MG Car Nut

By Peter Calabrese

Robert Frost once wrote, “Two roads diverged in a wood, and I—I took the one less traveled by…” So it is with me and my MG Midget.

While the purists among you Spridget owners may be content to drive the curvy back roads of the countryside in your stock Midgets or Sprites, I take the twisted, trial-and-error path to performance. Along the way I make frequent stops to experience life’s pleasures and to check for oil leaks.

It all began about seven summers ago after my friend, Joe Puma, alerted me to a splendid red Midget for sale, which would ultimately become my first convertible MG adventure.

Originally, I had no restoration intentions. However, after the first summer, the engine and transmission were in need of some attention, since one smoked and other went thump, thump, thump. Successful removal of those two items prompted a full restoration of the engine bay. After all, a tar-coated yellow engine compartment doesn’t really match a red chassis very well. Anyhow, the next thing I knew, the engine, transmission, and front fenders had taken over my garage…and so the work began.

Relatively speaking, money and free time were available in abundance—I was more than a few years out of college with several years of full-time employment completed. I was able to finish the engine, transmission, and engine bay restoration project during the course of one winter via enrollment in an adult education British Car Repair class taught at a local high school by our club’s chief technical advisor, Jim Pelletterie.

When the car season began the following spring, my fiancé and I enjoyed all those things a couple can do with a red MG sports cars—car rallies, picnics, car shows, road trips, cruises to restaurants, etc. (Did you know that an arch of helium balloons over your car at a national MG convention does nothing to increase your chances of winning any awards, and might entirely discourage spectators from approaching your car? Or that Styrofoam, plastic sheeting, and 15 pounds of HAPPY ICE can turn any Midget trunk into the ultimate Old Speckled Hen Beer cooler?)

Mechanically speaking, the car has undergone constant refinement, going against the old adage “If it ain’t broke, don’t fix it.” I derive as much pleasure from working on the car as I do from driving it. Especially on those rare occasions when something I do works as planned.

Down through the years I’ve owned the Midget, a Weber DGV downdraft carburetor has given way to the free-breathing Weber DCOE sidedraft. Then there was the temperamental Judson Supercharger, which ultimately led to my current induction setup—a 1970s vintage Rajay turbocharger kit originally designed for racing Minis. Along the way, I’ve assembled a nice collection of blown head gaskets as everlasting mementos in testament to things gone wrong.

The engine is bored 0.020”-oversized to yield a theoretical 1293cc displacement with a compression ratio of 8.8:1. ARP rod bolts and main studs keep the engine from fragmenting. A Rajay turbocharger breathes through a slightly modified single SU HIF6 (1¾”) carburetor. The lonely SU sports a custom-filed needle profile, optimized over several months using an oxygen sensor in the exhaust side of the turbo. Air/ fuel mixture readings from the LED sensor display (designed and constructed by Tim “Mr. Wizard” Weiskopff) is located in the driver’s compartment.

A Turbonetics wastegate limits boost to 14 psi. Varmint mesh and fiberglass insulation wrapped around the hot side of the turbo keeps the heat out of the engine compartment. A portion of the Mobil 1 synthetic oil passing through the nine-row oil cooler flows through braided stainless steel hoses into a separate filtration system, which lubricates and cools the turbo.

Clamped to the top of the original block with 11 ARP head studs is my imitation of a Cooper S-spec head—big stainless valves (1.401 intake and 1.22 exhaust) with hardened exhaust seats. A mild Kent 266 cam keeps the billet aluminum 1.5-ratio roller rockers dancing under a slanted, polished aluminum valve cover to the tune played by the two-inch exhaust system and straight-through turbo muffler.

Sparks fired from the high output Lucas Sport coil are controlled by a Crane electronic ignition system. An MSD boost-retard box pulls the ignition timing back as the boost comes up—an absolute necessity to prevent ruinous piston damage. Otherwise, on your way to an auto show 90 miles from home, you’ll learn that piston number four melts before the other three.

I had a local radiator shop construct a custom fat-core, four-row radiator to handle the increased thermal demands associated with a turbo motor. I made the rad side tanks myself using the art of sheet brass origami. Clearance and air flow requirements necessitated I ditch the whimsical, yellow plastic fan for a high-flow electric pusher unit mounted forward of the radiator.

Wherever advantageous, I adapt components from other British models in the style of BMC/Leyland engineers. I changed over to the large diameter Austin Mini water pump pulley and the bigger MGB alternator pulley to slow these belt driven units down.

Bolted to the business end of the motor is the stock four-speed rib-case transmission, which rotates the driveshaft into an early 4.22 differential. Rubber meets the road via 155R13 M&S tires mounted on wire wheels with spinners, reminiscent of the early days of motorsports when the drivers were fat and the tires were skinny.

Although not a muscle car, the Midget’s impressive power-to-weight ratio and deceptively diminutive stature does take many drivers by surprise. While turbo lag makes the car a big disappointment at low rpm, it’s an entirely different story once the turbo spools.

At full throttle, above 4000 rpm, there is a rapid buildup of boost and resultant torque, leading to an ever-increasing feeling of raw acceleration (fun). This continues unabated until I either lift off the gas, let the wastegate pop, or allow the valves to float. Field tests mashing through all the gears have proven a turbo-powered Midget will handily out-trot a factory 2001 Mustang. Similar experimentation with other field subjects has been known to result in prolonged grinning on my part.

The collection of goodies described above is far from optimal. Some items, in reality, may have a subtractive effect on performance. Nevertheless, the Midget is my way to display what I have found at local swap meets and the occasional eBay auction as I meander along the path to automotive bliss.