Best of British : Gardner 6LX diesel engine

Mike Humble

Ask many a seasoned truck or bus engineer the simple question ‘who made the best large diesel engine?’ and more than likely the answer without delay would be Gardner. Most of you out there in reader-land will claim not to have had any experience with such engines, some may not even know who they, but I’ll bet you ten bob that at some point in your life, you will have been either propelled or scared half to death thanks to a Gardner.

The world-regarded company of L Gardner & Son of Patricroft in Manchester for many years, were the world export leaders in diesel engines for commercial use all around the globe. Throughout the 50s 60s & 70s, most of the British made trucks and buses relied on Gardner power, and they were certainly engines of legend.

In the latter part of the company history, Brothers Hugh & John Gardner designed some of the longest lasting and fuel efficient commercial diesels of the 20th century, and just like Land Rover, a huge proportion of their output is still in daily use, if not for the original purpose it was designed for. Its swansong engine with no shadow of doubt, was the 10.5-litre 6LX design which first saw the light of day in 1958 being based on the previous 8.4-litre 6LW design but featuring many improvements to aid longevity and efficiency. What made Gardner quite unique in the world of engine building was the fact that most of the components involved, even parts of the fuel pumps, were all cast or fabricated in house to standards of utmost quality.

Initially offered with a rating of 150bhp in automotive tune, the 6LX went on to become the most popular engine of its type being fitted into generators, mobile cranes, boats, mining machinery, commercial vehicles & buses. Gardner used separate cast iron cylinder heads in a similar vain to the likes of AEC or Leyland, but the cylinder block also in iron, was fitted to a cast alloy crankcase.

Another unique feature that contributed to the lasting nature of the engine was the crankshaft main bearings that were not only located and secured vertically in the normal way, but also horizontally braced. This gave the bottom end of the engine phenomenal strength and rigidity with warranty claims for terminal failure being virtually unheard of.

Our very own Leyland & AEC also had respected engine ranges with the 680 and AV690 respectively and as the 1960s progressed, squeezed more power from them. The Leyland 680 engine in its exiting sounding power plus tune developed 200 or 220bhp but not without problems of cylinder head gasket issues. Gardner responded with the 6LXB vertical or 6HLXB in horizontal form putting out 180bhp amazingly with hardly any noticeable difference in fuel consumption.

So talented was Hugh Gardner that thermal efficiency of this variant was a shade over 40% – a figure unmatched before, and maximum torque was developed at a staggeringly low 975–1100rpm. Even maximum power was achieved at only 1850rpm where nearly all other rivals figures were gained at 2000 or 2100rpm.

The 6LX was the engine of choice for the municipal bus operator as can be shown with this brace of Northampton Bristol VRs.

A large capacity engine working well within its design capabilities were key to a long trouble free life. Leyland bus for example, were very reluctant to specify Gardner power units, but following some catastrophic disasters, notably with their fixed head 500 series and the impressive yet mortally under developed AEC/Leyland 800 V8 had to offer 6LXB in later model National buses. Bristol who was also in the BL group sold, thousands of RE and VRT buses with Gardner as the standard engine.

In a bid to offer even more output, Gardner further improved output following the addition of the 6LXC rated at 195bhp towards the latter part of the 1970s. This same period however, saw Gardner loose its independence following a sell out to the Hawker Siddley group.

To say that the Gardner family were stuck in their ways and traditions would be an understatement. Hugh Gardner, despite seeing foreign and UK competition engines offering ever more power ratings refused to offer turbocharged power units to his designs. The bus market remained fairly buoyant, but truck chassis from UK manufacturers started looking elsewhere for engines with the likes of Rolls Royce and Cummins simply picking off traditional Gardner customers one by one.

The 6LXC developed under 200bhp whereby a Cummins N series offered 250 and beyond with far superior torque. Subsequent designs in the Hawker Siddley era offered comparable levels of output but sadly lacked the development required to match the competition.

Gardner then introduced a turbocharged version known as the 6LXCT rated at 230bhp but the days of Gardner ruling the roads were numbered – the competition simply just got better. The 6LX series remained in production even after Hawker Siddley sold Gardner on to the Perkins group, right through the 80s and even into the early 90s, the 6LX remained the number one choice for British bus buyers. Sadly, Leyland bus entered a preferential purchase agreement with Cummins as did Dennis and the forthcoming Euro1 emission criteria tolled the knell for the Gardner 6LX series engine. Engine production of 6LX ceased in 1992 after a run of almost 100,000 units.

Where you find most Gardners today – At your local travelling fun fair

Gardner powered buses and trucks are pretty rare these days, but should you wish to enjoy the sound and smell of a plodding Gardner LX engine, peer round the back of your typical fairground ride where the generators reside or take a slow boat to China to witness one of thousands of fishing junks – most of which are powered by redundant Gardner bus engines.

Mike Humble


  1. Gardner had a long history of producing reliable engines. Sadly they never invested on their scuccess. By the early 90’s the LX was a joke. Very expensive to produce and not at all competative.
    Their early marine engines were based on a Sulzer design. the L2 & LW an engines I know well were manufactured to an extreemly high quailty.
    Shame Perkins/Cat could not have done more to develop the brand.

  2. You have Hugh Gardner to blame for that. When Rolls Royce hit the fan back in the 70`s nephew Paul Gardner suggested they buy the plant for RR in Salop to expand their portfolio and gain a foothold into the MOD and other markets. The idea was ignored by HG. It was only a subtle directors coup than sidelined HG into a pure engineering role, selling Gardner onto Hawker Siddley, but by then, the competition passed them by.

    Ironically, Perkins bought Rolls diesel and subsequently went on to swallow Gardner. Your mention of development by Perkins never happened as Gardner were labour intensive engines to build and subsequent new designs like the 6LYT were too big in relation to their size (15.5 litres for 350 bhp) where a 10 litre Cummins L10 offered 325.

    The only markets open to Gardner closed with the likes of Leyland Bus shutting down, besides, by the 80`s, Cummins were the new global force in propriety engines… years of blinkered management killed Gardner, nothing else and by the time any real future prospects could be had, there was no market available to them.

    • How often does one read of the demise of British manufacturing and engineering during the latter half of the 20th century and, in so many instances it was a case of not being able to change with the times. The British were damned by the delusionary belief that “British is best” and that products, the best, often, of their day, should be persisted with in spite of obvious obsolescence. They all went down pugnaciously clinging to this fatal belief. They simply couldn’t cope with innovative competition. Poor management hastened their end.

      • I agree with your last statement. I’ve been fortunate enough to work in the car industry all over the world. The only real difference between our car industry and others is the management. Ours is mostly hopeless.

        • Is that true for the Americans?

          It seems any time their economy takes a hit they have to get a government bailout and/or close some divisions to raise the cash to develop some smaller cars.

          • US car companies are unusual in some respects, compared to others I’ve experienced. If both Ford and GM were European, they’d have both gone out of business in the late 90’s. US bankruptcy laws saved them! As far as engineering goes, about 1/3 of the engineers are British, with a good showing of Australians too. We tend to be used as a fire brigade there….fixing the screw-ups. The average American engineer is ‘limited’. By our standards, not very well trained at all.

  3. I think its member of the Gardner family that runs a firm that recons & supplys spares for Gardner diesels
    Good write up by the way Mr H

  4. Not quite, Paul Garder did have an engineering facility on the site of the plant, but sadly it went bust a short while ago.

    Gardner parts are now dealt with by Leyland Exports LTD and offshoot of Leyland Trucks / Paccar who operate from a unit that once once part of the Leyland Motors LTD complex in Lancs

    News of receivership:

    Gardner parts:

  5. Mike, you made a whoops, the 6LX series were 10.75 litres 🙂 The 6LXB or ‘Gardner180’ when fitted to Atki’s etc was an almost nuke proof engine. They would leak oil everywhere, but so long as you kept an eye on the fluids, insane miles between rebuilds were known. The 6LXB was powering Olympians up until around 1991, and at one point it was Stagecoach’s standard engine, and the 2 tri axle Olympians they had built for the UK were both 6LXCT powered, when almost everyone else had switched to the smaller, lighter, and more powerful Cummins L10

    • The Gardner 180, was a Bullet proof engine. It used to be that when a Bus fitted with a Gardner was taken out of service by a Local Authority having only done 500,000 miles on the clock. The Gardner engine from it would be Cut in half and exported to Brazil. Once there it would be welded back together, and re-installed in a Bus, Truck or Boat. It would then comfortably do another 1.5 Million Miles.

      The Gardner 180 when fitted to, Atkinson, E.R.F., Foden, Guy and Seddon, 8 Wheeler Rigids, running at 24 Tonnes on British “A” roads at 30mph, it was pretty much impossible to break them. Even when Artics went up to 32 Tonnes, still not much problem. But when the Speed Limits, increased with Motorway building, especially across, the Pennines, from Sheffield to Manchester, they started to plod.

      The main problem with Gardner was, that their was a 2 year waiting list for the engines to be fitted to new builds in Atkinson, E.R.F., and Foden.

      Never understood why a deal wasn’t done with, Meadows of Wolverhampton, who were opposite the Guy Lorries works, (and must have had some relation, with that company, as it closed at the same time).

      Meadows (whose later engine designs, could have a terrible record on Piston failures), could then have supplied them directly to Guy, in Wolverhampton.

      E.R.F. and Foden in Sandbach, Cheshire.

      Maybe, also Dodge(Commer), in Dunstable. Bedford, in Luton.

      Dennis in Guilford, and possibly even Ford, at the Langley Plant, near Slough, would have used them in larger 6 Wheeler Rigids, and Artics running at Higher Weights.

      Instead, Cummins, opened their plant at, Shotts, in Scotland, to provide engines for the Plant manufactures, (more would be opened later in, Daventry and Darlington).

      Their NH 220 model would just slip comfortably onto the chassis, and under the Cab’s engine hump.
      Drivers, loved them, lots of torque, and more road Speed.
      Mechanics, loved them, as being so simple to work on.
      Operators, hated them, as Gardners sipped Diesel, while Cummins, liked a good glug, . (Rolls-Royce Eagles, were put up with, even though they were poor in cold weather).

      What happened with Gardner, was one of so many in British engineering.


      Out of interest, in the early 1970’s, Peter Foden of E.R.F., kept complaining when hauliers were asking him for Sleeper Cabs, to be fitted to his Lorries.

      The ironic thing is, that the local rival, Foden, had been building them for oversea sales in the 1950’s for South Africa and Rhodesia.

      D’oh !

      • IIRC Gardener were given the chance to buy Rolls Royce’s commercial engine division in the 1970s but turned down the chance.

        This would have given them some extra capacity if the extra tooling was worth investing in.

      • I served my apprenticeship with North Western Road Car Company, 1968 to 1973 as a Diesel Fitter. Gardeners were a delight to maintain and work on. I only ever remember doing one rebuild of a 6LX, re ringing the Pistons and re shelling the big ends. They lasted forever. Happy days.

  6. Don’t know if this is of intrest but Gardner also made some dam fine marine gearboxes. They are still actively sought. tremendously strong well made and simple. But just like the LX never developed
    A wheeler dealer friend bought a pair of handed (Both turned in opposite direction for a twin screw application) marine 8L2’s about 5 years ago they had been standing in a field for about 20 years. I thought he’s payed a lot of money, for what I thought was a pile of scrap or parts. I was then asked to restore them!! I stripped them down freed them off. I got one running of sorts. However he sold them to a dealer for something like 5X what he payed for them. Apperently they then went off to Egypt, where there is a big market for simple old, quaility diesels

  7. They certainly did H

    And before they stopped using the ‘hybrid’ fuel pumps they would run backwards too… All you needed to do was remove the air cleaner and push start a manual gearbox version forward whilst in reverse and hey presto…. An ERF B series tipper that would manage 60mph – backwards!

  8. Another credit to you Mike!

    A wealth of knowledge and experience that ARO are surely chuffed to be able to tap into.

  9. The World’s Best Diesel Engine, bar none, and an engine made by Engineers for Engineers. How forward thinking to today’s world – amazing levels of economy/fuel consumption (green), insane mileages between indefinite numbers of rebuilds (longievity,saves resorces), and widely recycled (boats and generating sets)!
    Sad that their management got complacent whilst the rest of the world moved onwards and upwards.
    Oh, and what a sound too!

  10. I remember a few years ago an 8 wheeler Ihad loaded tried to move but the engine stalled the truck was still in gear next thing,the engine was chucking smoke of the air intake the driver didnt know what had happend so I told him to stop the engine as it was running backwards,he said Ive never known that before,you learn something every day.

  11. Been involved with Gardner Engines for 50 years finest piece of engineering craftsmanship on the planet I have a 8 wheel Foden with a6 LXB in it which has clocked up 1,600000 miles in 43 years In the mid 70s whilst tipping at Pomona Dock in Manchester my workmate in a 6 wheeler with a 150 in it push started one of Sunters Volvo heavy haulage low loaders loaded with switchgear The crew man told us later that it weighed in at 124 tons

  12. We had a 5lw engine in our boat, I would spend hours, cleaning the engine bright work ,she used to gleam, so easy to work on, so reliable and diesel frugal, I swear you could fall asleep on it.
    The sound I will never forget…..
    The governor spring broke once and apart from the black smoke, the boat absolutely flew down the river..
    Dad bless him, lashed himself to the mast, I will never forget it.
    So sad to read of the companies demise but by the early 80s one could buy 3 new sabre engines with twice the horsepower,as against one Gardner such was the cost comparison. I still love them though, magnificent engines built by the tremendous engineers and technicians.

  13. i have a 1960 gardner 4lw in my 1978 32ft cygnus trawler yacht an wonder if anyone can say where it could have been for the 18yrs before it was fitted in my boat

  14. Greetings Mates,
    I own 4 Bristol Lodekka buses, vintages: 62, 64 & 2-66. They have either Bristol BVW, or Gardner LX or LXB engines. My restored 62 Lodekka has the LXB 6. Sadly she smokes when pulling up a hill or accelerating. It seems to me to be either black or white/grey smoke and it smells of diesel. I would die to find someone who could help me solve this problem or suggest fixes. I am looking ro parts for any of these engines & a set of the right hand bi fold doors for the FLF Lodekka bus. I live in NE Pennsylvania USA. My email is: Cell #: 570.236.3747
    Any help would be cherished. Thank you…. Cheers Peter Pilot

    • if smokes up hill look at the advance link bar(may be missing as mine was…) between throttle on injection pump and timing chain casing ….this would advance injection timing and stops smoking oncoming out cars going down hill with there windows down in the summer (i had to ease off throttle uphills ..)

  15. I obtained a 5 LW from Michael Harrison :info@gardnerdieselengines.comUK and installed it on my custom build steel trawler,have put 4000Miles on the boat cruising the Great Lakes all the way to Baltimore where I shipped the boat to Spain near Vallencia from where I picked up the boat and sailed to Igoumenitsa Greece summer 2014.
    The engine worked flawlessly and at 1180RPM was doing between 6 and 7 knots depending of the sea conditions and running 24/7 was never a problem. No smoke no leaks just a beautiful sound,and the fuel consumption on the average was 1,5 G/H. Dry exhaust and heat exchanger. For service if I ever need any, Michael is there to help any time .
    Is there a better engine ? I think NOT ! What do I know? Well I am an ex marine engineer and believe me you can not have a simpler and more reliable engine than a GARDNER.

  16. Talking of Gardner engines, is my memory playing tricks on me, or am I right in thinking there was a straight eight (8LXB?). It my have been fitted to some of the Atkinsons back in the day.

    • Correct. We had them in tractor units and chemical transport. Also had 6LXBs and never had any overhauls.

    • Yes, the 8LXB was a 13.93 litre straight eight, which added another two cylinders to the standard 6LXB. They produced 240bhp and made a super sound, but was Avery long engine to install. Often the rear two cylinders stick out of the rear of day cabs, people joking they were air cooled!!

  17. William Nuttall & Son transport at Clifton Manchester operated Atkinson Borderer tractor units with Gardner 8 cylinder engines. Does anyone know if such a vehicle exists today which is for sale?

  18. I drove the Gardner-engined Lodekkas for SMT between l961-l966 as a law student driver. Changing down to second before easily taking the hills around Edinburgh was joy and a pleasure. ev

  19. gardner 180 with david brown box righthand change cockpit built like a vintage car or boat blew smoke rings on startup 32 tons 10 miles to the gallon my dear old friend alan was always waiting when I got back from Dundee or wherever to drain the sump andI remember him telling me 100 thousand miles on a set of injectors was normal. when my perkins 4 108 required oil changes every 1000 miles and it came out like tar the conrods were polished, torque my oh my phenomenal

  20. The company I work for used to run Gardner engine Leyland Olympians, they were some of the best buses I drove. Sadly the age of the vehicles coupled with disability legislation meant they had to go.

  21. I am trying to fit a reconditioned starter motor into a Gardner 6lxB. Marine engine.
    Its a 6″- 12 volt starter motor.
    Previous one broke because corroded ignition key fail to disengage.

    Seems like there is specific distance that the starter is inserted into the ring gear, because moving it one way or the other my mere millimeters and the stater motor failed to disengage.
    Does anybody know if there is meant to be clearance between the housing and the starter of is it meant to be pushed in hard against the housing.

    Please reply ASAP I need the boat to start taking tours again.

    • I am new to this type off eng but my first problem was the starter. there is a spacer ring that goes over the starter bud we had the same problem, and the bloody thing had 13 teeth ?? can you tell me if that is normal??lol aye am from the north east of Scotland and have just got a creel boat fishing for lobsters !! any websites you could tell me about to get some info mate would be a big help thanks ! we hade a nylon spacer made for your problem ,,I know your question is old and you will have it fixed by now !!

  22. Served a apprenticeship at L.Gardner & Sons 1965 to early 70s worked in all departments from crank installation, flywheel assembly,fuel pump shop (dolls house), turning shop, grinding shop, crank machine shop, engine build, engine test bay, came out of my apprenticeship as test engineer testing 6LX 6LXB 6L3 8L3B wouldn’t mind contacting ex employees with similar histoy

  23. hey guys..just bought a6lxb came outa a burned out leyland olympian bus.there were no plates left oon yhe bus all melted..ime trying to identyfy the year..only thing i can find is chasis number on11564 ..vehicle type 02r5g13z4. and engine type eo6lxb38/22. cheers guys

  24. Hi,

    I have a 6LW In my dutch barge and she runs like a dream. I am due for an oil change but am having trouble working out what modern oils are acceptable. I have some Comma Transflow FL30 which the company says ‘should’ be ok. I also have some Elf Captain Neptunia SAE30 which i think shouldn’t be used but i cant find any info on it. I assume a monograde, mineral based oil is the go?



  25. I am new to GARDNER 6lxb. ,, can anyone help ?? the eng is smoking bad in the morning real bad but it clears after 20 mins or so with the handle down its in a small creel boat ( fishing boat ) any INFO what so ever or any sites would be a big help

  26. Willie Cormack, That’s what Gardners do,low compression ratio, when it’s really cold it takes a while before they fire on all six cylinders.

  27. Dear Sirs
    I’m considering buying a boat with an 6LX Gardner engine. It comes som oil smoke from the “breathing pipe” (as we call it in norwegian) engine top left side. The owner says it is only oil smoke before the eingine is warm? It is also leaking some oil from the top covers. Does this indicate severe wear or engine failure?
    Best Regards
    Per Vangsoy

  28. Dear Sir,
    Could you please quote for the following item with full specification, drawing and warranty? Kindly reply me with your best price including the delivery date lead time terms (approximate delivery charge up to Muscat). Note: Quotations must be submitted within 2 days of the date of invitation.
    Please treat the above request as very urgent.
    Kindly send your price and delivery time as soon as possible.
    Thanks & Best Regards
    Purchasing Manager
    AL Tamauez AL Raqi L.L.C
    P.O.Box: 983, P.Code: 130, AL Azaiba
    Phone : 0096824496098
    Fax : 0096824496099
    GSM : 0096895494885

  29. Hi we have a 8lxb engine in a 50 foot boat with 11000 hours on it and still going good as we have no manual could some one tell me what oil we sould be runing in it ?

    Cheers adrian cox new zealand

  30. I have a marine 6lx in my boat with over 180000 hours on it I would like to drain all the fresh water out of it and fill 50/50 anti freeze and water . Whats the best way to really empty the fresh system ?

  31. A very smart Gardner mechanic advised me to keep the oil level at the low mark on the stick.This seriously reduced external oil leaks on my 6LXB, which resides in a 40′ trawler with 13,000 hours.

  32. I drove MCW Metrobuses fitted with these engines across central Scotland for Midland Bluebird (Alexander’s to some) . Easily capable of 70mph laden. Very responsive engine with steady and predictable power (Leyland turbos were rather on/off by comparison). Even with an auto box the engine braking was perfect for twisty roads. And that MCW chassis!! (Anybody know the road between Dollar and Tillicoultry?) 50-flat out except for two corners. Modern buses just don’t have the same drivability. Yes the window-wipers are on the stalk rather than a switch somewhere behind you but that doesn’t compensate for handling. We did have some Leyland Olympians, I drove the last one, on its last day in service. A semi-automatic. Don’t know if it was Gardener or Leyland engined. It was a gorgeous drive but slow, the semi-auto couldn’t be rushed if you wanted a smooth journey. I’m really not sure that modern buses are better than those made 30-40 years ago. Ergonomics and fuel economy may have improved but passenger comfort and refinement have declined. (More lights do equate to better comfort -passenger or driver) And then those Volvo’s…. wonderful engines but woeful chassis. Up hill to Cumbernauld, 50+ all other buses struggled to do 30 (except 3 speed Merc 0405…40) And chassis, well….only time I ever had to stand up to make a corner was with a Volvo decker…

  33. More or less ignorant on commercial truck and bus engines in general, though where does the Rolls-Royce Eagle standard in comparison to the Gardner and other engines in spite of its rather fragmented history?

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