Don’t forget that Gardner’s made two-stroke engines, albeit massive slow-revving marine units, so the Gardner family was familiar with the two-stroke concept. There are some working Gardner two-strokes at the Anson Engine Museum.
[zb]
anorak:
A prompt response CF. I have copied the 8v71TI curves here:
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The graph shows a minimum full load SFC of 0.36 lb/bhp/hr between about 1700 and 2100RPM. The Gardner 6LYT had a min SFC of 0.32 lb/bhp/hr (thanks Mr. Edge), from memory this was at around 1400RPM, and the Gardner’s curve was quite “flat”. At lower loads, the Detroit would be further disadvantaged, as scavenging losses become a greater proportion of the total.
But then you’ve got to factor in the actual,specific,torque and horsepower outputs of the Gardner motor v the Detroit at those respective engine speeds considering that the Gardner needed to be running at 1,800 rpm to provide 350 hp.Which is what the ‘productivety’ figures are mostly based on,in addition to how reliable would the 6LYT have been,on a like with like comparison,of those output levels which the Detroit motor,amongst others like CAT and ■■■■■■■ etc,was capable of, throughout the operational engine speed range.Assuming that it could even have been developed to even meet them in view of the fact that as I’ve pointed out Gardner was hindered by not having a product that was designed with the ability to accept effective forced induction either by design or by accident as in the case of ■■■■■■■■■■■■■■■■■■■ the Leyland 680. 
Which probably explains why the Gardners don’t seem to have been such a big hit in the colonial export markets,as the big three of CAT,■■■■■■■■■■■■■■■ were,or even here in the case of ■■■■■■■ and the 680 in the DAF 2800.It was that type of typical British customer fixation on specific fuel consumption figures and not the bigger picture that was one of the main reasons why the British manufacturers foundered in trying to meet those flawed domestic demands.
However on the subject of low engine speed operation it’s obvious that even Detroit themselves decided that four stroke technology was/is the way forward although the large marine engine industry seems to show that there’s still some mileage left yet in the two stroke uniflow idea at the cutting edge of low speed diesel engine fuel efficiency.
I remember the 6LY Gardner series developed a reputation for poor reliability. However, it was very successful in motor coaches- did Neoplan not offer the 6LYT320 as their “standard” engine for a while? Does anyone know why it achieved such success in that market, yet was a flop in lorries?
[zb]
anorak:
I remember the 6LY Gardner series developed a reputation for poor reliability. However, it was very successful in motor coaches- did Neoplan not offer the 6LYT320 as their “standard” engine for a while? Does anyone know why it achieved such success in that market, yet was a flop in lorries?
Maybe because at it’s most fuel efficient and mechanically reliable engine speeds it was only putting out a lot less than it’s max power rating of 350 hp. The fact is if you wanted to shift 32 t gross around at reasonable motorway speeds then the 8V71 T fitted in a TM would probably have been more efficient and reliable.Shame that the Brits decided that a non turbo 6V71 or 8V71 was good enough for the job. 
A better comparison at 32t gross would be between the 318 Detroit in the TM4200 and the Gardner 8LXC in an ERF or SA400. If Commercial Motor did a roadtest of both (I think they did- has anyone got scans of the articles?), I bet my wedding tackle that the Gardner wiped the floor with the DD on fuel, with negligible difference in trip time.
[zb]
anorak:
A better comparison at 32t gross would be between the 318 Detroit in the TM4200 and the Gardner 8LXC in an ERF or SA400. If Commercial Motor did a roadtest of both (I think they did- has anyone got scans of the articles?), I bet my wedding tackle that the Gardner wiped the floor with the DD on fuel, with negligible difference in trip time.
The problem for Gardner though (and Bedford) was that it (eventually) became obvious to operators here that those levels of power ( and in the case of Bedford torque ) outputs,weren’t really up to the job of hauling 32 t gross around,let alone 38t,with a decent combination of fuel consumption and productivety.Hence more sales in the domestic market for the turbocharged ■■■■■■■■■■■■ the operators here finally got their act together,than engines like the LXC.Unfortunately for Bedford it was your type of comparison that won out rather than the relevant one ( which would/should have been ) between the turbocharged 8V71/8V92 and turbocharged ■■■■■■■ and other turbocharged euro engines and any type of Gardner ever fitted in a wagon.
Which is exactly the type of conclusion that many operators in the foreign export markets had already reached long before their British counterparts which is the only reason why the end of Gardner was a far more long drawn out situation than it should have been. 
Whereas Bedford’s mistake was in not just offering the TM with the only the turbocharged 8V71 AND 8V92 options in the wide cab from the start on a take it or leave it basis to customers.The result couldn’t have been any worse and maybe would even have been better.
Well getting back to the Gardner 2 stroke engine, they didnt have a gearbox when fitted into boats, they simply just stopped the engine & restarted it going backwards, great engineering I would say, Regards Larry.
As to the 6LYT being successful in coaches and not lorries. Two reasons possibly to consider. A big engine in a coach is always going to be operating well within itself, whereas a fully freighted lorry does impose different demands on an engine at various stages of its operating cycle. Also the premium price of a Gardner, by the time the 6LYT came along operators would not pay the premium price for one in an ERF or Seddon Atki. If you are spending, say, £100,000 on a super coach, then another £3,000 extra for a Gardner engine, rather than another make, is neither here nor there.
In terms of power outputs Gardner had been behind since the 1950s. A few 8LW engined Fodens were built for heavy haulage (160 bhp), but by then both Leyland and AEC had normal road going engines at 165 bhp. Gardner responded with its 6LX ‘150’ in 1958, touted as a brand new design, which it was in that it was the first Gardner that was designed as a 6-cylinder, rather than a series of cylinders such as the LW range, i.e. anything from 1 to 6 cylinders, then an 8-cylinder version for special applications. But it still relied on the LW design pedigree in many aspects. By 1961 AEC and Leyland were offering 192 bhp in 8-wheelers and artics for 24 tons gvw, then the new C&U Regs in 1964 permitted 30/32 tons maximum gvw, and it took Gardners until 1967 to re-tune the 6LX to 180 bhp with the 6LXB. In 1965 AEC had its AV760 at power outputs of 205 to 226 bhp, and Leyland similar with its O.680. We then had the European and Scandinavian offerings coming onto the market, and we all know the rest.
gingerfold:
In terms of power outputs Gardner had been behind since the 1950s. A few 8LW engined Fodens were built for heavy haulage (160 bhp), but by then both Leyland and AEC had normal road going engines at 165 bhp.
That’s similar to the point which I was making concerning the comparison with the Diamond T which,contrary to nmm’s comments,seems to show that Gardner had been behind in the horse power race long before the 1950’s.Which is why we had to send a delegation over to the states to sort out the importation of those prime movers because they knew that the Gardner powered Scammell Pioneer wasn’t up to the job.No surprise that no one here,with any sense,then suggested retro fitting the Diamond T with Gardner power during it’s service life throughout the war and long after in civilian use.
( There’s also a good story which I saw some time ago in a tv documentary of subterfuge going on in WW2 with a German delegation also trying,unsuccessfully,to get their hands on Diamond T’s through a neutral country either Spain or Swiss so obviously even Saurer wasn’t in the same league a the US even at that time ).
I don’t think that there can be any argument that AEC engines and possibly trucks,were ahead of Gardner powered ERF’s and Fodens during the 1950’s while the Leyland 680 turned out to be even more future proof in the hands of DAF.
The truth is,however unpalatable for the Gardner fans,that the Gardner was just a one trick pony of fuel efficiency at the expense of power output throughout it’s lifetime.
And of course during WW2 Gardner was ham-strung by its usual lack of assembly capacity problems. Most of its wartime output went to other installations, such as searchlight generators, pumps, radar station generators, marine auxiliary units, Harbour Defence Launch main engines, air / sea rescue launches etc. etc. This was why ERF and Atkinson had to fit AEC engines in the lorries they made for the Ministry of War Transport allocation scheme and Pool Petroleum transport.
gingerfold:
And of course during WW2 Gardner was ham-strung by its usual lack of assembly capacity problems. Most of its wartime output went to other installations, such as searchlight generators, pumps, radar station generators, marine auxiliary units, Harbour Defence Launch main engines, air / sea rescue launches etc. etc. This was why ERF and Atkinson had to fit AEC engines in the lorries they made for the Ministry of War Transport allocation scheme and Pool Petroleum transport.
I think it’s mostly been more a case of it’s performance not it’s supply in the case of customers who knew better.It’s just that it took ( a lot ) longer than it should have done for a (lot) of British customers to know better.It really was the definition of a guvnor’s motor at least those guvnors who’s ideas were based on that same flawed logic of fuel economy at the expense of go.By the standards of diesel technology as it stood in WW2 it was still a case,at that time,of petrol engines being the main power units of choice in the case of serious power outputs being the priority.In addition to which petrol engines were also preferred in many cases because of the problems involved in large scale supplies of two different types of fuel.
Ironically it’s now spark ignition technology which is again likely to be become more in demand again in future as the fuel efficiency,emissions issues,supply and cost equation,of using diesel,becomes less advantageous compared to alternative fuels like LPG.
dailymail.co.uk/moslive/arti … -boat.html
No surprise though that it was Detroits which played more of a part in front line service than Gardners when diesels were used.With the exception of the Hercules in the Diamond T.
youtube.com/watch?v=adEy5j4XiJk
Gentlemen youve completely lost me . Are you all engine designers.professors of advanced engineering or physics or what. I was adriver and self taught mechanic for many years what does it really matter if engine A produces 10lb more foot pounds of torque at 15 rpm less than engine B .What really matters is/ is the product reliable is it open to operator abuse and will it do the job it was designed for. Have a nice day.Crow.
Funny enough there was an article in the paper the other day about for the average family car with the advances in fuel economy and the cheaper price of petrol than diesel and the cheaper purchase price for the average motorist a petrol car will be cheaper to run in the long term.
A classic piece of British engineering!!!
…And I don’t think it came out of a Guy Big J!!!
geoffthecrowtaylor:
Gentlemen youve completely lost me . Are you all engine designers.professors of advanced engineering or physics or what. I was adriver and self taught mechanic for many years what does it really matter if engine A produces 10lb more foot pounds of torque at 15 rpm less than engine B .What really matters is/ is the product reliable is it open to operator abuse and will it do the job it was designed for. Have a nice day.Crow.
Hi Crow,
Please ignore all the guff about minute differences between engines. While some posts seem to be hell-bent on prevarication and hypothetical speculation, I attempt to celebrate the significant achievements of the engine manufacturers. This occasionally drags the discussion into theory, although none of the stuff I write is intended to confuse. Your comment about operator abuse is appropriate to the comparison between the 6LX and the Leyland 680, which Gingerfold mentioned above.
While Leyland, and others, were boasting 200-odd bhp to the Gardner’s 150, all of these 10-11 litre engines produced similar torque (without arguing over petty details). Gardner’s advantage was its lower limited speed, which prevented driver abuse- to get their extra 50bhp, the competition required another 400 or so RPM on the clock. Otherwise, the engines’ performance was comparable, but Gardner had a clear lead in economy and durability.
kr79:
Funny enough there was an article in the paper the other day about for the average family car with the advances in fuel economy and the cheaper price of petrol than diesel and the cheaper purchase price for the average motorist a petrol car will be cheaper to run in the long term.
I don’t think they’ve even started yet on the type of potential adavances possible in spark ignition technology.My bet for a useful truck engine would be something like this,maybe using uniflow technology instead of sleeve valves,around 13 litre,6 cylinder,with max power of around 550 hp,produced at around 1,000-1,250 rpm,using modern day engine management and electric blowers for scavenging and boost,therefore running independently of engine speed,with the turbocharger/s helping to charge the electric blower system instead of acting as the now redundant induction compressor.
Running on LPG at 70p per litre instead of diesel at £1.30 +. 
en.wikipedia.org/wiki/Rolls-Royc … 28Crecy.29
Which was an idea of one of the truly great engine designers.I don’t think there was any 150 Gardner competition available in 1915 to put in WW1 tanks.
[zb]
anorak:geoffthecrowtaylor:
Gentlemen youve completely lost me . Are you all engine designers.professors of advanced engineering or physics or what. I was adriver and self taught mechanic for many years what does it really matter if engine A produces 10lb more foot pounds of torque at 15 rpm less than engine B .What really matters is/ is the product reliable is it open to operator abuse and will it do the job it was designed for. Have a nice day.Crow.Hi Crow,
Please ignore all the guff about minute differences between engines. While some posts seem to be hell-bent on prevarication and hypothetical speculation, I attempt to celebrate the significant achievements of the engine manufacturers. This occasionally drags the discussion into theory, although none of the stuff I write is intended to confuse. Your comment about operator abuse is appropriate to the comparison between the 6LX and the Leyland 680, which Gingerfold mentioned above.While Leyland, and others, were boasting 200-odd bhp to the Gardner’s 150, all of these 10-11 litre engines produced similar torque (without arguing over petty details). Gardner’s advantage was its lower limited speed, which prevented driver abuse- to get their extra 50bhp, the competition required another 400 or so RPM on the clock. Otherwise, the engines’ performance was comparable, but Gardner had a clear lead in economy and durability.
But none of that is going to be much use when someone comes up with the idea of putting a turbocharger on the 680 and it works whereas it doesn’t when they try the same thing with a Gardner 150.But the roads weren’t exactly littered with the wreckage of blown up 680’s either which is no surprise considering that if it had been a weak basic design then there’s no way that turbocharging the thing would have made it any better.
While all the comparisons between contemporary Gardners and the American competition such as was in the Diamond T v the Scammell Pioneer let alone the turbocharged competition that came later isn’t exactly ‘minute’ differences.
Carryfast:
kr79:
Funny enough there was an article in the paper the other day about for the average family car with the advances in fuel economy and the cheaper price of petrol than diesel and the cheaper purchase price for the average motorist a petrol car will be cheaper to run in the long term.I don’t think they’ve even started yet on the type of potential adavances possible in spark ignition technology.My bet for a useful truck engine would be something like this,maybe using uniflow technology instead of sleeve valves,around 13 litre,6 cylinder,with max power of around 550 hp,produced at around 1,000-1,250 rpm,using modern day engine management and electric blowers for scavenging and boost,therefore running independently of engine speed,with the turbocharger/s helping to charge the electric blower system instead of acting as the now redundant induction compressor.
Running on LPG at 70p per litre instead of diesel at £1.30 +.
en.wikipedia.org/wiki/Rolls-Royc … 28Crecy.29
Which was an idea of one of the truly great engine designers.I don’t think there was any 150 Gardner competition available in 1915 to put in WW1 tanks.
Go back to when the diesel cars were much rarer and diesel was much cheaper to buy than petrol,the car manufacturers came on leaps and bounds in their refinement of these engines from the smokey slow older designs … and then the oil companies and the government put the price up so they are now (on low weekly mileage terms ) no cheaper to run than petrols , LPG will go the same way if it becomes popular ,im just waiting to see who will develop the first engine to run on salt water , now that would cause the governments some headaches :wink: ive got a nice Volvo S60 D5 for sale if anyone wants one i`m going back to petrol