Would the V8 have been better suited to the Marathon if the chassis had been able to accommodate it , I`m thinking on cooling issues here and air flow .
ramone:
Would the V8 have been better suited to the Marathon if the chassis had been able to accommodate it , I`m thinking on cooling issues here and air flow .
Reading between the lines of the policy document then it is possible to suppose that V8 “Mark 2” was being considered for the Marathon because there is no mention whatsoever of an engine in development, i.e. the TL12, for the T25 project. Given that the V8 “Mark 2” never materialised it makes the development of the successful TL12 in such a short time-frame even more remarkable.
ERF:
[zb]
anorak:Gingerfold has researched and knows more than anyone about the dynamics of the Leyland decision making process at this time.
I will leave him to answer that point, but from a pure engineering point of view, AEC went to production with a prototype engine. That is a fact that we proved more than once during the engine restoration.
I wouldn’t claim that accolade myself ERF, it’s kind of you to say so. Certainly by 1967 / 1968 when the V8 was launched Donald Stokes was in power. The decision to launch has always baffled all of the AEC people I knew because at that particular time of the mid-60s, and the quite recent introduction of 30 / 32 gvw artics, there wasn’t any need for such an advanced engine design. Waiting times for all existing models in the catalogue were lengthy, so there wasn’t any sales pressure to get the V8 launched. The only person who could answer the question as to why it was launched is Donald Stokes, and he’s been dead quite a few years.
gingerfold:
ramone:
Would the V8 have been better suited to the Marathon if the chassis had been able to accommodate it , I`m thinking on cooling issues here and air flow .Reading between the lines of the policy document then it is possible to suppose that V8 “Mark 2” was being considered for the Marathon because there is no mention whatsoever of an engine in development, i.e. the TL12, for the T25 project. Given that the V8 “Mark 2” never materialised it makes the development of the successful TL12 in such a short time-frame even more remarkable.
That would have been an interesting vehicle 
ERF:
Carryfast:
Firstly there seem to be references to rods/ends failures ?.Not sure if that means both the 740 and the 801 ?.Logically beefing the assembly up by extending the width of the rod and the rod end if at all possible would be one of the expected fixes ?.Especially in this case of an increase in bore diameter allowing the piston/rod/crank pin/journal to be extended accordingly ?.…it’s best chance is to make sure that it’s not loaded to anything like the type of duty regime that it was originally envisaged to meet by its muddle headed designers.
IE make no mistake this was always going to be best suited to no more than a 6 wheeler from day 1 and obviously nothing more than an empty artic now in preservation and retirement.
Where do I start…?!
Against my better judgement, I will try to help you see things differently (again).Connecting rod failures must have been very rare in this engine, because in all my years of association, I have not heard of a single one. Big end bearing shell failures, yes, but except in the worse cases the engine would get you home, not break the rod and put it through the block, if that is what you are saying?.
The AEC V8 designers were trying to create a engine with everything, high power, low weight, good torque, compact proportions…all from a clean sheet. They created four prototype running engines and fitted them into goods vehicle chassis for testing and evaluation. As any engine designer will tell you, a prototype engine is not built to production standards and design. Service life is part of the design that is addressed after initial prototyping, the first engines are built purely to assess data to see if the basics are right before any required changes are made and expensive production line tooling is bought and set up. This is where it went wrong for the AEC V8. The design engineers had good solid data from their test engines in all operating climates. They knew the big end journals were too narrow. They knew they had to completely re-think the coolant circulation path. They knew many other small detail changes had to be made to take the engine from a prototype to a full production reliable engine. This did not happen. The only changes made between prototype and production were minor, and I will list them. The block core was changed (presumably at Ley’s request) to incorporate long side openings to the outer water jackets. This was purely for reasons of casting, nothing to do with the base design. The fixing threads were all changed from BSF and UNF to Metric, purely to standardise with other engine production. The head castings were changed to the ‘A’ marked type which accommodated a single long rocker cover on each head, rather than the twin covers on each head as featured on the prototypes.
That is it.
In all other respects AEC were forced to start production of a prototype engine, and I say agan, I can only imagine the frustration of the design team, who everyone except yourself credits with a very innovative and clever design. Even seasoned professional engine designers with all the benifits of modern CAD systems at their disposal at world leading Diesel engine manufacturers acknowledge this.My own Mandator V8 operated dual shifted from 1970 to 1977. It was a single V8 in a sizable fleet of AV760 powered Mandator’s. They were a firm known around here for working their lorries hard, mostly on brick transportation. It was (and still is) rare to see their lorries going up the road anything other than fully freighted. In the early 1970’s they were a firm operating with stiff competition and with relatively modest margins. Despite all this, in 1971 when AEC wanted to take their V8 away and sell them a new AV760 powered replacement Mandator at cost, they refused. Every one of their drivers to a man wanted to drive the V8 because of it’s performance. Even later in it’s life it was seen as a lorry to ‘graduate’ upto by drivers, even over their brand new Marathon’s. It could haul a full load from A to B as efficiently (if not more so) than an AV760 powered Mandator - BUT at a maintenance penalty. They found the most efficient way to run it was to set realistic milages that the engine could cover without major issues, and when this mileage was reached, to swap the engine with another (prototype as it happened) V8 engine that had been fully overhauled ready to fit. Using this system, and with mechanically sympathetic drivers, the lorry managed seven years of hard work - a completely acceptable life span on their work in the 1970’s. When it was finally withdrawn in 1977 it was so highly regarded by all involved that they refused to scrap it off with all the other worn out lorries, and retained it for purely sentimental reasons - the only lorry they ever kept!.
As all (and I do mean ALL) those lucky enough to drive a Mandator V8 in anger have told me, it was so very right in so many ways. If the AEC engineers had been listened to, and the design changes made that they wanted to make before production, the outcome of this story would have been very very different. I have absolutely no doubt about that.
Premature rod or end bearing failures what’s the difference.When the cause is predictable and obvious in either case insubstantial rod spec v compromised leverage at the crank caused by the ridiculously short stroke.
Don’t see anything there which doesn’t justify everything which I’ve said.Leyland’s attitude would have rightly been if they couldn’t get the basics right from the start it’s too late and too expensive to fix it now.As for load and durability testing in service it’s difficult to believe that they didn’t have access to an engine dyno.
As for the design parameters you’ve listed.Why when its design was supposed to be a max weight long hauler not a replacement for the headless wonder in 6 wheelers.Oh wait AEC also thought that the Ergo cabbed Mandator was a suitable competitor to the Scania 110/140 just like its flawed under specced motor v the Scania V8. 
ramone:
Would the V8 have been better suited to the Marathon if the chassis had been able to accommodate it , I`m thinking on cooling issues here and air flow .
The only cooling advantage that the Marathon cab / chassis would have offered the V8 is it’s ability to house a more sensibly located radiator. I have said before that personally I don’t subscribe to the thinking that the low datum Ergomatic cab contributed significantly to the V8’s cooling issues due to poor airflow. The rear, sides and bottom of the engine are all fully open, and there is no conceivable way that air could be restricted to such a degree that a positive pressure could be generated around the engine, thereby restricting air entering the radiator. The fan itself, although ruunning at comparatively low crankshaft speed, is a huge twelve bladed cowled assembly, and more than capable of drawing enough air through the radiator. The big issues are the radiator itself, which was mounted incredibly low to the ground - hence the protection bars that many operators fitted to V8’s under the bumper (as can be seen in the photo on the previous page) and its relatively small fluid capacity. AEC had a fix for the capacity issue at their fingertips in the form of the thicker cored export specification radiator, but no home market vehicles were so equipped for inexplicable reasons.
The biggest cooling issue of all were hot spots inside the engine, caused by it’s poor ability to circulate coolant effectively. AEC used external pipes running across the rear of the engine to pass the coolant from one cylinder bank to the other and then back, and when we test ran the engine on the stand at high RPM you could see the top rubber link hose physically expand under the presssure generated by the coolant flowing inside. This was not expansion pressure, or pressure from boiling cooling, it was back pressure generated by flow restrictions further up the system that did not alter whether the thermostat was open or closed. Repeated failure of this link hose in early service led to a service bulletin (one of very few ever issued for the V8 - the only other one I can recall adressed poor routing of the engine stop cable!) advising service centres to change both rubber link hoses for wire reinforced ones. We had fitted all black silicone hoses, which as anyone with experience of old ■■■■■■■ engines will testify, last far longer than natural rubber, but the rear ones were just too soft for the pressure generated in the link pipe. I found a firm that would make wire reinforced silicone hoses for me, so that is how we overcame the problem - but to address the actual pressure issue is impossible without redesigning the entire cylinder block casting - something I would wager had been done in anticipation of the 1971 relaunch.
gingerfold:
I wouldn’t claim that accolade myself ERF, it’s kind of you to say so. Certainly by 1967 / 1968 when the V8 was launched Donald Stokes was in power. The decision to launch has always baffled all of the AEC people I knew because at that particular time of the mid-60s, and the quite recent introduction of 30 / 32 gvw artics, there wasn’t any need for such an advanced engine design. Waiting times for all existing models in the catalogue were lengthy, so there wasn’t any sales pressure to get the V8 launched. The only person who could answer the question as to why it was launched is Donald Stokes, and he’s been dead quite a few years.
How can Stokes be blamed for the V8 fiasco when it’s obvious that he had nothing whatsoever to do with AEC during its design stage.The fact that it was at best a headless wonder replacement rests with AEC’s designers and management not Stokes.In which case why would AEC’s ‘people’ supposedly be ‘baffled’ by its use when it was AEC who actually designed the bleedin thing not Triumph and if AEC didn’t see any need for it then why waste valuable resources on it instead of putting them into a longer stroke 690/691/760 replacement.
newmercman:
ERF you are banging your head against a wall as far as CF is concerned…
Well, as expected, you were spot on!. 
ERF:
ramone:
Would the V8 have been better suited to the Marathon if the chassis had been able to accommodate it , I`m thinking on cooling issues here and air flow .The only cooling advantage that the Marathon cab / chassis would have offered the V8 is it’s ability to house a more sensibly located radiator. I have said before that personally I don’t subscribe to the thinking that the low datum Ergomatic cab contributed significantly to the V8’s cooling issues due to poor airflow. The rear, sides and bottom of the engine are all fully open, and there is no conceivable way that air could be restricted to such a degree that a positive pressure could be generated around the engine, thereby restricting air entering the radiator. The fan itself, although ruunning at comparatively low crankshaft speed, is a huge twelve bladed cowled assembly, and more than capable of drawing enough air through the radiator. The big issues are the radiator itself, which was mounted incredibly low to the ground - hence the protection bars that many operators fitted to V8’s under the bumper (as can be seen in the photo on the previous page) and its relatively small fluid capacity. AEC had a fix for the capacity issue at their fingertips in the form of the thicker cored export specification radiator, but no home market vehicles were so equipped for inexplicable reasons.
The biggest cooling issue of all were hot spots inside the engine, caused by it’s poor ability to circulate coolant effectively. AEC used external pipes running across the rear of the engine to pass the coolant from one cylinder bank to the other and then back, and when we test ran the engine on the stand at high RPM you could see the top rubber link hose physically expand under the presssure generated by the coolant flowing inside. This was not expansion pressure, or pressure from boiling cooling, it was back pressure generated by flow restrictions further up the system that did not alter whether the thermostat was open or closed. Repeated failure of this link hose in early service led to a service bulletin (one of very few ever issued for the V8 - the only other one I can recall adressed poor routing of the engine stop cable!) advising service centres to change both rubber link hoses for wire reinforced ones. We had fitted all black silicone hoses, which as anyone with experience of old ■■■■■■■ engines will testify, last far longer than natural rubber, but the rear ones were just too soft for the pressure generated in the link pipe. I found a firm that would make wire reinforced silicone hoses for me, so that is how we overcame the problem - but to address the actual pressure issue is impossible without redesigning the entire cylinder block casting - something I would wager had been done in anticipation of the 1971 relaunch.
- Be careful with over-pressured hoses. Boiling water bombs are horrible. Weeks of agony, having the dressings changed…
- Nowt wrong with the design of the water pump, if it can work against such a restriction! Any evidence of cavitation, on or near the impeller?
- I wonder if changes to the block castings were a feature of the re-launched engine, or their cost was one of the reasons for it not going ahead?
Carryfast:
How can Stokes be blamed for the V8 fiasco when it’s obvious that he had nothing whatsoever to do with AEC during its design stage…
The previous two pages, plus many of the others, cite the decision to force the undeveloped engine into production, which was Stokes’ ultimate responsibility. How can you not have read that, just the once?
ERF:
newmercman:
ERF you are banging your head against a wall as far as CF is concerned…Well, as expected, you were spot on!.
archive.commercialmotor.com/arti … what-might
Remind us of Albert Fogg’s background it being obvious that he was the instigator of of all this being ‘Group Engineering Director’ not Stokes.Also how were they going to fix the over stressed nature of it when that had been set in stone by the excessively small overall capacity for a V8 let alone the stroke measurement chosen for it v the Scania V8.
The big question then being why the supposed need for a so called ‘compact’ 300 hp engine and what possible military application could Fryers have been describing.Bearing in mind that any such application in question was already served perfectly by the Detroit options in the day.Have to say Fryer’s claims sound unbelievable in that specific regard.
The V8 a replacement for the headless wonder , the headless wonder came after the V8 , just remind everyone how many restorations you`ve been involved in CF and how you seem to be an expert on everything from politics to engine designs … and almost everyone on here seems to have the same opinion of you. If you don’t have anything of any relevance to say why don’t you read and learn from people on here who have actualy been there. You have so far admitted to working in a fire engine factory for the first 5 years of your working life why didn’t you stay there or were you too clever for them too
ramone:
… You have so far admitted to working in a fire engine factory for the first 5 years of your working life …
Test driver for an aircraft fire tender maker, if I remember correctly. Says something, does it not?
[zb]
anorak:ramone:
… You have so far admitted to working in a fire engine factory for the first 5 years of your working life …Test driver for an aircraft fire tender maker, if I remember correctly. Says something, does it not?
Chief sweeper upper then relieved of his duties
How to be a successful troll and go undetected for years
- Masquerade as a knowledgeable expert
- Infiltrate as many threads as possible
- Criticise everything in sight
- Mount unwarranted attacks on as many ideas and transport products as you can
- To avoid detection, observe the forum rules and never attack a poster
- Ruthlessly and relentlessly disrupt healthy debate with non-sequiturs, disinformation and conspiracy theories
- Rubbish sound theories and good ideas and quickly move the goalposts to make counter criticisms look less credible
- When good forum members give up and stop posting, move quickly to a flourishing thread
Robert
[zb]
anorak:Carryfast:
How can Stokes be blamed for the V8 fiasco when it’s obvious that he had nothing whatsoever to do with AEC during its design stage…The previous two pages, plus many of the others, cite the decision to force the undeveloped engine into production, which was Stokes’ ultimate responsibility. How can you not have read that, just the once?
It could never have been ‘developed’ because all the relevant measurements were already set in stone from the design stage.
Assuming we’ve got F reg production examples on the road where is your evidence that Stokes had any ultimate responsibility over AEC’s decisions regarding the V8 at both the design stage or even before the start of its production stage.That taking place obviously well before 1968 and quite possibly before 1965.While it’s equally obvious that AEC didn’t design the small V8 grenade just for the fun of it and to then do it all differently later.
When it’s obvious that the whole thing was a joint enterprise between Fogg and Fryers to turn the sows ear of the Mandator into the silk ■■■■■ of a Scania 140 competitor and predictably failing spectacularly.No end of trying to shift the blame for that from Fogg onto Stokes will change that fact.While even if Stokes does share any blame for that it can only be in the sense of having been ordered by the bankers and the government not to tread on the toes of US foreign policy aims in Europe.Bearing in mind that the REME didn’t generally employ ignorant unqualified fools into it officer ranks especially during the make or break period of WW2.In which case an engineering apprenticeship seems like a strange qualification requirement if he was supposedly only supposed to be a employed as ‘salesman’ at Leyland.While no decent engineer would have tried to put the AEC V8 up against the Scania V8 let alone try to make it do the same job.The English Scania yeah right.
Excellently describes “CF” 's MO to a “T” ! Hopefully he will now explain why this description of him is 100% wrong 
Bewick. PS but if he is operating true to form he will lie low for a bit, maybe turning up on “Bullys” or even annoying the Professional Lads for a bit
Point 8 of Robert’s very good post is very true. Several good and informed posters are on record as saying that they give up on a thread, rather than wade through pages of pointless bumph that regurgitates the same nonsense. We seem to have lost railstaff which is a pity, he seems to be knowledgeable and informed.
Following on from Robert NGC’s well observed post; has anybody ever seen Carryfast and Jeremy Corbyn in the same room together?
ramone:
The V8 a replacement for the headless wonder , the headless wonder came after the V8 , just remind everyone how many restorations you`ve been involved in CF and how you seem to be an expert on everything from politics to engine designs … and almost everyone on here seems to have the same opinion of you. If you don’t have anything of any relevance to say why don’t you read and learn from people on here who have actualy been there. You have so far admitted to working in a fire engine factory for the first 5 years of your working life why didn’t you stay there or were you too clever for them too
The 500 fixed head wonder was introduced in 1968.Which puts its design stage and its failures in service when ?.
As for my employers.It was only matter of time until the same agenda that took out AEC and Scammell etc also took out us.In our case the result being a win for Oshkosh,Faun and Rosenbauer.The relevant bit being that even the ■■■■■■■ 903,let alone the AEC V8,weren’t ever considered as being a good option by any of us.