About Conversion Components

Colin Dray of Hamilton, New Zealand, has over 40 years experience in Engineering Design & Manufacturing.

He started automobile ownership with a 1928 Austin 7 Tourer, whilst in the last year of high school. At age 14 his dad purchased a Myford Lathe, and by reading books, he learnt to make many things on that little lathe. With the Austin 7 the flywheel drive key shearing off. So after about 3 replacement keys, he decided to make a special wider one, that would 'fit' the worn slot. That was his first fairly serious attempt at making a special part, at age 16. Colin and his brother got into 'Vintage Cars' (pre '31) and he purchased a 1925 Oakland Tourer and proceeded with a full 5 month restoration. That included a few modifications here and there, and 80,000 miles of rallying and personal daily use.

A trip to UK in 1961 led to the purchase of a 1936 3.5L Bentley, touring England and Europe following veteran car rallies. So Colin understands, the owners passion for their cars, and wanting to have them right for the road. He currently owns a 100-6 Healey and 70's and 80's Jaguars. Everyday use is by a 1981 S3 XJ6 complete with 5 speed gearbox - absolutely magnificent on the highway.

Colin trained with NZ government as a Mechanical Design Draughtsman, then as a turner fitter, and several years experience in tool making. Following 5 years as a development engineer with an appliance manufacturer, then a product design consultancy.

Late 1989 saw an opportunity to start Conversion Components and develop conversion kits for the Toyota range of bolt on gearboxes. Also as a gearbox conversion specialist many special conversions have been carried out for customers, including electric vehicle and marine conversions.

Since the early 1990's Conversion Components has been developing and refining conversion kits, to enable the fitting of Toyota 5 speed gearboxes (RWD) into a wide range of 1950's to 1980's Classic cars. Generally these conversion kits comprise: Cast aluminium bell housing from a heat treatable grade aluminium. Toyota type pressed steel clutch fork, release bearing and carrier to suit the hydraulic clutch application. A new or remanufactured clutch plate. To enable the pilot bearing to fit the classic car engine, special high tensile sleeves are manufactured to fit onto the 12mm dia input (pilot) shaft to match the original input (pilot) bearing. For some conversions a new (pilot) bushing unit is supplied.

The conversion kits are supplied with comprehensive installation instructions to help the owner / installer. For the conversion that utilises the Supra 5 speed gearbox, a range of special gearbox tops has been developed, to enable the gearlever to protrude throughout the opening of the original consol in the car. They range from 365mm (MK11 Jaguar) 390mm (XJS, XJ6 Jaguar) 425mm (Triumph TR2 - 6) 455mm (Healey 3000) 515mm (Ford & Holden) 530mm, 580mm (Rover V8 P6). These gearbox tops give a range of positions spanning 215mm.

GEARBOXES - SUPRA These generally are supplied, ex Japan, with reasonably low kms. They are thoroughly cleaned, checked over, and the worn shifter parts replaced where necessary. New input bearing, and seal is fitted. With 12 years of experience supplying these Supra gearboxes, they are very robust and seem to give many, many thousands of kms of trouble free excellent service. Many of the gearboxes ex Japan, when opened up for inspection, have really clean oil, there is hardly any build up of particles on the magnetic drain plug, and effectively are sparkling like new. For applications up to the 5.3L V12 Jaguar, installed in cars up to 2 tons in weight, they give reliable and consistent service. Where installed behind Chev and Ford 5L V8's, with higher torque than the Jaguar V12, it is our experience that if they are driven really hard the layshaft drive is prone to strip the teeth of the gears. Also Targa rally cars, MK7, MK2, XJS Jaguars, (all about 2 ton) have shown failure of the layshaft drive after one or two Targa seasons. For normal applications they are rated fine.

The R154 'Big Supra' is now available (in limited quantities) for HP applications over 350HP. These are a meaty gearbox, and only weigh 45kgs. A range of bell housings have been developed for this gearbox.

The smaller T50 5 speed gearbox are ideally suitable for Triumph Spitfire GT6, MGA, MGB Sunbeam Alpine conversions, and can handle up to 200BHP. These gearboxes come in 62 & 68mm input bearing sizes and therefore the conversion bell housing has to be machined to match the gearbox that is to be fitted. These gearboxes only weigh 27kgs and are ideally suited to the smaller classic cars up to 2.5L. The may be obtained from a Toyota Corolla 1600cc donor car or Sprinter.

Crossmembers have been developed where possible, to enable a straight forward bolt in installation. New speedometer cables are supplied as part of the kit. Speedometer calibration is the customers care, and can be solved by obtaining a very small gearbox to go onto the speedo drive output of the gearbox. We can supply a formula to work out the gearing required, and the corrective gearbox.

MG Midget A conversion for the Midget and the Healey Sprite has been developed utilising the Toyota 4K gearbox, out of the RWD Starlet. It is a compact robust gearbox, complete with bell housing. Minor modifications required, to part of the bell housing area to enable the Midget starter to clear, and it is fitted to the engine by means of a adaptor plate. The clutch fork is modified and operated by a slave cylinder mounted by a special bracket on the side of the gearbox. In these gearboxes, the front layshaft bearing is prone to wear after 100,000 + kms, so we supply a gearbox that has a rebuilt layshaft, input bearing and seal replaced and any other bearings required, replaced. Rear rubber mount is modified to accept bolts through original holes in chassis. A special speedometer cable and right angle drive is included with the kit. For the slave cylinder connection, a new flexible hose and pipe are supplied.

Packaging of Products Our conversion kits are substantially packaged in double corrugated cardboard cartons with 20mm (3/4') polystyrene foam between the cartons. This is for protection, for the occasional abusive handling by the shippers. Gearboxes are packed in a plywood box. Conversion kits (under 20kg) are shipped export - by air parcel post, and effectively arrive at your door. When a transmission is included with the conversion, they are shipped by air freight to nearest international airport. Our customers can request door to door shipping.

Auto to Manual Flywheels - We manufacture a range of steel flywheels, so customers can change from automatic to manual. (see our services).

Jaguar Pedal Boxes Where automatic cars are being converted to manual, we have developed a manual pedal box, for the XJ6 saloon. For XJ6 we are about to develop a manual pedal box. Generally original manual pedal boxes are very difficult to locate, hence the need for this development.
Also E Type, MK2, XJS.

'Happy 5 speeding'

Colin Dray 
Conversion Components 
Hamilton, New Zealand