Triumph Repair: red hot exhaust, rich mixture, exhaust gases

Question
Jim, I own a 1980 Spitfire. I bought it 9 years ago. The car has driven only 3000 kilometers since new. Although the car is virtually new, it has run rough since I purchased it. I have replaced the fuel pump, fuel filter, rebuilt the carb but she still runs rough. I replaced, the plugs, wires, points (with Petronix) and cap. However, I now noticed that the wires were not connected in the correct sequence. Sure enough when I connected them in the correct order, the car fired up and sounded great. Only one problem...the exhaust turns cherry red after the engine runs for a few minutes.Can you please advise. Regards,  Harry.  

Answer
Harry,

Are you positive the car is timed correctly?   That's the starting point on any engine questions.

Is it the cast iron manifold or the downpipe?

How do the spark plugs look?  Lots of carbon or bright white?  I'm guessing they probably look a bit dark, as it might be running a rich mixture.  

I've seen the aftermarket headers on a Spitfire glow red on a car in good shape after about 2 minutes of running in the evening.  It just means that the exhaust gases are hot.   Typically on a car tuned for racing, meaning it's running richer than normal for street use.

If you pull the spark plugs and they're bright white it means the mixture is too lean and you do run the risk of melting pistons (yes, literally) and burning valves/valve seats.

3000km since new in 30 years?   Hmmmmmmmmmmmmmmmmmmmmmmmm.

Cheers,

Jim