fuel economy. Occasional fast driving or highway use will keep the carbon buildup below a troublesome level; and for a car that is principally driven in such a manner, there is no reason why a Regular grade of gasoline cannot be used. Major Repairs When the need to make a major repair arises, there are several factors to consider before deciding whether or not to undertake the job. The most important point is to understand exactly what the repair entails. This can best be done by reading thoroughly the appropriate section or sections in the Workshop Manual and by talking with experts to resolve any unanswered questions. When such an understanding has been reached, the problem can be expressed in terms of the amount of money to be saved vs. the labor and equipment involved. Most repairs involve the use of a series of special tools to make the job easier, more eicient or even possible. Without a doubt, to achieve the best results the procedures should be carried out exactly as described. using all the special tools. However, in many instances similar or alternate methods can be used which will remove the need to purchase the factory tools. For example, seals can often be installed by the careful use of an arbor press or a hammer and drift punch; most of the commercially available gear and bearing pullers will work quite satisfactorily. There are, however, certain jobs which should only he at- tempted by experienced people using the -correct equipment. There is no other way to adjust properly a differential; and engine boring, bushing reaming, etc., require the services of a competent machine shop. One, therefore, needs to distinguish between what can and cannot be done. It is usually not worth- while to purchase expensive equipment to do a job only once. One will nd that a majority of the major repairs involve only one or two operations which require skilled personnel or special equipment. It is well within the abilities of the average person to perform all operations up to this point, go to an expert for the required steps, and to continue from there. For example, one can save a great deal of money in an engine overhaul by performing the disassembly, assembly and cleaning operations himself. In repairs of this sort, cleanliness is very important. Any time an engine block or gear case is disassembled, it and its contents should be cleaned thoroughly inside and out, including all oil passages. It is common practice to have an engine block boiled in a weak acid solution. This process results in a very Massachusetts Institute of Technology Cambridge, Massachusetts clean block but also destroys the pressed-in camshaft bearings. As the tting of new camshaft bearings involves the fairly ex- pensive process of align boring, it is often advisable to use a cold solvent instead. The importance of clearly understanding every step of the job cannot be overemphasized. Always read and understand the entire procedure before starting. It is also generally advisable to use only genuine replacement parts when making repairs of a major nature. Competition Preparation The Special Tuning Handbook and the competition parts lists were developed by the factory for use in sports car racing. They are proven modications and should yield the results indicated. The parts and procedures described are usually more than enough to make the car competitive in its class. It is generally inadvisable to proceed too far if the car is to be driven only on the street, as additional performance comes only at the expense of reliability, exibility, increased noise and reduced fuel economy. If the decision has been made to prepare the car for com- petition work, there are several factors to be considered. The most obvious of these is that any such modications will im- mediately void the warranty. Secondly, all such work is expen- sive. Thirdly, all performance modications work as a team and the various components must be compatible for best results. The teaming of modications is fully described in the 'various stages of thq; tuning handbook. Careful and meticulous work has a great value here, as the car must be running at the end of a race in order to win. The little things separate a winner from the also-rans. It is important to note that the presence of parts in the parts listings does not necessarily mean that they are legal for all types of racing. Its up to the individual to determine just what is allowed when planning the car, not after being protested. In non-sanctioned racing, such as gymkhanas and autocrosses, almost anything goes, but club racing and events regulated by national organizations generally have very strict limits concern- ing which equipment is permissible. An intelligent thing to do when planning any competition modications is to talk to others running your brand in the type of racing you wish to enter. They will be able to tell you not only what is legal, but also which modications produce the best results. In such matters, there is no substitute for experience. Richard Roberts, S. M. Mechanical Engineering Special Note , Editors Notes are provided when additional information is helpful to the readers understanding of the materi'al._These notes are found at the end of Part 1, at the end of 1ndlv1dual sections in The Workshop Manual, and at the end of Part 3. Note on the Third Revised Edition The third revised and updated edition of The Complete Ofcial MGB has been expanded to include the most recent Drivers Handbook, the Workshop Manual supplements issued from 197"] through the 1973 model year, and the engine emission control data applicable to 1972 and 1973 cars with the SU HIF 4 carburetors. The manual now covers models from 1962, the first year of production, through 1973. The former edition included a section on automatic transmission repairs. This has been omitted from the third revised edition since cars with an automatic gearbox have never been imported into the US. or Canada. In its place we have substituted much new material on the engine and cooling system, the semi-oating rear axle, the steering, brakes, body, and electrical system. Special thanks are due David G. Head Automotive Parts Manager CrandallHicks C0. Southboro, Mass.