PERKINS DIESELS

The diesel engine had been around for some time in various forms, indeed its application in heavy goods vehicles and PSVs was becoming almost universal by 1945. Various attempts had been made to launch diesel tractors onto the UK market, but most of these had fallen by the wayside. Strange to say there was not one totally new multi cylindered diesel on the British Tractor Scene pre-war. The AGE tractors using Blackstone and Aveling engines were basically Internationa122/36 frames with diesel engines fitted. A few International Petrol Start Diesels as fitted to their WD40 and TD35/40 Crawlers were imported, but like the domestic conversions they did not amount to much. Mainstay of the Compression Ignition picture was the Marshall, but even there production in total hardly got into four figures. As the majority of UK tractors were in any case multi cylinder units with automotive type engine and transmission layout, it was obvious that any manufacturer setting out to build tractor engines would adopt the multi-cylinder concept.

One of the immediate problems, which arose in producing a diesel engine, was its cost, not only in development terms, but in production also. Much finer tolerances were necessary and stronger components desirable to withstand the much greater compression pressures of such engines. Barford & Perkins of Peterborough became part of Agricultural and General Engineers (AGE). Their main product line was motor road rolling equipment. The Peterborough works was closed by AGE when they took over in 1928/29 and their road-roller business was merged with that of Aveling & Porter to form Aveling-Barford.

Mr Frank Perkins moved to Aveling's works at Strood as Works Manager. It was while he was there that the Vixen engine was designed, the drawings being done by a Short Bros. (Seaplanes) draughts- man working at weekends in the cellar of Mr Perkins' house. One or two engines were built at Aveling's before the big decision was made to form a Company to produce them.

Frank Perkins Ltd. was formed and premises at Queen Street, Peterborough, formerly occupied by Barford & Perkins, were rented. This was a case of 'coming home'; Frank Perkins obviously knew that the works were standing empty, and an approach to the owners, Milton Estates, secured a lease. Indeed, quite a lot of equipment, such as the benches, were still there. Here the application of medium sized diesels for industrial and marine work in the nineteen thirties, was pioneered. The Leopard, Wolf and Lynx engines were basically intended for multi use applications, covering vehicle, industrial and marine installations. However the use of the Leopard engine in tractors was instigated in the mid thirties. A Fordson N Land Utility tractor on Firestone wheels and tyres was supplied to F. Perkins Ltd. on 11th February 1937 by Willenhall, Staffs, Fordson dealer Reginald Tildesley. This was serial number 808499 and it was delivered to Peterborough without engine.

A Perkins Leopard engine serial number 7343, built on 16th June 1937 was fitted. This was a Leopard II engine with cast iron pistons and was rated at 34bhp at 1100 rpm, it being derated from the usual industrial rating of 46bhp @ 1500rpm to prevent damage to the rear axle.

The prototype tractor was tried out at Tettenhall near Wolverhampton in July 1937, prior to its  exhibition at the Royal Show, which in 1937 was at Wrottesley Park nearby.

In October and November 1937 a further 11 tractors without engines were supplied to Perkins ex Tildesley, and in 1938/9 a further 17 were supplied, making 29 in all. Incidentally, the TVO engines were used to provide a 'float' for Tildesleys' exchange engine scheme on the Fordson. The first Leopard conversion to go into full time farm service was bought by Mr T.R.C. Blofeld of Hoverton Fruit Farms, Wroxham, Norfolk. It had the reputation of being a bad starter, but the early models had no self-starter and were started on the handle using a decompressor. It would appear that most of the others were exported, and there is at least one extant in Australia and one in New Zealand. The latter example has a self-starter. Another engine was also installed in a Muir Hill 3 cu yd. twin wheel dumper that appeared at the Public Works Exhibition at Olympia in 1938 - this also had electric start.

With the advent of the war, conversion of tractors ceased, but in the meantime the development of a new range of engines was under way at Peterborough.

The result was the P series of engines that came onto the market in the early war years. By taking the design from the outset to produce three, four and six-cylindered units using common parts saved much in development and production costs. Incidentally, one and two cylinder prototypes were built but never produced in any quantity, and it took some time before the three-cylinder variant appeared. In fact, one P3 prototype was built in 1939, and fitted in a London Taxi, but it was to be 1951/2 before the engine was developed. The P series originally had names as had the other pre-war engines -the P6 was the Panther, the P4 the Puma, and the P3 the Python. In fact, the P4 was introduced November 1937 and the P6 in February 1938. There were of course two versions of the P series. That for use in applications where engine speeds of over 1500RPM were required had aluminium alloy pistons, and that for use where engine speeds of below 1500RPM were required had cast iron pistons. The calibration of the fuel injection pump produced engines with very different torque characteristics. There were common parts amongst al1 3, 4 and 6 cylinder variants, all of which shared the same bore and stroke of 3.5"x5". The swept volumes were P3 -2.36 litres, P4 -3.14 litres, and P6 -4.73 litres.

The design of the engines was such that different sumps, flywheel housings, front and side mounting plates, and exhaust/inlet manifolds allowed a diversity of use, whether with a wet clutch application such as the Fordson Major, or a dry one such as the Massey Harris 744D. For vehicle use of course mountings were different, but the sump used with Industrial applications had sufficient strength, when necessary, to include the engines in 'unit' applications. There was even a petrol version of the P6, developed in conjunction with Dennis Brothers of Guildford, to replace their equivalent petrol engine; two were built, and were only experimental.

The P series had not been used widely in tractors until Frank Perkins converted a Fordson Major for his own use. The result was that Ford Motor Co. sent two Majors for conversion, one with a P4, and the other a P6. Both had fabricated sumps and flywheel housings. Whilst both gave a satisfactory performance, the P6 was chosen due to its lower maximum speed which suited the E27N gearbox better, and in adopting the engine as a production option it also must be remembered that the Ford dealer network were already geared up for Perkins spares and service as the engine in its vehicle (V) form was fitted in the Thames lorry.

So it came to pass that the P6(TA) engine was born and graced a good few thousand E27Ns, either straight off the production line or as conversion packs which Perkins sold themselves.

Morris Motors were also looking for a diesel to fit in their new Nuffield Universal tractor. They chose the P4(TA) that fitted the Nuffield chassis in more comfortable form than the P6 fitted the E27N. In the case of the Fordson a special sump had to be cast to support both front axle and connect this with the flywheel housing. Whilst most P series engines were made for dry clutches, the E27N's wet clutch also required a special flywheel housing and suitable oil seal for the starter motor.

As we shall see in due course, other manufacturers made use of the Perkins engines in their (TA) Tractor adapted form.

One feature of the adoption of Perkins units in some applications was the fact that the power output of the engine was much more than the equivalent Petrol or TVO models. Also the initial cost of the diesel-engined version was much more than the equivalent spark ignition one.

With Ford and Nuffield offering Perkins engined variants, and David Brown their own engine, it was not long before Ferguson's sales force were calling for a diesel version of the TE-20. Now as Harry Ferguson himself was not a diesel fan, it took some considerable persuasion to get him to agree to a diesel-engined tractor at all.

The Perkins P3 was looked at, but the cost of installation and the modifications needed would not suit, so a Standard engine was fitted instead. This engine was designed by Freeman-Sanders specifically for Ferguson, and was built for them by the Standard Motor Co., who later developed the same unit for use in their 'Vanguard' car.

There was one thing which opened the way for a conversion pack from Perkins for the Fergie 20 and that was the fact that the diesel engine supplied by Ferguson could not be fitted to existing tractors. The first tractor converted by Perkins was actually a Ford-Ferguson 9NAN for his own use, but the principles of the conversion were the same for the TE-20. The 9NAN was acquired by Frank Perkins during the War and the engine fitted in this case was a P4, there being no P3's at that time. It was cut up in the mid 1970s under Customs supervision, along with an MF85 imported as a test tractor for the A4-300 engine, as no import duty had been paid on them!

Massey Harris were looking at building tractors in the UK, as there was great export potential, and the government were supporting the 'ground nut' scheme in Africa. A few type 44 frames were taken and fitted with the P6(TA) engine. Tractor assembly had commenced at Manchester in 1948. Due to shortage of space, the 744 as it became was then assembled at Kilmarnock from 1949.

Thus, not only were Perkins engines now being fitted in production by leading manufacturers, they were also available to convert s.i. engined units to diesel. By the late forties 'conversion packs' were available to convert the lions share of popular models.

The promotion of Diesel conversion packs was just as well, as new engine business fell off considerably with Ford fitting their own diesel to the New Fordson Major, and Nuffield fitting the BMC engine to the Universal by the early fifties.

The P series was not "without its problems in agricultural service. Unlike many road haulers and others who used the (V) "vehicle" version, farmers were not renowned for their care and attention to machinery, and a diesel engine requires more of this to maintain peak performance. The chain driven timing could, if not properly adjusted, cause starting problems, and early tractor applications had engine breather problems later cured by modification. The tendency to over-rev. the P series (TA) units with their cast iron pistons often caused bent con-rods, little end failures, and cylinder head gasket failures. Indeed later P6 engines all had alloy pistons that alleviated many of the problems, and many rebuilds received these also. This is why a lot of P6(TA) engines still extant appear to the unknowing to be "V" or vehicle ones! The main problem with the P6(TA) was the farmer's habit of leaving the engine running when not working, as they were in the habit of doing with paraffin engines. This caused the exhaust ports to choke with carbon and Dereck Lambe tells me that he has taken off manifolds to see ports with holes not large enough to push a pencil through. Of all the tractors fitted with the P6(TA) the Fordson Major E27N was the most successful. Early models had the habit of breaking half-shafts; however a new design with suitable heat treatment cured this, and the E27N back end was really the only one which could stand the full power of the P6, and indeed this was the tractor which has endeared the P6(TA) to present day collectors and enthusiasts above all other. Of course more were built than any other diesel engined tractor of the era.

1953 saw the introduction of a completely new engine for industrial use -the L4. This unit was designed expressly for low speeds up to 2000rpm. It had a bore and stroke of 4.25 x 4.75", a swept volume of 4.42 litres, and could be set to give up to 59bhp @ 2000rpm. A gear driven timing arrangement was fitted and the camshaft, unlike the P series, was in the normal position with push rod operation of the valves. The cylinder liners were, however, of the wet type.

The new engine was adopted by various manufacturers for use in tractors. The Massey Harris 745 used the L4(TA) from 1953, and M-H also adopted it for their combines. Just to confuse the issue the development tractors were 744 with the new L4 engine fitted! It was also available as a conversion pack for Old Fordson Major, New Fordson Major, Nuffield, and International Farmall M tractors. Later it was adopted as the power behind the new Track Marshall crawler.

Perkins dealers were keen to seize any opportunity to convert tractors to diesel, and indeed a few 'one offs' were built to satisfy customer requirements. Where a popular model was involved it was possible to supply the complete 'conversion pack' to suit. The approved and popular conversions were:
-    P3(TA): Ford 9N/8N. Ferguson TE-20. Farmall H. Allis B.
-    P4(TA) Nuffield Universal.
-    P6(TA) Fordson Major E27N.
-    L4(TA) Fordson Major E27N. New Fordson Major. Farmall M. International T6. Minneapolis Moline UT. Nuffield Universal.

It is believed that the most popular International L4 conversion was for the T6 crawler.

Perkins engines were also fitted into limited numbers of International W4, W6, and W9 tractors, A few Oliver 80s and 90s, a few Massey Harris 203 and 55 models, and a few Case D series. There was no approved conversion of the Fordson 'N'. It was naturally possible to fit either a P6 or a L4 to the standard Fordson, but as part of the agreement with Ford Motor Company which allowed Perkins to sell conversion packs to Ford dealers, it was agreed that conversion of the 'N' would not be encouraged. In any case the rear axle was considered not to be capable of taking the increased torque of the diesel. The agreement also allowed for supply of certain parts for the conversion packs from Ford's parts operation. Ford did not want the life of the thousands of 'N' models to be extended by dieselisation.

For the next chapter in the story we move back to the events taking place at the Ford Motor Company at Dagenham. Fords had long wished to build a model in the UK to compete with the "grey menace" or Fergie 20. It was quite possible to do this, but the cost of developing an engine for such at tractor, which by the mid fifties had to be a diesel, was prohibitive.

The Ford boys knew of the original Perkins conversion of the Ford 9NAN, and as the new tractor was very much an updated 8N Ford's took some P3 engines for evaluation during development of the Dexta. These were however a development version that had a simple gear driven train and a small Holburn-Eaton type oil pump driven from underneath the crankshaft timing gear. This allowed the CAV in-line injection pump to be flange mounted directly onto the back of the timing case. All external oil and water pipes were eliminated. It was called the P3.144 and eliminated the expensive features of the P3, the skew driven oil pump, and the chain driven timing. A four cylinder (P4.192) variant was also built. Although the P6-288 had a DPA rotary fuel pump it retained the chain timing. The gear-timed version was built in France as the 6PF, and was for Industrial use only (no vehicle version) and was never available in the U.K.

At Ford's request, Perkins fitted their 3 cylinder engines with Simms Pneumatically governed fuel injection pumps and injectors and also removed the company's name and trademarks from all parts. Perkins also designed the dress items such as exhaust manifold, water outlet housing, and gearbox adaptor plate. The engine went into production as the F3 in August 1957 and all were built at Peterborough.

In the early 'sixties the cylinder bores of the P3/ 144 were opened up to 3.6" diameter in common with other engines in the P series. A CAV. DPA fuel injection pump was fitted and the engine became the 3.152. The F3 was also up rated and a mechanically governed 'Minimec' version of the Simms in-line fuel injection pump fitted -this was known as the F.3/152 and was supplied for the Super Dexta from February 1962. Again all were built at Peterborough.

The engines supplied to Ford had all the blocks and heads cast at the Dagenham foundry of FMC, the rough castings being supplied to Perkins on a 'free issue' basis. The logistics of this operation were remarkable. No large stocks of engines were held, each day Perkins built just enough engines to cover the Dagenham assembly tracks requirement for the next day. These engines were delivered by Perkins' own lorries overnight. A small buffer stock of one day's supply of engines was kept in a special building at Peterborough to cover for any breakdown on Perkins' assembly line, and a similar number was held at Dagenham in case of breakdown or accident to any of the lorries on the delivery run. These lorries brought back the rough block and head castings as a return load, and the whole system seems to have worked remarkably well for the seven years that the contract lasted. This system is known today as just in time'. The Japanese fondly believe they were the first to introduce it!

Some 153,322 F3, and 64,496 F3.152 engines were supplied to Ford, a grand total of 217,818 engines between August 1957 and October 1964.

Perkins became part of Massey Ferguson Limited in 1959, and this consolidated the use of Perkins products in MF tractors. In fact from 31st August 1959 Massey Ferguson had taken over the Banner Lane Coventry plant of the Standard Motor Co. This did not involve any engine manufacture, and M-F was keen to move to a stage where their new subsidiary would provide all the engines for the tractor plant. The Standard 23C engine had a reputation as a bad starter, especially in cold weather.

The first Perkins engines used in a Massey Ferguson (as opposed to a Massey Harris) tractor were fitted in the new M-F 65 tractor introduced in 1958. The Perkins 4.192 engine was chosen to power this tractor and this gave the UK market a 50HP plus tractor with the Ferguson System that put the competition in the shade somewhat. It is interesting to note that the forerunner of this tractor, Frank Perkins' own 9NAN with P4 fitted existed some ten years earlier. Also, one of Harry Ferguson's LTX prototypes was fitted with an L4 engine. It took M-F that long to shake off the 'light tractor' ideals of Harry Ferguson, who was not in favour of high powered tractors, but believed in the lowest powered engine that would do the job with his draft control system.

Shortly after the M-F control of Banner Lane took effect, the M-F 35 was given a three cylinder Perkins 3.152 engine.

In 1961, a direct injection version of the 4.192 engine, which in its bored out form to 3.6" was the 4.203, came into production, and this was known as the AD-4.203. This was used from its inception, in the M-F 65.

With the Fordson Super Dexta on the market, ironically with engines from Perkins, the 35 was given the A3.152 engine from 1962. Perkins also supplied A3.152 engines for Ferguson's Detroit plant that were fitted to MF35s there, and also MF50 tractors. The Dieselmatic 65 used the 4A.203 engine in the USA, and later the AD4.203, whilst the Super 90, only built in the Western Hemisphere used the A4.300. This engine was a bit more than just a bored out 4-270. It had a dedicated tractor block, with cast-in tractor fittings, dry type cylinder liners, a 5 bearing crankshaft, and a harmonic balancer unit.

The 4.270 was an update on the old L4 engine, and brought direct injection to this engine, plus the use of a distributor type fuel injection pump. Conversion packs for the older tractors now used this engine instead of the L4, and other manufacturers such as Marshall took the newer engine instead.

Allis Chalmers had fitted Perkins P3 engines in their model B at the Totton Southampton plant, and continued to use Perkins engines -the P3.144 in their D270 and D272 models once assembly had moved to Essendine. The ED40 tractor used a Standard Motor Co. 23c engine however. This was a tactic used by Standard to annoy Perkins and M-F by selling engines at lower prices to take up the loss of production encountered with the loss of M-F business. They also got in to Fords by supplying a limited number of Petrol 87mm engines for Dextas sold in Denmark and elsewhere. These latter were, however, of special build to suit the Dexta gearbox housing.

Small numbers of engines were supplied to other manufacturers both at home and abroad, and examples of some of these are shown in the book. Notable crawlers that used Perkins engines were the Howard Platypus, the Bristol, and the French built Continental.

There we leave Perkins for the moment. As the sixties progressed and the seventies dawned an even greater variety of products came out of Peterborough, and a new factory was built. But that is another story!

Allan T Condie
Perkins Diesel Conversion & Factory Fitted Units
1990