Introducing the tera®

Building The Legend, XJ13, Neville Swales, Jaguar, LM69, Ecurie Cars

Introducing the tera®, Building The Legend Limited’s own unique quad-cam V12 engine. The type of power unit which could have been heard howling down the Mulsanne Straight at Le Mans in 1966 and beyond.

A beautifully sculptural engine and unashamedly “of the period”. Designed to be seen and with a purposeful beauty hinting at the power lying within.

The tera® draws inspiration from Claude Baily’s (former Chief Designer, Jaguar) legendary quad-cam racing engine – an engine designed to return the company to its glory days of Le Mans triumphs and domination.

Building The Legend, XJ13, Neville Swales, Jaguar, LM69, Ecurie Cars
Introducing the tera-™, Building The Legend Limited’s own unique quad-cam V12 engine

Sadly, the one-off car was destined to never turn a wheel in anger and the potential of Baily’s mighty power-unit was never fully realised. Instead, the company re-designed Baily’s racing engine into a SOHC version more suited to sedate applications.

In the words of Walter “Wally” Hassan …

“… Between 1949 and 1957 Jaguar were actively involved in motor racing in order to create the sporting image for their cars. Amongst their successes were the winning of the Le Mans 24 Hour Race in the years of 1951, 1953, 1955, 1956 & 1957 as well as Sebring and many other international races and rallies. These cars were powered by the six-cylinder XK twin-cam engine and it was thought to be desirable to develop a successor to compete in future races, particularly Le Mans …. in order to provide the maximum potential in power, a 12 cylinder ‘Vee’ configuration … was conceived to provide for safe running at 8000-8500 rpm. By way of comparison the 6 cylinder twin cam XK engine had been designed without racing in mind.

… during the development period it was decided to withdraw from racing and these policy changes eliminated the need for a competition engine and emphasis shifted to the production (SOHC) version.”


Drawing inspiration from Baily’s V12 and other classic racing engines of the period, Building The Legend’s tera ® represents an evolution of Baily’s concept. A “what might have been”. An engine born to race but whose potential was never fully realised – until now …

The engine is of course normally-aspirated and drivers of these cars will gain the full visceral experience of a howling V12 race-engine. Distributor-less with choice of period Lucas Mechanical or Electronic Fuel injection. Safe running rev-limit of 8,000 to 8,500 rpm. Available from street-spec to full-race. Applications of this engine are limited only by your imagination!

Building the Legend can upgrade your Classic Jaguar! From a “refresh”, engine-swap, full-restoration and everything in between.

Engine Specifications:

  • Capacity:         6.1 L (372 cu in); 6.8 L (415 cu in)
  • Bore x Stroke:  96 x 70 mm (3.8” x 2.8”); 96 x 78.5 mm (3.8” x 3.1”)
  • Power:             350 – 650 hp   (261 – 485 kW)
  • Torque:            300 – 600 lb ft (407 – 813 Nm)
  • Compression:  12.7:1
  • 2-valve, over-square architecture, duplex-chain-driven cams with convenient Vernier adjustment.

Contact details:

For details of pricing, specifications, applications and delivery, please contact:

Neville Swales

Building the Legend

Telephone:      +44791 644 5253


Transform your Classic


“to the power of 12”

from the Greek – “teras” = monster.

Contact us for details

Classic Workshop

Building The Legend Limited

Building The Legend Limited, creators of the sublime Le Mans Prototype inspired by Jaguar’s one-and-only XJ13, is proud to announce our extension of services to owners of classic Jaguars and our aim of matching their passion with our attention to detail and craftsmanship.

Based close to Jaguar’s spiritual home in the heart of Coventry our fully-equipped and staffed new workshop opens its doors to fellow-enthusiasts and owners of Jaguar E-Types, Classic Saloons and race-cars – whether re-creations or original.

Building The Legend will collect and deliver vehicles for service, repair and rejuvenation from and to any location in the UK or, in the case of overseas customers, any UK airport or port.

The expert engineers at our Classic Workshop are ready to help preserve and rejuvenate classic Jaguar cars from around the world.

One of the many services we offer is comprehensive rebuilds of Jaguar’s classic 6- and 12-cylinder engines – professionally built to the highest standards. We can rebuild your own matching-numbers engine, supply replacements on an exchange or outright basis. Engine removal and replacement service is also available at competitive rates.

Your “Building The Legend” Classic XK Engine

When your engine arrives it will be photographed and all serial numbers and components noted. This ensures that you will have your own unit and ancillary parts returned.

We can remove and replace your engine for you in our comprehensively-equipped workshop. We can also collect and deliver your car as required.

Your engine will be fully stripped and chemically cleaned, after which all components will be inspected by our Jaguar time-served senior engine builder – one of the UKs most experienced builders of classic Jaguar 6- and 12-cylinder engines. He is a Jaguar engine specialist. Specialising in the rebuilding and reconditioning of classic Jaguar engines. All Jaguar engines from 1948 -1979. XK120, XK140 and XK150. E-type engines 3.8/4.2 and Jaguar XJ6, XJ12 and XJS V12 engines. He has over 40 years specialist experience with rebuilds and reconditioning of Jaguar engines. He joined Jaguar as a works apprentice in 1971 and went on to work in the factory engine reconditioning department, working on all derivatives of the XK and V12 Jaguar engines.

He began his apprenticeship at Jaguar in 1971 and remained with Jaguar for the next ten years. His start at Jaguar coincided with the launch of their Series 3 V12-powered E-Type and he gained enormous experience assembling and rebuilding these legendary engines. As well as the V12, he has worked on the whole range of Jaguar power-units – from fighting-vehicle engines, through fire-truck engines to their production and race engines.

3.8 cylinder block Degreased, Acid dipped, rebored, steam cleaned and wire brushed ready for painting

Crankshafts, conrods, blocks and heads will be inspected for cracks and suitability for overhaul. From here your engine components will pass through the machine shop. Crankshafts will have the journals ground and polished as required. The complete crank assembly will be balanced. Conrods will be balanced, bushed, sized and matched and have new bolts and nuts fitted.

Cylinder blocks will be checked for main bearing alignment and rectified by line boring if required. Where applicable, cylinder liners will be removed and internal waterways cleaned. Replacement liners will be fitted.

At every stage, you can specify any enhancements/modifications to improve the longevity and power of your engine.

Outside of block etch primed

The block will be rebored and honed to suit replacement pistons and rings. It will then be surface ground and cleaned and painted. New core plugs will be fitted. The bottom end of the engine will then be carefully assembled using top quality, heavy-duty bearings, gaskets and seals. All timing chains will be replaced along with the tensioner and chain dampers. Sprockets and bushes will be checked for damage and replaced as required.

First coat of exterior paint applied

Oil pumps are replaced with standard specification rotor pumps, or up-rated units fitted.

First coat of internal paint applied

Cylinder heads are crack tested, waterways machined and welded as required. Valve guides are inspected replaced and/or linered and are compatible for lead free fuel. Exhaust valve seats are replaced for lead free use and cut to suit valves. Inlet seats are cut to suit valves. Bucket guides are inspected and sized. Larger buckets can be installed to cater for high-lift performance cams if desired. Loose or worn bucket guides are replaced. New valves, springs, stem seals, shims and followers are fitted.

Crankshaft chemically cleaned for inspection

Camshafts are reprofiled as required. Chamber sizes are checked and the head face surfaced. The head casting is refurbished as per original. (Painted and polished to correct original specification). The head is carefully assembled and shimmed and vacuum tested. New manifold studs are fitted.

Ready to fit sludge plugs
Crankshaft split lip seal fitted to crank

The head is then reunited with the block, using new cylinder head studs, chrome nuts and composite head gasket. Cam covers are either polished or repainted as applicable, fitted with new chrome nuts and copper washers. New spark plugs are fitted and installation gaskets supplied.

Bearings fitted to cylinder block

The finished engine unit is then either refitted with the customers own ancillaries (carbs, manifolds, water pump, distributor, filter head, flywheel, crank damper, etc) and hot tested under its own power in our test cell or basic units without customers own ancillaries can be tested under power using our ancillaries.

Crank torqued and thrust set to 0.004 thousandths of an inch

We offer a reconditioning service for carbs, distributors, filter heads, flywheels and crank dampers ‘in house’ at very competitive prices. We are also able to supply, from stock, clutch kits, cooler kits, coils, leads, engine mounts etc.

CONTACT US for details and pricing

The words Jaguar, Jaguar XJ13, XJ13 are used in a historical/descriptive context and in no way suggest our recreations/replicas are approved by Jaguar. It is widely known that there was only ever one Jaguar XJ13 and any others can only ever be replicas, facsimilies, tributes, recreations, toolroom copies or similar.