Storage Yard Classic: The Triumph And The Engine Swap – Not A Happy Ending

Tr7 engine swap3

With most classic cars an engine swap will decrease its value and the number of possible buyers significantly, especially when mixing and matching brands. If your swap recipient is a full classic or rare car you might need to seek the services of a witness relocation agency. Where a big V8 lump in a Jaguar XK120 would be considered a bit anti-social, almost no one would have a problem with a adding a couple cylinders to a Triumph TR7. Heck it would probably increase the value for most. Our example today is perhaps a little too far gone though.


The history of Triumph’s slant four cylinder engine is a little convoluted and often misunderstood. Some folks will claim it is “the Saab engine”. Perhaps they are Triumph apologists trying to deflect blame for this head gasket popping wonder but this turkey was definitely Triumph baked. With some rather aged engine designs in the fleet a Triumph team led by Lewis Dawtry and Harry Webster embarked on a project to develop a new, more modern overhead cam engine. Engine displacement was designed to be very flexible so that it could accommodate displacements from as low as 1.2 to over 2 liters. One can speculate that Triumph perhaps  also hoped to replace the Spitfire’s engine, whose design dated to the 1953 Stardard 8’s 803cc engine. Pure speculation, but what is quite clear is that they tilted the engine at a 45 degree angle with an eye to make a V8 possible as well.

Triumph Stag V8 engine

When the infamous Triumph Stag was developed starting in 1964 it was originally intended to use the straight six engine as fitted to the TR6 and 2000/2500 saloons. When its role moved from sports car to touring car, a larger V8 engine was deemed necessary. As planned, essentially two Triumph slant fours were added together to form this new V8 engine. The initial plan for the Stag’s V8 was a displacement of 2.5L. Coupled with  fuel injection, this would have given the Stag the performance it needed. But when the Bosch fuel injection was tossed in favor of twin Zenith-Stromberg carburetors, a last minute boost in displacement to 3.0L was needed to retain adequate performance. Unfortunately the bigger bore needed for the larger displacement cut into the water jackets which contributed to the Stag’s cooling issues.

Saab 99 engine

So where does Saab fit into this story? Saab had their own two stroke motors, and later augmented with the Ford Cologne V4. Neither engine was deemed to be suitable for the upcoming bigger car. Saab had contracted with the well-known UK based engineering firm Ricardo to build them a suitable four cylinder engine.

Unfortunately, Ricardo found themselves in a bit over their head designing an engine from scratch and was unable to deliver. Ricardo also contracted with Triumph regularly (but not on the slant four motor) so they knew of its existence and that it would soon be ready for production. Ricardo then put Saab and Triumph in the same room and a deal was hammered out to use the new engine in 1.7L form for the upcoming Saab 99.

Saab 99 fuel injection

Unlike most engines of the day, the new Triumph SOHC four could be used with an electric rather than crank driven fan, which worked well for Saab’s front wheel drive application. Perhaps to keep the Saab tradition of longitudinally-oriented engines, Saab mounted the Triumph engine “backwards”, with the output shaft and clutch gearbox in front, and with the transmission directly under the engine (the top of the transmission doubles as the engine’s oil sump).

Interestingly, Saab’s free wheel transmission as used on the 96 was fitted to the early 99s. Triumph built the engines initially, but Saab specified a specially tuned Zenith-Stromberg CD carburetor. In 1971 displacement was bumped via a larger bore to 1854cc, but Saab was increasingly unhappy with the quality of the engines delivered and brought the design in house. From 1972 to 1985, the Saab engine increasingly diverged from the Triumph design. Fuel injection and a turbocharger were fitted on some variants. Another interesting fact is Saab briefly considered using the Stag’s V8 engine to power the performance variants  of the 99 and even built a few V8 equipped prototypes. Saab eventually settled on turbocharging instead, and probably felt like they had dodged a bullet once the Stag’s issues came to light.

TR7 engine

Getting back to the TR7 (CC here): it was launched in 1975 with a 2.0L (1,998 cc) variant of the slant four engine. Horsepower was a competitive 105 for the home market and 92 for North America. Sadly the more powerful 16 valve version from the Dolomite Sprint was never fitted. Given that it had seen duty for a few years in Triumph’s own Dolomite 1850 line one would expect any issues to have been worked out already. As many a TR7 owner  knows that is simply not the case. The engine used an iron block with an aluminum head. Not a terribly uncommon thing to do in the 1980s but still somewhat novel for British car at the time.

Tr7 head

Unfortunately for TR7 owners there are several factors conspiring against long engine life. First of all many owners (especially in Britain) filled the cooling system with straight water rather than coolant which lead to corrosion with an aluminum head. The quality of the casting on the head itself was not high so they had a tendency to warp if overheated. The timing chains can stretch, the water pumps can die and fans can fail. So all sorts of cooling problem then. Blown head gaskets were a common complaint and to add insult to injury the retaining studs on the head are set at an angle which gives all sorts of grief and complication when replacing the gasket.

Triumph TR7 V6

The TR7’s problems didn’t end with the engine of course. The early units were fitted with a four speed gearbox shared with the Dolomite but also Morris Marina. It was a rather weak and uninspiring unit. The later cars (optionally starting in 1976 for North American, 1978 for the UK and later made standard) had a fine Rover five speed as well as a stronger rear axle.

TR7 door handle

Quality issues abound on the early cars with TR7s being a poster child for the results of militant labor relations. The early cars were built in the Speke factory and almost all have a 4-speed manual or a 3-speed automatic gearbox. Visually the early cars have TR7 script at the front on bottom of the bonnet/hood. The rear has Triumph in smaller letters followed by TR7 in large letters on the trunk lip. These are to be avoided as the bottom of barrel build quality wise unless they have been lovingly sorted.

Next up are the Canley built cars which can be identified by the large wreath logo on the slightly revised bonnet/hood with Triumph written in the middle. The long awaited convertible arrived in 1979. Production again moved for 1980 to Rover’s Solihull plant. These cars can be identified by the small raised badge on the hood/bonnet. The Solihull built cars actually have pretty decent build quality but it was too late by then as the TR7’s reputation was cemented in as proved by its common appearance on the worst cars ever lists.

V6 engine

This particular car is an earlier fixed head coupe with its troublesome engine tossed away. A friend of mine owned this very car a number of years ago. It has a Ford 2.8L V6 and C3 automatic swapped in that no doubt provided a healthy boost to both torque and reliability. The story he told me was the car was converted professionally by a local British automotive shop a number of years back (well previous to his ownership). I strongly suspect it would have been sometime in the 1980s as the Buick 3.8L V6 was offered in kit form later and took off as a much more popular swap option.

deerfoot trail

He only drove it once and that was one the way home from purchasing it. The route took him on the very busy and fast Deerfoot Trail in Calgary. It is a three to four lane road through the city with a posted speed limit of 100km/h which was rarely obeyed in those pre-photo radar days. Why all the back story on the road? Well, to set the scene for what happened next. He was driving it home along the Deerfoot testing out the V6’s improved acceleration when the steering column completely dropped in his lap. The experience was so harrowing that it got towed straight to his storage yard and it hasn’t been driven since.

Triumph TR7 interior

You can just see the zip ties holding it in place currently.

Triumph TR7 V6 rear

So there you go – a write up on the TR7 that didn’t include a reference to the famous tag line “The shape of things to come” or moan about the rather subjective area of styling. I happen to like the look of the coupe but there is no accounting for the taste of the majority, I suppose. The engine may have been troublesome as shown by Google’s first suggestion when you type “Triumph TR7 engine” is “Triumph TR7 engine swap”. You may have also hit rock bottom engine wise when you go shopping for a Pinto V6 to source an engine! But I suspect this one was quite a fast and fun little beast back in the day once that V6 was installed. I’d just prefer to take mine with a clutch pedal.