs High

When 30,000 miles have been covered, it is recommended that the cylinder head be removed, pistons removed and examined, new rings fitted, if required, and a top overhaul carried out. In reckoning the time for these operations, it is necessary to remember that the cylinder-head cover is already removed—for the 1,000 miles work. Injectors are taken out—for the 5,000 miles check, and the sump is off for the 15,000 miles inspection and cleaned. Even so, a further 10 man-hrs. will be necessary for the work to be done. The material costs may be heavy, especially if new rings be required. I estimate the labour costs at £3 10s. and £2, and the material cost at £3 10s., so that the total is £7 or £5 10s. for the respective methods.

These various operations are, of course, repeated at the appropriate periods until the time comes when the engine needs to be thoroughly overhauled. It is usual on such occasions to replace the old engine by a reconditioned one. Naturally, the mileage at which this becomes necessary will vary, but the principal determining factor of that period will be the degree of efficiency of maintenance operations. I think it is fair in the circumstances to assume that when 90,000 miles have been covered a complete engine overhaul will be necessary, including reboring or relining of the cylinders, crankshaft grinding, the 'fitting of new bearings, valves, valve springs, and so on. This obviously is workthat should be entrusted to a specialist. It should certainly not be undertaken by the average operator.

A Complete Cycle,

The most likely course will be to replace the engine by one completely reconditioned either by the manufacturer or by a dealer. The cost will be in the region of £120 to £140. In the schedule of expenditure which I give below I have taken a round figure, £130, as being a fair estimate: , It will be gathered from what has been stated that in the course of 90,000 mites a complete cycle of maintenance operations will have been effected. A new or reconditioned engine may be expected to run a further 90,000 miles, costing the same amount mile by mile as during the first 90,000 miles of its life. A schedule of costs may thus be assessed for the more expensive method as follows:- Omitting the odd shillings and pence it means that the cost for maintaining this engine for 90,000 miles may be anything from £204 to £251. If we divide those amounts by 90,000, we get the cost of maintaining that engine per mile run, and it is thus seen to be from 0.54d., in the case of the less expensive method, to 0,67d. in the case of the more expensive. The average of the two is approximately 0.6d. per mile for engine maintenance alone. S.T.R.

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