TUNING THE RILEY
TUNING THE RILEY SOME NOTES BY A. F. ASHBY (In on interview)
A. F. ASHBY A. F. Ashby commenced racing at Brooklands after the War with a s.v. 11-litre Riley, subsequently developed into a single-seater, which lapped at 103 m.p.h. With this car he won the 1927 Whitsun 75 m.p.h. Short Handicap at 76.41 m.p.h., the 3-lap Evening Open Handicap of 1928 at 81.11 m.p.h., and the second Evening 3-lap Handicap at 80.07 m.p.h. He then turned his attention to the 9 h.p. Brooklands Riley (see Monat SPORT, July 1930). He finished first in the 1930 Sussex Short Handicap, lapping at 91.38 m.p.h., and won. the 1931 Lincoln Junior Short Handicap, lapping at 95.78 m.p.h. Partnered by 1?. Paul ing he _finished 15th in the 1931 Double Twelve at 64.14 m.p.h., winning Class G. He then developed the four-carburetter “flat-iron ” Riley Nine with bodywork reminiscent of the ThomasSpecial, and won the Duke of York’s handicap at Guy’s Gala Meeting in 1982 at 102.69 m.p.h., although carburetter flooding kept his lap-speed
below 109 m.p.h. Al this period Ashby was doing tuning work on Riley Nines for Whitney Straight and E. K. Rayson, on an A kis for the former driver, and on an Alfa-Romeo for Flt.-Lt Donkin. This, of course, was additional to the Overhaul and tuning of sports Rileys of all types, which regularly occupies the Ashby workshop. A shby’s racing work was unfortunately interfered with at this time by ill-health. But last year he purchased from Ferrari a 3.2-litre monoposto Alfa-Romeo with Dubon net independent front suspension. RunninA,, at the Brighton Speed Trials he made 3rd fastest time of the day at 76.27 m.p.h. In the Campbell Trophy Race this year serious trouble arose and by sheer bad luck arepetition occurred on the Friday before the International Trophy Race. Ashby is now engaged on extensive development work of the Alfa-Romeo unit, as mentioned in last month’s issue. He favours the neu formula and plans a busi programme next season.
THE famous ” RCdWiI157. ” Riley „. litre side-valve sports job. in which Ashby and Victor Gillow deported themselves on Brooklands with conspicuous success thirteen years ago, preceded the famous Riley ” Nine ” of 1926. The Riley Nine was a sensational announcement, with then very revolutionary saloon bodywork and a decidedly advanced engine with valves inclined overhead in hemispherical combustion chambers, yet actuated by push-rods and rockers. Parry Thomas became intrigued with the design, although very occupied with his record-work with the Leyland-Thomas cars, and set about evolving a racing version. After his tragic death in 192’7 Reid A. Railton, chief engineer to Thompson and Taylor, at Brooklands, continued with Thomas’s
work. The car completed, Railton entered it for the 1927 Autumn B.A.R.C. Meeting and it won its first race, a 90 m.p.h. short handicap, very easily at 91.37 m.p.h. From this design was developed the famous” Brook-lands “sports-model Riley Nine, for many years one of Our premier
1,100 c.c. sports iobs, and a car which scored many notable racing successes. In variously modified forms the Riley has been raced by the Riley Company and others, numbering amongst its great victories the 1,000 Mile Race of the J.C.C. in 1932 at 84.4 m.p.h., the 1930 Saorstat Cup Race at 72.2 m.p.h., second place in the 1932 ” 500 ” at 99.61 m.p.h. and, with larger cars; the T.T. and ” 500″ victories.
Thompson and Taylor at first built the ” Brooklands ” cars, but after turning out about half-a-dozen—we believe— production was transferred to Coventry. Basically the Riley power-units have retained a continued similarity and have all used a system of valve operation with camshafts each side of the crankcase, operating push-rods that actuate the inclined o.h. valves via rocking levers. The low-built ” Brooklands ” model subsequently went out of production, but other sports models followed, notably the 1,100 c.c. ” Gamecock ” and ” Imp.’ Larger engines were also built, 1i-litre and 2-litre cars being raced, including the works cars and Freddie Dixon’s very famous Rileys, and the present production range now includes the I flitre sports “Sprite,” the 21-litre Big Four, the 1.7-litre ” Six ” and 2.1-litre V8.
Riley power-units are notably efficient aud in consequence have achieved most of their meritorious performances unsupercharged. S. C. H. Davis and B. K. Rayson have driven blown racing Nines and F. W. Dixon’s latest experiments with the 2-litre apparently lie in this direction. Tuning the 1,100 c c. Nine can be an absorbing occupation, for the design is definitely one that encourages the experimenter Ordinary early editions have a crankshaft with 1 -IV diameter big-end journals and the customary two bearings, and as this is the unit’s weak point tuning should be confined to improving the acceleration and pick-up, by the approved port-polishing, and carburational methods, rather than increasing the power output or maximum revs. The later units, and earlier “Brooklands ” jobs, have 1 ir journals which permit of liberties being taken. The models having this crankshaft have seven external webs round the clutch bell-housing of the crankcase, the other engines only three in significant webs. A crankcase with 1 fi# journals can be used in the earlier crankcases, but the ideal is the latetype” Brooklands ” shaft with 1 it” main journals, which is naturally not inter changeable. Ashby used a crankshaft with a 2″ rear main journal during his experiments with the racing “Flat-iron,” and later evolved a nitrified three-bearing crankshaft with 2i” rear journal, fully balanced. It is advisable to have the crankshaft statically balanced, which Laystall’s will do for about 30/-. The external copper oil-pipes on the crankshaft webs should be inspected and resoldered if loose. An interesting way in which those well acquainted with the ” Brooklands ” Riley can decide which crankshaft is fitted is to notice whether the reverse catch on the gear-gate vi brates over 5,000 r.p.m. The remote gear-control acts as a tuning-fork, as it were, and the smaller the crank the greater the vibration. Ashby has done up to 103 m.p.h. satisfactorily with a balanced 1 crank and late ” Brooklands” models and the ” Imp ” series have the I journals. No attempt should be made to lighten the connecting rods, but definitely they should all be brought to the same weight. The flywheel call be lightened by machining a groove behind the starter ring if this has not been done already. It should be possible to remove five to six pounds. With the normal ” Brooklands ” bead it is permissible to machine off “, putting the compression-ratio up to about 7 to 1. A 50/50 or 80/20 petrol-benzole mixture is then advisable. Care should be taken to see that the compressionratio has not already been raised, as many cars have been so modified. This alteration will not necessitate modification of the valve-gear, beyond tappetadjustment. Ratios as high as 12 to 1 have been used on the road and 14 to 1 for track work, Ashby actually going up to 15 to 1 or 20 to 1 experimentally, using a bronze head. The valves are of Silchrome steel and need not be replaced. Double Terry valve springs are advisable and pressures exceeding 100 lb. can be
employed without troubles arising. If the car has run a big mileage the cotters should be examined, but they are of 5 per cent. nickel steel and wear well and the design will withstand amply the increased loading. The inlet valve guides can with advantage be backed off and the ports polished. The exhaust valve guides can be shortened j.” and streamlined, but the guide should not be cut off flush with the port. The ” Brooklands ” jobs originally had twin Zenith triple-diffuser carburetters bolted to an unheated square-section manifold. Two Solex horizontal carburetters can be bolted to the same manifold. They should be given 105 to 110 main jets and a 28 to 24 choke, or 115 mains and 4 mm. choke for fast road work, as approximate settings subject to individual experiment. Early ” Brooklands ” models have Autopulse fuel-feed, which can with every advantage be replaced by hand-feed. Ashby, of course, introduced his famous plan of using four carburetters on this unit, which has since been widely copied. To accommodate the float chambers two carburetters are usually fitted each side of the block, the valve settings being modified to suit, which -rather places this modification beyond the scope of the ordinary
private owner. A possible solution is the use of Villiers carburetters with floatchambers directly beneath the mixingchambers ; otherwise Am al motor-cycle instruments are usually used, disposed as described. The exhaust manifold and off-take pipe should be very carefully lined up at ports and junctions. Early ” Brooklands ” jobs had small port areas and piping of the same diameter, but later cars had 30 mm. exhaust ports. It is an advantage to use late-type heads,
and piping to correspond. The ” Imp “
series have Vortex silencers. Early models have aluminium oil-pumps which are apt to distort if asked to maintain high pressures. The racing engines have alloy-bronze pumps with bigplungers that will maintain 90 lb. per square inch circulation. With these modifications and 7 to 1 compression-ratio K.L.G. 583 or Champion R17 plugs are advised for hard driving. There are several servicing points to watch. The water-pump has a flat impeller and the pipes allow of no thermosyphonic action, should the pump seize. The pump spindle, should be inspected frequently. On early models the dynamo runs at 5,500 r.p.m., and its armature seldom stands up. A special Rotax replacement dynamo should be fitted if much night driving is undertaken. The normal final drive ratio is 4.75 to 1. This ratio Ashby used in the Double Twelve Race. For fast road work a 5 to 1 ratio is useful. On the Track
Ashby used a 4.3 to 1 axle, giving 6,000 r.p.m. at 130 tn.p.h. and the car would still reach this speed with larger tyres. The valve timing is identical, inlet and exhaust, with openings 25° before T.D.C., closing 25° after T.D.C. The normal ignition advance is 450 before T.D.C., which should not be altered for road-work. A reasonable maximum for a fully-equipped ” Brooklands ” model Riley is 78 m.p.h., and after modifications the general liveliness should be considerably increased and the maximum should be around 83 m.p.h. If splitskirt pistons are fitted they should be scrapped, as only those in RR56 alloy of this type will prove reliable. Martlett pistons make an excellent replacement, or the Riley plain-skirt piston can be used for fast road work. When the compression ratio is brought up to 7 to 1 no alteration is necessary to the lattertype pistons. If the 1* ft crankshaft is
fitted a ratio of 9 to 1 is permissible, but special pistons will then be required to provide valve clearance. Turning to the chassis, the earlier ” Brooklands ” cars had satisfactory front shock-absorber brackets, but later models used brackets of unsuitable metal. Ashby can supply reliable re placements. Shock-absorber adjust ment plays a considerable part in realising the full performance of which sports Rileys are capable. Adjustments should be carefully carried out and defective shock-absorbers replaced. Binding the springs is of real value, unless they are of the Woodhead clipped variety. If quite drastic modifications are contemplated, the down-swept portion of the frame side-members may be boxed and have a welded angle-piece attached, while two additional cross-members can profitably be added at the centre of the chassis— alterations made to the chassis developed by Ashby for outer-circuit racing. The road wheels should be balanced and the cable-system of brake operation repays examination at points prone to seizure. The 9 h.p. “Ulster Imp” model, developed by Rileys for T.T. racing and using a 70/30 petrol-benzole mixture, gave 51 b.h.p. at 5,500 r.p.m. Ashby-‘s racing 9 h.p.. unit, with a compression-ratio that permitted using commercial fuel, gave 69 b.h.p. at 6;000 r.p.m., and peaked at a still higher speed, though prone to float-chamber vibration that affected the fuel feed above this speed. Ashby actually
claims to have lapped Brooklands at 112 m.p.h. on 71 b.h.p. with his Streamlined single-seater track car, by reason of low wind-resistance and good adhesion. Naturally the foregoing notes are intended to apply to private-owner tuning where reliability is an important factor and road-work is part Of the car’s regular duty. Methods of distinguishing between early and late ” Brooklands ” models, apart from the remarks already made, of which the reference to crankshaft sizes is very important, are obscure, as chassis numbering is complicated, but early cars had the Zenith carburetters, rod-operated brakes and aluminium gear lever extensions. The later Mark IV cars, of the type developed as works racing jobs, had four speed gearboxes, cable brakes, larger brake drums and elektron gear-extensions. Very early ” Brooklands ” models did not have remote gear control. These tuning notes relate primarily to the famous low-frame ” Brooklands ” cars, bit also larly to all 1,100 c.c. anti. 1-1-litre Riley units. The” Special Series “engines in standard form have twin carburetters but not ” Brooklands ” camshafts, the sports Gamecock ” model had a ” Special Series ” engine, while the ” imp ” has the big crankshaft and later Valve timing. The ” Sprite ” differs in having a three bearing crankshaft, pump cooling and 14 min. plugs, etc., and has its engine some 16″ further back in the frame than the ” Imp.” Study of Brooklands lap-speeds since 1930 shows that variouslytuned ” B rook lands ” models were Lip
ping at rather over 90 m.p.h. in the hands of a number of private owners. Racing editions, such as those of Ashby and Cuthbert, lapped comfortably at above 100 m.p.h. in the early days of their development. Eason-Gibson, we believe, lapped at 108 m.p.h. in a ” Brooklands ” model with standard bodywork, using a big crank, 14 to 1 compression-ratio and twin Solex carburetters, the special single-seater body, with conning-tower cockpit cowl, never being to any extent exploited. In 1930 Ashby was getting over 100 m.p.h., and over 75 in third, from his ” Brooklands ” model with two-seater body. If sufficient time and money is available the Riley engine can be very highly developed indeed. Ashby subsequently used a Special aluminium-bronze head with 14 nun. plugs and very carefully arranged -water passages. With this he employed his famous four-carburetter layout, altering the disposition of the cams to suit, first with Bowden R. 39 carburetters., later with Amal motor-cycle instruments. Special con-rods were made by the Glacier Metal Company Ltd., and the 2″ crank, previously mentioned, was used. The pistons were of elektron and the lightened tappets had roller-contacts. The compression-ratio was 20 to 1, reduced to 15 to 1 for long-distance races. This car lapped at 112 m.p.h. and finally reached speeds said to be in the neighbourhood Of 130 m.p.h. It is now for sale and would make an. extremely interesting car for any outer-circuit enthusiast, particularly as Ashby has a 21.” three bearing crankshaft with leadbronze bearings that has never been esed, but which was evolved to combat crankshaft difficulties that began to again intrude when speeds of around 8,000 r.p.m. were reached. In conclusion, we would close with a vote of thanks to Mr. Ashby for the ready information he
has given us. He has very modern equipment at his works at 9, Watford Way, Hendon, N.W., including heattreatment ovens and a Fronde dynamometer, and anyone who is engaged in pushing up Riley performance will find him at their disposal.