ramone:
So ut was the L12 and not the TL12 that was the anchor?
They were both an obvious reflection of each other.The L12 being as expected of an NA version of the TL12.As opposed to Rolls Eagle 220 and 280/305 respectively.
As for following the Mack’s design cues. 127 x 158 and inter cooled from the start was where they needed to be to translate that into a 12 litre package.Easily doable without needing to change the bore centre lines of the 590-760 with a wider skirt and main bearing position casting.That would have been a formidable motor.
While predictably the Mack 673’s 123 x 152 is the same dimensions of today’s Paccar MX11.
ramone:
So ut was the L12 and not the TL12 that was the anchor?
They were both an obvious reflection of each other.The L12 being as expected of an NA version of the TL12.As opposed to Rolls Eagle 220 and 280/305 respectively.
As for following the Mack’s design cues. 127 x 158 and inter cooled from the start was where they needed to be to translate that into a 12 litre package.Easily doable without needing to change the bore centre lines of the 590-760 with a wider skirt and main bearing position casting.That would have been a formidable motor.
While predictably the Mack 673’s 123 x 152 is the same dimensions of today’s Paccar MX11.
Cylinder pressures in the 1970s did not demand such an undersquare design as the Maxidyne. As we have discussed many times before, even overquare engines existed quite happily alongside more ordinary types. Sure, the Mack engineers have been proved “right”, if similarity to engines 50 years hence is your criterion. As it was at the time, the Maxidyne was no more successful in the marketplace than the others.
Carryfast:
Not according to Gingerfold.It was a new design with little in common with the 760.
( Obviously other than its crippled 590 based engine block dimensions ).
If this was so ‘crippled’ perhaps you would like to tell us all why your heroes, Detroit Diesel, first introduced their 60 series engine as an 11.1 litre with an even more ‘crippled’ “architecture” of 130x139 -
actually worse then the AEC 11.3L at 130x142.They came up with this too in 1987 not 1954. In spite of this unforgiveable sin they got 365 bhp and 1350 lbft of torque out of it. They achieved this torque figure without any ‘shrapnel’ from broken connecting rods either.
Ironically the 11.1 Detroit was far more popular in the less stressed environment of buses.
Leaving the question if the 11.1 was the way forward for Detroit why bother with the 12.7 version produced consecutively with the 11.1 and why was the 11.1 discontinued 10 years before the 12.7’s 20 year production run ended.
Remind me how they obtained the extra 1.6 litres in the 12.7.
The 11.1 never made more than 1,250 lb/ft and 350 hp at 1,800 rpm and it’s obvious that yes the thing would have been a grenade waiting to go off at the type of boost pressures needed to obtain that with a 139 mm stroke.Which is probably why bus operators were ok with it until Detroit rightly gave them the choice of take the 12.7 or leave it from '97.
Then got on with introducing the 133 x 168 14 litre version.
I’m not seeing AEC’s thought process in action there and strange that you’ve selectively left out the 12.7 and 14 litre progressions in that comparison.Which sort of contradicts your point while adding weight to mine.
As for my heroes no I’d prefer the pushrod MX.It’s all about objectivety not loyalty to any particular brand.
Carryfast:
As for following the Mack’s design cues. 127 x 158 and inter cooled from the start was where they needed to be to translate that into a 12 litre package.Easily doable without needing to change the bore centre lines of the 590-760 with a wider skirt and main bearing position casting.That would have been a formidable motor.
While predictably the Mack 673’s 123 x 152 is the same dimensions of today’s Paccar MX11.
Cylinder pressures in the 1970’s did not demand such an undersquare design as the Maxidyne. As we have discussed many times before, even overquare engines existed quite happily alongside more ordinary types. Sure, the Mack engineers have been proved “right”, if similarity to engines 50 years hence is your criterion. As it was at the time, the Maxidyne was no more successful in the marketplace than the others.
It’s obvious that less leverage means more cylinder pressure and/or piston area, both also with corresponding loads required to be transmitted from the piston to the crank shaft, to obtain the equivalent torque output.
So when you tighten up a truck’s wheel nuts do you use a spanner or a bleedin long bar and if you do try to use a spanner you’ll obviously damage your wrist or arm etc before you’ve finished the job.
That’s why Mack’s designers were using a 6 inch stroke in an 11 litre motor in 1973 just as the MX’s designers are doing same today.
ramone:
So ut was the L12 and not the TL12 that was the anchor?
They were both an obvious reflection of each other.The L12 being as expected of an NA version of the TL12.As opposed to Rolls Eagle 220 and 280/305 respectively.
As for following the Mack’s design cues. 127 x 158 and inter cooled from the start was where they needed to be to translate that into a 12 litre package.Easily doable without needing to change the bore centre lines of the 590-760 with a wider skirt and main bearing position casting.That would have been a formidable motor.
While predictably the Mack 673’s 123 x 152 is the same dimensions of today’s Paccar MX11.
newmercman:
Again we fail to understand what the TL12 was designed, built and sold for. It was never meant to be groundbreaking, never meant to win Top Trumps
^ Exactly and that was the problem.Unless your definition of ‘required of it’ is to be behind just about every competitor out there and go large with a 12.5 litre anchor to do it.
As for the car division it was actually the profits made by JRT that were keeping the whole tottering mess afloat from front wheel drive BMC junk to 500 and AEC bus engined trucks.The Buffalo being a prime example having actually got the full house of dumb and dumber motors under its cab.
No surprise we had the on message media praising Issigonis’ and the AEC’s efforts and even the ‘ground braking’ design of the 500.They couldn’t make it up.
While no one was bright enough or brave enough to question the obvious flaws contained in both.Let’s blame the workers at JRT and Scammell instead.It’s their fault.
For someone who is noted for writing rubbish that statement is just about your crowning glory. It is in the public domain that the profits from Truck and Bus division were more than swallowed up by the car division, that included Jaguar, Rover and Triumph which were all part of BMH which was taken over by the Leyland Motors Group under pressure from Harold Wilson’s government because it was “protecting” jobs in the car industry. I’m surprised that you, a Jaguar car lover, has not got the official Sir William Lyons biography in pride of place on your book shelves; it goes into some detail about the forced merger of BMH and Leyland, and I re-read that particular chapter last night just to check the facts.
Until Sir William Lyons retired in 1972, and uniquely in the car division of the group, Jaguar reported its annual financial results separately. This was at the insistence of Sir William. These financial results included Guy and Daimler. Until 1972 the Jaguar group was showing an annual profit, typically some 5% of turnover. Guy was marginally profitable, it always struggled for profits throughout its existence, and Daimler was profitable, on the back of an order for 1,100 Fleetline buses it was supplying to London Transport. No figures are quoted for Rover and Triumph.
What is also given prominence in the book for the period of late 1960s to early 1970s is the disruption Jaguar suffered in its supply chain through strikes in various companies it bought-in components from. Also mentioned is a lengthy strike by BRS drivers who delivered components to Jaguar. I don’t recall any details of that strike at all.
Carryfast:
But an engine introduced to the market in '73 will still need to be relevant in '83 - 88 if not later.
Eagle mk 111 305 1973 - Perkins TX 1990 -.
Volvo TD120 1970 - 1992.
Well the TL 's roots go back to the mid '60s
Not according to Gingerfold.It was a new design with little in common with the 760.
( Obviously other than its crippled 590 based engine block dimensions ).
I think the 590 was the 9.6 which they built alongside the 11.3 690/691 the TL was based but heavily developed from the 760
The A590 / A690 was a different design to the A691 / A 760. the former was a wet liner block, the latter was a dry liner block. The wet liner engines had a relatively short production life of 6 years, they were AEC’s first monobloc designs, replacing their traditional, and more expensive to produce, engines with separate crank cases and cylinder blocks.
Carryfast:
^ Exactly and that was the problem.Unless your definition of ‘required of it’ is to be behind just about every competitor out there and go large with a 12.5 litre anchor to do it.
As for the car division it was actually the profits made by JRT that were keeping the whole tottering mess afloat from front wheel drive BMC junk to 500 and AEC bus engined trucks.The Buffalo being a prime example having actually got the full house of dumb and dumber motors under its cab.
No surprise we had the on message media praising Issigonis’ and the AEC’s efforts and even the ‘ground braking’ design of the 500.They couldn’t make it up.
While no one was bright enough or brave enough to question the obvious flaws contained in both.Let’s blame the workers at JRT and Scammell instead.It’s their fault.
For someone who is noted for writing rubbish that statement is just about your crowning glory. It is in the public domain that the profits from Truck and Bus division were more than swallowed up by the car division, that included Jaguar, Rover and Triumph which were all part of BMH which was taken over by the Leyland Motors Group under pressure from Harold Wilson’s government because it was “protecting” jobs in the car industry. I’m surprised that you, a Jaguar car lover, has not got the official Sir William Lyons biography in pride of place on your book shelves; it goes into some detail about the forced merger of BMH and Leyland, and I re-read that particular chapter last night just to check the facts.
Until Sir William Lyons retired in 1972, and uniquely in the car division of the group, Jaguar reported its annual financial results separately. This was at the insistence of Sir William. These financial results included Guy and Daimler. Until 1972 the Jaguar group was showing an annual profit, typically some 5% of turnover. Guy was marginally profitable, it always struggled for profits throughout its existence, and Daimler was profitable, on the back of an order for 1,100 Fleetline buses it was supplying to London Transport. No figures are quoted for Rover and Triumph.
What is also given prominence in the book for the period of late 1960s to early 1970s is the disruption Jaguar suffered in its supply chain through strikes in various companies it bought-in components from. Also mentioned is a lengthy strike by BRS drivers who delivered components to Jaguar. I don’t recall any details of that strike at all.
Ironically as a Jaguar car lover ( with the exception that I don’t buy the idea that they couldn’t have got as much or more from the XK and V12 by making them both as simpler to maintain pushrod motors ) I also don’t buy the idea that Leyland were a bad thing for Jaguar bearing in mind that it was Leyland Group that put the XJ6 and XJ12 into production without which there wouldn’t have been a Jaguar for Thatcher to flog off.
As opposed to Lyons’ stupid idea of tying the firm to BMC and by association predictably being dragged down by Issigonis’ stupidity in the process before Leyland rescued the resulting mess.
As for JRT it was it’s profitability v BMC which was much of the reason why the group was actually split away from that sinking ship which should have been closed down.I’ve got numerous editions of Motor and Autocar from the day all stating the fact of JRT’s profitability if I can dig them out of the loft.Then it was decided that it would be a good idea to put them all back together again with predictable and obvious results.JRT’s profits being swallowed up by BMC’s losses.Just as happened before to Jaguar when Lyons thought it would be a good idea to do the same.
Against which you’ve provided no evidence to back your statement that JRT was part of the problem.While AEC’s contributions in the form of the V8 and L12/TL12 and the Leyland 500 were all heroic attempts to save the Group.
There were loads of strikes throughout the 1970’s including my employers at the time.All justified unless you want an economy with zero growth because wages aren’t being kept in line with prices.Including the scam whereby Triumph’s workers were forced to accept a fixed rate.Rather than the piecework rates which had, until then, made the firm a paragon of industrial content among its workforce.Then followed by Edwards thinking that it would be a good idea to turn over Rover and Triumph production to fwd badge engineered Hondas.What could possibly go wrong.
As for Jaguar car lover no with hindsight I could have saved a fortune over the years by keeping my old Triumph 2.5 saloon and putting a stroked 4 litre + Rover V8 in it.
Just like the factory could have done.But no Edwards decided to go for the Acclaim and dumber Honda based 820 to follow the dumb SD1 and allow the BMW 5 series to clean up that sector.Just as the truck division was sacrificed to the advantage of the foreign competition.
I’m not saying that Jaguar wasn’t profitable, I have shown that it was, but Sir William had taken the company into BMH, which he later admitted to regretting. As for Rover and Triumph, I wouldn’t know their profitability status. I do know that the Triumph TR6 I had was a good car and I wish I had kept it (along with my Lotus Cortina, but all car lovers can make similar claims).
The Leyland and BMH merger was forced through by the Wilson Government despite serious reservations by many senior directors at Leyland. Stokes was in favour because he was promised the top job as the head of the biggest vehicle company in the UK… flattering his ego.
There’s no doubt that the AEC V8 was a costly mistake, but only in the short term. Not enough were sold to destroy confidence in the company or its products. Totally different to the Leyland 500 series, which did seriously damage Leyland and knocked the confidence of its customers in Leyland products. (Digressing slightly I set on a casual driver a month ago, he’s 74 years old and drove a Mandator V8 for Leather’s Chemicals. Unprompted he told me it was a fantastic lorry for its time and better than anything else then on the road for journey times)
The TL12 did what it had to, that is provide Leyland with a reliable, relatively high powered engine (for the 1970s) and buy Leyland time to build a competitive new unit, but the T45 came about 5 years too late. The TL12 was produced on a shoe string budget and designing an engine for 15 years in the future wasn’t in the design brief given to Keith Roberts and his team. At the time BL was fighting to stay in business, it’s a miracle it survived as long as it did.
gingerfold:
The A590 / A690 was a different design to the A691 / A 760. the former was a wet liner block, the latter was a dry liner block. The wet liner engines had a relatively short production life of 6 years, they were AEC’s first monobloc designs, replacing their traditional, and more expensive to produce, engines with separate crank cases and cylinder blocks.
But they all had in common and retained the same 142 mm stroke measurement from 590 powered Routemaster bus to L12/TL 12 powered 32 tonner.Which suggests that everything other than the dry liner design was similar/same.There was no way of using the Mack’s bore/stroke ratio.
That then just takes the bravery of the designer/s to say I/we need a new block design to providing the clearance needed to accomodate the required crankshaft throw.
gingerfold:
The A590 / A690 was a different design to the A691 / A 760. the former was a wet liner block, the latter was a dry liner block. The wet liner engines had a relatively short production life of 6 years, they were AEC’s first monobloc designs, replacing their traditional, and more expensive to produce, engines with separate crank cases and cylinder blocks.
But they all had in common and retained the same 142 mm stroke measurement from 590 powered Routemaster bus to L12/TL 12 powered 32 tonner.Which suggests that everything other than the dry liner design was similar/same.There was no way of using the Mack’s bore/stroke ratio.
That then just takes the bravery of the designer/s to say I/we need a new block design to providing the clearance needed to accomodate the required crankshaft throw.
Or I/we resign.
…which brings us to the inevitable question: were you ever offered a design engineer’s role?
[zb]
anorak:
…which brings us to the inevitable question: were you ever offered a design engineer’s role?
Never just as I was never offered the role of PM or trade and industry minister.
You’ve been talking to engineers on this forum, in many different roles, for years now, and remain at odds with all of them, almost completely. I would vote for you as PM- I would love to see you and Donald working together.
[zb]
anorak:
You’ve been talking to engineers on this forum, in many different roles, for years now, and remain at odds with all of them, almost completely. I would vote for you as PM- I would love to see you and Donald working together.
It’s clear that understanding the link, between maximising the stroke/leverage of any engine design to maximise its torque output potential, is in no way ‘at odds’ with most accepted engineering practice out there.As it stands I’m in agreement with with numerous car and truck engine designers and more than a few after market modifiers on that.
The Rolls 220 might have looked good on paper but in service was unreliable and also thirsty with it. We had two in Foden eight wheelers when Gardner had supply issues but they were not good and no more were ordered until the 265’s came out.
