Derby Models Print
TECHNICAL SPECIFICATION OF DERBY BENTLEYS 1933-40

 

CHASSISLadder frame - channel section side members with tie rods and riveted cross-members
BRAKESServo-assisted mechanically operated 12" drums
REAR AXLESemi-floating: hypoid gears with differential
SUSPENSIONSemi-eliptic cadmium plated leaf springs - hydraulic dampers (MK V - independent front/coil springs)
GEAR BOX4 Speed & reverse (overdrive fitted to late 4¼ litre cars), attached to engine
CLUTCHSingle dry plate
WHEELSWire, splined hubs - 18" x 4" (overdrive models - 17" x 4")
STEERINGRolls-Royce worm & nut steering box (overdrive models - Marles cam & roller type)
RADIATORshutters controlled by thermostat in header tank
ENGINESix-cylinder cast iron monobloc & detachable head, aluminium crankcase, sump & clutch casing
.Two valves per cylinder - overhead inlet & exhaust operated by pushrod
.Nickel chromium crankshaft in 7 white metal main bearings, big ends white metal bearings
.Camshaft carried in seven plain bearings, driven by helical gears
.Aluminium alloy pistons
IGNITIONCoil & distributor, single plug per cylinder
CARBURETTORTwin 1 3/8" S.U. ( 1 5/8" on all 4¼ litre cars)
  
3½ litre
3 1/2 Litre
4¼ litre and MK V
4 1/4 Litre & MK6
 3½ litre4¼ litre and MK V
Bore3¼" / 82.6mm 3½" / 89mm
Stroke4½" / 114.3mm4½" / 114.3mm
Capacity3,669cc 4,257cc
RAC rating25.3hp 29.4hp
Brake horsepower114 125
Compression ratio6.5:16.8:1/6.4:1
Maximum speed91mph92mph (93mph -overdrive models)
           
Dimensions & Weight
 3½ and 4¼ litreMK V
Wheelbase10' 6" 10' 4"
Track4' 8" 4' 8¼ (front)
4' 10" (rear)
Overall length14' 6" 15' 11"
Overall width5' 8" 5' 9"
Weight3½ - 2510 lbs2719 lbs
 4½ - 2558 lbs 
   
           
Production Figures
3½ litres (1933-36)1,177
4¼ litre (1936-40)1,234
MK V (1939-40)9 Delivered