Refreshing Restoration: 1973 Triumph Stag – Sold?

June 8, 2023, Update – We confirmed the listing for this “Classifind” expired, so with no replacement found, we’re assuming this ride is “Sold?” While this one got away, please reach out either by email or call us directly if you’d like to be informed when we come across something similar.

For many reasons, the Triumph Stag proved to be the poster child for everything wrong with the English automotive conglomerate British Leyland in the early 1970s.  Forcing Triumph to design its own V8 geared towards the US market proved problematic and unreliable. Consequently, of the few examples we come across occasionally, most have had their original V8s swapped out for something more reliable.

This restored French Blue 1973 Triumph Stag for sale currently on Craigslist in Canoga Park, Wisconsin, is an exception as the seller notes a number of upgrades designed to make their Stag much more reliable than when it was originally produced.  In addition to retrofitting a modern A/C system, the seller notes that everything on his Stag works, including the clock.  His only regret is that he does not have the time to enjoy the car more, which is why he is offering it for sale.

Currently offered for $19,500 or best offer, Classic.com, the analytics and search engine for the collector car market, confirms the ask is slightly below the one-year rolling average of this guide’s summary for Triumph Stags produced between 1970 and 1978.  By clicking on the green dots in the graph below, you can navigate to each comparable car sold as a way to help you evaluate the price of the Stag featured here:

As a second data point, the  Collector Car Market Review Online Tool reveals the seller’s ask falls between this guide’s #3 Good” estimate of $11,400 and its #2 “Very Good” appraisal of $17,400 before deducting ten percent for the less desirable automatic transmission.

​Under British Leyland ownership, Triumph built the V8-powered, 2+2 Stag convertible from 1970 through 1978.  Envisioned as a luxury sports car, the Triumph developed the Stag to compete directly with the Mercedes-Benz SL class models. All Stags were four-seater convertible coupés, but for structural rigidity – and to meet proposed American rollover standards of the time – the Stag required a B-pillar “roll bar” hoop connected to the windscreen frame by a T-bar. A body-color removable hardtop with defrost wires on the rear window, full headliner, and lever-operated quarter windows was a popular factory option for early Stags that eventually became standard equipment.  Designers developed the Stag with a unitized body featuring fully independent suspension: MacPherson struts in front, semi-trailing arms at the rear. Braking was by front disc and rear drum brakes, while steering was power-assisted rack and pinion.

The initial Stag design was based on the company’s 2.5-Liter inline-six engine, however, Triumph management intended the Stag, large saloons and estate cars to use a new Triumph-designed overhead cam (OHC) 2.5-Liter fuel-injected V8. The V8’s design parameters changed to 3.0 Liters during development to increase torque. To meet emission standards in the US, a key target market, engineers dropped troublesome mechanical fuel injection in favor of dual Zenith-Stromberg 175 CDSE carburetors. In common with several other manufacturers, a key aim of Triumph’s engineering strategy at the time was to create a family of in-line and V engines of different sizes around a common crankshaft. The various configurations Triumph envisaged would enable the production of four-, six-, and eight-cylinder power plants of capacity between 1.5 and 4 litres, sharing many parts, and hence offering economies of manufacturing scale and of mechanic training. A number of iterations of Triumph’s design went into production, notably a 2.0-liter slant four-cylinder engine used in the later Dolomite and TR7.  The Stag’s V8 was the first of these engines to be fitted to a production car. Sometimes described as two four-cylinder engines sandwiched together, it is more strictly correct to say the later four-cylinder versions were the left half of a Stag engine.

Urban legend has it that British Leyland management urged Triumph the proven all-aluminium Rover V8, originally designed by Buick, however, engineers claimed that engine would not fit.  It can be made to fit the space, but the decision to go with the Triumph V8 was probably more due to the Buick’s different torque characteristics and weight would have entailed substantial re-engineering of the Stag when it was almost ready to go on sale. Such a substitution would also have required a rethinking of the wider engineering strategy, both of which were important “fit” considerations beyond the comparatively trivial matter of the relative dimensions of the two engines. Furthermore, Rover, also owned by British Leyland, could not necessarily have supplied the numbers of V8 engines required to match the anticipated production of the Stag anyway.

Triumph launched the Stag one year late in 1970, to a warm welcome at the various international auto shows. Unfortunately, the Stag rapidly acquired a reputation for mechanical unreliability, usually in the form of overheating. These problems arose from a variety of causes.

First, the late changes to the engine gave rise to design features that were questionable from an engineering perspective. For example, the water pump was set higher on the engine than is usual. If the engine became hot in traffic, and coolant escaped from the cooling system via the expansion bottle, the reduced volume of fluid left when the engine cooled down again fell below the level of the pump, which would eventually fail as a result. Water pump failures sometimes occurred due to poorly-hardened drive gears, which wore out prematurely and stopped the water pump.

A second cause of engine trouble was the lack of attention to corrosion inhibitors in the coolant. The block was made from iron and the heads from aluminum, a combination that required the use of corrosion-inhibiting antifreeze all year round. This point was not widely appreciated by owners or by the dealer network supporting them. Consequently, engines were affected by electrolytic corrosion and white alloy oxide sludge collected in radiator cores, reducing radiator efficiency and causing overheating. The result was head gasket failure due to cylinder head heat distortion, a very expensive repair. Owners would usually get their repaired cars back with the radiator still clogged, leading to repeat failures.

The third cause of the trouble was the engine’s use of long, simplex roller link chains, which would first stretch and then often fail inside fewer than 25,000 miles, resulting in expensive damage. Even before failing, a stretched timing chain would skip links and cause valves to lift and fall in the wrong sequence so that valves hit pistons and damaged both. This fault may have been worsened by poor-quality chains.

Another problem with the cylinder heads was said to be the arrangement of cylinder head fixing studs, half of which were vertical and the other half at an angle. Anecdotally, this arrangement was used to reduce production costs, as the cylinder head mounting studs and bolt were all accessible with the rocker covers fitted. This allowed the factory to assemble the cylinder head completely before fitting it to the engine. The same arrangement worked well enough on the 4-cylinder engines, but in the V8 the angled and vertical studs, when heated and cooled, expanded and contracted in different directions sufficiently to give rise to sideways forces that caused warping of the engine block.

Finally, although pre-production engines cast by an outside foundry performed well, those fitted to production cars were made in-house by a plant troubled with industrial unrest and inadequate quality control. Engines are still being discovered with casting sand inside, blocking the coolant passages, and causing overheating.  Consequently, many owners replaced the troublesome engine with units from other cars, such as the Rover V8, or the Triumph 2.5-Liter inline-six engine around which the Stag was originally designed.

The Chris Offer YouTube Channel features this modern video of the fifty year history of the Triumph Stag all while driving one through the English countryside:

It’s very rare to come across an example featuring its original engine, so this 1973 Triumph Stag is a refreshing change that remains updated yet true to its original form. 

If you are serious about buying this Stag, you can start the conversation by contacting the seller using the information provided in their Craigslist ad. When you connect, please remember to mention you saw their restored Triumph featured here on GuysWithRides.com. Good luck with the purchase!

Here’s the seller’s description:

Show or go: What would you do with this restored 1973 Triumph Stag?  Please comment below and let us know!