Mercedes-Benz Grand-Prix racing car W 125, 1937

Engine type:
M 125 F
Inlet valves:
2 inclined overhead valves per cylinder, actuated via finger followers
Ignition sequence:
1-3-6-8-4-2-7-5
No. of cylinders / arrangement:
8 / in line
Outlet valves:
2 inclined overhead valves per cylinder, actuated via finger followers
Configuration:
Front, longitudinal; vertical
Valve operation:
2 overhead camshafts, gear drive
Ignition adjustment:
Automatically
Combustion principle:
Four-stroke Otto (with supercharger)
Crankshaft:
9-bearing (roller bearings)
Bore x Stroke:
94 x 102 mm
Fuel system:
2 Suction carburetors / Roots supercharger
Total displacement:
5660 cc
Spark plugs:
1 per cylinder, Bosch M 400 G 1
Fuel supply:
Graetzin or Junkers pump
Compression ratio:
8.8
Fuel tank capacity:
300 l
Maximum / output / rated output:
592 hp at 5800 /min
Fuel consumption:
app.100 l
Rated torque:
125 mkg at 3000 /min
Cooling:
Glycol/water circulation cooling via rotary pump
Maximum revolutions:
6000 /min
Lubrication:
Dry sump lubrication via lubricating pump
Cylinders:
2 steel blocks (of 4 cylinders each) with welded-on cooling-water jackets
Oil consumption:
0.5 l
Cylinder head:
Not removable, welded together with cylinders
Starter:
External unit
Generator:
Not fitted
Battery:
Not fitted
Ignition:
High-voltage magneto ignition
Ignition system:
Bosch twin magneto MZ/ZJ 08 R

Hand brake:
Not fitted
Foot brake:
Acting on front- and rear wheels
Steering:
Worm-and-nut steering
Wheels:
Wire-spoke wheels, center mounting
Front tires:
5.25 x 19
Frame design:
Oval-tube frame with 4 cross members
Rear tires:
7.00 x 19
Front wheel suspension:
Double wishbone, coil springs, hydraulic shock absorbers
Drivetrain:
By cardan shaft to transaxle and rear wheels
Rear wheel suspension:
De Dion axle, longitudinal torsion-bar springs, hydraulic shock absorbers
Brake system:
Hydraulically actuated dual-circuit brake system
Front brakes:
Inside shoe brakes with finned light-alloy drums, 400 mm diameter
Rear brakes:
Inside shoe brakes with finned light-alloy drums, 400 mm diameter

Transmission:
4-speed manual transmission with differential gear, transversally mounted below rear axle
Shifting:
Gate shift with locking system
Clutch:
Dry single-disc clutch
Transmission type:
Change-speed gear
Gear ratios:
I: 2.13; II: 1.37; III: 1.18; IV: 0.94
Final drive ratio:
3.43
Maximum speed:
over 300 km/h