DB3

DB3 Description

In production: September 1951—May 1953

Chassis numbers: DB3/1—DB3/10

Late in 1950, Eberan von Eberhorst (of pre-war Auto Union fame) joined the company to design a new sports/racing car to replace the DB2 in international race events. The outcome was the DB3, which had its first outing in the Tourist Trophy in September 1951. Of the first cars, DB3/2 was a road car for David Brown. The car was described for the first time in Motor for June 4 and Autocar for June 6, 1952.

Of the ten cars built, five were built for sale, although it was reported that the original sanction was for 25 cars.

The chassis was completely new, consisting of a ladder frame made of large diameter tubes. Suspension was by torsion bars, with trailing links at the front, parallel links and a Panhard rod located a de Dion rear axle.

The rear brakes were mounted inboard on the hypoid bevel differential. The exceptionally large Alfin drum brakes had a friction area of 224 sq. in. Transmission was through a Borg and Beck hydraulically operated single dryplate clutch, originally drove through a special David Brown five-speed gearbox (S 527) 4.11:1 final drive, 1,000 r.p.m. in top was equivalent to 24.2 m.p.h

For the 1952 season, the team cars used the S5275 box with a lower overdrive top ratio (0.885:1 instead of 0.83). But after Le Mans these five-speed boxes, which had never been completely satisfactory, were replaced with the four-speed box (S 430/63R) developed for the lightweight DB2. The ratios were 1:1, 1.26:1, 1.87:1 and 2.92:1.

The standard two-seater bodywork was notable for its simplicity and cleanliness of line, with slab-sides and a “portcullis” radiator grille. There was a minimum of framing and the floor pan served as an undershield. For Le Mans 1952, DB3/1 was fitted with a hard top.

Originally the engine (LB6C) was the 2,580 c.c. (157.5 cu. in.) Vantage unit (bore 78 mm., stroke 90 mm.) used in the DB2. With (35 DCO were fitted originally to the team cars) and a compression ratio of 8.16:1 140 b.h.p. at 5,300 r.p.m. was claimed.

George Abecassis’s impressions of driving the DB3 were published in The Field (October 25, 1952) It was described in The Motor (June 4, 1952) and The Autocar (June 6, 1952).

DB3 Derivatives

DB3

David Brown knew that 'Racing improves the breed', and soon after buying Aston Martin, he brought in Eberan von Eberhorst of pre-war Auto Union fame to develop a sports racing car using DB2 parts. The result was the DB3 which was first raced in 1951 under the famous Team Manager, John Wyer. Power was provided from a 133bhp 2.6 litre DB2 Vantage tuned unit using triple Weber carburettors; later the 2.9 litre engine was always tried which produced 163bhp. This brought success at Silverstone in 1952 in the Production sports car race with a 2nd (Reg Parnell), 3rd (George Abecassis) and 4th (Lance Macklin) place behind a Jaguar C-type.

All three Works cars retired from the 1952 Le Mans race but the DB3 recorded an overall win at Goodwood in the 9 hour race driven by Peter Collins and Pat Griffith. But the car, relative to the competition both lacked power and carried too much weight. Thus the decision was taken to go with the plans of ‘Willie’ Watson to develop a smaller, lighter car (DB3S) and sadly von Eberhorst left Aston Martin.

Altogether, 10 DB3’s were built, five as works cars, the remaining five were sold to customers to race privately. Some DB3’s have had fixed head coupe bodywork although many have reverted to open cockpit.

DB3 Fixedhead Coupe

Other DB3's did at one time or another have coupe coachwork, but chassis DB3/7 was the only example built as a coupe from new. The first owner decided on closed coachwork both for aerodynamic reasons and comfort during long endurance sports car races.

There is a suggestion in an early edition of the AMOC club magazine that the first owner, Tom Meyer, had added the ‘home-made’ body although exactly who did make the coachwork is not actually known. It certainly does not follow the styling of the regular open DB3 in any way.

Following participation in the Spa 12 hours, Goodwood 9 hours and the Mille Miglia, the owner sold the car through HWM in 1954. DB3/7 was purchased by Angela Brown, daughter of David Brown. Initially the car had an unsightly rectangular grille but Angela Brown has a new bonnet fitted with a similar oval intake. The car retains the same bonnet to this day.

With a 2.9 litre engine tuned to give 175 bhp, the DB3 Fixedhead Coupe was claimed capable of a maximum speed of 140 mgh, some 10 mph more than the open car. One rather charming period feature was a walnut dashboard with a range of special instruments. Again, these still remain fitted to the car.

DB3/7, as with other DB3’s was road registered, with the UK plate NXY23 although their natural place remains on the race track.

DB3 Specification

Contact breaker gap 0.012"
Engine
Twin overhead camshafts
Hemispherical combustion chambers
Bore 78 mm, stroke of 90 mm, capacity of 2,580 c.c.
Compression ratio 8.15:1
Valve clearances Inlet 0.011" - 0.013" Exhaust 0.012" – 0.014" Cold.
Valve timing: Inlet camshaft; Set No 1 piston to TDC firing stroke. Turn crankshaft 10° after TDC. Turn camshaft until inlet valve no 1 cylinder is open 0.082" – 0.087" on opening side. Bolt up sprocket. Exhaust camshaft; Set No 1 piston to TDC on firing stroke. Turn crankshaft 10° before TDC. Turn camshaft until exhaust valve no 1 cylinder is open 0.082" – 0.087" on closing side. Bolt up sprocket
Fuel System
Three Weber 36 DCF5 carburettors
Two SU electric pumps
Ignition System
12 volt coil and engine driven distributor.
KLG 10mm L30 spark plugs.
Vantage engine KLG 10mm ProL80.
Static ignition timing 10° before TDC.
Electrical System
12 volt system and dynamo.
Transmission
Borg and Beck 9" single dry plate clutch
S527S David Brown gearbox
Various axle ratios. 3.5, 3.67 and 4.1:1
Ratios Cose ratio
Top 0.885:1
4th 1:1
3rd 1.275:1
2nd 1.89:1
1st 2.9:1
The David Brown, S430/6SR was also available
Steering
Rack and pinion.
Brakes
Front: 13" Wellworthy Ltd. light alloy 'Al-Fin' drums. 2 leading shoe.
Rear: 11" Alfin drums mounted inboard, plus hand brake operated by central lever.
Total friction area, front and rear, 224 sq. in. (125 sq. in at the front.)
Suspension
Front: Top and bottom trailing link with cross over torsion bars and Armstrong lever dampers.
Rear: Centrally mounted Salisbury differncial unit and de Dion tube axle beam located by trailing links and suspended on torsion bars and Armstrong lever dampers.
Body
An aluminium skin over a frame of steel tubes. Quickly removable.
Interior
Leather covered seats
Wheels and Tyres
16" wire, splined knock-off with 600 x 16 Dunlop Road Speed or Avon tyres.
Main dimensions
Length 13' 2½"
Track 4' 3"
Height 3' 4"
Ground Clearance 5"
Width 5' 1½"
Turning Circle 32'
Wheelbase 7' 9"
Weight18 cwt. with 9 galls. fuel
Fuel System
Capacity 32 gall.
Fuel Type: Petrol 95 Ron, leaded.
Maximum power
140 b.h.p. at 5300 r.p.m.
Maximum torque
Vantage 140 lbs/FT at 2400 RPM
Price
£3,700, including U.K. purchase tax.
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