Carryfast:
robert1952:
I’ve just looked up the 1974 ERF Earls Court brochure itself. It states quite clearly that the NGC had an RT9509A split torque 'box with direct top gear. Oh, and a wheelbase of 3.4 m. Robert
0
I can understand Anorak’s disbelief but it’s safe to assume that they really did gear a 335 ■■■■■■■ to hit the engine governor at around 92 kmh.Partly it seems as a way of providing the NGC with a speed limiting facility. 
Thereby producing by accident a niche heavy haulage tractor. 
You make a good point with the heavy haulage niche. Robert
Carryfast:
robert1952:
tiptop495:
robert1952:
The ^^^above Jack Cooke bit, more importantly, goes on to state that resolving this problem led directly to a policy of standardising on direct top gearboxes for all models, including the NGC, with suitably higher ratio rear axles. Robert
Hey Robert thanks for the solution, that looks better, and by seeing this brochure the ERF was the most torquey
engine on the continent at that time.
It shows max 1261 NM nett at 1300, against Scania with 1225 @1450 revs and the F89 with 1245@1300.
Eric,
Cheers Eric. To sum up: I reckon the CM reporter knew something of the history of this gearbox/axle development and simply used the word ‘governed’ to convey the idea of clipping the beast’s wings a little. Forty-three years later we have been left to do our homework to ascertain what he meant by ‘govern’. I think we’ve probably arrived at a conclusion! Robert
Unfortunately there was no way of ‘clipping its wings’ in the day other than by what the evidence shows in the form either ridiculous under gearing.Or using the disciplinary process to make drivers drive at a reasonable speed and make best use of the high torque nature of the engine with the high peak power output just being a by product of that and usually avoided.Unfortunately for the NGC’s fuel consumption figures they obviously chose the former.
Which leaves the question why didn’t any of the trade journalists in the day raise the issue of the gearing.Bearing in mind that the supposed higher final drive,to compensate for the direct top box,obviously didn’t happen. 
Probably explained by ERF’s customer driven decision,to deliberately use the engine governor as a speed limiter and because of confusion among all concerned,regarding the finer points of ultimate running speed gearing,based on the most advantageous use of the torque curve,as opposed to power peak. 
Bear in mind that the NTC 335 was an old school engine, and although it was torquey much of that torque wouldn’t have been at low revs like a V8 Scania but more at the other end of the rev band! Robert
‘Under geared’ or just appropriately geared? ERF’s chief engineer said: ‘This gave us two benefits. We gained about two per cent efficiency changing from the overdrive box; also, by using a numerically lower ratio axle, further gains were made in mechanical efficiency.’ This led to a policy of standardising on direct top gearboxes for all models, including the NGC, with suitably higher ratio rear axles.
The net result was a comfortable ride with not too much noise for the day and a lorry that could reliably go all day for several years. The piece in the yellow inset (see card below) very much describes what erstwhile drivers have told me, and matches my own experience when travelling in KCH. Robert
robert1952:
Bear in mind that the NTC 335 was an old school engine, and although it was torquey much of that torque wouldn’t have been at low revs like a V8 Scania but more at the other end of the rev band! Robert
The curve suggests that 1,400-1,800 rpm would have been its best operating range.IE no reason to gear it,or drive it much,if any,differently to the Gardner.With the final 300 rpm only really being needed in the lower gears and more severe terrain to make use of the taller power peak.
download/file.php?id=195889&mode=view.
Which leaves the question was the improvement with the later big cam types,possibly more a case that they’d learn’t more about the finer points and critical nature of getting the gearing right than previously and less pressure from the erroneous demands of the continentals by then ?.
robert1952:
‘Under geared’ or just appropriately geared? ERF’s chief engineer said: ‘This gave us two benefits. We gained about two per cent efficiency changing from the overdrive box; also, by using a numerically lower ratio axle, further gains were made in mechanical efficiency.’ This led to a policy of standardising on direct top gearboxes for all models, including the NGC, with suitably higher ratio rear axles.
The net result was a comfortable ride with not too much noise for the day and a lorry that could reliably go all day for several years. The piece in the yellow inset (see card below) very much describes what erstwhile drivers have told me, and matches my own experience when travelling in KCH. Robert
0
Hey,
You have right Robert, A direct top gear is Always more efficient as an overdrive, but from about ±2000 you saw come back some with overdrive because of withstand the high torque. Same an 13 speed RT is more efficient as an RTO 13.
And yes the NTC 335 was an old school engine but gave more torque at lower revs a many other even Scania’s V8.
I speak about end the sixties till mid seventies. Than you got the 141 and NTE low rev engines.
And the double or triple overdrive boxes I made some time ago would be more inefficient even, something what
Renault even did with its V8 Mack engined AE’s triple overdrives in about ±1990 till 2005.
Eric,
tiptop495:
robert1952:
‘Under geared’ or just appropriately geared? ERF’s chief engineer said: ‘This gave us two benefits. We gained about two per cent efficiency changing from the overdrive box; also, by using a numerically lower ratio axle, further gains were made in mechanical efficiency.’ This led to a policy of standardising on direct top gearboxes for all models, including the NGC, with suitably higher ratio rear axles.
The net result was a comfortable ride with not too much noise for the day and a lorry that could reliably go all day for several years. The piece in the yellow inset (see card below) very much describes what erstwhile drivers have told me, and matches my own experience when travelling in KCH. Robert
Hey,
You have right Robert, A direct top gear is Always more efficient as an overdrive, but from about ±2000 you saw come back some with overdrive because of withstand the high torque. Same an 13 speed RT is more efficient as an RTO 13.
And yes the NTC 335 was an old school engine but gave more torque at lower revs a many other even Scania’s V8.
I speak about end the sixties till mid seventies. Than you got the 141 and NTE low rev engines.
And the double or triple overdrive boxes I made some time ago would be more inefficient even, something what
Renault even did with its V8 Mack engined AE’s triple overdrives in about ±1990 till 2005.
Eric,
Ah! Then if the 335 had high torque at low revs, that would entirely justify the gearing and would also explain why the NGC sailed along without any bluster in top. It’s beginning to sound as if the chief engineer knew his onions after all! Robert
robert1952:
tiptop495:
robert1952:
‘Under geared’ or just appropriately geared? ERF’s chief engineer said: ‘This gave us two benefits. We gained about two per cent efficiency changing from the overdrive box; also, by using a numerically lower ratio axle, further gains were made in mechanical efficiency.’ This led to a policy of standardising on direct top gearboxes for all models, including the NGC, with suitably higher ratio rear axles.
The net result was a comfortable ride with not too much noise for the day and a lorry that could reliably go all day for several years. The piece in the yellow inset (see card below) very much describes what erstwhile drivers have told me, and matches my own experience when travelling in KCH. Robert
0
Hey,
You have right Robert, A direct top gear is Always more efficient as an overdrive, but from about ±2000 you saw come back some with overdrive because of withstand the high torque. Same an 13 speed RT is more efficient as an RTO 13.
And yes the NTC 335 was an old school engine but gave more torque at lower revs a many other even Scania’s V8.
I speak about end the sixties till mid seventies. Than you got the 141 and NTE low rev engines.
And the double or triple overdrive boxes I made some time ago would be more inefficient even, something what
Renault even did with its V8 Mack engined AE’s triple overdrives in about ±1990 till 2005.
Eric,
Ah! Then if the 335 had high torque at low revs, that would entirely justify the gearing and would also explain why the NGC sailed along without any bluster in top. It’s beginning to sound as if the chief engineer knew his onions after all! Robert
The point is that the chief engineer just made the choice between low final drive and over drive box v direct drive box and higher final drive and chose the latter.‘But’ what ‘actually’ happened in reality was that it didn’t get the higher final drive part of that equation.That’s why it ended up running on the engine governor at 92 kmh in total contradiction with the idea of making any use whatsoever of that great torque output in top gear.
As for the low final drive and over drive box combination the advantage is that it provides more flexibility in retaining the low final drive for hauling heavy weights in severe terrain and therefore less gear shifting required together with fuel efficient normal motorway use performance.The problem with the NGC being that it combined neither the direct box/high diff route or the over drive box/low diff one.Just combining low box with low diff.
Hence a brilliant niche heavy haulage wagon which would be ideally geared for running at heavy weights at relatively low speeds.But would equally guzzle fuel like it’s going out of fashion when running at 80-90 kmh + in normal haulage operations.While being effectively useless for general UK haulage operations in the day without some serious drive line modifications regarding either final drive or gearbox or possibly even both.So now we might have more of a clue as to why the NGC wasn’t going to be any good here.IE slower than a Gardner 240 powered Atki with the fuel consumption of a V12 Detroit.
On that note I wouldn’t call running a turbo ■■■■■■■ on the governor at more than 2,000 rpm + at just 92 kmh ‘running without any bluster’.Nor would I guess that’s actually what the designer in question actually intended.With it being more likely that he slammed his office door swearing in a foul temper when they answered his question of you did what ■■?! with the gearing I’d called for.
They had 1200x20 tyres, an RTO9509 gearbox and a 4.71:1 final drive. Is that correct?
Carryfast:
robert1952:
tiptop495:
robert1952:
‘Under geared’ or just appropriately geared? ERF’s chief engineer said: ‘This gave us two benefits. We gained about two per cent efficiency changing from the overdrive box; also, by using a numerically lower ratio axle, further gains were made in mechanical efficiency.’ This led to a policy of standardising on direct top gearboxes for all models, including the NGC, with suitably higher ratio rear axles.
The net result was a comfortable ride with not too much noise for the day and a lorry that could reliably go all day for several years. The piece in the yellow inset (see card below) very much describes what erstwhile drivers have told me, and matches my own experience when travelling in KCH. Robert
0
Hey,
You have right Robert, A direct top gear is Always more efficient as an overdrive, but from about ±2000 you saw come back some with overdrive because of withstand the high torque. Same an 13 speed RT is more efficient as an RTO 13.
And yes the NTC 335 was an old school engine but gave more torque at lower revs a many other even Scania’s V8.
I speak about end the sixties till mid seventies. Than you got the 141 and NTE low rev engines.
And the double or triple overdrive boxes I made some time ago would be more inefficient even, something what
Renault even did with its V8 Mack engined AE’s triple overdrives in about ±1990 till 2005.
Eric,
While being effectively useless for general UK haulage operations in the day without some serious drive line modifications regarding either final drive or gearbox or possibly even both.So now we might have more of a clue as to why the NGC wasn’t going to be any good here.
Now THAT’S an interesting observation. And I can see where you are coming from. You will remember a page or two back I reported a letter in one of the magazines quoting a conversation between Peter Foden and a customer who wanted to buy a substantial number of UK-spec NGCs and Mr Foden wasn’t interested. Let’s look at what the most successful examples did: those that did several trouble-free years on the Middle-East run, for example. They would have shipped to Calais run at speeds of around 50mph on European motorways, less on the ‘Nationals’. Once into the Balkans or Eastern Europe the speeds would have dropped considerably and stayed low on average traversing Turkey and the rest of the Middle East where roads were pretty grim in the '70s. They were doing this at exactly the time ‘Destination Doha’ was filmed so you can get a really good impression of what the average Vijore NGC was doing. The NGC would have been fine on those runs but not so brilliant up the M1 on a Friday night (better than a Gardner though because it had a turbo, remember! ). Robert
[zb]
anorak:
They had 1200x20 tyres, an RTO9509 gearbox and a 4.71:1 final drive. Is that correct?
EDIT:
1200x20 tyres; RT9095A with 4.64:1 final drive; then later in 1975 the RT9509 with 4.71:1 final drive. Remember that the suffix A simply denotes a different set of ratios. These figures are borne out by the successive NGC brochures issued by ERF over a period of years. I have some of them but not all. Robert
CF’s comment about UK-spec NGCs reminds me that this rather odd gearing, instigated to prevent abuse of the driveline, probably accounts for ERF’s refusal to supply NGCs to UK operators in the first two years; as well as its refusal to sell a UK-spec version for domestic use.
I earlier quoted these figures for the Ardenne test route:
ERF NGC: 5.23 mpg
Saviem SM340: 5.14 mpg
Scania LB 140S: 5.19 mpg
Merc 1932S: 5.63 mpg
DAF 2800 DKS: 6.12 mpg
Volvo F89.32: 5.38 mpg
In the light of the findings of the last two pages, I wonder what the readings would have been for Friday night up the M1 from London to Birmingham in 1975? I well remember in the early '80s driving artics nose to tail at 70 mph was commonplace (13 mph on the hills of course but these were '70s machines!). Perhaps CF has a point. Robert
Robert
robert1952:
[zb]
anorak:
They had 1200x20 tyres, an RTO9509 gearbox and a 4.71:1 final drive. Is that correct?
EDIT:
1200x20 tyres; RT9095A with 4.64:1 final drive; then later in 1975 the RT9509 with 4.71:1 final drive. Remember that the suffix A simply denotes a different set of ratios. These figures are borne out by the successive NGC brochures issued by ERF over a period of years. I have some of them but not all. Robert
Another set of questions arises out of this move from one set of ratios to another. Was it to:
a) Make it easier for drivers because it changed the ‘U’-shift to an ‘H’-shift (highly doubtful, but that’s what it did)?
b) Improve fuel consumption?
c) Improve performance?
d) Raise the top speed?
Just a thought. Robert
I’ve just checked throught the Eurotest article. The gearbox was a direct top RT and the final drive ratio was 4.6:1, which gives a top speed of 94km/h.
[zb]
anorak:
I’ve just checked throught the Eurotest article. The gearbox was a direct top RT and the final drive ratio was 4.6:1, which gives a top speed of 94km/h.
That’s about right, then, given that the test vehicle would probably be in the best of condition. And actually, 59 mph is logical, given that they’d have to hold their own up the M2 from Dover! One can see perhaps where Peter Foden was coming from, when he assured his customer who wanted to buy a number of domestic-spec NGCs that he would not be building them for UK roads! It really is all beginning to fall into place. I’ve been agonising for the last few years over why ERF dragged its heels over availability here in the UK both in the books and on this thread. Now it seems quite clear: the NGC was designed for Continental (and trans-Continental) use, not for the M1/M6. Damned interesting couple of days on here, I’d say! Thanks to all contributors (Carryfast, Dean, Eric, Anorak) for your sterling work 
. And I’m sure other factors will arise to confound us ere long! Robert
robert1952:
Now THAT’S an interesting observation. And I can see where you are coming from. You will remember a page or two back I reported a letter in one of the magazines quoting a conversation between Peter Foden and a customer who wanted to buy a substantial number of UK-spec NGCs and Mr Foden wasn’t interested. Let’s look at what the most successful examples did: those that did several trouble-free years on the Middle-East run, for example. They would have shipped to Calais run at speeds of around 50mph on European motorways, less on the ‘Nationals’. Once into the Balkans or Eastern Europe the speeds would have dropped considerably and stayed low on average traversing Turkey and the rest of the Middle East where roads were pretty grim in the '70s. They were doing this at exactly the time ‘Destination Doha’ was filmed so you can get a really good impression of what the average Vijore NGC was doing. The NGC would have been fine on those runs but not so brilliant up the M1 on a Friday night (better than a Gardner though because it had a turbo, remember! ). Robert
In the case of the M1 night run scenario the turbo is nothing but a hindrance because while it’s making plenty of unneccessary power it’s also blowing out loads of unburnt fuel that the engine hasn’t had the time to burn properly.While we’re also being overtaken by Gardner powered Atkis.Because we not only don’t have enough gearing to get the revs down to a decent level,to make use of the torque where the engine is able to use less fuel to greater effect,we also don’t have enough gearing to go any faster than 92 kmh.
We’re also going to be facing a similar situation in the case of the European motorway system.Although look on the bright side while we’re still using as much fuel as a V12 Detroit at least the Mercs etc won’t be overtaking us doing it. 
But at non Motorway speeds agreed it’s making more sense just as hauling heavy plant up the M1 would.
As for me if I was lucky enough to be running on general international work in the day I’d hopefully also have been lucky enough to have had a KW with a 400 NTA,or maybe even a Detroit 8v92TA,and RTO 13 speed geared for 65 mph at around 1,800 rpm. Then I could happily run at 60 mph + here and run at less than 1,800 rpm at 55 mph through Europe or even less after that.Not to mention leave the NGC standing on the hills of the Ardennes or in the Alps etc. But if I ever wanted to get into the heavy haulage scene then the NGC would have been at the top of my list.Suitably converted to 6x4 ballast tractor configuration. 
But seriously with the interesting further details on the topic I can now understand how the NGC was never going to make a big impression with the average haulage operation here.Mostly if not all because of it being crippled by under gearing.Which would have obviously involved some serious drive line changes,for anyone intending to use it here.In addition to it inevitably being a fuel consumption liability in its intended Euro market.
No surprise that,with the exception of heavy haulage operations,Peter Foden would have had to think up some fast diversionary excuses to brush off any domestic interest in that case.Although 4x2 tractor unit/rigid configuration obviously again wasn’t even ideal in the case of potential heavy haulage interest.
robert1952:
[zb]
anorak:
I’ve just checked throught the Eurotest article. The gearbox was a direct top RT and the final drive ratio was 4.6:1, which gives a top speed of 94km/h.
That’s about right, then, given that the test vehicle would probably be in the best of condition. And actually, 59 mph is logical, given that they’d have to hold their own up the M2 from Dover! One can see perhaps where Peter Foden was coming from, when he assured his customer who wanted to buy a number of domestic-spec NGCs that he would not be building them for UK roads! It really is all beginning to fall into place. I’ve been agonising for the last few years over why ERF dragged its heels over availability here in the UK both in the books and on this thread. Now it seems quite clear: the NGC was designed for Continental (and trans-Continental) use, not for the M1/M6. Damned interesting couple of days on here, I’d say! Thanks to all contributors for your sterling work . And I’m sure other factors will arise to confound us ere long! Robert
Realistically no one then or now would ideally have used maximum peak power engine speed as the reference to base the intended maximum road speed figure on at least in the case of a turbo ■■■■■■■■■■■■■■■■ understandable in the case of much lower torque/power outputs when ironically manufacturers often did the exact opposite in the form of over gearing it such as in the case of the DAF 2500.While that final drive ratio in no way meets the design definition of direct drive gearbox compensated for with ‘higher’ final drive.On that basis the NGC was under geared regardless of market.Which leaves the question why would an assembler want to limit their options regarding the offering of any particular drive line configuration.In which case a UK spec NGC would still have been doable with just a RHD option and a transmission spec option of RTO 9 speed ?.The resulting fuel consumption improvement no doubt then being noticed in the Euro market.The idea of a fixed transmission spec line up defeats the advantages of the assembly operation model and raises as many questions as it answers in this case.
I wonder why Van Steenbergen and Guwez commissioned RTO9509 'boxes, then. Perhaps ERF allowed this kind of request. Or perhaps they were retrofitted: after all the other Belgian users of NGCs boldly chose their replacement gearboxes: look at De Meulemeester and Eyckmanns for example with their 13-speed Fullers. We can’t rule out the possibility that the information is incorrect, but I prefer not to doubt my sources too hastily! Robert
A useful snippet from the 1977 Euro Test (TRUCK mag) which includes units from previous tests. Speaks for itself! Robert
robert1952:
Another set of questions arises out of this move from one set of ratios to another. Was it to:
a) Make it easier for drivers because it changed the ‘U’-shift to an ‘H’-shift (highly doubtful, but that’s what it did)?
b) Improve fuel consumption?
c) Improve performance?
d) Raise the top speed?
Just a thought. Robert
If I’ve got it right U v H shift pattern denotes RTO v RT ?.While top always remains direct in the case of RT regardless ?.
While changing intermediate ratios can change the shift points enabling earlier upshifts in the case of shorter ratios and possibly allowing faster in gear acceleration through the gears from rest and/or when climbing a gradient.While higher intermediate gears realistically just creates later shift points and relatively slower acceleration and at worse more clutch slippage.
While depending on the torque curve and/or final drive ratio a higher top gear ( over drive ) can mean higher top speed for a given rpm just as it can mean lower rpm for a given speed.While there is a point where higher gearing in whatever form creates over gearing.In which case the vehicle won’t reach its peak power rpm on the flat or at least takes forever to get there and is hopeless at the first sign of a gradient or head wind.The definition of over drive often being accepted as meaning an over geared situation in which the vehicle is actually faster in the gear below it being direct drive.Which doesn’t seem to make much sense if an over drive ratio is used to compensate for a very low final drive.In which case it’s possible that over drive top gear will also provide a higher road speed than the direct ratio below it.Which I’d guess would be the case in the case of the NGC using the RTO 9 or 13 speed with the stated final drive.
robert1952:
[zb]
anorak:
They had 1200x20 tyres, an RTO9509 gearbox and a 4.71:1 final drive. Is that correct?
EDIT:
1200x20 tyres; RT9095A with 4.64:1 final drive; then later in 1975 the RT9509 with 4.71:1 final drive. Remember that the suffix A simply denotes a different set of ratios. These figures are borne out by the successive NGC brochures issued by ERF over a period of years. I have some of them but not all. Robert
Hey, It looks that later even was used still a bit slower ratio, which made it even a little bit slower !!!
And would the latter box not be called RT9509C as in the Transcontinental ■■? Which had a slower crawler and
a wider gap between 4th and 5th which paved the way to use more the high crawler.
Eric,
