Barwell Motors, of Leatherhead Road, Chessington, Surrey, do not specialise in any particular make of car; in fact they either have a standard conversion already in existence for many modern cars or are prepared to carry out a conversion on any car which they feel will benefit from tuning.
The firm’s two principals, Mr. Lucas and Mr. Golding, place a great deal of reliance on the gas-flowing of cylinder heads, and they believe they have one of the only two air-flow chambers in the country, the other belonging to Harry Westlake. The device is simply a means of forcing air through the ports of a cylinder head. When a new engine is received the cylinder head is subjected to various tests in this chamber to determine the rate of flow, then modifications are carried out and more tests made until the best results are obtained. Plasticine is used to modify port shapes or if too much metal has been removed.
Naturally the B.M.C. “A” series engine receives a great deal of attention because of its popularity in racing and rallying. Barwells offer four stages of tune for the ”A” series engine. Stage 1 consists merely of a modified cylinder head with a 9.0 : 1 compression-ratio, modified and polished combustion chambers and ports, for £12 10s. Stage 2 also concerns the cylinder head but a much higher standard of finish is given to the head, while the compression-ratio goes up to 9.5 : 1 and large inlet valves are fitted. The induction manifold is also carefully matched to the enlarged parts. With special valve springs Stage 2 costs £26 10s. Stage 3 consists of the Stage 2 cylinder head together with a combined inlet and exhaust manifold and twin H2 S.U. carburetters — all for £56 10s. Stage 4 is for the racing man, and for your £140 the engine is removed, the flywheel lightened, crankshaft, con.-rods and pistons balanced, high-compression pistons, high-lift camshaft amid special distributor fitted, while the push-rods and valve-gear are lightened. On the induction side twin H4 S.U.s are fitted, and to extract the gas a special exhaust manifold and silencer are used.
Barwell are probably unique in not taking any standing-start acceleration figures for their conversions. Ron Golding, who takes most of the Barwell performance figures, considers that so much depends on the skill of the individual driver that standing-start figures requiring a number of gear-changes can be misleading. All Barwell figures are taken in top gear, and since this merely means pushing the accelerator to the floor there can be little variation. A complete list of acceleration figures can be supplied for all stages of tune of all conversions.
Perhaps the most exciting and certainly the newest development from the Barwell stable is an aluminium cylinder head for the B.M.C. “A” series unit. This head, which weighs only 9 lb., has been exhaustively tested on an Austin Healey Sprite for some months now and has given no trouble. It is designed to replace the existing cast-iron head without modification and could be done by any competent owner in an hour or so. The prototype head was fitted to an otherwise standard Sprite and the figures obtained were very similar to those obtained with the Stage 3 conversion costing £56 10s. The new head will retail at the relatively modest price of £37.
A number of competition cars have been tuned by Barwells, one of the best known being Paul Fletcher’s very fast Twin-Cam M.G. The cylinder head was gas-flowed, combustion chambers and ports carefully cleaned up and larger valves fitted, while twin double-choke Weber carburetters are used to boost the power output to 140 b.h.p. Even with twin S.U.s 130 b.h.p. has been seen. This car, which has had over £1,000 spent on development, is now up for sale as Fletcher will be racing a Formula Junior Cooper with a Barwell-tuned Ford 105E engine next season; this also has twin Weber carburetters. Development work on the 105E is well advanced and the cylinder head has been fully modified to racing standards, but there is some doubt as to whether the crankshaft will withstand sustained high r.p.m. Only tests on the track will verify this. Should everything go well several Formula Junior cars will be seen at the Brands Hatch Boxing Day meeting fitted with Barwell-tuned Ford engines.
Apart from their work on conversion measures, Lucas and Golding have done some original design work. They have worked in close collaboration with A.C. Cars for a number of years and, in fact, tune an average of two Bristol engines per week for fitting to A.C. Ace and Aceca models mainly for export to the U.S.A. Some years ago A.C. designed a twin overhead-camshaft 2.4-litre six-cylinder engine ostensibly to power the Ace, and much of the cylinder-head design work was carried out at Barwell Motors. On paper the engine was giving phenomenal power outputs but the high tooling costs of such a project caused it to be dropped. Now that the Bristol engine has reached the limit of its development the A.C. directors probably wish they had taken the risk.
The Rover is not generally regarded as a tuneable vehicle but the now-out-of-production 90, 105 and 105S have all received the Barwell attention, and for £28 one receives a considerably modified cylinder head with larger valves and highly polished combustion chambers and ports which will increase the top speed of the 105S from 95 to 100 and the top-gear 70-90 m.p.h. time from 16.4 sec. to 12.6 sec. Probably regarded as the ultimate in engine design, the 3.4-litre engine fitted to the XK120, Mk. VII and 3.4 Jaguars is capable of considerable development, and a steady flow of these models come to Chessington for attention. The top speed of the Mk. VII is raised from 102 to 115 m.p.h., while the 80-100 m.p.h. time is reduced from 14.4 to 10 sec. This is all gained with extensive modifications to the cylinder head costing £36 for the XK120 and Mk. VII and £34 for the 3.4.
Other models breathed on by Barwells include the M.G.-A, TR3, Sunbeam Rapier II, Renault Dauphine. Standard Eight, Simca Aronde and Grande Large, Austin A30, Ford Anglia, Consul, Zephyr and Zodiac, Fiat 1100 and Singer Gazelle (o.h.c.), all of which have gas-flowed cylinder heads giving a useful performance increase for around £30-£40. — M.L.T.
V. W. Derrington
The firm of V. W. Derrington Ltd., of London Road, Kingston, Surrey, has been in the tuning business for 36 years, and was established long before tuning became fashionable. The proprietor, Mr. Victor Derrington, has been a racing driver for a good many years; in fact his exploits were described in our April issue. He has become best known for the large number of exhaust pipes and manifolds now produced at the Kingston works, models being made for most modern production cars. The four-branch manifold for the TR3 engine, which costs £20, is fully approved by the factory, and the Morgan company offer the Derrington modifications as optional equipment for the Morgan Plus Four. The modified cylinder head for TR2 and TR3 gives a compression-ratio of 9 or 9.5 : 1, and the combustion chambers are reshaped and polished, as are the inlet and exhaust ports. An exchange head costs £25. The standard inlet manifold obstructs the passage of the gas to quite a considerable extent and the Derrington induction pipe feeds the gases direct into each, giving a much higher gas speed. This manifold costs £12 10s., or with twin H6 S.U. carburetters £40. There are, of course, a number of other mods. for the TR series, including high-lift camshafts, Alfin brake drums, modified driver’s seat, anti-roll bars, magnetos, competition springs, and so on which can make it into an extremely potent and more comfortable car.
A great deal of the Derrington business is done by mail order and, rather surprisingly, nearly 40 per cent. of their output is exported to all parts of the world. America is the biggest customer, with large quantities of conversions being supplied for the M.G.-A, Sprite and Austin Healey 100 models, but orders have even come in from such unlikely places as Jerusalem and Greece. ln fact, the Greek owner of an M.G.-A fitted the H.R.G.-Derrington cylinder head and made an extremely fine showing in the Acropolis Rally.
Two popular items, both of which are made at the Derrington works, are luggage grids and wooden steering wheels. A large range of grids is made for most modern cars and prices range from about £7 to over £12. Wooden steering wheels are made for such models as TR3, Austin Healey 100 and Sprite, Jaguar 2.4 and 3.4. The manufacture of these wooden wheels, which started as a sideline, now employs eight people practically full time. The bosses have to be cast, the frames cut from stout-gauge Birmabright, and the laminated rims carefully fitted and polished. These are priced at around the £12 mark and are especially popular in the States, several hundred being exported every year.
Derringtons manufacture all the exhaust manifolds for Lotus, Cooper, Vanwall and, indeed, most of the leading racing-car manufacturers. A vast number of manifolds must be kept in stock, which strains the organisation somewhat as the company has outgrown the premises which it has occupied for a number of years. For instance, six different manifolds must be kept in stock for the Ford Consul and Zephyr range to cater for one, two or three-carburetter inlet manifolds, while the convertible models need a different-shaped tail-pipe. In fact on only two models, the Riley 1.5 and Wolseley 1500 are the Derrington exhaust systems interchangeable.
Full conversions are available for a large number of vehicles, including Ford Anglia, Prefect, Squire, Escort, Thames van, new Popular — in fact, for all 100E and 93A-engined vehicles; all B.M.C. “B” series engine models, for which the H.R.G.-Derrington cylinder head is available at £58 10s., or, of course, a modified cast-iron head at £20; the Austin Healey four- and six-cylinder models and the Sprite; all B.M.C. “A” series engines, including the A30; Morris Oxford side-valve models from 1940 to 1954; Morris Eight, Series I, II and “E” and Minor side-valve models; Standard Eight, Ten Pennant and Herald; M.G. XPAG and XPEG engines as fitted to TC, TD, TF and Y; Wolseley 4/44 and Morris Ten; o.h.v. Hillman Minx, Sunbeam Rapier, Sunbeam-Talbot 80, 90, Mk. II and III. and Humber Hawk; Fiat 1100, 500 and 600 models.
From this list it can be seen that there are few modern popular cars which are not catered for by Derringtons and, although being an old-established firm, they intend to keep abreast of all modern developments and modify new models as they are introduced. — M.L.T.