Theme: Compromise – Ford’s Valencia engine. A Curious Orange?

A missed opportunity or a masterpiece of compromise?  We look at the unassuming little engine that drove the Fiesta’s success.

The cack-handed rendering is inexcusable given that that the magazine includes a close-to-production photo mischievously taken by an attendee at a customer clinic in Düsseldorf earlier in 1974.  Security was tightened considerably thereafter.

CAR March 1974 was confident in its prediction about the Fiesta’s engine; “it is a completely new water-cooled, in-line four with single overhead cam and Heron head. It will come in two sizes – a little over 900cc and 1090cc for the top of the range model.” As we now know, the “scoop report” could scarcely have been more wrong, but it is easy to understand the reasons for their conjecture. The engine was to be built in a new plant in Spain, on all-new tooling. The Heron “bowl-in piston” head was a feature of the existing Kent and Essex engines. The new car’s competition might have given some clues to the stratum of technological advancement Ford would be aiming for. The Fiat 127 and Renault 5 used 1950’s pushrod designs which did a far better job than might have be expected.

The Peugeot 104’s all-new, all-aluminium ohc engine was way beyond the level of sophistication Ford were able or willing to achieve in a mass-produced engine in the mid-‘70s. Indeed its intricacy suggests something which could have originated in the watches and micromechanics valley stretching from Switzerland into Besançon, not so far from Sochaux.

A 1972 Peugeot XA engine, or more precisely XV3. Source: Autocar

A more realistic benchmark would be VW’s EA111 engine, in production since early 1974. This was an iron-blocked near-square in-line four with an alloy crossflow head and a belt driven overhead camshaft.

Valencia engine  Source:

The engine which arrived with the first generation Fiesta may have surprised many. With its iron head and block, pushrod valve operation, and three main bearing crankshaft it appears to belong more in the  mid-fifties than the enlightened 1970s.

The Seidler book consistently infers that it is an adapted version of the Kent ohv unit first seen in the 1959 Anglia. It’s true that the Kent served as the template for the engine officially known as ‘L-series’ (The ‘Valencia’ toponym was officially adopted after years of informal use), but it was altered in so many ways that it is a different engine with virtually no interchangeability of parts with the older engine.


The shock is that the adaption process seemed so regressive. Pushrod operated valves and an iron cylinder head might be expected, but three main bearings instead of five seems merely tight-fisted.  The justification given was that as the block was shortened – bore centres were drawn closer in line with a reduction of the bore dimension from 81mm to 74mm – the block was stiffer and the two intermediate main bearings were unnecessary. It took ten years for mean old Ford to relent and give the newly introduced 1.3 litre Valencia five main bearings.

The 1976 abridged Kent engine was 30.5mm shorter and 7kg lighter than the 81mm bore original edition.  The weight reduction seems unimpressive considering the level of re-working, but with a target capacity of 400,000 engines per year, must have saved a considerable quantity of iron.

There’s a myth that the Fiesta’s engine is a revived version of the 1959 Anglia unit. It’s not, but the confusion may arise from the 1976-on Kent being commonly referred to as the “Crossflow”, and the Fiesta engine as the “OHV”, although it also has a crossflow head; the Anglia’s was reverse-flow.

Ford made a perfectly rational choice in developing a cheap, simple engine for their B-sector car. The R5 and 127 were not held back by their ageing engines, and when more power was called for, the full-size Kent, and eventually CVH were there to do the job.

There are other explanations for Ford’s conservatism in the engine matter. The 1959 Kent had been something of a bullseye; short stroke small capacity engines with eight port heads and strong bottom ends were a rare commodity, and delighted racing engine builders and fleet managers alike.

Dagenham built on its success with five main bearing 1300 and 1500 cc versions, followed in 1967 by a major rework, with a crossflow head layout, bowl-in piston combustion chambers and across the board adoption of the five main bearing bottom end.

The Kent was a triumphant achievement for a company which only abandoned side valves for its smallest engines in 1959, but Ford’s other European engines of the period were less of an ornament to their reputation.  The 1965 Essex V4 was unrefined, inefficient, and prone to head gasket failure – and there were two to fail. Its 1969 in-line replacement, the Pinto OHC unit showed more promise, but the all-iron engine’s clever valve-gear design quickly developed a bad reputation for premature wear. This was later mitigated by positive lubrication and nitriding of wear-prone components.

Linking the Fiesta’s engine with Ford’s most trusted European power unit looks like a sound managerial decision, but there wasn’t much Kent left in the Valencia, or L-Series, to give it its Sunday name.

The biggest Valencia departure was the abandonment of the Heron head in favour of a wedge shaped in-head combustion chamber with inclined valves, following Renault and Fiat practice at the time. In the Ford context this is surprising. The bowl-in piston combustion chamber is particularly effective in very oversquare engines, as it overcomes the problem of quench surfaces, areas of the combustion chamber which remain cool enough to retain “wet” fuel which makes its way to the exhaust unburnt. The 957cc and 1117cc Valencias were still well oversquare, but the volte-face suggests that Ford were already embracing the new emissions-led thinking which put effective combustion chamber design ahead of maximisation of valve areas.

What we have is an engine of strictly limited ambitions. There was no need for room to expand since the Kent, and later the CVH, could fulfil the 1300cc and upwards jobs. The early global ambitions for the Bobcat project most probably played some part in the conservative specification of its engine.  Pushrods and all-iron construction are well suited to labour-intensive low-precision manufacturing. The Almusafes plant was as advanced as the best in Europe, but in the context of Ford’s ambitions to conquer Spain the simplicity of the engine it produced made eminent sense. Ford had to establish a dealer network from a base of zero. A powertrain as intricate as the Peugeot XA, would have been disadvantaged in a country familiar only with the worthy pushrod engines made by SEAT, Renault, Simca, and BMC.

Capacities were set as a tax-friendly 957cc, and a longer stroke 1.2 litre, which would have given a useful advantage in the sector. Within weeks of the Yom Kippur war in October 1973, Ford management took a decision to reduce the capacity of the larger Valencia to 1117cc. At launch in September 1976, the 957cc units were offered in 40 and 45bhp tunes, while the 1117cc version gave 53bhp, well up to the standards of its rivals. Those lusting after real Kent power had to wait until October 1977 for the 66bhp 1300, available only in the S and Ghia.

So was the Valencia a bad engine?  Not at all. It was designed in the image of the heroic little four cylinder engines which mobilised much of Europe, and at least on that continent, it outlived the disappointing CVH by ten years, eventually bowing out in 2002, to be replaced by the rather good Rocam, an 8 valve OHC unit with capacities from 1.0 to 1.6 litres, built in Brazil and South Africa.

In between, the Valencia demonstrated an ability to answer every question it was asked, much in the manner of the Austin A series and Renault Cleon. It was never going to be the most refined, powerful or efficient in its class, but it was dependable and easy to fix in the rare event of failure.

Source:  Ford Motor Company Ltd.

Of all the Valencias, my favourite is the humble 957.  It has a mere 45bhp at 6000rpm. That last number is telling. The little Valencia has shares with the VW flat fours the ability to be driven flat-out for as long as conditions will allow without feeling as if it will explode at any time. It’s a short-stroke thing. The piston speed is lower than an equivalent undersquare engine, and the changes in piston direction happen less violently.  We should regret that the predominance of long-stroke engines, and the petty strictures of the law have made such simple pleasures a thing of the past.

22 thoughts on “Theme: Compromise – Ford’s Valencia engine. A Curious Orange?”

  1. Speaking of the Ford Kent engine heard it was capable of being reliably bored out to 1700cc, also did Ford UK at any point in the mid/late-50s ever consider developing an enlarged 1600/1800-2000cc OHV (pre-Pinto OHC) Inline-4 slotting above the existing Ford Kent engine in place of the 1700-2000cc Ford Essex V4 engine?

  2. I’ve wondered too about the abrupt dropping of the in-line Zephyr four and six in favour of the Essex V4 / V6. The in-line engine looks like it should have more stretch, bur never went beyond 1703 / 2553cc in production form and I can’t find any evidence of big capacity increases by modifiers, despite it being a tuners’ and specialists’ favourite.

    I suspect the dictates of Dearborn were to blame. The V4 / V6 project started in Detroit intended, for compact cars and light trucks, then was considered surplus to requirements and handed over to Dagenham. At least the British did better than the Germans, who got a V4 and a troublesome car by the same process.

    Increasing the Kent capacity by enlarging the bore is possible, but only 20% of each casting batch can be enlarged safely by a worthwhile amount. Quite a lot of new Kent engines left the factory with larger capacities than nominally stated, owing to Ford’s policy of taking defectively bored blocks off the line and reboring them, rather than scrapping them.

    1. So it is possible that Ford UK developed Essex V4 / V6 engine family due to Dearborn wanting to also foist the Cardinal project (aka Taunus P4) onto both Ford UK and Ford Germany, only for Ford UK to develop the Cortina and find further stretch in the Kent engine?

      Is strange that Ford UK were unable to stretch the Zephyr 4/6-cylinder engine into a 2-litre / 3-litre though tuning potential aside, wonder whether they would have been suitable engines to sit above the 1.6-litre Kent short of developing either a 1.8-2-litre Kent or Kent-derived engine.

  3. Nice essay, Robertas. I’m not very up to speed on engine design so it’s a sign of clarity I got anything out of it. The Ford and Peugeot contrast is particularly insightful.
    I imagine 7×4000,0000 is a lot of tonnes of steel. Such attention to quantities is how money is saved. It comes with a cost though…

  4. Interesting article about these Valencia engines because the Mk 1 Fiesta only made it over here with the 1600 crossflow engine and fragile front suspension. So I knew not much except what my remembrances from CAR of 40 years ago happened to be.

    I may be the only one old enough here to have extensively driven the 1500 cc pre-crossflow and 1600 crossflow in mighty twin-choke Weber form, i.e. the Cortina GT. No comparison in my opinion, the older engine was comprehensively nicer. Of course back then in the mid to late sixties these engines had no idea they were Kent engines; everyone called them 105E derivatives. The whole Kent name thing came along later, probably after the opening of Valencia, in order to differentiate the two.

    Still, we had both a 997 and 1198 cc versions in my dear old Mum’s 1960 Anglia and 1964 Anglia Super, both of which made numerous banzai runs at full throttle – her sister, my aunt, used to religiously post Motoring News, a UK weekly broadsheet out to me, an ex-English kid in the colonies. I think my Mum read them and thought of herself as the local Pat Moss. In any case, the best woman driver I’ve ever been chauffered by. She had a feel that included cornering Anglias on three wheels at lower speeds when chasing obstreperous VW Beetles driven by teenagers. Spirit, she had in spades.

    Still, one remembers all the 1960s Heron head hoopla, a mostly British phenomenon, and tries to remember a really decent engine with that arrangement. Its main virtue was it was cheap to make. The Rover 2000, with a square bore and stroke was a bit of a rough old cob in the vein of the 1600 crossflow, and the Mays Jaguar V12 frightened nobody with its rather low output. Heavier pistons than otherwise required needing more crankshaft counterbalancing, more piston surface area to absorb combustion heat and waste it, and focused quench areas in that it was all because the piston raised rim gave symmetrical squish, and whatever focused turbulence that was generated wasn’t at the spark plug location due to only two valves. A bit of a loser really in historical terms.

    If one accepts the premise that good fast combustion means that smaller amounts of maximum spark advance are needed, then the Cosworth DFV at less than 30 degrees total was a breakthrough. Heron heads and domed-piston hemis aren’t much cop on this score. The current FCA Hemi pushrod V8 needs two sparkplugs to even get it to work, as orange-rind-shaped chambers are a bit of a nightmare on the flame-front progression score. It seems as though engine designers are as likely to have old-fashioned ideas as the next person. I mean these days still thinks hemi-heads are best due to right-up-to-date 1948 thinking which has entered the old wives’ tale and myth category. My final design project in the IC Engine design course in 1969 prior to graduation as an engineer was a solidly four valve pentroof chamber design, straight six, 2800cc. Everyone else chose hemis, and the professor was completely unaware of anything much after 1955, so I gained few extra points with him. The full dynamometer room was nice though.

    The best fundamental descriptions of what happens inside piston engines have to be by Kevin Cameron of Cycleworld magazine. He writes lucidly and understands his subject so well, people can read his stuff without feeling they are being preached at. His writings go well back:

    1. “I mean these days still thinks hemi-heads are best due to right-up-to-date 1948 thinking which has entered the old wives’ tale and myth category.”

      Blame Chrysler and Madison Avenue, probably. Ninety-nine percent of the population couldn’t identify a hemi chamber if it blew up in their face, but they know it’s worth having. Not that I claim to have any engineering chops, but even someone like me who is only vaguely aware of the principles at work inside the metal bits knows that hemi heads haven’t been cutting-edge tech in my lifetime.

      If one was cruel, and I am, one might note that Chrysler’s continued embrace of ‘Hemis’ as a marketing strategy belies an unusual degree of truth in advertising, insofar as it accurately reflects their degree of technological sophistication.

    2. Bill, that’s the only magazine called “Cycle World” I would contemplate reading…

  5. LJKS once pointed out that if an engine had a true hemisphere as a combustion chamber, its stroke would have to be four times the bore to achieve a workable compression ratio. I haven’t checked the numbers, but I hold it to be true as an act of faith.

    I share Bill’s suspicion of the Heron head. Ford must have loved the flat head face for its simplicity of manufacture. Reading Jeff Daniel’s Jaguar – the Engineering Story, there’s a strong hint that going for the simple, low-cost SOHC Heron head for the V12 was a piece of last-ditch expediency on the part of Mundy and Hassan to meet cost targets and get the engine into production.

    The 1978 Leyland O series engine also had a Heron head, influenced by the Jaguar duo’s influential position on the company-wide Engine Development Group. It worked acceptably, but the engine was little if any better than the B series it replaced in matters of refinement and efficiency. The real gain was in cost and buildability, which benefited both from the flat head and the belt driven overhead camshaft.

  6. With some experience of many rental Fiesta’s – mostly 957cc post-83 facelift models, I’d concur that the smallest Valencia engine was both willing and rev-happy. In tax-crippled Ireland, this was the default power unit, larger capacity models were offered, but sold in very small volumes.

    Whatever variant they used in early KA’s was a flaccid and rev-averse thing by comparison.

  7. The early Kas had the 1.3 litre Endura E which is an improved version of the HCS which is an upgraded Valencia. All had pushrods, five main bearings and slightly undersquare (74 x 75.5) dimensions. The pre-HCS Valencia 1.3 was in production for only two years.

    The only Ka I’ve driven was a 2005 1.3 with the Rocam engine. (Ford will tell you it is a Duratec. I hate their engine naming system, which wilfully obfuscates, with a passion)

    Anyway, it turned out to be a thoroughly competent engine over 2000 miles in a week, capable of running serenely at an indicated 100mph where the law allowed. The Rocam is made in Brazil and South Africa. The South African version is made on Kent tooling, but in 1.3 litre form has the same dimensions as the 1.3 Valencia. The 1.6 used in the SportKa and StreetKa has the same 75.5 stroke, but an 82.07mm bore – bigger than any production Kent.

    Also made on Kent tooling – in this case in Dagenham – are the vile LT/Lynx/Endura DE Diesels, originally developed in the early ’80s in collaboration with Klöckner-Humboldt-Deutz, who must have been in the pay of VAG or Peugeot. For those interested in how big a Kent engine might have grown, the dimensions are:

    1608cc (80 x 80)
    1753cc (82.5 x 82.0)

    For comparison, the 1599cc Kent’s dimensions are 81 x 77.62, and to achieve the longer stroke the deck height of the block had to be raised 28mm relative to the Anglia series. The change to bowl-in piston combustion chambers may have had a bearing on the deck height increase, in any case it looks as if the diesels required the deck height to be raised further still.

    1. Know that tuners and those involved in motorsport managed to enlarge the Ford Kent engine to 1650-1760cc and actually read of a Kent-based 1800cc diesel outboard motor.

      It makes one wonder how a production 1753cc Kent engine (in tandem with a 2-litre Ford Zephyr 4-cylinder) would have impacted Ford’s range beyond making the Ford Corsair less of a white elephant and possibly avoiding the 1.7-2.0 Ford Essex V4 (or even utilized by Lotus).

  8. Ford UK’s engine policy in the ’60s and ’70s was mainly set by making the best use of engine production capacity, and the vehicles they would fit. The Corsair wouldn’t take a straight six, and needed two litres to have any “executive” credibility, so the only way was Essex.

    Likewise the Transit, exclusively V4 in petrol form, but with a prosthetic nose it could accommodate a Perkins 4.108 or an Essex V6, or even a 200 cubic inch straight six for the Australians. What’s little known is that Ford quietly dropped the 1664cc V4 in the Transit in mid 1976, replacing it with a 1.6 litre Kent. The conversion was achieved without needing the diesel’s proboscis. The extirpation of the short stroke Essex was paralleled in the dropping of the 2.5 litre Granadas in late ’76 or early ’77. (Myles Gorfe will put me right on this).

    I wonder if Ford ever considered making a straight-six Kent. I suspect not.

    1. The Essex V4 seems a bit of blind alley unless the X Pack / GP1 performance upgrades used on the 3.0 Essex V6 in the mk3 Ford Capri were capable of transforming the Essex V4 into a decent engine.

      It is doubtful that Ford looked into a Straight-6 Kent since such an engine would be limited to around 2400-2600cc via the 1599-1753cc 4-cylinders units.

  9. I have reasonably fond memories of a V4 LWB Transit I drove across France in 1973 but, back then, you expected a van to sound pretty rough. However the V4 in a Corsair was horrid. I suppose if you were used to the 2 stroke clatter of a Saab, then the fitment of the Ford unit wouldn’t be that much of a wrench, but it truly was a fate-worse-than-death that so many sublime NSU Ro80s ended up having their Wankels replaced by the rough Essex unit.

  10. Great article. Interestingly a Ford Anglia 105E (997cc) has a shorter stroke than a Honda C90 (86cc)!

    1. An interesting and telling observation.

      In full Boring Slag mode, I did a bit of checking and the generally quoted dimensions for the C90 engine are 89.535 cc and a bore and stroke of 50 mm x 45.6 mm.

      The 997cc Anglia stroke is 48.41 mm, however there is a 940cc crossflow, still with the 81mm bore and a stroke of 45.62mm, almost the same as the Honda. That one was used in Mk.1 and 2 Escorts for Italy and France.

      I did a bit more searching and there’s a long stoke series of the Honda single – the 86cc version has a bore x stroke dimensions of 47mm × 49.5mm. The bore is the same as the C70. It seems to be used in mini-ATVs now – was it also used in later C90s?

  11. The Jaguar V12 with the Heron type head was not anything to do with May. The May head came late in the V-12 production run as a scheme to improve fuel economy at part load and also to improve emissions. The May head allowed high compression ratio and allowed stable ignition of lean mixtures. The trouble was that emissions regulations went in a direction which did not suit its characteristics.

    The Heron head design was not used by Jaguar. What Jaguar used was closely related to the Heron design but it is not the same. While the Jaguar head is flat faced and the corresponding piston has a bowl, there is no squish zone in the Jaguar V-12 whatsoever. The piston never gets anywhere near the head face. At TDC it remains “down the hole.” The combustion chamber shape is that of a thin disc with a mild bulge. It is “open”. What turbulence there is in the chamber at TDC is not from squish (for there there is none), it is from the induction process and it is not very energetic. The early Jaguar V-21 combustion chamber layout provides amazing refinement for an ICE (better in terms of smoothness and silence than anything built since, including electric cars). It has reasonable efficiency at full throttle and elevated rpm, but the efficiency collapses at part throttle (which is why it was replaced by the May “Fireball” cylinder head.

    Jaguar did have a four valve head for this engine (as did TWR). One version of the four valve V-12 nearly made it into the Aston Martin range. It is a shame that the four valve was not made available to the public.

    1. Thanks for stopping by Ratu. You are quite right about the ‘May Head’ Jaguar V12 being a different design to that of the original production unit. The production V12 was apparently intended to run with a compression ratio of 11.6:1, a figure which was reduced owing to emissions requirements. It was also intended to have fuel injection from the off, but Jaguar’s supplier reneged at the last minute, leaving them with no choice but to develop a variant using four downdraught carburettors. However, once Jaguar developed a compatible digital injection system the V12’s compression ratio was raised to 10:1 – many of these engines were said to have left the factory with well over 300 bhp.

      The May head was championed by Jaguar’s Harry Mundy during the mid-70’s to mitigate the engine’s part-throttle thirst and saw the compression ratio raised once more. However, Jim Randle recently admitted the resultant design was a disappointment in this regard and didn’t live up to its technical promise, even if it did in PR terms. There can be little doubt it gave the engine another decade of life it otherwise would not have had.

      The four valve V12 was another of Mundy’s projects I believe. One of these engines was fitted to the prototype XJ220 and resides there still. I would be interested to learn more about what Aston Martin model was to have received this engine – I would imagine it had something to do with Tom Walkinshaw, as I rather doubt Jaguar’s engineering staff would have willingly countenanced such a development.

  12. On the subject of the mediocre Ford CVH, to what degree was it within Ford’s ability to produce an earlier Zeta engine from the outset (thereby avoiding wasting a decade with the existing CVH) or failing that at minimum manage to substantially improve the CVH engine by incorporating aspects of the 135 hp 1.6-litre Schrick 16V conversion and ZVH hybrid engine (the latter comprising of a Zeta block and CVH head)?

  13. The 1600 Kent engined Transit was a revelation in 1976. So much quieter, smoother and economical than the v4.
    The gearbox was about an inch further back iirc (shown by an odd connection at the base of the gear stick, held by a cotter pin!!)
    The engine looked lost under the bonnet, with really oversized engine mounts, we used to say you could have a mechanic in there for servicing.
    Loved that Daytona Yellow van. Differentiated by black grille, headlight surrounds and a black stripe at the bottom of the rear doors.

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