WHAT TO LOOK FOR
The monocoque shell can be weakened by rust. Heritage bodyshells aren’t available for the MGC but all exterior panels except the bonnet are shared with the MGB, as are the sills. These are a key area to check and they are tricky to replace. Other areas to keep an eye on are the front inner wheelarches (see if the box section at the top is intact), the outer wheelarches, spring hangers and battery trays. The top of the fuel tank is corrugated for strength but collects water, then rots. Roadster and GT fuel tanks are interchangeable and the same as chrome bumper MGB units. On GTs the double-skinned tailgate rots along with the scuttle where it meets the base of the windscreen. Also check for rusty door bottoms – MGC doors are the same as post-1968 MGB items. Marque specialist Paul Depper adds: ‘Crash damage can be an issue, especially in the nose. But it’s not always obvious, so make sure everything lines up properly.’
Although the engine is based on the Austin 3.0-litre six-cylinder unit, the valves, springs and sump are unique to the C. It’s a tough old engine but the piston rings wear so watch for oil being burned. Rocker shafts also wear so listen for a clattery top end. Don’t assume it’s just a question of adjusting the valves.
Get into gear
Gearboxes are weak – the layshaft bearings wear, resulting in the shaft dropping and putting pressure on the cogs. Listen for whining, as worn gears will be noisy even if the bearings and alignment are fixed. Many owners fit a Ford five-speed conversion offering lower transmission losses so economy is improved. They also have better ratios, quieter operation and the ability to accommodate a faster clutch change. Budget £2500 for a professional conversion or £1000 for the parts. Gearbox ratios varied – early non-overdrive cars are the same as the B but overdrive brought a close-ratio gearbox. Then from November 1968 all cars got this unit and the differential ratios were changed. Initially nonoverdrive cars featured a 3.07:1 ratio with overdrive and automatics getting a 3.3:1 unit. This changed in 1968 so autos and non-overdrive cars got the 3.3 unit while overdrive cars got a 3.7:1 differential. Vibration from the driveline signifies one or both of the propshaft universal joints (UJs) has worn; considerable gearstick movement suggests worn or broken gearbox and/or engine mountings. Replacing UJs is easy while renewing mountings is fiddly but straightforward.
Unless the kingpins are greased every 3000 miles they’ll wear, so jack up the front of the car and rock the wheel top and bottom while somebody applies the footbrake. Any detectable movement means the kingpins need replacing at £140 each plus fitting