Renault 16TS

Introduction

The Touring Sport version of the Renault 16 built upon strengths well displayed by the original iteration released in 1964. In the preceding 3 years, the 16 had developed a stellar reputation as a car offering smooth, refined transport and excellent roadholding, combined with a touch of French ingenuity in creating versatile accomodation, along with arguably the most comfortable front pews in the business.

But there was one (minor) complaint - a lack of performance. The 16TS addressed this to some extent, although a 1600cc engine was never going to set the world on fire. But what it did do was transform a wonderful and well sorted car into something a little more adept at providing driver enjoyment, not only because of the larger engine, but also thanks to the numerous road holding improvements Renault made.

Today many confuse the engine fitted to the TS as that which Renault supplied to Lotus for fitment to their Europa. That engine was however a 1470cc unit that was highly tuned, with modified carburation, warm camshaft and the original cylinder head. The engine fitted to the TS had a slightly larger swept volume, a compression ratio of 8.6 to 1 (compared to 10.25 to 1) and a completely new cylinder head with opposed valves and a hemispherical combustion chamber.

The Renault Hemi

The cylinder block and crankshaft remained basically unchanged, although aluminium-tin big end bearings were adopted to look after the increased power and inertia loadings. Minor changes to the block included beefed up cylinder head stud bosses.

Stretching the engine out from 1470cc to 1565cc was made via bore and stroke increases, increasing from 76 x 81mm to 77 x 84mm, which in-turn made the engine slightly undersquare. Wet liners were a feature of the engine, and to preserve water circulation around each cylinder both the inside and outside of the liners were machined.

The pistons had more rigid skirts, modified machining and smaller cylinder clearances above the compression rings, these ring designs also being modified. However the big changes happened above the cylinder head face. To ensure there were worthwhile improvements the engineers realised it was essential to boost the breathing capability. They soon determined that the original head would not allow such changes due to the inclinded valve configuration, restricted inlet manifolding and having the exhaust ports located on the same side as the head.

No half-measure was taken, instead a completely new head was designed, with the original camshaft position being retained in a trough at the top of the cylinder block. The inlet side of the engine was re-located to the left, while the exhaust side stayed on the right. The head also featured opposed valves and two rocker shafts, while the spark plugs were offset in the hemispherical combustion chamber, which had a recess cast into it. There was a sizeable squish area which pushed compressed gases across towards the plug at the top of the compression stroke.

More ambitious valve timing was adopted, with a bigger overlap period around TDC (Top Dead Centre). Double valve springs were fitted, the inlet ports were smoothly matched into an inlet manifold fed by a compound twin choke Weber 32DAR carby. Mounted remotely to the engine was an enormous air filter, which fed air to the Weber via a flexible pipe. Finally, an entirely new exhaust system (jointly developed with Peugeot) was fitted, the Renault engineering team having revealed that the unit fitted to the standard 16 would have robbed 14 precious horse power.

Chassis Improvements

While the transmission remained unchanged, the tyres were upgraded to Michelin XAS's instead of the 145 14 in. X covers fitted to the 16, which had the effect of making the gearing slightly higher. Better brakes were needed to deal with the 100mph performance, so front 10in. dia. disc brakes were fitted to the front, which was hooked up to a direct acting servo to bring down pressures. The fantastic Renault 16 body shell remained unchanged, although the fascia was completely re-styled. Gone was the long strip-speedo of the 16, it being replaced by circular instruments which included speedo, tachometer, fuel and water temperature gauges.

The 16TS features two speed windscreen wipers which were uniquely operable from either of two positions, a switch mounted on the dash or a switch mounted on the floor which combined with the washer function. Optional extras included a metal sliding sunroof and front power windows. The 16TS was available in 3 distinctive new colours, blue, green and bronze, and all interiors were in stretch bronze leathercloth. The Renault engineers had done far more than simply bore the motor out a little, and the 16TS remains an object lesson in how to make something good something great.