Porsche 968 Manual Basics

The information here has been supplied by the Register’s Technical Adviser, Alex Eacock, who is a senior family member of EMC Motorsport. 

Oil

Minimum specifications for road use
- 10w40
- 10w50
- 10w60
- 15w40
- 15w50

Recommended viscosities for track use
- 10w50
- 10w60
- 15w50

All oils should be semi or full synthetic and an API rating of SF or above, is a minimum requirement.

Oil filters should be original Porsche or OE specification, cheaper makes have a thinner metal for the case and can burst under high load.

Oil filter and engine oil should be replaced every 6000 miles for normal road use or every 3000 miles for regular track use.

Spark plugs

NGK BP6ES, set at 1mm electrode gap.

Tyre pressures

Road use
- 16” wheels front 30-32 psi (2-2.2 bar) rear 30-32 psi (2-2.2 bar)
- 17” Wheels front 30 psi (2 bar) rear 30-32 psi (2-2.2 bar)

Track use
Most tyres work best at 30-32 psi hot, for most track orientated tyres, the cold starting pressures are around 24-25 psi (1.6-1.7 bar) for the fronts and 26-27 psi (1.8-1.9 bar) for the rears. On hotter days, the tyre pressures may, once set hot, drop below the above cold pressures. Take care to not let the cold starting pressures fall below these minimums as the tyre may suffer a failure.

Belt intervals

Timing belt should be changed at 36,000 miles or every 4 years, whichever is sooner.

Balance belt should be checked every timing belt change and, if required be replaced, the balance belt should be changed every 2nd timing belt service regardless of condition.

The timing belt tensioner idler must be replaced every belt change, the secondary idlers/deflection pulleys must be checked every belt service and replaced every 2nd timing belt change regardless of condition.

After replacement, the belts should be checked at 1000 miles for tension and if required, be re-tensioned. There should be a further check at 20,000 miles.

Common problems

Symptoms - Engine turning over but not starting. No fuel at the injector rail, no spark.
Problem – DME relay failure.

Symptoms – Engine harsh when revved. Alternator and/or power steering tensioner failure. Exhaust fractures around boxes. In extreme conditions, oil pick-up fracture is also common.
Problem - Balance shaft timing misaligned

Symptom - ABS light on
Common causes – Alternator output too low. Wheel speed sensor failure. ABS earth to body/suspension corroded/fractured