The Gilbern G.T.

Road Test—

A 110 m.p.h. version of the only car built in Wales

When we tested the Gilbern GT in January last year we remarked that it stood virtually alone as a 4-seater GT car selling for under £1,000. Since then no really comparable car has been introduced, except perhaps for the Reliant Scimitar GT which appeared at the last Motor Show; this sells for £1,292, as compared with the £945 of the Gilbern in kit form. The amount of work required to assemble the Gilbern is very small and most people complete it in a weekend.

Since our last test no radical alterations have been made to the specification and the makers have concentrated on improving the existing design. The car features a multi-tubular chassis of square-section tubing with built-up structures front and rear; side-members are kept low to avoid obstructing entry to the car. Mechanical components are taken from the M.G.-B almost entirely, so that the car can be taken to a B.M.C. dealer for any routine maintenance work. The engine is the 1800 M.G.-B, which is now available with the 5-bearing crankshaft. (One advantage of building cars using proprietary components is that you automatically benefit from any improvements made by your supplier.)

The M.G. gearbox remains unchanged and is available with overdrive on 3rd and top gears. Drive is taken to the M.G. rigid axle, which is located by radius arms and a Panhard rod. Springing is by Woodhead Monroe coil-spring/damper units, instead of the leaf-springs used by B.M.C. The double wishbone M.G. front suspension is used with different spring and damper rates, as the Gilbern is some 2 cwt. lighter than the M.G.-B. Lockheed disc brakes of 10-3/4 in. diameter are fitted at the front and 10-in. drums are fitted at the rear. Wire wheels of 14 in. diameter are fitted as standard, as are Dunlop RS5 tyres.

To refresh our memory of the Gilbern the London distributors, Ace Motor Co., 20, Radley Mews, Kensington, W.8, offered us a car fitted with a mildly-tuned engine which had a Taurus-modified cylinder head, a modified camshaft, and a Mangoletsi inlet manifold. These relatively minor modifications improved the performance all the way through the range quite noticeably and at the top end allowed the car to reach a top speed of 110 m.p.h. in overdrive top. As the table shows, the performance of our test car was much better than that of the car tested last year, and if a really highly-tuned engine was fitted the Gilbern would be a very quick car indeed. As it is, the Gilbern is well up with most other medium-sized GT cars, for there are not too many cars capable of achieving 100 m.p.h. in 40 sec. from a standstill, with another 10 m.p.h. or so to come.

The M.G.-B engine is not the quietest available but the 5-bearing crank has eliminated the vibration period we noticed in the previous model and it revs cleanly to 6,000 r.p.m. There is not a lot of power below 2,500 r.p.m., but once over this the engine really flies round to 6,000 r.p.m. in the lower gears. First and 2nd are a little low and are good for 30 m.p.h. and 50 m.p.h., respectively, but the change to 3rd drops the rate of acceleration somewhat. This gear is good for 80 m.p.h., while overdrive 3rd will encompass 100 m.p.h. Naturally, performance tails off in top and overdrive top, but overdrive allows a cruising speed of 100 m.p.h. to be maintained at an indicated 4,500 r.p.m., at which speed the Gilbern is relatively quiet. There is some whine from the gearbox but wind noise is kept at a very low level.

The ride is quite firm with only the driver on board, but with two or more passengers and a tankful of fuel the ride softens, especially at speed. At no time did the suspension bottom, even on a notorious dip we know of which usually catches out most cars. Rear-seat passengers reported that the ride was quite comfortable although they would have preferred a little more leg room. The 1965 model has an improved rear seat which gives more leg room and more width across the seat.

The rack-and-pinion steering has most of the attributes of this layout except that it is heavier than on the M.G.-B, although an increase in tyre pressures above the normal 22 p.s.i. will help it to become lighter. Handling is good, with very little body roll, but the inside rear wheel lifts fairly easily under hard cornering. Rear-end breakaway can be induced quite easily in the wet but the quick steering (2.9 turns) soon catches any slide. The brakes are well up to the performance and although they demand high pedal pressures they bring the car to a halt extremely rapidly. Owing to an offset driving position it is difficult to give a straight push on the pedal. The 1965 model has dual brake master cylinders.

The new seats are most comfortable and can be adjusted to suit any driver; a small handwheel gives fine adjustments to the back-rest and a lever allows the back-rest to drop into the fully reclining position. The new seats lack the curved back-rest of the old ones but we noticed no loss of lateral location. The p.v.c.-covered facia is stocked with all the necessary instruments, including rev.-counter, speedometer, ammeter, fuel gauge, combined oil-pressure/water-temperature gauge, and an electric clock. A row of toggle switches looks after the 2-speed wipers, washers, heater fan, panel lights, fog and spot lamps, while separate toggle switches operate reversing lights and the engine cooling fan; the latter comes into operation automatically when the temperature rises to 95˚.

The body of the Gilbern is made from glass-fibre reinforced plastics and is an excellent example of its type in fit and finish. The shell is not designed to take any of the chassis stresses and the doors and bonnet are hinged on chassis members, thus overcoming one of the great difficulties of this type of construction. The doors on the test car shut well and such things as window winders worked properly, which is not always the case with kit cars. The interior is tastefully trimmed and is as good as can be found on most factory cars.

Our re-acquaintance with the Gilbern has shown once again that it is an attractive car in many ways. By using the mechanical components from a popular car Gilbern have ensured that service is only as far away as your nearest B.M.C. dealer, and by using glass-fibre body they have ensured that rust will not add to depreciation costs. The fact that they are hard pressed in turning out three or four cars a week shows that there are plenty of people willing to spend nearly £1,000 on a hand-built 4-seater.—M. L. T.

Gilbern GT
Engine: Four cylinders, 80.26 x 88.9 mm. (1,798 c.c.). Push-rod-operated overhead valves. 8.8-to-1 compression ratio. 96 b.h.p. (net) at 5,400 r.p.m.

Gear ratios:1st, 14.11; 2nd, 8.66; 3rd, 5.37; top, 3.91. (Overdrive extra.)

Tyres: 5.90 x 14 Dunlop Road Speed on wire wheels.

Weight: 17 cwt. (with 2 gallons fuel).

Steering ratio: 2.9 turns lock-to-lock.

Fuel capacity: 9-1/2 gallons. (Range approximately 215 miles.)

Wheelbase: 7 ft. 7-3/4in.

Track Front, 4 ft. 2 in.; rear, 4 ft. 2 in.

Dimensions: 12 ft. 6 in. x 5 ft. x 4 ft. 2-1/2in. (high).

Price: £945 (in component form).

Makers: Gilbern Sports Car (Components) Ltd., Pentwvn Works, Llantwit, Nr. Pontypridd, Glamorgan.

Car supplied for test by: Ace Motor Co., 20, Radley Mews, Kensington, London, W.8.

Performance data

0 – 30 m.p.h. …… 3.3 sec.

0 – 40 m.p.h. …… 6.2 “

0 – 50 m.p.h. …… 8.4 “

0 – 60 m.p.h. …… 11.8 “

0 – 70 m.p.h. …… 15.8 “

0 – 80 m.p.h. …… 20.2 “

0 – 90 m.p.h. …… 29.2 “

0 – 100 m.p.h. …… 38.9 “

Speed in gears:

1st (6,000 r.p.m.) …… 30 m.p.h.

2nd ( ” ” ) …… 50 “

3rd ( ” ” ) …… 80 “

3rd o/d (6,000 r.p.m.) …… 100 m.p.h.

Top ( ” ” ” ) …… 104 “

Top o/d ( ” ” ) …… 110 “

Standing start 1/4-mile …… 18.4 sec.