Triumph V8
Encyclopedia
The Triumph V8 is a 3.0 litre V8 developed in house by Triumph for the Triumph Stag
. This was basically two Triumph Slant-4 engine
s 'stuck' together. It consisted of a single overhead cam cast iron block with aluminium heads.
version of the Triumph 2000
saloon, as development progressed the Stag gained its own identity until the final design shared no body panels or pressings with the 2000. The Stag was intended to use Triumph's existing 2.5-litre straight-6 engine. When the Stag design evolved into a grand tourer
rather than a more conventional sports car
it became clear that a more powerful, more refined engine was needed.
As far back as 1963 the designer of the Triumph Slant-4 engine
, Lewis Dawtrey, had foreseen the possibility that the engine design could be 'doubled-up' to create a V8 unit. Whilst at this point the engine had only been produced in 1.7-litre form by Triumph for sale to Saab
, the basic design of the engine enabled capacities as low as 1.2-litres to be built. Triumph revived the V8 concept, initially settling on a 2.5-litre engine (in essence two 1.2-litre versions of the slant-4) with mechanical fuel injection
provided by Bosch
.
Following the take-over of Triumph by Leyland Motors in 1967 Spen King was placed in charge of product development at Triumph. The V8's Bosch fuel injection was running into numerous difficulties in development and King was unable to convince Leyland to divert extra funds to Triumph to solve the problems. Instead, King dropped the fuel injection in favour of twin Zenith-Stromberg
carburetor
s. To maintain the required power output the capacity was increased to 3-litres, which then entailed modification to the Stags other drivetrain systems included the gearbox, back axle
and brake
s. This relatively 'last-minute' capacity increase was achieved by expanding the bore of the engine instead of the stroke, which explains the Triumph V8's unusual 'oversquare' internal dimensions. This widening of the bore also meant that the water galleries surrounding the cylinders were narrower than originally planned, thus creating the engine's major weakness (see below).
and cylinder block
were made from chromium iron whilst the cylinder head
s were aluminium alloy), the engine featured a unique arrangement of studs and bolts attaching the cylinderheads that allowed the cylinderheads to be removed without firstly removing the overhead camshaft
s and disturbing the valveplay adjustment. The water pump, oil pump and distributor
were all driven at their required speeds from a single jackshaft driven from the timing chain via sets of skew-cut gears. The cooling fan was a 16-blade plastic item driven through a hydraulic viscous coupling that limited fan speed to 2,500 RPM to reduce noise as well as controlling the fan speed in relation to engine temperature.
Many modern day upgrades and sticking to the manufacturers recommended service schedules help to solve these problems. An air dam for a TR-6 helps solve a cooling problem by scooping up the air in front of the car. A 12 blade fan helps to pull more air though the radiator.
. Triumph also tried to sell the engine to the Morgan Motor Company
but that company chose the Rover V8 as well. Saab
tested V8 in Saab 99
mainly for US markets but oil crisis in 1973 finally caused cancellation of the project in favor of turbocharging
. The result was the V8 remained unique to the Stag.
Triumph Stag
The Triumph Stag is a British car that was sold between 1970 and 1978 by the Triumph Motor Company, styled by the Italian designer Giovanni Michelotti.-Design and styling:...
. This was basically two Triumph Slant-4 engine
Triumph Slant-4 engine
The Triumph Slant-4 is an engine developed by Triumph. According to Triumph historians Graham Robson and Richard Langworth in Triumph Cars, the complete story, the engine was developed in-house by a design team led by Lewis Dawtry and Harry Webster....
s 'stuck' together. It consisted of a single overhead cam cast iron block with aluminium heads.
Development
The Stag was developed between 1966 and 1969. Whilst originally seen as little more than a convertibleConvertible
A convertible is a type of automobile in which the roof can retract and fold away having windows which wind-down inside the doors, converting it from an enclosed to an open-air vehicle...
version of the Triumph 2000
Triumph 2000
The Triumph 2000 is a mid-sized, rear wheel drive automobile which was produced in Coventry by the Triumph Motor Company between 1963 and 1977. Larger-engined models, known as the Triumph 2.5 PI and Triumph 2500 were also produced.-Engine:...
saloon, as development progressed the Stag gained its own identity until the final design shared no body panels or pressings with the 2000. The Stag was intended to use Triumph's existing 2.5-litre straight-6 engine. When the Stag design evolved into a grand tourer
Grand tourer
A grand tourer is a high-performance luxury automobile designed for long-distance driving. The most common format is a two-door coupé with either a two-seat or a 2+2 arrangement....
rather than a more conventional sports car
Sports car
A sports car is a small, usually two seat, two door automobile designed for high speed driving and maneuverability....
it became clear that a more powerful, more refined engine was needed.
As far back as 1963 the designer of the Triumph Slant-4 engine
Triumph Slant-4 engine
The Triumph Slant-4 is an engine developed by Triumph. According to Triumph historians Graham Robson and Richard Langworth in Triumph Cars, the complete story, the engine was developed in-house by a design team led by Lewis Dawtry and Harry Webster....
, Lewis Dawtrey, had foreseen the possibility that the engine design could be 'doubled-up' to create a V8 unit. Whilst at this point the engine had only been produced in 1.7-litre form by Triumph for sale to Saab
Saab
Saab AB is a Swedish aerospace and defence company, founded in 1937. From 1947 to 1990 it was the parent company of automobile manufacturer Saab Automobile, and between 1968 and 1995 the company was in a merger with commercial vehicle manufacturer Scania, known as Saab-Scania.-History:"Svenska...
, the basic design of the engine enabled capacities as low as 1.2-litres to be built. Triumph revived the V8 concept, initially settling on a 2.5-litre engine (in essence two 1.2-litre versions of the slant-4) with mechanical fuel injection
Fuel injection
Fuel injection is a system for admitting fuel into an internal combustion engine. It has become the primary fuel delivery system used in automotive petrol engines, having almost completely replaced carburetors in the late 1980s....
provided by Bosch
Robert Bosch GmbH
Robert Bosch GmbH is a multinational engineering and electronics company headquartered in Gerlingen, near Stuttgart, Germany. It is the world's largest supplier of automotive components...
.
Following the take-over of Triumph by Leyland Motors in 1967 Spen King was placed in charge of product development at Triumph. The V8's Bosch fuel injection was running into numerous difficulties in development and King was unable to convince Leyland to divert extra funds to Triumph to solve the problems. Instead, King dropped the fuel injection in favour of twin Zenith-Stromberg
Zenith Carburetters
Zenith Carburetters was a British company making carburettors. In 1955 they joined with their major pre-war rival Solex Carburettors and over time the Zenith brand name fell into disuse...
carburetor
Carburetor
A carburetor , carburettor, or carburetter is a device that blends air and fuel for an internal combustion engine. It is sometimes shortened to carb in North America and the United Kingdom....
s. To maintain the required power output the capacity was increased to 3-litres, which then entailed modification to the Stags other drivetrain systems included the gearbox, back axle
Axle
An axle is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to its surroundings, with the wheels rotating around the axle. In the former case, bearings or bushings are provided at the mounting points where the axle...
and brake
Brake
A brake is a mechanical device which inhibits motion. Its opposite component is a clutch. The rest of this article is dedicated to various types of vehicular brakes....
s. This relatively 'last-minute' capacity increase was achieved by expanding the bore of the engine instead of the stroke, which explains the Triumph V8's unusual 'oversquare' internal dimensions. This widening of the bore also meant that the water galleries surrounding the cylinders were narrower than originally planned, thus creating the engine's major weakness (see below).
Design
As launched in 1970 the Triumph V8 had several innovative features. As well as its unusual construction (the crankcaseCrankcase
In an internal combustion engine of the reciprocating type, the crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine and is located below the cylinder, which in a multicylinder engine are usually integrated into one or several cylinder blocks...
and cylinder block
Cylinder block
A cylinder block is an integrated structure comprising the cylinder of a reciprocating engine and often some or all of their associated surrounding structures...
were made from chromium iron whilst the cylinder head
Cylinder head
In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head gasket...
s were aluminium alloy), the engine featured a unique arrangement of studs and bolts attaching the cylinderheads that allowed the cylinderheads to be removed without firstly removing the overhead camshaft
Overhead camshaft
Overhead cam valvetrain configurations place the engine camshaft within the cylinder heads, above the combustion chambers, and drive the valves or lifters in a more direct manner compared to overhead valves and pushrods...
s and disturbing the valveplay adjustment. The water pump, oil pump and distributor
Distributor
A distributor is a device in the ignition system of an internal combustion engine that routes high voltage from the ignition coil to the spark plugs in the correct firing order. The first reliable battery operated ignition was developed by Dayton Engineering Laboratories Co. and introduced in the...
were all driven at their required speeds from a single jackshaft driven from the timing chain via sets of skew-cut gears. The cooling fan was a 16-blade plastic item driven through a hydraulic viscous coupling that limited fan speed to 2,500 RPM to reduce noise as well as controlling the fan speed in relation to engine temperature.
Issues
This engine can suffer from unreliability as a result of the following design problems:- Overly long single link chains with poor automatic tensioning that only last about 25000 miles (40,233.5 km). The damage is extensive if they fail;
- Inadequately sized main bearings - these have short lives as a result;
- The aluminium heads warp due to poor castings which restrict coolant flow, leading to overheating;
- Water pump failures relating to the drive gear shearing.
- As a legacy of the V8's beginnings as a straight-4 design the sender unit for the temperature gauge is located in one cylinder head (rather than a point of the cooling system common to both heads as on other multi-bank engines). This means that problems can go undetected in one head until enough damage and/or overheating has occurred to affect the one fitted with the sender unit.
Many modern day upgrades and sticking to the manufacturers recommended service schedules help to solve these problems. An air dam for a TR-6 helps solve a cooling problem by scooping up the air in front of the car. A 12 blade fan helps to pull more air though the radiator.
Potential other uses
Triumph originally intended their V8 to be used across their range, which was the reason for the company's willingness to fund the engine's high development costs. Plans were made to create a 'Triumph 3000' by fitting the engine into the 2000 saloon, but these plans were halted when Rover joined Triumph in the Leyland grouping as the resulting car would have been a direct competitor for the Rover 'P6' 3500Rover P6
The first P6 used a 2.0 L engine designed specifically for the P6. Although it was announced towards the end of 1963, the car had been in "pilot production" since the beginning of the year, therefore deliveries were able to begin immediately. Original output was in the order of . At the...
. Triumph also tried to sell the engine to the Morgan Motor Company
Morgan Motor Company
The Morgan Motor Company is a British motor car manufacturer. The company was founded in 1910 by Harry Frederick Stanley Morgan, generally known as "HFS" and was run by him until he died, aged 77, in 1959. Peter Morgan, son of H.F.S., ran the company until a few years before his death in 2003...
but that company chose the Rover V8 as well. Saab
Saab
Saab AB is a Swedish aerospace and defence company, founded in 1937. From 1947 to 1990 it was the parent company of automobile manufacturer Saab Automobile, and between 1968 and 1995 the company was in a merger with commercial vehicle manufacturer Scania, known as Saab-Scania.-History:"Svenska...
tested V8 in Saab 99
Saab 99
- Development :On April 2, 1965, Gudmund's day in Sweden, after several years of planning, the Saab board started Project Gudmund. This was a project to develop a new and larger car to take the manufacturer beyond the market for the smaller Saab 96...
mainly for US markets but oil crisis in 1973 finally caused cancellation of the project in favor of turbocharging
Turbocharger
A turbocharger, or turbo , from the Greek "τύρβη" is a centrifugal compressor powered by a turbine that is driven by an engine's exhaust gases. Its benefit lies with the compressor increasing the mass of air entering the engine , thereby resulting in greater performance...
. The result was the V8 remained unique to the Stag.