A brief history of the Six-Cylinder 4-1/2-litre Lagonda

The M.45 continued unaltered in 1933-34-35, but in 1934 the first of the Rapides were produced. They were influenced by the successful Fox and Nichol T.T. cars, and the number of 3-1/2-litre chassis frames left over from that then superfluous model. There were several important differences between the M.45 and the M.45R engine and there is no doubt the M.45R is a better job, especially as regards durability. The compression-ratio was raised to between 6.6 and 7.0 to 1. Heavier con.-rods were used and the small-end boss was 1.31 in. o/d. against 1.28 in. of the M.45; in addition, the con.-rods were not split to allow the pinch bolt to grip the gudgeon pin. Instead the gudgeon pin was merely located by a bolt that did not exert pressure on it. The omission of this split in the con.-rod makes it much stronger at the little-end. The overall depth of the M.45R rods across the web was also greater, being 1.26 in. against 1.06 in. The crankshaft was increased in size too, the big-end journals being 2-1/8 in. diameter, 1/8 in. larger than the M.45. In addition to more robust reciprocating parts, an extra stud was fitted at the front of the crankcase to assist in holding down the cylinder block.

It should be mentioned that most of the dimension’s given above and later on were obtained by direct measurements of the parts concerned.  When taking these measurements, it was found that no two components were absolutely identical, so they may differ slightly from the designed dimensions. LG. Motors’ drawings were destroyed during the war and it seems quite impossible to obtain definite and authentic figures from any known source of information; that is why it was found necessary to measure the actual components.

In the M.45R a Scintilla horizontal magneto replaced the B.T.H. and a Tecalemit full-flow oil filter replaced the wire gauze. No b.h.p. figures were published and the rev-limit remained at 3,800.  Nevertheless, this engine must have been distinctly more powerful as the maximum speed of the Rapide was approximately 5 m.p.h. higher and the acceleration better than that of the M.45, with no substantial difference in weight or frontal area. The catalogue published for the 1934 Motor Show, although it gave 108 b.h.p. as the output for the standard engine, made no specific claim for the Rapide which was introduced then. Through the kindness of Mr. Arthur Fox, I have the bench test report of the Lagonda Rapide engine fitted to the 1933 Monte Carlo Rally car Registration No. BPK 743; this special engine according to the data given, had a compression-ratio of 7.1 to I. In the series of four tests made, the highest power it produced (Test No. 4) was 119 b.h.p. at 3,400 r.p.m. A note attached to the report says “Mr. Bolton (a Lagonda engineer) states that Test 2 shows better results than the standard Rapide.Test 2 gave a maximum reading of 105 b.h.p. at 3,200 r.p.m. The Lagonda catalogue claims for the ordinary engine must therefore be treated with reserve.

The LG. 45 Engine

The following year (1935) the LG.45 was introduced. The first version of the engine, the Sanction I, was virtually, identical with the M.45R except for a different and much more effective type of inlet air silencer. It is generally considered that the LG.45 Sanction I had a slightly lower compression-ratio, 6.6 to 1, than the M.45R, but it is impossible to find authoritative contemporary figures. The LG.45 Sanction II which followed in early 1936 differed from its predecessor only in that twin Scintilla Vertex magnetos replaced the coil and magneto arrangement.

At the 1936 Motor Show the LG.45 Sanction Ill, also with the twin Vertex magnetos, was produced. This engine owes something to W. O. Bentley, who joined Lagonda in 1935. He was primarily concerned in designing the V12 car from scratch, but as Chief Designer he supervised the alterations to the six-cylinders cars, whose engine he described as “a fundamentally sound if rather coarse basis on which to start, a six-cylinder o.h.v. push-rod engine: sturdy, powerful, and with a quite outrageous crankshaft roar.” The Sanction lll had a completely redesigned cylinder head. The carburetters bolted directly on to the head, which had an internally-cast induction manifold designed to give greater turbulence to the charge. The shape of the combustion chambers was altered and the exhaust valves were just over 1/10 in. smaller in diameter than the inlet valves, which were approximately 1.7 in. in diameter, thus being some ten-thou, larger than in the preceding engines.

The new head undoubtedly gave better results at the top of the speed range. Incidentally, the red line on the rev-counter was moved up to 4,000 r.p.m. The cooling of cylinders 5 and 6 was improved by the addition of an extra water transfer at the rear of the block.

All who have owned both M.45, M.45R and LG.45 Sanction Ill models will confirm that whereas the earlier two start to get short of breath at about 3,000 r.p.m., even in the gears, the Sanction III will rev freely to over 4,000 r.p.m. (except, of course, in top, where it would represent over 100 m.p.h.), in addition to which it appears smoother at all speeds, an objective W. O. Bentley desired to achieve.  Once more the real power output of these engines remains a mystery, but 140 b.h.p. was claimed in the 1935 (1936 models) catalogue!

From the Fox and Nichol files I have before me the bench test report dated August 26th, 1937, on engine No. LG 45/260/S.3. These tests were carried out by Lagonda Ltd. on the car entered for the 1937 Donington T.T. by Fox and Nichol. The compression-ratio given in the report was 7.96 to 1, and larger carburetters than standard, using V.B. or V.C. needles, were fitted, with consequent modification to the inlet ports. The highest powers obtained were 143.25 b.h.p at 3,800 r.p.m. using a Brooklands-type silencer and 145 b.h.p. at the same r.p.m. with open exhausts. This engine was specially prepared for racing and the compression-ratio was much higher than the standard LG.45 production unit which was only 6.68 to 1 (vide the 1938 catalogue). It is extremely unlikely that the power developed by the standard LG.45 engine approached that of the racing one, therefore, the claim of 140 b.h.p. cannot be taken seriously.

In 1936 the LG.45 Sanction III Rapide was introduced at the Motor Show. This was based on the engines prepared for the team cars, the main difference from the normal Sanction III being the improved exhaust system. Separate pipes led from each port, the front three and the rear three merging into two pipes that came out through the side of the bonnet. These pipes, still separate, led out to a large common silencer. In addition, the compression-ratio of the Rapide was higher than on the ordinary version.

In the 1936 catalogue the LG. Rapide engines were said to develop 150 b.h.p. and subsequent literature indicated a maximum compression-ratio of 7.5 to 1. Even so, production Rapide engines had a lower compression-ratio and smaller carburetters than the Donington T.T. car. Disregarding the extra care that would be devoted to the preparation of the racing unit, it is quite unbelievable that the ordinary Rapide engine should produce even as much as the 145 b.h.p of the T.T. engine, let alone the 150 b.h.p. mentioned in the catalogue pages. Production engines generally appear to be able to produce substantially more, power on the pages of a catalogue than they do on the dynamometer, and this characteristic is not confined to any one make. The Sanction IV engine produced for the LG.6 has no important differences from the Sanction lll and no higher power was claimed for it.

The Chassis

The M.45 Chassis

The M.45 (1933-34) chassis was a substantial “ladder” structure of 10 ft. 9 in. wheelbase, braced by six stout cross-members. The suspension was conventional by rather stiff semi-elliptic springs each controlled by two Hartford friction dampers. One pair on each axle were Tele-controls adjustable from the drivers’s seat. Bishop steering gear was employed. The brakes involved an excellent vacuum-servo assisted system, the durability of which was such that today it is still working effliciently on almost all M.45s on the road. It has been said that the servo motor was added on as the original design required enormous pedal pressures, but this criticism can be levelled at most systems designed from the first to operate with servo assistance as anyone who has driven a Rolls-Royce with defective servo knows. The relatively light pedal pressure required by the 1933-31 cars compares favourably with the Girling brakes employed on later chassis. This is not to imply anything against the latter, which pull up a 34-cwt car in 30 feet from 30 m.p.h. Girlings were first used on the 1934 T.T. cars prepared by Fox and Nichol, and subsequently were included in the specification of the 1935 Le Mans winner. It seems likely that they were adopted because they were appreciably lighter than the servo brakes, while adjustment and balancing could be carried out very rapidly. Furthermore, sudden engine failure, which might occur in racing, would render the servo inoperative.

The clutch for the M.15 was a Roper and Wreaks 11 in. with solid centre plate and a type of clutch stop which, when properly adjusted, permitted gear changes as fast as one could move the lever. The T.8 gearbox had no synchromesh but there was dog engagement of third and top. It was a delightful unit, trouble-free, and one which allowed easy clutchless changes by any fairly skilful driver. The overall gear ratios were: First, 11.52; second, 7.36; third, 4.76; top. 3.66 to 1. Nineteen-inch wheels were fitted, and plain bearing universal joints were employed. The whole chassis was constructed in a high-class manner: such refinements as grouped Tecalemit grease nipples, concealed battery master switch, P.100 headlamps and spot lamp, etc., making it clear that nothing was sacrificed on the altar of economy.

The M.45 Rapide Chassis

The chassis introduced in 1934 for the first Rapides was called the M.45R. This employed the same frame as the short-lived 3-1/2-litre model. It was of 10 ft. 3 in, wheelbase, but at the front was of more massive proportions than the M.45; it weighed just as much as the longer wheelbase car. The centre of gravity of this model was farther forward than on the M.45. Having driven several examples of both M.45 and M.45R. I would say that no improvement in handling is achieved by the use of the shorter chassis. If anything, the M.45 handles better, but that is offset by the superior performance of the M.45R engine. It is worth noting that no team cars used the M.45R chassis frame. The 1934 cars and 1935 Le Mans team cars had the 10 ft. 9 in. chassis frames with approximately M.45R engines and brakes; the 1936 team cars had LG.45 chassis, also of 10 ft. 9 in. wheelbase.

The M.45 Rapide chassis had Girling brakes and the semi-elliptic springs were each damped by Girling-Luvax vane-type hydraulic shock-absorbers and Andre-Hartford tele controls. The Autocar, in describing the Rapide in 1934, stated that the rear springs had slight negative camber under load. The specialists in these cars today advise the same spring setting as the M.45, which is a distinct positive camber. I had the springs on my M.45R set up both ways and can say that the positive (M.45) setting gave a more comfortable ride, but made the back end more skittish when cornering fast.

The clutch on the M.45R was the same as its predecessors but the T.8 gearbox had a free-wheel built on to the rear end. This device was only current for one year, and if it was kept in use all the time it was not up to dealing with 33 cwt. of car and the high torque of the engine. Very few still work today. It is rather pleasant to drive one of these cars with the free-wheel functioning, as the brakes cope easily with the extra work required of them, and the use of the clutch pedal is rendered nearly superfluous. These early Rapides were equipped with 19 in. wheels. A built-in hydraulic jacking system, which could be operated from inside the car, added to the already extensive standard equipment.

The LG.45 Chassis

The LG.45 chassis, as far as the frame was concerned, was similar to the M.45, being of 10 ft. 9 in. wheelbase. It was the first of the firm’s chassis to be influenced by W. O. Bentley. He decided that the Lagonda could not be regarded as an out-and-out sports car, but was a high-speed luxury car. He carried out such modifications as the existing design permitted to make it smoother, more silent and more comfortable. This was accomplished with no sacrifice of performance, except for some increase in body sway on corners taken very fast. Girling brakes were employed, and the springs were much more flexible than on the earlier cars, still damped in the same as on the M.45R. A thick double bulkhead was interposed between the engine compartment and the dash. Between the two walls of this bulkhead were located the 90-a/h. 12-volt battery, a space for the radio and a space for some tools and an inspection lamp. An 11 in. Borg and Beck clutch replaced the earlier unit. This operated more smoothly and with less shock to the transmission, but it is a fact that the Lagondas so fitted were a trifle less quick off the mark than the cars equipped with the earlier clutch. The G.9 gearbox was introduced, with synchromesh on third and top. It was extremely pleasant to use, very light in operation, with well-chosen ratios; changes as fast as one could move the hand could be made with ease. Unfortunately, it was less durable than the T.8 and when used in competitions has very often proved troublesome. For example, Goodhew broke third speed three times and second speed twice, in two seasons racing.

The overall ratios on the G.9, as fitted to Sanction I and II LG.45s were: First, 11.63; second, 5.98: third, 4.48; top 3.58 to 1. These cars were fitted with 18 -in. wheels. Gear ratios for the LG.45 Rapides were: First, 8.66; second, 5.66; third, 4.30; top 3.31 to 1.

Automatic chassis lubrication from a pump operated when the clutch pedal was depressed replaced the grouped grease nipples. Oil was piped to every point in the chassis requiring lubrication, except the universal joints, which were Hardy Spicer needle-roller-bearing type, instead of the plain-bearing ones.

The LG.45 chassis made for the Sanction III cars in 1937 differed slightly from the preceding  LG.45s. The G.10 gearbox replaced the G.9. It was very much stronger and easily transmitted the 220 b.h.p. of the Le Mans twelve-cylinder cars. This gearbox had synchromesh on second, third and top and was operated by a massive central gear lever instead of the right-hand lever which had graced Lagondas prior to 1937. This box demanded very considerably more muscular effort to operate than the G.9 and although the synchromesh was powerful it is quite impossible to change gear on G.10 as quickly as on its predecessors. The overall ratios were: First, 11.63; second, 5.98; third, 4.48; top, 3.58 to 1. Eighteen in. wheels were used and Luvax ride-control shock-absorbers were featured. In addition to the 10 ft. 9 in. chassis an 11 ft. 3in. chassis was produced.

The LG.6 Chassis

The last 4-1/2-litre chassis was the LG.6. This was the first Lagonda six-cylinder with i.f.s., the springing medium for which was long torsion bars. Semi-elliptics were retained at the rear, but were mounted outside the frame. This 10 ft. 7 in, chassis frame was very different from the previous models. It was a W. O. Bentley design, much more rigid than its predecessors, being a cruciform-braced structure of great strength. Luvax ride-control dampers were employed and Lockheed hydraulic brakes with twin master cylinders replaced the Girlings. An alternative long chassis 11 ft. 3 in. was available with lower final-drive ratios. The G.10 gearbox was used with overall ratios as follows: On the short chassis cars: First, 11.63; second, 5.98; third, 4.48; top 3.58 to 1. The LG.6 Rapide had the following ratios: First, 10.76; second 5.53; third, 4.14; top, 3.31 to 1. Equipment was even more lavish than before and these cars always seem quieter, more powerful and very much smoother than the LG 45s. There is little doubt that it was one of the finest 4-1/2-litre chassis produced before the war. Its considerable size and weight, while limiting the performance to a top speed of about 95 m.p.h., contributed greatly to its long life. The condition of the average LG.6 in use today, 20 years old, is as a rule, quite outstanding. Both body and chassis are free from rattles and all the small items, such as windows, door catches, etc., work as well as when they were new.

In 1938, when the LG.6 made its debut, it was an advanced chassis design. It is one of the few cars in the high performance luxury class that had a form of independent front suspension that remains effective today, even when compared with the ride given by most modern vehicles. The six-cylinder 4-1/2-litre Lagondas have not been remarkable for mechanical innovations (except possibly the LG.6 chassis). They have followed well-tried methods and have been developed steadily. The quality and quantity of materials, and workmanship, has always been of a very high standard, no cost-saving skimping being evident in any detail. The result is they all wear exceedingly well and not a single “dud” model can be found in the series. In their day they provided very nearly the best performance obtainable from a British-made production cars, not only as regards performance figures, but in their manner of going too.

The Coachwork

Closed Bodies