D Sports racer

The Imp Site

D Sports Racing Imp

This car was built in 1967 for the newly formed D Sports Racer classification (1 liter and under; slick tires). It's rather lightweight (950 lbs. / 430 kg) with a dark blue fibreglass body and aluminium wheels. There's nothing to the interior but a single seat and a 5 point harness.

It was constructed in southern California. Serial Number: Cal Club #19013. It's a one-of. Cal Club was a racing club formed in the late 1960's and the number 19013 may reflect the thirteenth car registered in the club.
In 1969 the builder updated the car with parts from Roger Nathan of London: a Number six cam shaft, full race carrier, new tappets, and a cam shaft dowel pin.

The details of its early years are currently unknown, but according to the remaining logbooks (1980-1991), the later years were spent racing throughout the West Coast. It has not run since 1991.

Purchased by Greg Jacobson's father: Philo Jacobson (southern California), summer of 2000.
Condition: "Decent. Complete, mothballed roller. Chassis needs restoration." The windscreen is missing, and so is the cockpit belly pan.

Both the Jacobsons belong to an H Mod club. They were looking to buy an H mod car (to race amongst the many acquaintances they'd made over the years in the class), but settled for a DSR (which has more performance) when one became available.
Following up on a small advert in a US auto magazine 'Vintage Racecar', Greg found this DSR Imp was located in a small racing shop no more than a mile from his house. After having had a quick look, he decided he did very much like the little car, and he read up on the subject of Imps.

Their intention [Sep. 2000] is to have the car competing within a year or so.
Since the car has not run since 1991, many areas require looking into:
The entire plumbing systems: hydraulics, gas, cooling, oil need to be reconditioned.
It needs a new brake, clutch, and throttle pedal assembly.

"Actually the beauty of the vintage classes is the cars are essentially running today as they did in their prime and our intention is to restore it little by little as we run it. We naturally would like to maximize the engines potential with an emphasis on dependability."


Engine bay

It has an Imp unit and transaxle. The transmission is installed upside down (with a converter plate) to allow mid engine configuration.


Cooling System

Fuel System

Electrical System

Spares: 5 stock heads; 3 875cc blocks; 3 transmissions; assorted gears; 4 crank shafts; 5 cams of various profile; 1 set aluminum wheels; 2 water pumps; assorted bearings, pistons, rods; 2 axles; 1 rear hub; 1 flywheel; 1 used clutch pressure plate and disk; etc.

Imp specials
The Imp Site

US auto magazine: Vintage Racecar

© Franka



The D Sports classification followed chronologically the demise of the H Modified racing classification which ran from the early 1950's to 1968 in the States.

H Mod allowed any closed wheeled purpose built race car with a cubic displacement of 750cc or less to compete although in 1962 the SCCA (Sports Car Club of America) adopted a maximum of 850cc. This was back in the days of what were referred to as 'Specials' which were kind of conglomerate cars made up of many different auto companies components i.e. a Crosley engine and rear end matched with an MG transmission, a Fiat front suspension, steering and brake parts, a mild steel tube frame, and a fiberglass or sheet aluminum body. Many different powerplants were used from two and four stroke motorcycle engines with chain drive to outboard marine engines.
A book on the class lists the Imp as a suitable powerplant. It doesn't mention how one would decrease the displacement. "Maybe 25cc was not enough to quarrel about."

As you can imagine, the cars were from hilarious to frightening to marvelous. Treaded tires were mandatory. The majority of the cars were front engined and only select later models sought to emulate the modern mid engine configuration. The class encouraged low cost racing and an aptitude for ingenuity.

H Mod competes today in vintage events throughout the US including all the major historic races.
These tiny cars can be extremely nimble and often have faster times through the twisty bits than cars with five times the horsepower! Greg Jacobson and his father know a couple of H Mod owners and belong to an H Mod club, 'The Over the Hill Gang' and try to get out and watch them as often as possible.

Sports Racers - The Sports Racing classes are also made up of pure racing cars, but unlike the Formula cars, they have full bodywork. Spec Racer Ford and Sports 2000 are two of the most popular classes, and their use of identical stock-based engines makes for close racing. The C and D Sports Racing classes are among the smallest in terms of numbers, but they frequently lead the way in terms of technical innovation in chassis design, engines, and aerodynamics.

In 1968 the SCCA sought to form a new class that would absorb H Mod and also allow non production vehicle motors to be used such as fire pump and generator engines. The new class would allow slick tires similar to what the top classes were using as well as encourage new technical advances.
Later on the class jumped to the 1000cc as it is at today. The older H Mod cars were instantly out classed and events eventually ceased to be held for them.

Many of the smaller English purpose built race cars of the era raced in the DSR category, including the smaller displacement Lotuses and Elvas. Others included Devin, Bobsy, Ambro, and countless single run cars like the Imp I purchased. The Beach marque actually ran an Imp engine and running gear and is a beautiful and sought after little car.

D Sports Racing - DSR, one of the sports racing classes, features relatively wide-open rules and allows a good deal of creativity and complexity. The rules do not exclude the use of electronic engine management and data acquisition systems, and this allows enhancements such as active traction control, shift without lift, full fuel and ignition mapping, and logging and analysis of a myriad of sensors. Aerodynamics and suspension design is relatively open. 150 SCCA members compete in DSR nationally (U.S.) and there are probably an additional equal number of participants at the regional level.

The Rules - Basically the DSR rules limit the car's overall height, width, and length and mandate DOHC engines of 1000cc maximum displacement or pushrod engines less than 1300cc. Rotary engines and turbochargers are allowed, but the rules require intake restrictor orifices. 2-cycle engines are allowed 850cc displacement. Cars using a motorcycle engine and chain drive have a minimum weight of 900 lbs. including the driver. Designs using automobile-based engines with transaxles must weight in over 1,000 lbs. Tires and wheels are free. Aerodynamically the car must have a flat bottom between the axle lines. Rear diffusers are not permitted. Wings are allowed front and rear.