These 1 and a half litre Rileys were very popular and it’s sometimes known as the 12/4 – which is named as such because of the 12 horse power rating. No it doesn’t mean the engine is 12 horsepower but relates to the RAC taxation classes of the era. Again, it’s why you see cars like the Austin 10, the Morris 10. It’s all related to that taxation class and I believe for each additional horsepower so jumping from 10 to 11, you’d incur an additional £1 extra tax. If you’re wondering why they switched it up from 12/4 to 1 and a half litre after the 1934 revision.
source.image: idriveaclassic
It’s because they felt the 12/4 naming convention was too close to the 12/6 naming convention and they wanted the vehicles based as the 12/6 to have clear market distinction to the buyer. The range is then completely overhauled once more in 1936 and that’s when you see a little more distinction come in and you see the Lynx and Falcon bodies change slightly but for the Kestrel as we’re testing here today, they move that on somewhat with the introduction of the 6-light body.
There are many nuances, changes and upgrades pre war including a body change for the Falcon and a continental touring saloon – which ends up making everything rather complicated when you’re retelling the story or trying to sell it in to a buying public. Too much choice is never a good thing – but we’ll come back to that later. Coming back to the engine, Riley were shrewd in their development and ensured it was a touch under 1500cc and the reason for this?
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So they could enter it into rallies and races. Realistically, I could do a full hour long video on the Riley racing triumphs but in short, Riley were known for their prowess and a lot of this was down to their keen engine development. In fact, the engine was first conceived in the early 30s to fill the gap between the 9 and 14/6 – Percy Riley was adamant the soon to launch 12/6 would do the trick but his brothers asked him to rethink and they then developed a new 4 cylinder block. This new block closely mirrored Percy’s 9 engine but was enlarged and refined to achieve greater power.
