1929 Bentley 4½-Litre Supercharged (Blower Bentley), Vanden Plas-style four-seat body
- Engine
- Supercharged 4.5L inline-four with Amherst Villiers blower, close-ratio D-type gearbox
Chassis SM3903 is the first production 4½-Litre Supercharged Bentley built, completed in 1929 and nominally the third production chassis but the earliest to be finished — making it effectively the closest thing to a Blower prototype. Shown at the 1929 Olympia Motor Show on the Bentley stand, it was subsequently used as a press demonstrator and road-tested by The Motor. With a history spanning pre-war British dealership ownership, competition use, and worldwide travel through Australia, Switzerland, and the UK, it retains its Service Record and has been the subject of detailed research by Bentley marque expert Clare Hay.
Ownership
- —Auction saleEstimate £3,800,000 – £4,200,000
- 1929 → 1931Factory deliveryBentley Motors (factory/demonstrator use)full documentation
Retained by the factory as a demonstrator for press road tests and exhibited at the 1929 Olympia Motor Show; bodywork was changed during this period from the original show configuration to a standard four-seat layout.
- 1931-11-01 →Private saleJack Barclay and Jack Oldingpartial documentation
Acquired from Bentley as the factory settled financial obligations; Jack Barclay's name remains associated with a London Bentley dealership still operating today.
- Date unknownPre-war owner who entered Syston Inter-Varsity Speed Trialpartial documentation
One of a small number of pre-war custodians; this individual entered the car in a speed trial in early 1935.
Competition
- 1935-03-01Syston Inter-Varsity Speed Trial
Entered by one of the car's pre-war owners; no result recorded in the available documentation.
Maintenance & restoration
- 1929ModificationVanden Plas
The show body fitted for the Olympia Motor Show was subsequently replaced with a standard Vanden Plas four-seat open tourer configuration, as seen in The Motor road test of 1930.
The original show bodywork is believed to still exist, possibly mounted on a different chassis.
- 1980Engine rebuild
The car is believed to have been reunited with engine SM3907, the unit listed in its original Service Record, during the 1980s.
Exact year within the decade is not confirmed; the reunion of matching-numbers engine is considered significant for provenance.
- —Modification
At some point the car was fitted with engine FS3605, sourced from a heavy-crankshaft 4½-Litre car, replacing the earlier engine.
Exact date of this engine swap is not recorded in the available documentation.
- —Bodywork
In later ownership the car was fitted with a Vanden Plas-style four-seat replica body replacing the earlier coachwork.
Date of this rebodying is not specified in the available documentation.
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