newmercman:
nobody at AEC had a crystal ball.
It didn’t take a crystal ball to realise that they were working to a design tilted too far in favour of ‘A’ and ‘N’ at the expense of not enough ‘P’ and ‘L’.Ironically to the point where they created the worst of all worlds situation of less ‘P’ than a Gardner with more force going through the con rod to get it because they’d forgot all about ‘L’. 
I don’t know about PLAN, but I wish you would STFU every now and then [emoji16][emoji16]
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Carryfast:
It didn’t take a crystal ball to realise :
I haven’t one either, so what application had the option of a 903 or a Detroit back in the day?
I get it now,we see a VT903 on youtube with a failure and CF doesn’t like the 4 stroke cycle as it overloads the piston-to rod-to crank assembly(not my words) so every VT903 in the world is rubbish.Were still waiting to hear (cf) your work experience to qualify all these misbeliefs,do you understand 903 has celebrated nearly five decades in service.It was first introduced in the 60,s and the UK military still use thousands of them,not to mention around the world,not bad for a grenade.
Carryfast:
Silverdale:
Carryfast:
Within that formula you can obviously create power by increasing MEP and L at the expense of A and N.So no power isn’t ‘dependent’ on piston area.It’s a combination of all of those and they can all be interchanged.rSomething tells me you do not understand diesel engine engineering principles or physics. Power is dependent on all of the items in the formula - change any of tne conditions and it will affect the output - but to blithly state power is independent of piston area is not only wrong, it is disingenuous. As with all science years of experiment and experience have found the best balance between PLAN to give what is the optimum at present - that is not to say it will change to something else in the future.
You’ve contradicted yourself.In that I can make the same or even more power,by increasing specific torque ( P ) by increasing the leverage of crankshaft stroke ( L ) at the expense of reducing piston area ( A ) and engine speed ( N ).So no power obviously isn’t ‘dependent’ on piston area and/or piston speed,as suggested in the article.
Sorry old chap no contradiction and piston speed is a function of revs.
I cannot see in going any further with the explanation as you obviously refuse to see scientific logic and understand engineering theory.
I still haven`t seen any evidence of the TL12 being unreliable due to its short stroke , 2 piston failures for BRS anything else ■■?
Carryfast:
gingerfold:
Carryfast:
Which leaves the question why was the 680 the motor of choice in the Scammell Routeman 8 wheeler and not the TL12 which would seem to be its natural home if anywhere ?.Because there was no requirement, or demand, for a 273 bhp eight-wheeler in the 1970s. The Leyland O.680 at 200 bhp was deemed powerful enough for 30 tons gvw. Eight-wheeler tippers, of which the vast majority of Routemans were, didn’t exactly spend their time on Motorway long haul work. Honestly, it’s not rocket science to get the answer if you knew the 1970s truck market.
We know for a fact that the Rolls 265 was being specced in 6 wheelers in the day.As for powerful enough I’d guess this isn’t anywhere near 30t.
youtube.com/watch?v=FVE8s5aXkQs
Ironically I’d guess that a derated TL12 ( 240 hp ? ) put in rigids would have been a much better option for all concerned than the NA 680 let alone the headless wonder at least.
I thought you were a fan of the Leyland 680 . Fancy thinking that this was a Rolls, when in fact it is a Leyland 680 screaming its nuts off:
youtube.com/watch?v=FVE8s5aXkQs
This is a Rolls:
railstaff:
I get it now,we see a VT903 on youtube with a failure and CF doesn’t like the 4 stroke cycle as it overloads the piston-to rod-to crank assembly(not my words) so every VT903 in the world is rubbish.Were still waiting to hear (cf) your work experience to qualify all these misbeliefs,do you understand 903 has celebrated nearly five decades in service.It was first introduced in the 60,s and the UK military still use thousands of them,not to mention around the world,not bad for a grenade.
Firstly I ‘actually’ said that replacing the induction stroke with another power stroke is a game changer ‘if’ anyone really must compromise on ‘L’. 
As for the 903 it was the reason ‘why’ I actually went looking for such a failure and found it not to mention the other comments out there which all seem to be in line with what I’d heard in the day which is the point.As for military service it seems strange how the Rolls Eagle and Detroit two stroke all have a claim to fame at the heavier end of the military and civilian duty range in the Crusader and the Oshkosh.But not the 903,let alone the AEC V8 or the TL12.No surprise either that the military saw the need to jump up to the C18,with a 7.2 inch stroke 
as a worthy replacement for the 8v92 in the HET.
Which is consistent with what I’ve said in that the silly AEC short stroke designs would have been ok ‘if’ they’d have been limited to relatively lighter duty applications like 6-8 wheeler rigids.But way out of their league put in a max weight long haul truck. 
Silverdale:
Carryfast:
You’ve contradicted yourself.In that I can make the same or even more power,by increasing specific torque ( P ) by increasing the leverage of crankshaft stroke ( L ) at the expense of reducing piston area ( A ) and engine speed ( N ).So no power obviously isn’t ‘dependent’ on piston area and/or piston speed,as suggested in the article.Sorry old chap no contradiction and piston speed is a function of revs.
I cannot see in going any further with the explanation as you obviously refuse to see scientific logic and understand engineering theory.
That’s what I said.You can increase P and L at the expense of A and N resulting in a net corresponding ‘reduction’ in engine revs to the point of ‘lower’ piston speed for the equivalent hp.On that note you did see the reference to the Rolls Eagle’s lower engine and corresponding piston speed at 280 hp ( 1,800 rpm ) than the TL12’s let alone what the AEC V8’s piston speed would have been at that output.That’s an unarguable understanding of engineering practice and theory as applied in numerous designs today from the Scania V8 to Paccar MX to ■■■■■■■ ISX.
cav551:
Carryfast:
We know for a fact that the Rolls 265 was being specced in 6 wheelers in the day.As for powerful enough I’d guess this isn’t anywhere near 30t.youtube.com/watch?v=FVE8s5aXkQs
Ironically I’d guess that a derated TL12 ( 240 hp ? ) put in rigids would have been a much better option for all concerned than the NA 680 let alone the headless wonder at least.
I thought you were a fan of the Leyland 680 . Fancy thinking that this was a Rolls, when in fact it is a Leyland 680 screaming its nuts off:
youtube.com/watch?v=FVE8s5aXkQs
This is a Rolls:
I posted an obviously NA 680 powered Routeman to make the suggestion that a ‘TL12 powered Routeman’ ( or Marathon rigid ) would actually have been a better option. Let alone than the headless wonder or the AEC V8 put in anything.
Nothing whatsoever to do with the Rolls which as you know I actually rate higher than the 680 or the DK,let alone TL12,in large part because of its longer stroke. 
IE nothing there which doesn’t fit the theory that Leyland deliberately sabotaged itself to help the foreign conmpetition.
Carryfast:
…
IE nothing there which doesn’t fit the theory that Leyland deliberately sabotaged itself to help the foreign conmpetition.
The only “sabotage” would have been promoting a silly salesman like Stokes to the position of MD, when engineering progress was the focus of all the other sensible firms, at the time.
Throughout the 1970s and further, there was an absolute consensus that Leyland must survive. Having read your previous anti-European rants, I am now convinced that the reason you are continuously wrong is that you have been radicalised by a hate preacher.
railstaff:
I’m sorry to say as a new member I’m starting to find this frustrating.You(CF) have no idea over the design problems engine manufactures face.When AEC were producing engines they were no worse than any other manufacture……What I know of the 800 series could have easy been cured,the premature failure of the mains was put down to not enough surface area and the oiling hole in the wrong place,the overheating was mainly due to the fan having a direct drive off the crank pulley,again lifting the cab could have ment relocation of fan and geared up the fan speed.Another problem seemed to be injectors sticking open,did the fuel pump not include delivery valves.All easy stuff to remedy.
Keep the faith ‘railstaff’. It’s clear that you are one of ‘us’!.
I have been reading through the last two pages in the company of a retired senior design engineer from Perkins, and there has been a lot of grinning, one raised eyebrow and head shaking from him at certain posts…I won’t say who from!. He did reiterate that very experienced professionals in his field of work had the utmost respect for the bravery and achievement of the AEC design team engaged on their ‘clean sheet’ V8 project, and although it ultimately failed because of it’s premature production application in a heavy road haulage vehicle, from an engineering development standpoint it was far from regarded as a ‘lemon’, and yealded very useful and significant data - which was exactly what it was intended to do as an engine development experiment. This information enormously benefited AEC, component manufacturers and indeed ultimately even some of AEC’s competitors.
In my many years of association with them, I have personally not heard of injectors sticking open in an AEC V8. It’s difficult to see how that could happen, they utililised standard design CAV / Simms injectors and Simms injection pump (which did include delivery valves). The injectors in an AEC V8 are housed in water cooled copper sleeves, in common with other designs from AEC and others. There were some governor issues with early engines, and I wonder if that is where some confusion perhaps is?.
Are you guys interested in the next instalment from the V8 rebuild story? (All based on hard experience and engineering facts…! )
It probably could be,many years ago I spoke with an Air products driver who actually had one.He remembers having injector problems on night runs,but this is only hear say.Again I have not got first hand knowledge like your self so I’m only repeating what ive read.
I have been eagerly waiting since your last installment and wondered if you had lost faith in this thread please post asap
Carryfast:
railstaff:
I get it now,we see a VT903 on youtube with a failure and CF doesn’t like the 4 stroke cycle as it overloads the piston-to rod-to crank assembly(not my words) so every VT903 in the world is rubbish.Were still waiting to hear (cf) your work experience to qualify all these misbeliefs,do you understand 903 has celebrated nearly five decades in service.It was first introduced in the 60,s and the UK military still use thousands of them,not to mention around the world,not bad for a grenade.Firstly I ‘actually’ said that replacing the induction stroke with another power stroke is a game changer ‘if’ anyone really must compromise on ‘L’.
As for the 903 it was the reason ‘why’ I actually went looking for such a failure and found it not to mention the other comments out there which all seem to be in line with what I’d heard in the day which is the point.As for military service it seems strange how the Rolls Eagle and Detroit two stroke all have a claim to fame at the heavier end of the military and civilian duty range in the Crusader and the Oshkosh.But not the 903,let alone the AEC V8 or the TL12.No surprise either that the military saw the need to jump up to the C18,with a 7.2 inch stroke
Which is consistent with what I’ve said in that the silly AEC short stroke designs would have been ok ‘if’ they’d have been limited to relatively lighter duty applications like 6-8 wheeler rigids.But way out of their league put in a max weight long haul truck.
Forget engines,whats your back ground?
[zb]
anorak:Carryfast:
…
IE nothing there which doesn’t fit the theory that Leyland deliberately sabotaged itself to help the foreign conmpetition.The only “sabotage” would have been promoting a silly salesman like Stokes to the position of MD, when engineering progress was the focus of all the other sensible firms, at the time.
Throughout the 1970s and further, there was an absolute consensus that Leyland must survive. Having read your previous anti-European rants, I am now convinced that the reason you are continuously wrong is that you have been radicalised by a hate preacher.
Firstly do you really think that Stokes was acting unilaterally and not just a puppet of the bankers and politicians above him who were really running the show.
Forcing designs like the AEC V8 into production,against the advice of even its designers,rather than a blank cheque to make a decent 760 replacement,doesn’t seem like the best ‘Leyland must survive’ move.Sabotage absolutely.
If you think that,doing what’s best for your own country at the expense of the foreign competition,is a hate issue then it’s obviously you who’s been radicalised.
ERF:
I have been reading through the last two pages in the company of a retired senior design engineer from Perkins, and there has been a lot of grinning, one raised eyebrow and head shaking from him at certain posts…I won’t say who from!. He did reiterate that very experienced professionals in his field of work had the utmost respect for the bravery and achievement of the AEC design team engaged on their ‘clean sheet’ V8 project, and although it ultimately failed because of it’s premature production application in a heavy road haulage vehicle, from an engineering development standpoint it was far from regarded as a ‘lemon’, and yealded very useful and significant data - which was exactly what it was intended to do as an engine development experiment.
It’s ironic that Perkins chose to buy up Rolls and with it obviously the rights to produce the Rolls Eagle/TX rather than offering Leyland the cash for the rights to produce the AEC V8 and TL12 instead in that case. 
Yes others did learn a lot from AEC’s ( and ■■■■■■■■ ) mistakes.That main thing being don’t follow their example of using a silly short stroke on a heavy truck engine. 
Carryfast:
ERF:
I have been reading through the last two pages in the company of a retired senior design engineer from Perkins, and there has been a lot of grinning, one raised eyebrow and head shaking from him at certain posts…I won’t say who from!. He did reiterate that very experienced professionals in his field of work had the utmost respect for the bravery and achievement of the AEC design team engaged on their ‘clean sheet’ V8 project, and although it ultimately failed because of it’s premature production application in a heavy road haulage vehicle, from an engineering development standpoint it was far from regarded as a ‘lemon’, and yealded very useful and significant data - which was exactly what it was intended to do as an engine development experiment.It’s ironic that Perkins chose to buy up Rolls and with it obviously the rights to produce the Rolls Eagle/TX rather than offering Leyland the cash for the rights to produce the AEC V8 and TL12 instead in that case.
Yes others did learn a lot from AEC’s ( and ■■■■■■■■ ) mistakes.That main thing being don’t follow their example of using a silly short stroke on a heavy truck engine.
Can you answer the question please so I at least can take you seriously.
railstaff:
Carryfast:
Firstly I ‘actually’ said that replacing the induction stroke with another power stroke is a game changer ‘if’ anyone really must compromise on ‘L’.As for the 903 it was the reason ‘why’ I actually went looking for such a failure and found it not to mention the other comments out there which all seem to be in line with what I’d heard in the day which is the point.As for military service it seems strange how the Rolls Eagle and Detroit two stroke all have a claim to fame at the heavier end of the military and civilian duty range in the Crusader and the Oshkosh.But not the 903,let alone the AEC V8 or the TL12.No surprise either that the military saw the need to jump up to the C18,with a 7.2 inch stroke
Which is consistent with what I’ve said in that the silly AEC short stroke designs would have been ok ‘if’ they’d have been limited to relatively lighter duty applications like 6-8 wheeler rigids.But way out of their league put in a max weight long haul truck.
Forget engines,whats your back ground?
Making and testing fire trucks ranging from domestic to airport types for 5 years after leaving school.Then just an ordinary driver like most others here.
railstaff:
It probably could be,many years ago I spoke with an Air products driver who actually had one.He remembers having injector problems on night runs,but this is only hear say.Again I have not got first hand knowledge like your self so I’m only repeating what ive read.
The company I work for had one of the three pre-production V8 prototypes in 1966 and ran it for three years, under close supervision with AEC personnel. Obviously all the drivers who drove it are now either retired or deceased, but I knew all of them very well. They would confirm that the engine did have a tendency to race, or surge at times, and it was a pump timing fault, cured by fitting a new design of governors. That prototype was fitted with three different types of gearbox by AEC, a 6-speed overdrive, a 10-speed range change, and a 10-speed splitter. All those drivers were unanimous to a man that for sheer performance there was nothing on British roads in the mid-1960s that could get anywhere near the V8.