Articles

There is something hugely imposing about a vintage Bentley automobile aside from its massive scale; perhaps it’s a combination of the famous ghosts each car carries, the spirits of wealthy playboy racers, forward-thinking engineers and the man who was determined to build England’s finest sporting cars. Despite the legends that surround the original Bentley cars—those sometimes called “W.O.s” after the company founder—a great portion of those near 90-year-old cars are in fine running order today. Enthusiast motoring is these cars’ raison d’être, and the faithful who maintain them take pride in upholding the founder’s ideal. If you’ve ever harbored dreams of thundering down the Mulsanne Straight at Le Mans behind the winged “B,” you may be the right sort for vintage Bentley ownership.

It may be hard to imagine, considering that most of the models built in the last half century have been ultra-luxury sedans, but the first Bentleys were based on race cars. Patterned after the Humber racers built for the Isle of Man Tourist Trophy, and using advanced engine design technology and the future industry-standard light aluminum pistons that W.O. developed during World War I for aircraft engine use, the first series of Bentley cars were called 3 Litres, for the displacement of their four-cylinder engines.

The 3 Litre entered production in the spring of 1921, and like many high-end cars of the period, it was available in different chassis lengths. The standard 9-foot, 9 1/2-inch chassis was intended for lighter, more sporting coachwork, and a long standard 10-foot, 10-inch chassis, new for 1923, was intended to support formal coachwork; cars so adorned often wore a blue “label,” or a blue-colored background for the radiator shell’s cloisonné badge. A high-performance short chassis variant built from 1924 to 1929 was designated “Speed,” and it was embellished with a red label badge.

The 3 and 4.5-liter four-cylinder engines are virtually bulletproof; their only durability issues are the possibility of broken cross-shaft gears and failed center main bearings, after many miles of hard use.

Adjustable Andre Silentbloc shocks, which effectively damp vertical wheel motion, can be rebuilt. Bentley specified two spark plugs per cylinder, activated by two magnetos; their controls are durable.

The 3 Litre’s engine used a five main bearing crankshaft and was cast en bloc, so there was no possibility of head gasket failure. It displaced 2,996cc via its 80mm bore and 149mm stroke, and followed Grand Prix engine practice by incorporating a single overhead camshaft to geardrive four valves per cylinder. Twin ML magnetos modulated two spark plugs per cylinder, and the standard fuel delivery system was a five-jet Smith-Bentley carburetor, while Speed models were fitted with twin “sloper” SU carburetors. The standard 4.3:1 compression ratio allowed for 70hp at 3,500 RPM, while Speed models’ 5.3:1 ratio gave them 85hp. The only transmission available was a four-speed manual, and rear axle ratios from 3.78 to 4.23 could be specified.

Because every Bentley left the Crickle-wood factory in North London as a rolling chassis, owners had their choice of coachbuilders to craft the car bodies. A number of prominent firms had their hand at bodying Bentleys in all forms of ‘saloon’ (sedan) and ‘tourer’ (open car); among them were famous names like J. Gurney Nutting, Hooper, H J Mulliner, Thrupp & Maberly and Freestone & Webb. It was the artisans at Vanden Plas who constructed, among other body styles, the famous Weymann-type fabric-covered open touring bodies that were used on Bentley’s Le Mans racing cars. Other coachbuilders worked in this style, too: the H.M. Bentley and Partners (W.O.’s brother) firm actually rebodied our photo car in 1935, as it had been born in 1928 as a George Maddox & Sons of Huntingdon four-door saloon.

Although they happily sold their standard cars to wealthy clientele to engage in more sedate motoring, it was in competition that W.O. Bentley knew his car’s value would be proven. The second Bentley car ever built drove to victory in the Whitsun Junior Sprint Handicap in 1921, and in 1922, the first three cars, now prepared as a team, took on Britain’s grueling Isle of Man Tourist Trophy race and finished, a rarity even for established automakers. Winning a team prize inspired Bentley to build 71 “TT Replica” models—short standard wheelbase cars with raised compression and a Claudel-Hobson carburetor, costing £1,295—in 1922 and 1923.

In an unusual move, W.O. had a special boattail racer built to run in that year’s Indianapolis 500, although it finished in 13th place; not letting this seeming flop dissuade him, he took the special highoutput, 9-foot ‘short’ chassis version of the 3 Litre to France to run against Bugattis, Mercedes-Benzes and the like at Le Mans, where his cars won outright in 1924 and 1927, inspiring numerous Le Mans replicas and the 18 “100 MPH” models, also known as the “Supersports” green label cars built between 1925 and 1927, the latter being the last year that the 3 Litre was produced.

Most 1921-1931 Bentleys use a fascia of aluminum or varnished wood, depending on the style of the coachbuilder; the gauges fitted give the cars a vintage aircraft feel, and all can be rebuilt if needed.

Fine leather covers every soft surface, and skilled upholsterers can recreate an interior with ease.

Six-cylinder Bentley cars, in the form of the 147hp 61/2 Litre and 180hp Speed Six, were introduced in 1926, and these cars would win Le Mans again in 1929 and 1930. The four-cylinder 3 Litre was revised into the 4 1/2 Litre, the car that would spawn what is arguably the most famous of all W.O. cars, despite it being one that he himself didn’t approve of: the 50 supercharged, 175hp “Blower Bentleys” built in 1929 at the request of one of his prominent patrons for racing homologation purposes.

Being a development of the 3 Litre models, the black label badged 1927-1931 4 1/2 Litre Bentley was also available in long standard (10 feet, 10 inches) and short standard (9 feet, 9 1/2 inches) chassis lengths, although just 10 short chassis were built. Its twin SU-fed 4,398cc fourcylinder engine used a 100 x 140mm bore and stroke and a 5.1 to 5.3:1 compression ratio to make 100hp at 3,500 RPM. This change raised the car’s average maximum speed from 80 to more than 90 MPH; light, open cars like the famous cyclefendered, Vanden Plas-bodied Le Mans replicas could now better 100 MPH off of the showroom floor, a boon in the competition in which these cars were often engaged. Some late 4 1/2 Litre cars were fitted with the heavy-duty crankshaft of the supercharged model, improving their legendary durability yet further. Sadly, Bentley Motors Ltd. was nearing the end of its days as an independent company; Rolls-Royce purchased the firm in 1931.

The issue of placing a standardized value on a vintage four-cylinder Bentley can be a thorny one, explains Robert McLellan, Bentley historian and the host of the www.vintagebentleys.org website. “The most fundamental aspect is learning about the cars before buying one,” he explains. “The biggest problem is that most buyers think they are getting an original car when they are not; they then realize they paid too much. Our website tells the history, so buyers and sellers will actually know what they are looking at. Most ‘experts’ cannot tell the cars apart—two cars can look identical, and one is only worth half of what the other is worth.”

David Brownell, former editor of Hemmings Motor News and Special Interest Autos magazine, Automobilia Auctions founder and the 25-year owner of a 1924 Bentley 3 Litre touring car, adds, “In terms of values, the car that’s never been mucked with is worth more than a comparable car that is running its second body, but the fact that a body’s been changed doesn’t eliminate it from Bentley Club activities. Some people will try to bring a chassis or car back to its exact correct original configuration, but the penalty of doing that with a closed car—a sedan or limousine— is that the market demand and value aren’t there for all of that work, and it usually costs more money to build a closed car body than it does to build a roadster or phaeton.

“Gooding just sold a 1927 long-wheelbase 3 Litre tourer at Pebble Beach; this was a matching numbers car with a one-off body by Harrington, and it was very well restored and presented. That car, with the buyer’s premium, brought $308,000. The sellers of a 1924 3 Litre Speed that was featured at the Bonhams Brookline [Massachusetts] auction turned down a bid of $230,000, and that car needed a lot of loving; I think if that car had cracked $250,000, they probably would have let it go. That’s a strong price to pay for a car that essentially was all right, but cosmetically was in need.”

David continues, “They’re great fun, a good value. Dare I say, [vintage Bentleys] are a good investment, because there’s an international demand for them. People want them here, they want them in England and in Europe. These cars work on a number of levels in terms of use: They’re Full Classics, they’re a vintage sports car that you can race, they’re eligible for AACA activities, they can go to concours, they have a lot going for them in terms of acceptability. They have quite a heritage, and that’s part of what you’re buying when you buy a Bentley. It’s that great racing heritage, the great engineering, the toughness. Everything’s very overbuilt—there’s nothing delicate about a vintage Bentley,” he says. “I couldn’t afford to buy mine today—they’re not cheap. They’re going to cost you a lot of money.”

Body/Frame
A huge variety of coachwork was fitted to the three chassis lengths that 3 and 4 1/2 Litre cars were built on, and the frames themselves were overbuilt with truss braces and five crossmembers; an even sturdier frame was employed under the 4 1/2 Litres built after the spring of 1929. Original frames are available from specialist sources today for those who want to body a vintage Bentley in their chosen style and trim.

As we’ve noted, many 3 and 4 1/2 Litres look different today than they did new, but this is not necessarily detrimental, as sporting open bodies are more highly sought than formal closed ones. Because they were coachbuilt cars with bodies and fenders crafted in aluminum or aluminum, wood and fabric, skilled restorers can bring even the worst basket cases back to life, given suitable time and money.

Engines
The 2,996 and 4,398cc 16-valve four-cylinder engines have been lauded for decades for their durability, but cars that have been driven with vigor may experience broken cross-shaft gears. “These are the gears that go across the tower that goes up to the camshaft, and their teeth engage the gears that run the magnetos. The reason they break is not because they’re weak or badly designed, but because on start-up, they’re the last part of the engine to get lubrication,” David explains. “The man who previously owned my car was a professional restorer, and this happened to him on a tour in California. He stopped into a place that did machine work for the aircraft industry, and had new gears made out of Delrin, a space-age plastic. This Delrin doesn’t need lubrication, so my cross-shaft gear worries are over.” Another engine mod that helps longterm durability is the addition of a modern oil filtration system to improve upon the primitive original.

“If you have a really worn engine, the center main bearing is liable to let go, as that’s the one that takes a lot of crankshaft whip from the unbalanced crankshaft. This happened to my car when it had already done about 200,000 miles, and at that time, we measured the taper in the cylinders: It was zero. We didn’t have to replace the pistons or rings, and that’s a hell of a tribute to the metallurgy in that car. They’re very, very hard to hurt.” Because the head and block are cast as one, the engine must be removed to do this work.

There are a number of vintage Bentley specialists in the United Kingdom and the U.S., so any engine part that may be required can either be sourced new or refurbished.

Transmission/Diff erential
W.O. Bentley specified a number of different transmissions in his four-cylinder cars for the different bodies and uses that they would encounter, and they differed in gearing. All were four-speed manuals, and among the variants were the closeratio A and D type units, the wide ratio B type and the wide/close ratio C type unit. An inverted cone clutch with Ferodo lining was used until a plate clutch replaced it in 1929, and like the gearbox, this often requires a bit of effort to engage.

Because many vintage Bentleys remain in serious use today, the swapping of interchangeable gearboxes to achieve better performance is considered quite acceptable, as is the adoption of a modified Laycock overdrive unit, a similar type as used in Austin-Healey sports cars.

The semi-floating rear axle with spiral bevel gears is another notably sturdy component, and substituting different gearing can improve the performance of a car with little hassle.

Suspension/Brakes
Three Litre models built through the fall of 1923 had mechanical drum brakes on the rear wheels only, but after that, front drums were added, and the handbrake acts on separate shoes on the rear wheels. “For their time, they have excellent brakes,” David says. “That doesn’t mean that they’ll stop like Brembo discs today, but in the context of their time, they have really good brakes.”

All 3 and 4 1/2 Litre cars use semi-elliptic leaf springs, those in the rear underslung, as well as adjustable duplex Hartford shock absorbers at all four wheels, offering a firm ride with little body lean. Rudge Whitworth wire wheels in 21- inch diameters were standard on early cars, and later ones used 19-inch wheels. As would be expected, steering effort is high, although it is laudably accurate.

The addition of a power steering kit—seemingly inconceivable in such an old car—is also an accepted modification, as David explains; “This kit fits in so neatly that you literally don’t know it’s there.”

Interior/Trim
If your 1921-1931 Bentley is missing its dashboard clock or fender lamps, you won’t be able to ring up your local auto parts store to find replacements. It is therefore lucky that vintage Bentley specialists and enthusiasts within the Bentley Owners Club are a tight-knit bunch who are willing to help each other with spares, and if necessary, patterns to remanufacture needed part.

Specialists
Dennison-Jayne Motors
610-436-8668
www.dennisonjaynemotors.com

Tim Houlding International Vintage
Bentley Cars
011 44 1905 352 419
www.vintagebentley.co.uk/index.htm

Stanley Mann Racing
011 44 1923 852 505
www.stanleymann.com

The Vintage Garage
802-253-9256
http://vintagegaragevt.com

Vintage Bentley Parts Ltd.
011 44 1926 496 739
www.vintagebentleyparts.co.uk

Parts Prices
Brake shoe, front or rear - £300 ($483)
Bulkhead, 4½ Litre, original - £580 ($935)
Complete 9-foot 9½-inch chassis, 3 Litre - £6,936 ($11,176)
Engine block, 3 Litre original - £1,000 ($1,611)
Engine, 3 Litre original - £12,500 ($20,141)
Gas tank, 4½ Litre restored - £700 ($1,128)
Grease gun, Tecalemit original - £75 ($121)
King pin - £155 ($250)
Mirror, original - £225 ($363)
Pedal shaft, cone clutch - £1,656 ($2,668)
Wrench set, original - £100 ($161)

Club Scene
The Bentley Drivers Club Ltd.
W.O. Bentley Memorial Building
Ironstone Lane
Wroxton, Banbury, Oxfordshire
OX15 6ED England
011 44 1295 738 886
www.bdcl.org
Dues: £50.00 ($81); Membership: 3,600

www.vintagebentleys.org
Historical Bentley restoration information and references, links and profiles

Values - Bentley 3 and 41/2 Litre*
                   Low             Average       High
3 Litre        $185,000      $250,000     $600,000
41/2 Litre  $300,000      $450,000     $800,000

*Values vary widely and depend upon condition, body style, originality, provenance etc.

Bentley Production*
3 Litre
Long standard wheelbase: 765
Short standard wheelbase: 194
Speed model: 513
Tourist Trophy and Tourist Trophy replica: 71
Light Tourer: 40
Supersports/100 MPH: 18
Indianapolis 500 racer: 1
Unknown: 11
Total 3 Liter production: 1,613

4 1/2 Litre
Long standard wheelbase: 657
Short standard wheelbase: 10
Total 4 1/2 Litre production: 667

*Production figures courtesy Bentley-Fifty Years of the Marque, Third Edition, by Johnnie Green.