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The A-series engine did service in a variety of cars for almost 50 years, during which time it was available in a bewildering variety of capacities and states of tune.

A hard act to follow
The A-Series engine was certainly a case of the "British Curate's egg" - good in places. In fact, that is not quite true: the A-Series was a fine engine. Of course, by the time of the launch of the Austin Metro in 1980, great play was made by the British press about the fact that here they had a new car, which truly competitive and (in the context of the small/medium BL range of cars), as good news as it was, it was still powered by an engine that first saw service in the Austin A30 some thirty years previously. Of course, to make this criticism was to miss the point entirely.
British Leyland had expended much time and effort on the task of replacing the A-Series engine, but the trouble was that it was capable of delivering fantastic fuel consumption figures thanks in no small part to its excellent torque characteristics and thermal efficiency. Because of this, the A-Series became a victim of its own success: why produce a replacement, when there was doubt that anything new that was produced would be any better to drive?
Discounting the remarkable 9X power unit, the first serious attempt to replace the A-Series engine was the anticipated motive power for the ADO74 programme, instigated in 1972. This engine, dubbed the K-Series engine was an OHC design, which had been designed to be canted backwards some 70 degrees in order to improve the packaging of the new car. The signs were promising - and although when bench tested, the power output was significantly higher than the standard A-Series could manage, it still did not produce the same impressive torque figures. Nevertheless, the engine was cancelled, not because it would have proven to be an unworthy successor to the A-Series engine, but simply because it was part of an ambitious development programme that BLMC could ill-afford.

Signs that the company were becoming keen on developing the (by-now) long in the tooth A-Series engine resurfaced in 1975, when a new OHC cylinder head was produced. The intention was for introduction in the ADO74's (Austin Design Office) replacement, the ADO88, but there emerged some problems. Like the K-Series before it, this engine produced more power than the older engine, yet did not offer a big enough advantage over it to warrant the expense of a full development programme. Not only that, but following the Ryder Report of 1975, the finances of the company were now controlled by the Government, and as a result, all non-essential spending was placed under minute scrutiny. The decision to call a halt to the A-OHC programme, therefore, was an easy one to make.
From the ashes of A-OHC did emerge the A-Plus programme, which involved a modest upgrading of the engine, which facilitated a small rise in maximum power output (without affecting its torque characteristics) and a lengthening of main service intervals.
As a result, the A-Series engine enjoyed something of an "Indian Summer" being, as it was, the power unit for the Austin Metro during the whole of the 1980s. It also saw service in the Austin Maestro/Montego and without the disadvantage of the somewhat flawed transmission-in-sump layout; it would prove to be a reliable and strong performer in these cars. Eventually, an engine called K-Series did replace the A-Plus, but it was not the same engine as that from 1972 - and it took a radical change in thinking to produce something significantly better - and this would not arrive until 1989. Had the A-Series not been so eminently suitable for the task in hand - reasonably powerful, economical and compact, the Mini would probably not been the success it was and the Metro would probably never have come into being in the form it did.
The Mini remained A-Series powered all through its life, starting out with just 34bhp in 1959, and ending its days with the 63bhp, twin-point injection unit developed in 1997 by Rover engineer Mike Theaker.
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Specifications & applications
Capacity Bore Stroke Max. Power Max. Torque  Applications

803cc 58.0mm 76.2mm 28bhp @ 4400rpm 40lb ft @ 2200rpm

1952-56: Austin A30 30bhp @ 4800rpm 40lb ft @ 2400rpm

1952-56: Morris Minor Series II
848cc 62.9mm 68.26mm 33bhp @ 5300rpm 44lb ft @ 2900rpm

1969-80: Mini 850 / Mini City 34bhp @ 5500rpm 44lb ft @ 2900rpm

1959-69: Austin Seven / Austin/Morris Mini

1961-62: Riley Elf / Wolseley Hornet

1964-68: Austin Mini-Moke
948cc DIESEL: 1965-1968: BMC MINI-Tractor 9/16 diesel

948cc 62.9mm 76.2mm 34bhp @ 4750rpm 50lb ft @ 2000rpm 1956-62: Austin A35

1958-61: Austin A40 Farina
37bhp @ 4750rpm 50lb ft @ 2500rpm 1956-62: Morris Minor 1000
37bhp @ 5000rpm 50lb ft @ 2500rpm 1961-62: Austin A40 Farina MkII
43bhp @ 5200rpm 52lb ft @ 3300rpm 1958-61: Austin-Healey Sprite
46bhp @ 5500rpm 53lb ft @ 3000rpm 1961-64: Austin-Healey Sprite MkII

1961-64: MG Midget
970cc 70.6mm 61.91mm 65bhp @ 6500rpm 55lb ft @ 3500rpm 1964-67: Austin/Morris Mini Cooper S
997cc 62.43mm 81.28mm 55bhp @ 6000rpm 54lb ft @ 3600rpm 1961-64: Austin/Morris Mini Cooper
998cc 64.58mm 76.2mm 38bhp @ 5250rpm 52lb ft @ 2700rpm 1962-69: Riley Elf / Wolseley Hornet

1967-80: (Austin/Morris) Mini

1969-75: Mini Clubman
41bhp @ 4850rpm 52lb ft @ 2750rpm 1969-80: Mini Clubman (auto)
55bhp @ 5800rpm 57lb ft @ 3000rpm 1964-69: Austin/Morris Mini Cooper
A+ specification 39bhp @ 4750rpm 52lb ft @ 2000rpm 1980-82: Mini 1000 / City / HL
40bhp @ 5000rpm 50lb ft @ 2500rpm 1982-88: Mini HLE / City E / Mayfair
41bhp @ 5400rpm 51lb ft @ 2700rpm 1980-90: Austin Metro
42bhp @ 5250rpm 58lb ft @ 2600rpm 1988-92: Mini City / Mayfair
44bhp @ 5250rpm 52lb ft @ 3000rpm 1980-82: Austin Allegro
1071cc 70.6mm 68.26mm 70bhp @ 6000rpm 62lb ft @ 4500rpm 1963-64: Austin/Morris Mini Cooper S
1098cc 64.58mm 83.72mm 45bhp @ 5250rpm 55lb ft @ 2900rpm 1975-80: Austin Allegro
45bhp @ 5250rpm 56lb ft @ 2700rpm 1975-80: Mini Clubman

1979-80: Mini 1100 Special
48bhp @ 5100rpm 60lb ft @ 2500rpm 1962-71: Morris 1100 / Morris Minor 1000

1963-74: Austin 1100
49bhp @ 5250rpm 60lb ft @ 2450rpm 1973-75: Austin Allegro
55bhp @ 5500rpm 61lb ft @ 2500rpm 1962-68: MG 1100

1963-67: Vanden Plas Princess 1100

1965-68: Riley Kestrel / Wolseley 1100
56bhp @ 5500rpm 62lb ft @ 3250rpm 1962-64: Austin-Healey Sprite MkII

1962-64: MG Midget
59bhp @ 5750rpm 65lb ft @ 3500rpm 1964-66: Austin-Healey Sprite MkIII

1964-66: MG Midget MkII
1275cc 70.6mm 81.28mm 54bhp @ 5300rpm 65lb ft @ 2550rpm 1974-80: Mini 1275GT
58bhp @ 5250rpm 69lb ft @ 3500rpm 1967:      MG 1275 / Riley 1275

1967:      Wolseley 1275

1967:      Vanden Plas Princess 1275
58bhp @ 5250rpm 69lb ft @ 3000rpm 1967-74: Austin 1300

1967-73: Morris 1300

1967-68: MG 1300 / Wolseley 1300

1967-68: Riley Kestrel 1300

1967-68: Vanden Plas Princess 1300
59bhp @ 5300rpm 65lb ft @ 2550rpm 1969-74: Mini 1275GT
59bhp @ 5300rpm 69lb ft @ 3000rpm 1973-80: Austin Allegro
60bhp @ 5250rpm 69lb ft @ 2500rpm 1968-71: Austin America (auto)

1971-80: Morris Marina
65bhp @ 5750rpm 71lb ft @ 3000rpm 1968:      MG 1300 / Riley Kestrel 1300

1968-73: Wolseley 1300*

1968-74: Vanden Plas Princess 1300*
* Automatic models retained 58bhp unit (see above)
65bhp @ 6000rpm 72lb ft @ 3000rpm 1966-74: MG Midget MkIII

1966-70: Austin-Healey Sprite MkIV

1971: Austin Sprite
70bhp @ 6000rpm 74lb ft @ 3250rpm 1969-74: Austin 1300GT

1969-71: Morris 1300GT
70bhp @ 6000rpm 77lb ft @ 3000rpm 1968-73: MG 1300 MkII

1968-69: Riley Kestrel 1300 / Riley 1300
76bhp @ 5800rpm 79lb ft @ 3000rpm 1964-71: (Austin/Morris) Mini Cooper S
A+ specification 50bhp @ 5000rpm 66lb ft @ 2600rpm 1992-2000: Mini Sprite / Mayfair
61bhp @ 5550rpm 61lb ft @ 3000rpm 1990-91: Mini Cooper
61bhp @ 5300rpm 69lb ft @ 2950rpm 1980-84: Morris Ital
62bhp @ 5600rpm 72lb ft @ 3200rpm 1980-82: Austin Allegro
63bhp @ 5700rpm 70lb ft @ 3900rpm 1991-1996: Mini Cooper 1.3i / Cabriolet
63bhp @ 5500rpm 70lb ft @ 3000rpm 1997-2000: Mini Cooper 1.3i (TPi)
63bhp @ 5650rpm 72lb ft @ 3100rpm 1980-90: Austin Metro
64bhp @ 5500rpm 73lb ft @ 3500rpm 1983-85: Austin Maestro HLE
68bhp @ 5800rpm 75lb ft @ 3500rpm 1983-93: Austin Maestro
68bhp @ 5600rpm 75lb ft @ 3500rpm 1984-89: Austin Montego
72bhp @ 6000rpm 73lb ft @ 4000rpm 1982-89: MG Metro
73bhp @ 6000rpm 73lb ft @ 4000rpm 1989-90: Metro GTa
77bhp @ 5800rpm 80lb ft @ 3000rpm 1991-2000: Mini Cooper S 1.3i
78bhp @ 6000rpm 78lb ft @ 3250rpm 1990-91: Mini Cooper S
93bhp @ 6130rpm 85lb ft @ 2650rpm 1983-89: MG Metro Turbo
96bhp @ 6130rpm 1989-90: Mini ERA Turbo
John Cooper Garages
During the 1990s Mini Cooper revival, John Cooper Garages offered a number of factory-approved "Cooper S" and "Cooper Si" upgrades to the standard Coopers. The conversions came with a full Rover warranty, and could initially be fitted by any franchised Rover dealer.
Type Max. Power   Type Max. Power
S pack (carb.) 77bhp   3rd Si pack (SPi) 86bhp
1st Si pack (SPi) 77bhp   1997 Si pack (TPi) 85bhp @ 5500rpm
2nd Si pack (SPi) 82bhp   1999 Si pack (TPi) 90bhp @ 6000rpm

The B-Series engine started out as a humble 1.2-litre unit that powered the Austin A40 Devon. Over time, it was developed - and developed - and developed.

Middle-market mainstay
After the end of World War II, Austin and Morris continued to rely on pre-war engines for their mid-range family cars. Out of the two companies, it was Austin that managed to introduce an entirely new engine for its A40 Devon model. This engine displaced 1.2-litres (65.5mm x 88.9mm bore/stroke), produced 39bhp at 4300rpm and was an overhead valve design. Morris, on the other hand, continued to rely on the side-valve solution for its engine, as used in the Issigonis designed Morris-Cowley.
By the time of BMC's formation in 1952, this was still very much the engine situation, and it meant that the company had a choice between the Austin A40 engine and the 1477cc Morris unit.
Given the relative merits of the two engines, and the Austin-biased management in the new organisation, it comes as no surprise that the Austin unit was adopted as the new engine to power all of the company's cars in the mid-range.
Logically enough, it was subsequently dubbed the B-Series, and it proved to be significant in BMC's history because its features defined the style for all of BMC's later engines. Included in this list would be the location of its electrical equipment and the induction/exhaust complex on opposite sides of the engine block. Also, the pushrods passed through passages on the induction side of thecylinder head in order to avoid the use of pressed-in tubes passing across the plug cavity. The crankshaft had three main bearings and the connecting rods were split diagonally.
In 1954, the first three-box BMC saloon was launched; the Austin Cambridge, which employed the B-Series engine in 1.2-litre guise, as well as a newly-enlarged 1489cc version. The uprated B was produced by a simple process of "boring-out" to 73mm. The power output of this version of the engine was 50bhp, which was produced at 4400rpm. This engine was also used in the Morris Oxford series II and the MG ZA Magnette, although the MG was treated to a twin-carburettor set-up, which boosted power to 60bhp at 4600rpm.
It was with the engineers at MG that the B-Series went through further development in order to release more power - eventually resulting in the 68bhp version that powered the 1956 MGA.
In 1961, the B-Series had been further evolved: the B's engine block was redesigned in order to accomodate newly-siamesed bores, thus enabling the bore to be increased to 75.4mm. This increased the capacity to 1622cc and it was possible - with tuning - for it to produce 83bhp. This extra power was produced at 5600rpm, and these higher rev limits were possible thanks to the use of Vandervell VP3 in the main bearings. Among the other changes were improved valves, pistons and rings. It was not until the following year that a "cooking" version of the B found its way into the Farina saloons... they made do with a more realistic 61bhp at 4500rpm.
Further development of the B-Series led to a 1798cc version of the engine, which - in three-bearing form - first saw the light of day in the MGB. The bore centres remained the same as the original 1.2-litre A40 Devon engine, but the bore measurements grew out to 80.3mm. In time for the launch of the ADO17 in 1964, the three-bearing crankshaft was replaced by a five-bearing item in the interests of increased smoothness, and this new set-up resulted in a power output of 84bhp (gross) at 5300rpm. Development continued as far as the addition of twin-carburettors, a set-up developed with the help of Daniel Richmond, which was used in the Austin and Morris 1800S versions.
By the early 1970s, it became clear that the B-Series needed to be replaced with a new unit that would be able to meet with upcoming US emissions regulations. The B-Series was by then, well established in 1800cc capacity alone, and was used in the front wheel drive 1800 models as well as the rear wheel drive Marina and MGB. Because a development programme to replace it never got far off the ground, the engineers at Abingdon worked hard on an OHC version of the engine, which would meet and exceed the forthcoming emissions regulations. This was the nearest thing to a replacement in the pipeline, and when it became clear that the ADO17's replacement would need a de-smogged engine, the new car, which subsequently evolved into the Princess was designed to use the OHC version of the B-Series engine.
Given that the two engines were initially going to be physically very similar, the development of the newer engine would not need to be accelerated to meet the new car. And that led to the MG engine being adopted as the corporate replacement for the B-Series, which resulted in further and wider ranging changes. The result was the O-Series; an engine that started out as being related to the B-Series, but became more of a case of the Irish hammer - two new handles, three new heads, but the same hammer!
In 1978, the O-Series was launched in 1.7- and 2-litre form, and over time, that evolved into the O2-Series in 1985 (seen in the Maestro and Montego EFi); a prelude to the technically interesting M16 engine of 1986; which shared the O2's engine block. The M16 was used in the Rover 820, and in 1992, it took on it's final metamorphosis, into the T16...

The C-Series engine was the shortest lived out of the triumvirate of BMC engines, and has since gained infamy for being the motive power behind of the MGC and Austin 3-Litre.

Unloved, but not unworthy

The C-Series engine first made an appearance in 1954 in the Austin A90 Westminster, and unlike the A and B-Series units, it was designed at the Morris engines drawing office in Coventry. As it was devised by a different set of engineers, it is unsurprising to learn that it shares little in common with the two smaller units.
One important difference, is that the camshaft and and pushrods are located on the plug side of the engine. The advatage of this is that it allows the designer to separate inlet ports. This advantage was negated somewhat by the fact that the main inlet gallery was cast in one with the head. This was fed through two ports via a "Y-shaped" branch manifold, from a single carburettor. A twin-carb set-up was effected by the use of a twin-port inlet manifold (as seen in the Wolseley 6/90).
The bottom-end employed a counter-balanced crankshaft with four main bearings; vibration was absorbed by a rubber damper. Like the B-Series, this engine employed Vandervell copper-lead bearings - but due to its newer design, this was used from the beginning. Bore and stroke were 79.4 x 89mm, the engine capacity was 2639cc and maximum power was 85bhp by 4000rpm (in the SU-carburetted Morris Isis) or 83bhp (in Zenith carburetted Austin version).
By 1957, this specification had improved (thanks to a raised compression ratio) to 92bhp at 4500rpm in the A95 Westminster and in twin-carburettor form, 102bhp at 4600rpm in the A105. This was the first BMC engine to produce in excess of 100bhp, when it was announced in the Austin-Healey 100/6 type BN4 in 1956. The following year, the 'Healey's output was upped significantly to 117bhp at 4750rpm, thanks to the introduction of a new cylinder head incorporating separate manifolds - it was in this form that the 'Healey achieved its first rallying victory.
When the Farina-styled A99 came along in 1959, the C-Series was expanded to meet the task. The expansion to 3-litres was effected by increasing the bore to 83.3mm, which resulted in an new engine capacity of 2912cc. Power was also up to 112bhp (gross) at 4750rpm; the Austin-Healey version developed a healthier 124bhp (net) at 4500rpm. Following this, the 'Healey was then a recipient of a triple-SU HS4 carburettor set-up, boosting the power still further to 132bhp.
For the 1968 launch of the Austin 3-Litre, a seven-bearing crankshaft was introduced, and it was in this form that the C-Series saw out its final days in this and the MGC. Production lasted until 1971.

...more BMC C-Series engine

Austin C-Series engine in an Austin-Healey 3000 Mark II
The BMC C-Series was a straight-6 automobile engine produced from 1956 to 1971. Unlike the Austin designed A and B-series engines, it came from the Morris engines drawing office in Coventry. Displacement was 2.6 to 2.9 L (2912 cc) with an 83.3 mm bore and 88.9 mm stroke.
Applications:
* 2.6 L (2639 cc) 77x89 mm
* 1954-1959 Wolseley 6/90
* 1954-1959 Austin Westminster A90/A95/A105
* 1955-1958 Morris Isis
* 1958-1959 Riley Two-Point-Six
* 1956-1959 Austin-Healey 100-6
* 2.9 L (2912 cc) 83.36x88.9 mm. Four bearing crankshaft.
* 1959-1968 Austin Westminster A99/A110
* 1959-1968 Wolseley 6/99 and 6/110
* 1959-1964 Vanden Plas Princess 3-Litre
* 1959-1967 Austin-Healey 3000
* 2.9 L (2912 cc) 83.36x88.9 mm. Seven bearing crankshaft.
* 1967-1971 Austin 3-Litre
* 1968-1970 MGC
An enthusiastic and active worldwide owners club called the Cambridge-Oxford Owners Club caters for the 'C-Series'-powered Farina and pre-Farina cars and their 'Cambridge' derived four cylinder 'B-Series' sisters. The club aims to keep the cars on the road, provides advice, spares and a social forum for enjoying the cars.