Splitting gears was a big improvement, but loyal customers had now seen what else was available.
The typical Mack owner needed the heavy rear end and quad box. Bog gear was so slow you didn’t use the clutch, just hit the stick and it would drop into gear.
The Maxidyne thinking was aimed more at the highway market and in that situation it worked.
But there were new kids on the block now and their offerings had quite a few comforts plus your choice of horsepower, drivetrain etc.
Heavy vehicle leasing also started to gain a foothold so owners moved to a price range they would not have previously considered.
Usually the US trucks, locally assembled KW and Western Star.
Forgot, no appreciable turbo lag, it was ready to go as soon as the next gear was in.
I think they continued injecting fuel with application of the engine brake to keep the turbine rpm’s up. (or some such trick)
Carryfast:
gingerfold:
Carryfast:
Thereby suggesting that the issue of in house as opposed to assembly and specialist engine suppliers is a red herring.It’s all about how good the product that comes out of the door is that matters.In Europe at the present time Mercedes is achieving considerably better mpg than any of its competitors, and fuel usage is an operator’s highest running cost. Mercedes is a loose engine supplier so if the above statement is true then why aren’t Volvo, Scania, DAF et al offering Mercedes as an option? Just a thought.
I thought the word was that all the major players including Mercedes are all about in house availability only.
Assuming that we’ve got a loose engine supplier producing a considerably more efficient and a reliable engine range and the cash reserves to maintain that position then that’s obviously likely to be a threat to those producers who are reliant on an in house only operation in the long term.Just as was the case with AEC v ■■■■■■■ and Rolls in the day.Just as I’ve said it’s the product that matters not the issue of in house production v assembly operations.
It’s just that unlike then we haven’t now got any assembly operations left to take advantage of the opportunity ‘if’ it’s correct.
Oh, and why is that then 
gingerfold:
Carryfast:
gingerfold:
Carryfast:
Thereby suggesting that the issue of in house as opposed to assembly and specialist engine suppliers is a red herring.It’s all about how good the product that comes out of the door is that matters.In Europe at the present time Mercedes is achieving considerably better mpg than any of its competitors, and fuel usage is an operator’s highest running cost. Mercedes is a loose engine supplier so if the above statement is true then why aren’t Volvo, Scania, DAF et al offering Mercedes as an option? Just a thought.
I thought the word was that all the major players including Mercedes are all about in house availability only.
Assuming that we’ve got a loose engine supplier producing a considerably more efficient and a reliable engine range and the cash reserves to maintain that position then that’s obviously likely to be a threat to those producers who are reliant on an in house only operation in the long term.Just as was the case with AEC v ■■■■■■■ and Rolls in the day.Just as I’ve said it’s the product that matters not the issue of in house production v assembly operations.
It’s just that unlike then we haven’t now got any assembly operations left to take advantage of the opportunity ‘if’ it’s correct.Oh, and why is that then
The same reason as AEC.They ran out of cash in an investment environment that let’s just say wasn’t UK industry friendly.The difference was in AEC’s case that translated as no money for people like Stokes to put right the zb ups of it’s designers and none to build on the small successes of products like the Detroit,Rolls and ■■■■■■■ powered Crusader and Rolls and ■■■■■■■ powered T45 in the form of design,production,and development budgets concerning them.While,as I’ve said,the idea of in house production or specialist loose engine supplier and assembly operation makes no difference.It’s all about how good the product is and how much cash there is to throw at designing it,producing it and developing it and how good the designers are in getting it right. 
Thank you for clarifying your statement. I was under the impression that it was because operators preferred the vertically integrated truck design, as mentioned in the past by certain esteemed and respected posters, who had extensive experience of running marques that were built both by that method and also by chassis assemblers using proprietary components. I stand corrected. Others can speak for themselves.
It would have been interesting to see how the last V8 that apparently had all its problems ironed out but never put into production would have performed in a Marathon , the higher cab would have allowed better cooling and the 9 speed fuller would have been a better match ,not sure about the Albion rear axle though .I wonder if any went on trial with operators■■?
ramone:
It would have been interesting to see how the last V8 that apparently had all its problems ironed out but never put into production would have performed
Not in this case.Because,contrary to Anorak’s ideas,‘the problem’ that needed ‘ironing’ out was that of the flawed concept of the short stroke heavy truck diesel engine.
Carryfast:
ramone:
It would have been interesting to see how the last V8 that apparently had all its problems ironed out but never put into production would have performedNot in this case.Because,contrary to Anorak’s ideas,‘the problem’ that needed ‘ironing’ out was that of the flawed concept of the short stroke heavy truck diesel engine.
You do not understand anything I say. Do not quote me in future, please.
[zb]
anorak:Carryfast:
ramone:
It would have been interesting to see how the last V8 that apparently had all its problems ironed out but never put into production would have performedNot in this case.Because,contrary to Anorak’s ideas,‘the problem’ that needed ‘ironing’ out was that of the flawed concept of the short stroke heavy truck diesel engine.
You do not understand anything I say. Do not quote me in future, please.
The statement seemed clear enough to me. 
viewtopic.php?f=35&t=68096&start=600#p1778129
The question in that case being how can you ‘execute’ the ‘concept’ any differently.The fact is if you trade leverage at the crank in favour of more force at the piston you’re imposing more stresses in the chain of componentry/link between piston and crank than vice versa.In addition to an engine which is inherently short of torque in favour of producing what power it does have by way of higher engine speed.Rusulting in worse durability and higher fuel consumption.
^^^physics^^^
For all his craziness, he is correct on that issue.
No matter the improvements made, the basic design was fundamentally flawed and as such would’ve always been a lemon.
newmercman:
^^^physics^^^For all his craziness, he is correct on that issue.
No matter the improvements made, the basic design was fundamentally flawed and as such would’ve always been a lemon.
It’s not just heavy truck diesels where the they’re learning that basic fact either.
Yes, I think that everyone is agreed that the fundamental design of the AEC V8 was flawed for its intended purpose as a heavy truck engine and that no amount of tinkering around the edges was ever going to make it any better.
gingerfold:
Yes, I think that everyone is agreed that the fundamental design of the AEC V8 was flawed for its intended purpose as a heavy truck engine and that no amount of tinkering around the edges was ever going to make it any better.
Correct me if I am wrong, but the durability failings were due to overheating and crank journal wear, due to poor coolant circulation and insufficient bearing area. There was also mention of too-short connecting rods. While these mistakes are “fundamental” in that there is little that can be done once production engines are in service, they are not things which would trouble any company at the development stage. The prototype engines would display the faults on rig tests, then the designers would change things to rectify the problems. If there was a need to change the block castings or crank forgings, then so be it. A second batch of prototypes would be built and tested, before any engines found their way onto the road.
Making the crank journals too small is a schooboy error, you would think. This suggests that the original design brief was, “Make it as small as possible; take things to the limit, regarding power versus package volume.” This thread has also discussed an incorrectly-specified fuel injection system. That is something which would be fixed as a matter of course, in any development programme. Why would they just bolt a standard injection pump onto it, other than as a temporary measure to get engines on test? I reckon the engine was an experimental project, which was forced into production without going through the normal development process- just like the ■■■■■■■ V’s.
None of this tells me that the fundamental concept was wrong, just that it set ambitious goals, so a bit of work would be needed to achieve those goals. If we are to discuss historical engineering, we must put ourselves in the shoes of the designers of the period: in 1960, turbochargers were years away from universal acceptance, fuel was cheap and durability expectations were far lower than would become the norm two decades later. Increasing the number of cylinders and the engine speed was what excited everyone in the sixties, and most of the successful European makers followed that route. The more adventurous engineers adopted the oversquare approach, to make the most of the new developments, and they were successful, culminating in that superb Fiat 17.2 litre V8. Those commenters who dismiss, with their half-blind hindsight, oversquare diesels should consider what an undersquare engine of that capacity would look like- if it was to fit under the Fiat cab (or any other cab), you would be using the rocker covers as armrests.
In the context of 1960s engineering, AEC was on the right track, until the intervention of the charlatan Stokes, so it seems. Gingerfold, do you have any more details of the V8’s development programme, to confirm or deny my deductions in this post?
[zb]
anorak:gingerfold:
Yes, I think that everyone is agreed that the fundamental design of the AEC V8 was flawed for its intended purpose as a heavy truck engine and that no amount of tinkering around the edges was ever going to make it any better.Correct me if I am wrong, but the durability failings were due to overheating and crank journal wear, due to poor coolant circulation and insufficient bearing area. There was also mention of too-short connecting rods. While these mistakes are “fundamental” in that there is little that can be done once production engines are in service, they are not things which would trouble any company at the development stage. The prototype engines would display the faults on rig tests, then the designers would change things to rectify the problems. If there was a need to change the block castings or crank forgings, then so be it. A second batch of prototypes would be built and tested, before any engines found their way onto the road.
Making the crank journals too small is a schooboy error, you would think. This suggests that the original design brief was, "Make it as small as possible; I reckon the engine was an experimental project, which was forced into production without going through the normal development process- just like the ■■■■■■■ V’s.
None of this tells me that the fundamental concept was wrong, The more adventurous engineers adopted the oversquare approach, to make the most of the new developments, and they were successful, culminating in that superb Fiat 17.2 litre V8. Those commenters who dismiss, with their half-blind hindsight, oversquare diesels should consider what an undersquare engine of that capacity would look like- if it was to fit under the Fiat cab (or any other cab), you would be using the rocker covers as armrests.
Firstly the strength and bearings at the con rod big ends on any V type engine are by definition a compromise of being narrower than ideal regardless because a V engine is all about increasing the number of cylinders,without a corresponding increase in length,by making two con rods share,what would,on an inline engine be,one crank journal.In which case the last thing you want to do in that case is to trade more leverage at the crank with more force at the piston.
As for an undersquare 18 litre let alone 17 litre having rocker covers for armrests not exactly.Although the FIAT V8 was obviously going to have a lot more leverage and therefore less con rod big end stresses with it’s actual longer stroke measurement than either the ■■■■■■■ or AEC V8’s.
Anorak, I think that most of the (known) information about development of the engine has been posted on the thread. In service failings were, as you rightly state, the result of limitations imposed by the cab, i.e. cooling issues, rapid big end wear because of the compactness of the engine, etc. From what I was told the big end problem could have been solved but it would have meant scrapping the new crankshaft turning machinery that had been imported from Sweden and replacing it. By the late 1960s money was not avaialable to do that. Bob Fryars stated in his article that revived this thread that development on the turbo-charged 350bhp version was going well under the AEC development team led by a chap called Mac Porkess (does anyone know of him?), but test bed development can look promising until an engine goes into service when engines have to earn their keep.
Just a little curve ball here, but do any of the more knowledgeable amongst us (even you Geoffrey) think that with today’s oils, coolants, materials, electronics and manufacturing tolerances, would the AEC V8 design be able to made into a reliable engine?
An interesting question, I don’t think that there was a manufacturing quality issue with the V8, it was made on new machinery and before the Leyland merger AEC had invested heavily in engine manufacturing plant (late 1950s) for its in-line engines, so it had a history of investment if compared with such as Gardner. Those same machines did give problems with variability in quality in the mid-1970s, with A505 and A760 engines, due to the age of them, and the wear and tear on them that had not been dealt with because Leyland was strapped for cash and Southall was being run down for closure. Compare that with the new machinery at Leyland for the 500 series engine that still had a 35% manufacturing failure rate because the engine design and tolerances demanded were too much in advance of the available technology in the late 1960s / early 1970s. Modern lubricants would probably have helped cooling and big end wear.
newmercman:
Just a little curve ball here, but do any of the more knowledgeable amongst us (even you Geoffrey) think that with today’s oils, coolants, materials, electronics and manufacturing tolerances, would the AEC V8 design be able to made into a reliable engine?
Modern engines have a BMEP of up to 27bar- much more than the AEC V8, so I would guess that the big end problems would be solved with modern bearing materials, oil and statistical process control. Of course, none of the developments of the past half a century were available to AEC’s engineers.
The attempts to cure the problems, at the time, were fire-fighting measures. The only scenario I can imagine, that would have made the engine good, would have involved the project not being shelved in 1962. The two(?) years following would have given the designers enough information to create a competitive production engine: the connecting rod would have been a bit longer, the bore spacing greater and the coolant flow through the block and heads more optimal. The package size of the engine would have been a bit worse, IE bigger but, wth those failings eliminated, Leyland would have had an engine which did the business. Who knows what would have come out the other end? They might have even decided that an increase in the rated speed was acceptable- 300+bhp @3000rpm from a 12 litre engine, which would fit easily under any cab! That would have made it very attractive in the “loose engine” market. The 1973 oil crisis would have effected a reduction in the rated speed, plus the addition of a turbocharger, just like it did with all the other engines. In short, the engine would have enjoyed a typical production life and, through that period, Leyland would have made good money from it.
newmercman:
Just a little curve ball here, but do any of the more knowledgeable amongst us (even you Geoffrey) think that with today’s oils, coolants, materials, electronics and manufacturing tolerances, would the AEC V8 design be able to made into a reliable engine?
It seems obvious that optimising the stroke measurement,with the over square/short stroke idea having ( rightly ) been effectively abandoned in favour of the under square layout,is an important part of modern engine design.The conclusion being that while modern materials and lubricants can make a good design even better they probably won’t be able to compensate for the inherent compromises in trying to make power/torque without sufficient leverage being applied at the crank to reduce the forces within the engine required to get it.As for BMEP figures they are based on the overall specific torque figure which is a ‘combination’ of the force applied at the piston ‘and’ the leverage applied at the crank.As stated it’s best to make the latter part of that equation as large as possible in order to reduce the former.Both in terms of efficiency and durability.Which seems to be an accurate description of the thinking in modern engine design in everything from light cars to heavy trucks.
Having said that the idea of a 12 litre + V8 heavy truck engine that needs to be run up to 2,000-3,000 rpm to get any work out of it is there for any designer who chooses to use it. 
So the stroke measurement would always be a compromise then, but still I bet that 3000rpm V8 would sound good through a nice free flowing exhaust system.
newmercman:
So the stroke measurement would always be a compromise then, but still I bet that 3000rpm V8 would sound good through a nice free flowing exhaust system.
Maybe something like this in which case you’ve got the ‘sound’ of 3,000 rpm + without having to blow the engine up to get it. 
youtube.com/watch?v=fl8zCfWB7uE
Other than that if it’s all about revs and noise it’s going to be the 903.In which case the maintenance budget will probably be more than the fuel budget for the Detroit.