Specialists in High-Efficiency Tuning

Specialists in High ciency Tuning

The Works of D. M. K. Marendaz, Ltd. THE term " super-tuning " is one which is frequently mis-applied. The everyday garage man will use it in connection with a perfectly normal engine overhaul, while the amateur mechanic

will often describe as such, a quite simple adjustment. Pot these people in particular, a visit to the premises of D. M. K. Marendaz, Ltd., would be definitely enlightening, for here one finds workshops not onl\ equipped for carrying out "hotting up" by the most modern methods, but where accumulated scientific knowledge is utilised as well, to carry out that class of work for which Mr. Marendaz has

been well-known.

Mr. Marendaz has specialised in highefficiency tuning a good deal longer than most people, and he combines a very extensive scientific technical knowledge with practical race driving in all his undertakings. Before the War, he concentrated his efforts almost entirely on the problem of increased power of output of internal combustion engines, while during 1914 1918 his services were utilised in the R.F.C. and R.A.F., both as a technical expert and test pilot. His more recent accomplishments can be found in the list of records at Brooklands and elsewhere on cars of various makes, and more particularly on the" Marendaz Special." Amongst his many successes are the following :—

World's International Class records : 1 i litre Class, 24 hours ; Class " G ", 24 hours, 1,000 miles, 12 hours and 3 hours ; Class" B "200 miles ; Class" C "5,000 miles. He also has the distinction of having lapped Brooklands at 90 m.p.h. in a saloon car, the highest speed ever attained there with a closed vehicle.

In the production of such a car as the new straighteight 11-litre " Marendaz-Special," which will be completed in some two months time, nothing is left to chance or guesswork. Practically all the parts of the engine are made throughout in the works at Brixton, and as indication of the way in which Mr. Marendaz goes the job in hand, it may be mentioned that he makes rule of carrying out laboratory tests on metals selected for highly-Stressed parts.

His shop is unusually complete in regard to testing plant. An apparatus which has ptoved of great value in the production of engines of phenomenally high r.p.m. is an Avery connecting rod specific-gravity balancer.

This machine not only ensures that connecting rods on an engine are of the same weight, but also that the corresponding halves (the big ends and small ends) of the rods are also equal. In this way a " couple" is obviated. As with the con. rods so is balance of vital importance in regard to the crankshaft, and a crankshaft dynamic balancer is employed ; static balancing (on knife edges) is 'also resorted to, but naturally when a mere fraction

of an ounce in weight variation may produce a formidable unbalanced force, the former device is a necessity. Incidentally the balancer used is somewhat exceptional in being capable of running at a rather higher speed than usual (1,800 r.p.m.), by the incorporation of a frictiondriven gearbox.

The plant also includes a Heenan and Fronde dynamometer, and an Avery tensile testing machine. Looking round the workshops one finds further equipment and machine tools of such variety that it becomes easy to realise that the making of camshafts, gear cutting and other intricate production jobs are all well within the scope of Marendaz, Ltd. Moreover, Mr. Marendaz is a man who is intensely keen on the class of work in which he specialises, and every job is done under his personal supervision. At the time of our visit we saw a number of very interesting cars in various degrees of completion, 'rejuvenation and modification. They were just a few which have passed through his hands during the season's

racing. One or two were definitely of the " hush-hush" variety, and it is probable that we shall hear more of these before very long. It is interesting to find, also, that Mr. Marendaz, like a number of other ex-pilots, is now renewing his interest

in aircraft (it may be remembered that he entered a " Moth " in the King's Cup Race), and without revealing any secrets, his name may be expected to figure in flying in the near future.

W. T.