ramone:
So on that basis why did ■■■■■■■ need over 14 litres to produce 270 bhp when the TL12 was producing 273 from 12.47 and Volvo up to 360 bhp with a 9.6 all pretty irrelevant to me , its how the reliability fuel consumption and performance figures stack up
AV691 AV760 would have been more comparable to the 220 ■■■■■■■ which i thought entered the Uk in 180/205/220 hp
At the end of the day Leyland ended up with an almost 12.5 litre motor putting out less power and torque than a smaller capacity 1959 ■■■■■■■ development.As you rightly suggested yourself.
It’s inconcievable that they ended up with that output by choice as opposed to being forced to settle on that based on the durability equation.Because to meet the equivalent torque by definition had to come at the expense of pushing more load through the con rod v ■■■■■■■ or Rolls.
Just as the TL12 didn’t cut it v ■■■■■■■■■■■■■ in the Marathon and T45.
It’s obvious that ■■■■■■■ had no intention of upgrading to the 14 litre just to stay in the sub 300 hp bracket.Also bearing in mind that the 743 and 855 were actually produced concurrently with the 220 development introduced after the first larger bore 855 was made.
While the NFC engineers’ valid comments are the smoking gun in all cases regarding trying to get a quart out of a pint pot.
In which case we can arguably disregard sub the 10 litre category as being inherently flawed being too small and therefore over stressed.Obviously relatively less so in the case of the Volvo than the Leyland 500.Also confirmed by Gingerfold’s correct view that the 500 should have been discarded from the start.
While AEC’s leverage at the crank limitations crippled Leyland’s essential need to trump ■■■■■■■ and Rolls and the TD120 if it wanted to maintain an in house engine programme.
The modern day Paccar MX 11’s and 13’s 123 x 152 and 130 x 162 architecture is where Leyland needed to be before the introduction of the T45.At which point we’re in business.
The L12 came about because Leyland realised some of their customers were dead against turbocharged engines. The L12 was a non turbocharged version of the TL12 which was designed for turbocharging and which has been explained to me as the reason the L12 was down on power . The AV760 was the more powerful of the two engines . If the E290 had been marketed without a turbo maybe you would get similar outputs.
ramone:
The L12 came about because Leyland realised some of their customers were dead against turbocharged engines. The L12 was a non turbocharged version of the TL12 which was designed for turbocharging and which has been explained to me as the reason the L12 was down on power . The AV760 was the more powerful of the two engines . If the E290 had been marketed without a turbo maybe you would get similar outputs.
The 760 v L12 is an interesting comparison and actually adds weight to the idea of Leyland having doubts over the 760’s durability at high outputs.
The latter had no peak torque advantage at all over the 691.It also had an 88 lbft torque drop at 2,200 rpm from its 573 peak the 691 marginally less.
Ironically the larger bore 14 litre 250 ■■■■■■■ also had a less than 10% increase in specific torque for a more than 16% increase in engine capacity over the 220.
While the larger bore 760 had a slightly lower specific torque output than the 691.
While in all cases it seems to follow the rule add around 30% for turbocharging + potentially much more with intercooling whether Rolls 220 or ■■■■■■■ 220, or ■■■■■■■ 250 or Leyland L12.
Which leaves the question why would Leyland not have wanted to maintain the 760 for remaining NA customers and why doesn’t the TL12’s output seem to follow the 30% rule over the 760’s output as opposed to the L12’s.
It’s obvious that the TL12 was a ( necessarily ? ) derated design to the point where it was predictably not fit for purpose v Rolls, ■■■■■■■■ Volvo and even DAF.
Especially if an intercooler had been added.
Not seeing anything here which would affect a basic premise that leverage at the crank is ( much ) more important than bore size and that was the basic failing of the 760/L12/TL12.
Also seemingly confirmed by modern ■■■■■■■ and MX and Volvo type architectures at least.
As for not aborting the 500 at the drawing board stage it’s all too much to believe ■■■■ up not conspiracy.
The “techno-geeks” can theorise and pontificate as much as they want. The proof of the pudding, so to speak, was in the engine’s performance and its whole-life reliability, and operating costs. Irrespective of what ‘leverage’ it had at the crankshaft or not. The TL12 scored heavily on ALL operational parameters and it was definitely more reliable than the Rolls Royce. Absolute fact, Carryfast, and you cannot disprove it. Again I will quote the late, very knowledgeable Pat Kennett, who by the way was a fully trained and qualified engineer. He said about the TL12, “Scottish operators, some of the most demanding and critical hauliers in the business, rate the TL12 very highly”.
gingerfold:
The TL12 scored heavily on ALL operational parameters and it was definitely more reliable than the Rolls Royce. Absolute fact, Carryfast, and you cannot disprove it. Again I will quote the late, very knowledgeable Pat Kennett, who by the way was a fully trained and qualified engineer. He said about the TL12, “Scottish operators, some of the most demanding and critical hauliers in the business, rate the TL12 very highly”.
The idea that the L12 and TL12 was actually superior to the Rolls Eagle/Perkins TX in all its variants.That’s a very big sell.Rolls definitely had a more than credible contender to the TD120 in that package.
ramone:
The L12 came about because Leyland realised some of their customers were dead against turbocharged engines. The L12 was a non turbocharged version of the TL12 which was designed for turbocharging and which has been explained to me as the reason the L12 was down on power . The AV760 was the more powerful of the two engines . If the E290 had been marketed without a turbo maybe you would get similar outputs.
The 760 v L12 is an interesting comparison and actually adds weight to the idea of Leyland having doubts over the 760’s durability at high outputs.
The latter had no peak torque advantage at all over the 691.It also had an 88 lbft torque drop at 2,200 rpm from its 573 peak the 691 marginally less.
Ironically the larger bore 14 litre 250 ■■■■■■■ also had a less than 10% increase in specific torque for a more than 16% increase in engine capacity over the 220.
While the larger bore 760 had a slightly lower specific torque output than the 691.
While in all cases it seems to follow the rule add around 30% for turbocharging + potentially much more with intercooling whether Rolls 220 or ■■■■■■■ 220, or ■■■■■■■ 250 or Leyland L12.
Which leaves the question why would Leyland not have wanted to maintain the 760 for remaining NA customers and why doesn’t the TL12’s output seem to follow the 30% rule over the 760’s output as opposed to the L12’s.
It’s obvious that the TL12 was a ( necessarily ? ) derated design to the point where it was predictably not fit for purpose v Rolls, ■■■■■■■■ Volvo and even DAF.
Especially if an intercooler had been added.
Not seeing anything here which would affect a basic premise that leverage at the crank is ( much ) more important than bore size and that was the basic failing of the 760/L12/TL12.
Also seemingly confirmed by modern ■■■■■■■ and MX and Volvo type architectures at least.
As for not aborting the 500 at the drawing board stage it’s all too much to believe ■■■■ up not conspiracy.
Why wasn’t the TL12 fit for purpose ? Was it unreliable … No…p Was it heavy on fuel … No … Was it a slow ponderous performer … No … So what evidence do you have of it being not fit for purpose. If it was any of the aforementioned you may have had a case but none of them applied to the TL12
ramone:
Why wasn’t the TL12 fit for purpose ? Was it unreliable … No…p Was it heavy on fuel … No … Was it a slow ponderous performer … No … So what evidence do you have of it being not fit for purpose. If it was any of the aforementioned you may have had a case but none of them applied to the TL12
What was its fuel consumption at over the 1,200 lbft and 300 hp mark.We don’t know because it never even got there to find out.
How did it perform relative to the TD120 or even DAF DKS.Skip that question.
Which engines saw the the T45 out of production and what was their respective outputs here’s a clue it wasn’t the TL12.
I’m sure that Pat Kennet would have given credit where it was due and reviewed his comments regarding the TL12’s potential.Or for that matter given some thought to the question of conspiracy not ■■■■ up regarding what happened to the UK truck manufacturing industry if he’d have read this.
ramone:
Why wasn’t the TL12 fit for purpose ? Was it unreliable … No…p Was it heavy on fuel … No … Was it a slow ponderous performer … No … So what evidence do you have of it being not fit for purpose. If it was any of the aforementioned you may have had a case but none of them applied to the TL12
What was its fuel consumption at over the 1,200 lbft and 300 hp mark.We don’t know because it never even got there to find out.
How did it perform relative to the TD120 or even DAF DKS.Skip that question.
Which engines saw the the T45 out of production and what was their respective outputs here’s a clue it wasn’t the TL12.
I’m sure that Pat Kennet would have given credit where it was due and reviewed his comments regarding the TL12’s potential.Or for that matter given some thought to the question of conspiracy not ■■■■ up regarding what happened to the UK truck manufacturing industry if he’d have read this.
What on earth are you going on about . What has a F12 engine got to do with the TL12 or a Daf engine . The statement you made was the TL12 wasnt fit for purpose , explain why , not compare wirh totally irrelevant engines. If it wasn’t fit for purpose there would have been big problems in service which there wasn’t. Did it actually perform worse than the E290 which was infact a 272hp motor . Check the roadtests and see which came out on top . One well known haulier on here admitted he wouldn’t touch the big cam ■■■■■■■ because they were too thirsty for his opperation . Running a transport operation you have got to take into account costs and fuel was a big factor and the TL12 proved frugal on that point just as it did on reliability and performance .
gingerfold:
The TL12 scored heavily on ALL operational parameters and it was definitely more reliable than the Rolls Royce. Absolute fact, Carryfast, and you cannot disprove it. Again I will quote the late, very knowledgeable Pat Kennett, who by the way was a fully trained and qualified engineer. He said about the TL12, “Scottish operators, some of the most demanding and critical hauliers in the business, rate the TL12 very highly”.
The idea that the L12 and TL12 was actually superior to the Rolls Eagle/Perkins TX in all its variants.That’s a very big sell.Rolls definitely had a more than credible contender to the TD120 in that package.
As for the 500 at least we can agree on that.
I will agree with you that by the 1980s the Rolls Royce engine had become reliable and quite well-regarded, but it had taken 3 re-workings, overseen by former AEC man Keith Roberts to achieve that,from the original Eagle version. Rewind to the mid-1970s when the TL12 had become established and compare the RR engines of that period, then the TL12 wins hands-down for reliability. The NA version of the Eagle was offered in the Marathon as the low power alternative to appeal to Big J operators. The TL12 was dropped from the Roadtrain line-up in 1983 for two reasons; firstly Leyland deemed it more cost effective to buy-in engines given that the TL12 production machinery had been brought to Leyland from Southall and it needed capital investment to replace it, which BL didn’t have. As a corollary to that, and it’s a chicken and egg situation, senior management decided that the future was with bought-in engines… a situation which would change completely in due course when the market went in the other direction with vertically integrated manufacturing.
ramone:
What on earth are you going on about . What has a F12 engine got to do with the TL12 or a Daf engine . The statement you made was the TL12 wasnt fit for purpose , explain why , not compare wirh totally irrelevant engines.
How are two of its major competitors supposedly ‘irrelevant’.
So you’re saying that the DAF 2800/3300 and F12 wasn’t a competitor to the Marathon or T45 Roadtrain.
Or the 220 ■■■■■■■ or Rolls wasn’t a relevant competitor to the L12.
You’re just being silly now.The fact is the thing was soundly beaten into being an irrelevance itself by the 680 based DAF DK motor let alone the TD120 or Rolls Eagle all of smaller capacity.But unlike the 500 not too small.That type of stupid takes planning and deliberation.
ramone:
What on earth are you going on about . What has a F12 engine got to do with the TL12 or a Daf engine . The statement you made was the TL12 wasnt fit for purpose , explain why , not compare wirh totally irrelevant engines.
How are two of its major competitors supposedly ‘irrelevant’.
So you’re saying that the DAF 2800/3300 and F12 wasn’t a competitor to the Marathon or T45 Roadtrain.
Or the 220 ■■■■■■■ or Rolls wasn’t a relevant competitor to the L12.
You’re just being silly now.The fact is the thing was soundly beaten into being an irrelevance itself by the 680 based DAF DK motor let alone the TD120 or Rolls Eagle all of smaller capacity.But unlike the 500 not too small.That type of stupid takes planning and deliberation.
Beaten ■■? How ? The 220 Rolls and ■■■■■■■ weren"t about when the L12 was launched , the F10 was the competion and a Daf up to 280 bhp not a 320 plus F12 . Did no one ever buy TL12s do the road test figures and in service reports lie … 9h dont bother we’ve been down that road before with your aquisations of conspiracy and fudging the figures
It’s now also time to bury the mis-truth that the DAF 2800 engine was based on the Leyland O.680. It wasn’t. The only Leyland engine that DAF actually used was the O.350 in the 1950s. DAF did use some Leyland expertise and know-how in a consultancy capacity, but to say that the O.680 was the basis of larger DAF engines is complete bollox, akin to the myth that the Scania V8 was based on the AEC V8.
Thanks for posting those Dean , it just goes to show what a terrible unfit for purpose engine the TL12 was. It may have completed the course with a higher average speed and went up the hills slightly faster but hey ho that means nothing. The E290 needed to be driven carefully to get the best out of it and that’s what the testers did. It was higher geared to keep the mpg figures looking good at the expense of uphill speed. Don’t get me wrong the E290 was a very good engine but so was the TL12 . The stats don’t lie , no doubt a conspiracy theory will be in the pipeline. 14 litre E290 12.47 litre AEC TL12
Carryfast:
You’re just being silly now.The fact is the thing was soundly beaten into being an irrelevance itself by the 680 based DAF DK motor let alone the TD120 or Rolls Eagle all of smaller capacity.But unlike the 500 not too small.That type of stupid takes planning and deliberation.
Beaten ■■? How ? The 220 Rolls and ■■■■■■■ weren"t about when the L12 was launched , the F10 was the competion and a Daf up to 280 bhp not a 320 plus F12 . Did no one ever buy TL12s do the road test figures and in service reports lie … 9h dont bother we’ve been down that road before with your aquisations of conspiracy and fudging the figures
How do you make the TD 100 the relevant competitor to the 12.5 litre TL12.
You also seem to have conveniently missed the DKS version of the DAF motor.So your motor can’t handle the competition just downgrade that competition until you find the right output to meet your inferior design.Let’s totally ignore the capacity comparison and what the competition have actually got ranged against us.
As for the L12.What evidence are you going by that the NA ■■■■■■■ 743 versions and Rolls 220 weren’t still in the game at that point.Bearing in mind the Eagle Mk111 was introduced in 1973 and the NA version still listed within that range.
gingerfold:
It’s now also time to bury the mis-truth that the DAF 2800 engine was based on the Leyland O.680. It wasn’t. The only Leyland engine that DAF actually used was the O.350 in the 1950s. DAF did use some Leyland expertise and know-how in a consultancy capacity, but to say that the O.680 was the basis of larger DAF engines is complete bollox, akin to the myth that the Scania V8 was based on the AEC V8.
This thread has some more information about the progress of DAF’s 11.6 litre engine:
ramone:
Thanks for posting those Dean , it just goes to show what a terrible unfit for purpose engine the TL12 was. It may have completed the course with a higher average speed and went up the hills slightly faster but hey ho that means nothing. The E290 needed to be driven carefully to get the best out of it and that’s what the testers did. It was higher geared to keep the mpg figures looking good at the expense of uphill speed. Don’t get me wrong the E290 was a very good engine but so was the TL12 . The stats don’t lie , no doubt a conspiracy theory will be in the pipeline. 14 litre E290 12.47 litre AEC TL12
The 14 litre ■■■■■■■ wasn’t at its best at such low outputs who would have thought it.
Your stats don’t look so good when the marketing department sends you a memo asking for a 300 hp + version of your 12.5 litre boat anchor to match the Rolls or DKS or F12 or ■■■■■■■ 320.
Or in the case of the Buffalo the customer walks away when the insult of a 12.5 litre motor with less than 600 lbft is added to the injury of the 500.
No problem we’re going with a production life of only around 5 years at most we’ll just make another motor that’s up to the job when the time comes.
Then people ask why Leyland failed.Blame it on the workers it was their fault.
gingerfold:
It’s now also time to bury the mis-truth that the DAF 2800 engine was based on the Leyland O.680. It wasn’t. The only Leyland engine that DAF actually used was the O.350 in the 1950s. DAF did use some Leyland expertise and know-how in a consultancy capacity, but to say that the O.680 was the basis of larger DAF engines is complete bollox, akin to the myth that the Scania V8 was based on the AEC V8.
The 680 was actually used in the 2600.
Ironically it’s obvious that whatever DAF did with the DK it’s a lot closer to the 680’s than the either the 691’s let alone the 760’s architecture to the tune of just adding 3mm to the 680’s bore size.
As for Scania V8 v AEC V8 that would obviously have wrecked Scania’s plans just as, or even more than, a 691 or 760, not 680, based DK would have wrecked DAF’s.
Some say the Mack V8’s design played a part in Scania’s design but even that is unlikely.
The fact that both the MX 11 and the 15 litre ■■■■■■■ ISX went for smaller bore sizes than their DK and N14 predecessors respectively and even the MX13 didn’t increase bore size over the 11.6 DK’s is a clue.
I’ve finally discovered the reason for all this vitriol CF has for AEC, Gardner and Foden. It was the trauma he suffered when he first spat his dummy out of his pram, after the yankee excavator which he had been so avidly watching had a screaming engine runaway and expired in a cloud of oil and smoke, and then saw his dummy first run over by a London bus, and then two Fodens; one which which sounded remarkably similar to the now deceased excavator and the other which had a much deeper pitch and tempo.
Poor mite he’s never recovered from the sight and re- lives it in regular nightmares.
cav551:
I’ve finally discovered the reason for all this vitriol CF has for AEC, Gardner and Foden. It was the trauma he suffered when he first spat his dummy out of his pram, after the yankee excavator which he had been so avidly watching had a screaming engine runaway and expired in a cloud of oil and smoke, and then saw his dummy first run over by a London bus, and then two Fodens; one which which sounded remarkably similar to the now deceased excavator and the other which had a much deeper pitch and tempo.
Poor mite he’s never recovered from the sight and re- lives it in regular nightmares.
I’ve already said that AEC engines belong in London buses and medium weight trucks but have no place in anything over 24 tonnes maybe a 50’s/60’s 8 wheeler with a two axle trailer being the exeption which proves the rule.
While from experience Fodens were great users of Rolls Eagle engines and even the Leyland 680.So no complaints there either.
As for excavators I think the CAT 3406 was one of the best truck engines ever made and and like the Rolls and ■■■■■■■ certainly made more specific torque than the TL12 without going bang in a big way.
I think we’re talking about the trauma of flying shrapnel embedding itself in the surroundings in that case if Leyland ever had the bottle to try it rather than just a bit of oil and smoke.
