Australian Car Guide

Jan Derieuw writes of his 1974 ex Swiss Army 4x4 Pinzgauer 710M -

Note 1: Both the 4x4 and the 6x6 use the same 2.5 liter 4-cylinder petrol engine (air cooled). During the eighties however, they switched to a 2.5 liter turbo charged diesel engine (watercooled) (made by Volkswagen, used in their LT series light truck and also used in the Volvo 740).

Note 2: There are also 'tropical design' versions available; they have different air filters and the air entrance is outside, at a higher position (like a snort). Although they use the same engine, the end result is slightly different (184 or 18.4mkp at 2000, and looses 2 hp).

Standard Design:

Type: 4 cylinder, 4 stroke, vertical engine, air cooled

Bore: 92 mm

Stroke: 94 mm

Cubic capacity: 2.499 cm

Compression ratio: 1:7.5

Fuel ron: min. 87

Output at 4000: 87.0 DIN hp or 91.0 SAE hp (64 )

Maximum torque at 2000: 18,0 mkp or 180

Ignition sequence: 1-2-4-3

Ignition timing: 0.2mm before TDC, measured at the fanbelt drive pulley

Piston: autothermic

Material: light metal alloy, forged

Piston rings:

1. rectangular ring, chromium plated

2. nose ring

3. oil scraper ring (equal-phase)

Wrist pin: in piston, sliding

Crankshaft: 5 bearings

Material: alloyed heat-treatable steel, forged and heat treated

Main bearing: three component slide bearing, split

Conrod bearing: three component slide bearing, split

Connecting rod material: alloyed heat-treatable steel, forged

Wrist-pin bearing: bronze bushed bearing

Valve gear

Cam-shaft: 5 bearings in crank-case

Cam-shaft drive: from crank-shaft via helical-gear

Arrangement of valves: overhead type, operated by push rod and rocker arm

Valve clearance: Intake 0.2mm, Exhaust 0.2mm

Valve timing:

I opens 4 degrees before TDC

I opens 40 degrees before BDC

E opens 40 degrees before BDC

E closes 4 degrees after TDC

Lubrication: forced feed type lubrication by twin gear pump. A pump pushes the oil from the front part of the crank case into the oil sump

Oil cooler: ribbed radiator with superimposed thermostat in oil filter case

Thermostat: opens at 83C

Oil filtering: by oversized full flow micro oil filter

Oil pressure: 2.5 - 3 atm when idling and warm engine

Fuel-supply: mechanical fuel pump

Carburettor: 2 TWIN (yes, this makes FOUR!!) cross-country down-draught carburettors, type SOLEX 36 NDIX

Air filter: micronic filter with super-imposed cyclone

Cooling: Axial forced air cooling

Clutch: Fichtel & Sachs

Type: membrane single dry clutch

Gearbox: ZF, 5-speed, synchronized REMARK: the 5th gear is NOT an overdrive; the 1st is a very small gear.

Gear ratios:

Reduction gearbox: Road: 0.88, Off-road: 1.69

1st speed 5.33, R: 19 km/h, O-R: 10 km/h

2nd speed 3.24, R: 32 km/h, O-R: 17 km/h

3rd speed 2.04, R: 51 km/h, O-R: 27 km/h

4th speed 1.30, R: 80 km/h, O-R: 42 km/h

5th speed 1.0, R: 100 km/h, O-R: 54 km/h

Reverse 5.47, R: 19 km/h, O-R: 10 km/h

Steering type: ZF-Gemmer 7330

Ratio: 25.7:1

Turns of steering wheel: 5

Turning diameter between curbs: 9.5m

Turning diameter between walls: 10.7m

Brakes: drums all around

Foot brake: tandem - oil pressure brake with brake energizer

Front wheels: duplex - brakes with 2 brake cylinders per wheel

Rear wheels: duoserve brakes with one brake cylinder per wheel

Operating pressure: max 125 atm.

Driven by the rear axle on 4x2; 4x4 activated manually (hydraulic)

Differential locks on both the front and the rear axle (hydraulic)

Front has one progressive helical spring (and one shock absorber)

Rear has two progressive helical springs (and two shock absobers)

Two 12V batteries, providing 24V to electrical systems

Uses 7 liter SAE 30 oil for the engine

All other (gearbox, reduction, ...) use SAE 80 oil

Brake, clutch and locks use ATE brake fluid blue

Thanks to the four carburettors, the fuel consumption is quite large. During normal road driving, he consumes about 17 liters per 100km. During heavy-duty off-road, this goes up to 25 liters... The fuel tank can carry 75 liters, and there is room for a jerrycan of 20 liters. With these 95 liters of fuel, I can do about 450km (mixed road and off-road), which gives an average of 21 liters per 100km.
- Jan Derieuw [4/'96]

Pinzgauer and Steyr Daimler Puch pages