We are delighted to announce the launch of our A-Series 5 speed gearbox kits for MG Midgets and Austin Healey Sprites, for £2200.
The Suzuki Jimny gearbox provides synchromesh on all gears, a 5th gear for cruising and the durable reliability needed for high performance. Combined with an improved clutch system, lightweight flywheel and high torque starter motor, this kit will transform your car without compromise.
Included is all of the hardware needed for an easy to fit, bolt-in conversion, down to the last gasket. We can even provide a refurbished gearbox.
We expect to be able to ship the first batch in approximately 12 weeks. Pre-order now to avoid disappointment!
Introducing our prototype A-Series 5 speed kit! Road testing is tantalisingly close now, we can’t wait.
A challenge we have had to overcome to get the the Suzuki Jimny gearbox to fit into the Spridget chassis is the gear change.
In the Suzuki the shift housing is a separate casting sitting too far back for our application. We have successfully welded housings to the gearbox in the past but want a simple, bolt on solution that negates the need for donor parts and a lot of time consuming modification work.
After several design iterations, multiple prototypes and many hours of work this is what we have come up with;
A modern gearbox is all well and good but a clutch is equally important. To get around relatively shallow bellhousing in the Suzuki gearbox we have designed a new flywheel with a 190mm clutch. This has a torque capacity of over 150Nm but with a pedal no heavier than the original.
The cable operated Suzuki roller release bearing and arm make failed carbon bearings, leaking slave cylinders and worn clutch forks a thing of the past.
As an added bonus, the billet flywheel weighs only 4.5kg. The reduced inertia really brings the engine to life without losing idle quality.
We have often been asked how our Nissan engine conversion compares to a ‘normal’ Midget engine, which is a fair question to ask and one we wanted to know ourselves. As we are all too aware, rolling road figures can vary massively due to differences in calibration, correction factor and general levels of fudgery. To overcome this, we took our two Midgets – one standard, one with our Nissan CG conversion – for back-to-back testing at DC Performance and Tuning in Funtington to see the difference.
For setting a benchmark: our 1970 Midget, ‘Ruby’. Sporting a rebuilt 1275 A-Series with just 7000 miles on the clock and with marginally improved breathing over standard with a K&N filter and an LCB exhaust manifold, it fits the bill perfectly. We thoroughly checked and serviced the engine for good measure before testing.
On this particular rolling road it produced 52.4hp at 4300rpm and 77.3lb.ftat 2900rpm at the wheels. The SU’s did a great job keeping a steady 12.5:1 air fuel ratio over the range. Torque is actually better than the book figures for the flywheel but we did notice peak power was a bit lower down the rev range than we would have hoped for. We would expect flywheel numbers to be 15 – 20% greater, allowing for transmission losses.
Now it’s time to see how our Nissan CG powered 1963 Midget ‘Nidget’ compares. The engine is a 1275 CG13 from a 1994 Micra. With over 100k miles on the clock it’s no spring chicken and is internally standard. It breathes through Mikuni carburettors, our 4-1 tubular manifold and a 42mm exhaust.
79.4hp at 5400rpm and 85.8lb.ft at 3000rpm. With a 50% increase in power over the A-Series it’s little wonder that it flies!
Throw into the mix a near 50kg weight saving and you have a dramatic improvement in performance, all the while retaining the drivability of a Japanese hatchback. To put the weight saving into perspective, to get the same power-to-weight ratio from an A-Series Midget an additional 6hp is needed at the wheels to match the Nissan CG, even more so with a lardy 1500!
We are very happy with the results and feel it clearly demonstrates the benefits of our bolt-in Nissan CG engine conversions. Get in touch if you’re interested in finding out more or ordering a kit.
Say hello and meet our newest recruit, Ruby! This lovely 1970 MG will be our dedicated development and testing car and will soon be upgraded with the prototype of our Suzuki 5 speed gearbox kit. She’ll then be put through her paces for several thousand miles, ensuring we can quality check the kit before releasing it to market.
We’re looking forward to showing you more of Ruby in the future!
It’s often said that the devil is in the detail, or in the case of these flywheels the devil happens to be in their diameters – which are unfortunately not up to spec and require further attention.
With every part, we aim to meet the highest standards of product quality and customer satisfaction through inspection. Before reaching our customers, every part is checked prior to dispatch, meaning you can focus on fitting and enjoying your purchase with confidence.
And if anything did slip past our eagle eyes, we’re happy to resolve the problem as quickly and efficiently as we can – as we know ourselves how stressful it can be!
As the evenings draw in and we retreat back into our workshops for the winter, why not take the opportunity to upgrade your Spridget?
Our bolt-in kits retro fit the twin cam Nissan CG engine, either reusing your existing gearbox or upgrading to a modern 5 speed Suzuki transmission. Our kits are carefully engineered to ensure no modifications to the chassis or bodywork are needed.
Decades of development by Nissan turned the A-Series into a high revving, powerful and durable engine, but none of the Spridget character is lost.
Whether you’re looking for a cost effective upgrade for a daily driver or are planning to make the most of the weight reduction benefits and tuning potential for the track, we can provide a kit to suit you.