The Slightest of Mods

The British Roadster has an honored place in the motoring world. Emerging in post-WWII Europe and embraced by US soldiers during their tours in Germany, France, and England. Some early models made their way home with US servicemen, and later were imported and sold directly to the American public. Small, lightweight, responsive, and fun to drive -- these open-top two-seaters quickly found favor with auto enthusiasts and even inspired early versions of the Corvette and Thunderbird. 

By sheer numbers, none was more successful than the MGB. Offered mostly unchanged from 1962 through 1980 with over half a million examples produced, the vast majority convertible roadsters with a 1.8L 4 cylinder engine and a 4-speed manual.

While all models produced were similar, they can be broken down into three groups. The first version offered from 1962 through 1967 is considered the purest with the final two years having sorted most issues. The next version was introduced in 1968 and offered through mid-1974. These models added an alternator-charged negative ground electrical system and updated dash but suffered from ever-increasing power-robbing federal emission restrictions. The final variant was sold from 1974 through 1980. Often referred to as the rubber bumper MGB featuring improved safety features like large black rubber bumpers and more ground clearance to meet US NHTSA regulations. 

Today's example is the from 1967 considered by some to be the most desirable year to own and collect. It retains the elegant look of the original design, has none of the power-robbing emission controls of later models, and has necessary upgrades like the 5 bearing crankshaft. While enthusiasts like to keep these models as original as possible, some basic upgrades will make the car much more reliable and enjoyable to drive.

The original 4-speed transmission was virtually bulletproof but did not have synchromesh in first gear and electronic overdrive as a rare upgrade. Many options to upgrade to later syncro transmissions with overdrive exist but the most popular appears to be the Mazda MX-5 gearbox featured here. Complete bolt-on kits can be had for virtually any MGB and while a bit pricey they provide smooth shifting, full synchromesh, and wonderful 5th gear overdrive for enjoyable highway cruising. 

The dual 6-volt battery positive ground electrical system charges with a generator that is large and taxing on the 1.8 L engine. It also requires a clunky external mechanical voltage regulator. A simple and popular upgrade is to install a Delco alternator, bypass the regulator and install a single 12-volt battery with a negative ground. The alternator is far more reliable, easier to spin, provides the proper voltage, and the 12V negative ground allows for easy fitment of modern accessories such as radios, LED lights, and alternators support AGM batteries.

The electrical system upgrade is fairly simple but you will need a bracket (Moss part 130-115). Once you have all the parts simply remove the generator, replace it with the alternator, bypass the regulator, reverse the polarity of the battery, upgrade your fuel pump and most work is done. If you have an aftermarket Pertronix ignition you should get the negative polarity version. If your car has an aftermarket heater blower motor you will need to reverse the polarity. All incandescent lights, the starter, and wipers will work with no modification. 

Note: If you plan to upgrade from points to Pertronix ignition for a more reliable spark and virtually no maintenance, your tachometer should be converted by Nisonger. 

A final simple modification will make oil changes much easier. For less than $40 you can upgrade from the original canister filter to accept a modern spin-off filter. While purists enjoy the experience of removing, cleaning, changing the cartridge, and replacing the canister -- being able to simply spin off the old filter is much easier and cleaner. 

There are other popular upgrades including gear reduction starters, easier-to-service air filters, chrome wire wheels, LED dash illumination, and LED headlights that will increase the drivability of the MGB and more reliable while retaining much of the driving experience intended by the designers. Even better, these upgrades will go undetected by all but the most knowledgeable enthusiasts.