coomsey:
I’ve mentioned on TN before that I drove Terex dumptrucks with D D engines at least 25yr old. God knows how many mls /hrs they’d done. We were working them 16hrs a day for 5yr n never heard of one blowing an engine. A 9yr old Cat I had popped a piston very unusual. Not sure that is relevant to road motors but says a bit about their design. Cheers Paul
I’ve been down at the squirrel time after time lifting major components off those poxy cat dumpers ,since they’ve had second hand komatsus from oz I’ve never been back !
newmercman:
Carryfast, please quit with the stroke comparisons, you’ve been saying the same thing for the past couple of weeks now, I think it’s safe to assume that we get your point.
Your true colours are starting to show now, I agreed with you a few posts back and got no response from you, no quote, no YouTube video, I’ve just given you plenty of material with my post singing the praises off the American diesel engines and nothing from you in response.
By definition this means you only quote and post to spew your vitriol and that is called trolling. Your opinion is welcome, but if you’re just going to keep on and on about the same thing in every post, you should rethink your tactics.
I certainly did respond positively to your agreement that the AEC was the wrong engine put in the wrong truck.
I didn’t respond to the American ( or British ) thing because I obviously don’t think it’s an issue of which country designed it it’s just one of ‘how’ it’s designed and that doesn’t get much more important than the basic architecture as the start point.
By that standard I’d obviously put the Rolls Eagle/TX as easily being a match for the 6 cylinder Mack or ■■■■■■■ engines in the usually accepted terms of reliable torque per litre output.In which case how could I possibly respond to an over simplistic Brit bad American good comparison when there’s loads of shades of grey.
Which is why the Scania V8 is the last surviving V8 design still in common road use production by moving away from the Mack 864’s architecture let alone following that of the 865,and it’s also why DAF based its DK engine design architecture on the 680 not the AV760 and the Paccar MX isn’t based on the DK’s architecture ( or the Mack 673’s or the ■■■■■■■ N14 ).
While I could join in by saying perhaps I’m wrong and the AEC V8 could have produced the goods in terms of a reliable usable 275 hp let alone 350 given more cash and time and its all Stokes’ fault.But I still wouldn’t believe it myself because designing a truck engine is supposed to be all about torque not power output at silly engine speeds and Stokes was never employed as an engine designer.How is that trolling.
Compare what you’ve just written to one of your other posts, it’s much better, leaving out a lot of the silly stuff will allow others to read what you’re actually trying to say with infuriating them. You do raise a lot of valid points, it’s the way in which you raise them that causes all the grief. Oh and the fact that you raise them over and over again in a way that suggests that it’s your way or the wrong way. It’s a matter of etiquette, plain and simple. Whether you’re right or wrong is of no significance, it’s how you say it.
gingerfold:
A good question and probably not one definitive answer. Being simplistic then I think that the dimensions of British engine designs must have been a factor. And I’m not talking about piston stroke and cylinder bore dimensions. It’s the old historical factors of trying to design the lightest possible lorry to carry the maximum weight under restrictive C&U Regs that dominated designers’ thinking for many years. You’ve hit the nail on the head with your reference to “big yellow powerhouses”. Look at a say, 12 litre capacity Yankee diesel engine side by side with a 12 litre British or European engine, the Yank is bigger. So, a bigger block, bigger cylinder heads. Would that not allow larger coolant passages in the engine for better reliability? Cooling issues were the Achilles heels of several British designs. The design brief of the AEC V8 encapsulates the thinking: - a lightweight, compact engine was demanded. The only British engine that looked bigger than its output was the Gardner, and weight saving with Gardner was achieved by extensive use of aluminium alloys. I think that pre-WW2, and cav551 will either confirm or otherwise, both Leyland and AEC also made use of aluminium alloy in some of their engines, but it wasn’t continued by them post-war. The designers in the USA probably weren’t restricted to the same extent by worrying about weight as their British counterparts. The 1960s and '70s major users of ■■■■■■■ engines, notably Atkinson and ERF, compensated for the heavier weight of the engine by using lighter cabs with non-steel panels.
The early 1930s saw great interest among manufacturers in developing an automotive diesel engine to power their products. Prompted by the need to improve fuel consumption some operators as early as 1930 had fitted Gardner L2 marine diesel engines. Several were fitted to Crossley buses which prompted that company (later taken over by the AEC) to develop it own diesel. Crossley, Leyland and AEC were the first to market a competitor to Gardner’s LW engine.
It would be fair to say that the AEC are probably the company who deserve the most credit for their research into the experimental development particularly in the area of combution chamber design of a successful automotive diesel, with various designs put into production. As was to follow many years later the the V8 AEC came up against a patent issue with the Leyland Pot cavity piston for which they eventually signed a short term licence agreement.
Following Gardner’s LW lead these manufacturers incorporated light alloys in their designs. The first popular non Gardner one being Elektron used for crankcases. The early AEC diesels were numbered A155, A161, A164 and A165, the latter introducing aluminium alloy for the cylinder head as well as the crankcase. Interestingly the cylinder heads were made in RR50 alloy, the same alloy as Rolls Royce used for their much troubled in development and early production Merlin engine. AEC found it necessary to abandon its use for cylinder heads because of cracking - a problem which persists to this day but which can be overcome.
Just reading some posts and was thinking did AEC ever offer Daf the choice of using their engines .I would think not why would they let a competitor albeit many years latter take 1 of their designs ■■? We know Leyland did but that says more about the Leyland management than anything else
ramone:
Just reading some posts and was thinking did AEC ever offer Daf the choice of using their engines .I would think not why would they let a competitor albeit many years latter take 1 of their designs ■■? We know Leyland did but that says more about the Leyland management than anything else
That’s another Stokes story right there- Leyland flogged their engineering superiority firstly to Scania Vabis, then Daf, without bothering to take another stride forward, to maintain their lead. I wonder if that is why the 700/500 engines failed- Leyland expected to move ahead with that ambitious design, but had not equipped themselves with enough brains to do it?
newmercman:
Compare what you’ve just written to one of your other posts, it’s much better, leaving out a lot of the silly stuff will allow others to read what you’re actually trying to say with infuriating them. You do raise a lot of valid points, it’s the way in which you raise them that causes all the grief. Oh and the fact that you raise them over and over again in a way that suggests that it’s your way or the wrong way. It’s a matter of etiquette, plain and simple. Whether you’re right or wrong is of no significance, it’s how you say it.
Does that make sense?
That’s all fair enough nmm.
So to round up my view as diplomatically as possible.An engine ‘designer’,as opposed to the managing director,would be expected to be working on the principle of extracting as much torque from the design as possible as reliably as possible ?.
The relevant measurement in that is the force applied by the con rod after the piston to the crank multiplied by the distance of the crank throw.A reduction in the distance side of that equation obviously means more force required to be applied by the con rod to create the equivalent torque output with all the resulting stress implications of that.Or it means compromising on the torque figure.Or even a combination of both.
While lack of torque means more engine speed to create the equivalent hp which then creates relatively more thermal stress/loading on the cooling system.ERF and Anorak etc obviously don’t agree with my view which is absolutely fine.While it’s them who seem to have the problem with me disagreeing with them.
While I’d suggest that the design of the Scania V8 and its fortunes to date v the AEC V8 seem to confirm my view of it ( the AEC V8 was the wrong engine specifically designed so as to fit in the wrong truck ).As opposed to ( it will/would have ) worked fine with more time and cash thrown at it ).Mostly seeming to be based on the idea of just concentrating the thermal loading/stress part of the equation in the design and forgetting about all the rest ?.
But whatever the answer I think we can clear Stokes of blame.‘Unless’ that is we can find the slightest shred of evidence that Roberts and Arthur Fogg let alone Albert Fogg said to Stokes oh wait we’re probably trying to produce the wrong engine for the the wrong truck let’s knock it on the head.When they all seem to have said and done exactly the opposite.
newmercman:
What I struggle to understand is why the Americans were so far in front of us in terms of engine development. I know they had a much larger market, so more profits to reinvest, but they were leagues ahead of us, the Mack based V8 from Scania was in production for nearly 30yrs without changes to the basic design, intercooling and EDC being the only notable changes and they eventually gave it 530hp from the original 335hp and that Svempa bloke had 1200hp out of admittedly highly tuned versions, all from a 1960s Mack design.
Their inline sixes were pretty ■■■■ good too, almost everything pre ISX from ■■■■■■■■ the Series 60 and the big yellow powerhouses that are my personal favourite. Even Daimler AG chose the current DD range as their world engine platform and Mercedes-Benz made some bloody good engines themselves, yet the yanks got the job.
What made us so far behind?
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Quite simply “cast iron engineering” and simplicity.Besides AEC who were tryers,the rest of UK engine makers seemed to suffer with the British attitude of either “that will do” or “lets sell up”
Take Gardner for an example,superb engine but left turbocharging till the last minute.Rolls refused to spend proper money on research.Leyland were a joke with the TL11.It didn’t leave much else.
newmercman:
What I struggle to understand is why the Americans were so far in front of us in terms of engine development. I know they had a much larger market, so more profits to reinvest, but they were leagues ahead of us, the Mack based V8 from Scania was in production for nearly 30yrs without changes to the basic design, intercooling and EDC being the only notable changes and they eventually gave it 530hp from the original 335hp and that Svempa bloke had 1200hp out of admittedly highly tuned versions, all from a 1960s Mack design.
Their inline sixes were pretty ■■■■ good too, almost everything pre ISX from ■■■■■■■■ the Series 60 and the big yellow powerhouses that are my personal favourite. Even Daimler AG chose the current DD range as their world engine platform and Mercedes-Benz made some bloody good engines themselves, yet the yanks got the job.
What made us so far behind?
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I would disagree with the statement that the Americans were ahead. They had their successes, but so did the Europeans. Mack’s first DI diesel, the END673, was developed with Scania’s assistance in the 1950s. Not long before that, the engine on which Mack based their work was made good (having been notably poor before) by the Swedes’ consultation with Leyland.
Moving on to the present day, the predecessor of the Detroit engine on which the present-day Mercedes engine (OM471) is based is the 55 Series. That engine was a version of Mercedes’ six-in-line version of the original Merc/MAN OM400 series of engines. I reckon the OM471 is more German than American.
I would not disagree that the big inline sixes of ■■■■■■■■ Detroit (Case) and Caterpillar were great. I have already stated my opinion that Mack’s innovative engine work in the 1960s put them ahead of every other make in that decade. I also think that the two stroke Detroits- 53, 71 and 92 Series- were great. The same basic design powered everything from buses to huge quarry dumpers, simply by varying the number of cylinders.
At the same time, I would put the products of Gardner, Unic, Fiat and Deutz on equally high pedestals.
railstaff:
AEC who were tryers,the rest of UK engine makers seemed to suffer with the British attitude of either “that will do” or “lets sell up”.Rolls refused to spend proper money on research.
Let’s get this right AEC run out of talent at around 45 lb/ft per litre with a dodgy V8 arguably crippled through being specifically made to needlessly fit in a weird idea of a max weight long haul truck.Or at best they run out of potential at around 65 lb/ft per litre with their best shot 6 cylinder offering.
Meanwhile the poor cash starved Brits,working in a shed in Shrewsbury,manage to take on the combined financial might of Mack,■■■■■■■ and Caterpillar with a nice smooth running reliable motor with well over 100 lb/ft per litre from around 1,200 rpm and almost 8 mpg at 38t potential built into it.
railstaff:
AEC who were tryers,the rest of UK engine makers seemed to suffer with the British attitude of either “that will do” or “lets sell up”.Rolls refused to spend proper money on research.
Let’s get this right AEC run out of talent at around 45 lb/ft per litre with a dodgy V8 arguably crippled through being specifically made to needlessly fit in a weird idea of a max weight long haul truck.Or at best they run out of potential at around 65 lb/ft per litre with their best shot 6 cylinder offering.
Meanwhile the poor cash starved Brits,working in a shed in Shrewsbury,manage to take on the combined financial might of Mack,■■■■■■■ and Caterpillar with a nice smooth running reliable motor with well over 100 lb/ft per litre from around 1,200 rpm and almost 8 mpg at 38t potential built into it.
The AEC engine had similar power to the Eagle of that time. If both engines were geared appropriately, they would have similar performance. The AEC engine would have done so with a lower cylinder pressure, lower piston speed, less piston/rod acceleration, less weight, greater volumetric efficiency and less space consumed. That summarises the thinking behind all of the V engines of the 1960s, and there were lots of them.
We ran two Eagle 220’s in the mid seventies and they were not that brilliant fuel wise, they were both fitted in 30 tonne gross eight wheelers and fuel consumption was poor so no more were ordered until the 265 came out which was later. They did motor well though, the gearboxes and prop centre bearings didn’t like the pace and expired occasionally!
The Rolls Royce engine plant at Shrewsbury, formerly the Sentinel works, was one of the most modern engine production lines in the UK in the early 1970s. That was why Paul Gardner called an emergency board meeting at Patricroft when Rolls Royce went into administration. Paul believed that the modern facility at Shrewsbury was exactly what Gardner needed to replace their ancient machinery. Needless to say the older Gardner directors weren’t interested and Paul was berated for wasting their time. Because of its military contracts Rolls Royce was nationalised, so Government funding kept it afloat.
Carryfast:
Meanwhile the poor cash starved Brits,working in a shed in Shrewsbury,manage to take on the combined financial might of Mack,■■■■■■■ and Caterpillar with a nice smooth running reliable motor with well over 100 lb/ft per litre from around 1,200 rpm and almost 8 mpg at 38t potential built into it.
The AEC engine had similar power to the Eagle of that time. If both engines were geared appropriately, they would have similar performance. The AEC engine would have done so with a lower cylinder pressure, lower piston speed, less piston/rod acceleration, less weight, greater volumetric efficiency and less space consumed. That summarises the thinking behind all of the V engines of the 1960s, and there were lots of them.
To be fair I was referring to railstaff’s American v Brit observations regardless of whether 6 cylinder or V8.
As for Rolls v AEC comparison the Rolls already has a specific torque advantage over the AEC even in 220 NA form and even more surprisingly considering the V8’s greater piston area and 4 power strokes per revolution v the 6 cylinder Rolls. On that basis it’s obvious that the Rolls was always going to end up in the situation of an ultimately higher specific torque output potential meaning a relatively higher power output at lower engine ( and piston ) speed than the AEC or the TL12.While the V8 configuration only seems to have made sense above the 14 litre threshold and ideally using Scania/Mack 864’s architecture as a reference point for 8 cylinders to make any sense over 6 ? and certainly not to the point of choosing to use such a compromised 8 cylinder design through being needlessly governed by an equally compromised cab design.
Realistically the thing should have been written off from the point when its BMEP figure of less than 50 lb/ft per litre first appeared on the dyno.
newmercman:
Hard to argue with that. With EDC it could have been a 450-500hp engine.
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In the late 70,s/early 80,s Rolls produced a 14 litre 24 valve version of the Eagle as a test engine.It produced 500hp and although the plant was advanced the development funding wasn’t.A perfect example was the said 265,with its bad starting and smoking.The bad starting was dealt with by an increase in compression.The smoking issue was partly erased with an improved turbocharger but once the smoke critera was met the development was stopped when in reality a lot more could have been done,and once a period in service had been accumulated they were smoking once again.
One issue engine makers had,which I call the transitional period is/was,was that most makers already engines in place like Rolls or a classic example MAN that traced their roots back in time.The emission ratings started to appear.Mechanical engines struggled to make the emissions.Most never had space for a third lobe on the camshaft for a mechanical unit injector,Common rail was not even at its infancy.So Rolls hung on to Euro 2 with mechanical inline fuel pump.The vast majority then switch to Bosch,s EDC 6.1 and 6.4 rotary and inline electronic governor fuel pumps.Which proved to be a disaster zone.I refer to it as the transitional period because most makers were “in between engines” and were waiting to see what was going to appear.
newmercman:
Apart from packaging, I can’t see the advantage of a small V8, not against a turbocharged in line 6 of equal power.
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It fits in places better than a inline six.Perfect example was MANS F8 underfloors.I realise they used the D25 on its side but because it wouldn’t fit under a cut down F8 day cab.A Vee eight would have fitted no problem.
