Porsche 911 G-Series 1973-1977 Buyer's Guide

The engines are the most critical point of this era. There are two constructions:

The 2.7-litre engines (magnesium): Used in the 911, the 911 S and the Carrera 2.7 MFI. The magnesium case is light, but thermally problematic.

• Pulled head studs: Because the steel studs and the magnesium case expand at different rates, the threads pull out. The consequence: leaks and a loss of power. The repair: the engine has to come out, plus thread inserts (case savers), costing €8,000 - €20,000
• Oil leaks: Cam covers, oil return tubes, seals
• Chain tensioner: The original hydraulic units often fail. Conversion to the Carrera 3.2 tensioners is recommended

The 3.0-litre engine (aluminium, Carrera 3.0): Derived from the Turbo (930), it uses a robust aluminium case.

• The advantage: No problems with pulled head studs. Extremely long-lived
• Weak points: Head studs can break here too (Dilavar), but less often. The usual oil leaks

The G-Series introduced the impact bumpers (an aluminium section with concertina bellows). US cars have hydraulic dampers, RoW cars (rest of world) have impact absorbers.

The evolution of corrosion protection:

• 1973-1975: Partly galvanised (floor panels only). A high risk of corrosion.
• From 1976 (model year I): The body hot-dip galvanised. Considerably better protection, but not corrosion-free after 50 years

Critical areas: Sills, jacking points, the B-pillar (the striker panel), the headlight bowls, the inner wing closing panels, the front battery box, the window frames.

The standard fitment was the type 915 gearbox (four or five speeds). More robust than its predecessor (the 901), but with quirks.

• Shift feel: A little notchy and doughy when cold. That is normal
• Synchromesh rings: Wear in first and second (a crunch on a fast shift). Overhaul: €2,000 - €5,000
• Clutch: A wear part (€800 - €1,500)
• Sportomatic: A rare semi-automatic. Parts are scarce and servicing expensive

Suspension: Torsion bars. The rubber bushes age and make the car feel vague. Replacing them (with polyurethane if you wish) brings the precision back. Check the dampers (Bilstein/Koni).

Brakes: Solid disc brakes all round. The callipers can seize. Carrera cars often have aluminium callipers (S callipers), which cost more to overhaul.

Interior: Seats with integrated head restraints (a safety feature). The materials (cloth, vinyl, leather) age. Dashboards often crack (sunlight). Check the carpets for damp.

Electrics: Manageable, but corrosion on contacts and fuses is common. Wiring looms can become brittle. Check every convenience (windows, sunroof, ventilation).