Two separate issues:
The freedom of speech
The freedom to behave badly (or inappropriately)
Separate rules apply to those issues in society because when we ask the ill-behaved to leave, we are not focussing on freedom of speech even if that is inherent because the behaviour issue is greater.
Temporary cooling off periods ‘out’ are often very effective.
Robert
Let’s just draw (another) line under this whole saga and get back on track now please.
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How far from completion are you ERF , and will it be ready for Newark , I will be there if it is 
newmercman:
Ramone, to be honest I think the lorries of today are all pretty much the same, my number one priority would be dealer service, previously I had good luck with IVECO, the trucks give a big bang for a small (ish) buck, the engines are bulletproof and I had a good dealer workshop close by.The other option would be Scania, V8s of course (relevant to the thread) but not the fire breathing 730, the lowest rating they do, 560 I think, a nice unstressed engine, reliable, reasonable economy, very good residuals and desirability amongst drivers.
A bit of a contrast I know, but the middle ground is of no interest to me, you go cheap and cheerful and make as much money as you can, or you go premium and make as much money as you can, the difference between the two boils down to initial purchase price and residual value, the bit in the middle works out almost the same for both.
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Im glad you said that regarding the 560 V8 , i think its the most sensible option for over here but they are out pricing their selves now, but the Iveco imho have got worse , i agree with the engines being bulletproof but apparently the electrics are a nightmare a problem that as been long standing with Ivecos and if that warning light is on even though its probably a sensor fault its going to cause you grief . A manual Scania or maybe a manual Daf would be my choice
I never had a single electrical problem on any of the IVECO I’ve owned, although things have changed since 05 when I bought the last one I had.
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It looks like another thread as bit the dust for obvious reasons
ramone:
It looks like another thread as bit the dust for obvious reasons
I believe gingerfold’s accounts of the drivers’ reports of the turbocharged vehicles have yet to be posted. ERF’s catalogue of the manufacturing faults in the engines he has analysed is far from complete, I’m sure.
For my own part, I would like to see some investigation into the coolant flow issues. So far, there seems to be some confusion as to what happens to the stuff when it is in the block. Are there any sectioned show engines still in existence? Are there any scrap blocks about, which could be cut up (and preserved in that condition, for future observers)? Being optimistic, maybe the design details responsible for the flow restriction and/or the local overheating could be modified.
I realise that ERF’s engine must look as original as possible, but another engine could incorporate improvements. Given the amazing lack of “finish” that the engines had, I would be fairly confident that even a group of amateurs like us (with respect to all those professionals amongst us!) could make some of the missing progress. Just look at what that Swiss bloke did with the prototype Unic V8.
If you had an unused block, you could drill and tap holes into the water jacket, at intervals, then pump water through it, measuring the pressure in different places. If there was a place where the pressure dropped significantly, that would be the place to arrange some sort of modification.
If an engine could be run, with temperature sensors arranged in a similar fashion, the hot-spot issue could be traced.
Many years ago I was in Rotherham trying to find a delivery point and stopped outside a fire station , I called in to ask for directions and there was an AEC unit there with no cab on , Im almost certain it was a V8 but I was in a rush so I didnt get to look at it or find out what it was doing there I`ve often wondered what became of it
Ramone the cab less unit could have been used for RTC training along with one or two cars, most stations keep a vehicle or two on site for this, usually donated by the public the AEC chassis could also have arrived this way. During my time at Tyne and Wear we were putting together an HGV Heavy Vehicle Rescue course at the training centre, located on the right of the road leading to Nissan. We were supplied with many old HGV’s by a local scrap dealer we used for this and cars from Nissan, Customs and Excise and the public, we did get through many vehicles in a week at this time. We had a set of new air bags on test loan and the lead Instructor of the course being an ex 2 Para lad had arranged for us through a mate to go down to Catterick Camp as they had some old tankers they would let us lift. I was a bit surprised and a little sad that these six wheel tankers were Ergo cabbed Marshals, military of course but the cabs were in really good condition for their age apart from the slight damage that had occurred during various exercises the army lads had carried out at times.
After a few hours doing different lifts etc on these old machines someone suggested that we should test the ability of these air bags on lifting a Chieftain tank. My mate was a little nervous about this he didn’t think it wise but me and the other army guys talked him round and sure enough these bags lifted a Chieftain Tank no bother both tracks off the deck, the air supplied for these came from our normal BA cylinders at 200 bar. Suitably impressed these bags became a part of the heavy rescue equipment and are still in use now carried by the new Volvo FH twin rear steer six wheeler the Service bought shortly before I retired from the Service in April and used many times with some renewals of course over the period, no doubt though those Ergo Marshals haven’t survived as long. Cheers Franky.
Come on lads, the loon is busy on a political rant over at Bully’s, let’s make hay while the sun is shining
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Nothing to argue about here…
Cobden Mandator V8, high datum cab, with sleeper. OFJ 472G, chassis number 2VTG4R 051, dated 28/03/68
We are left with speculating upon what AEC might have done to overcome the problems with this engine. To claim that nothing could be done is nonsense. If as I have indicated Rolls Royce could make so many significant changes to their aero engine then AEC could given the will, have done whatever was necessary. The cooling issue would have been investigated by the experimental department, possibly by repeating the method used in 1946 and substituting see-through water jacket panels to observe what was happening to the circulation and then installing thermocouples to record the temperature gradient.
By 1970 the competition to supply a vee engine to fit under GUY’s cab had evaporated, the high datum tilt cab had appeared and tentative plans had already been made to turbocharge the engine. There were plainly problems not just with cooling but with bearing area. If the conclusion had been reached that an increase in cylinder centre spacing was necessary then an increase in overall length of the engine would not have been too serious a handicap as far as chassis installation goes. I am sure that Gingerfold can comment on whether or not the Mammoth Minor points to overall chassis length being an overriding consideration.
The fact that during experimental and production development up until withdrawal had seen four cylinder heads replaced by two which were then modified, makes clear that if new castings were required then they had been made so one can assume that the same development would continue.
While noise has been given as an excuse to withdraw the engine, even if knowledge at the time was limited regarding what could be done physically to the engine to reduce it, sound deadening encapsulation was the method first introduced by chassis manufacturers to meet regulations. Since AEC produced the chassis as well as the engine they would have had full control over such installation significantly with being able to observe its effect upon engine cooling.
It would be particularly interesting to hear not just what modifications Perkins engineers considered necessary, but the experimental process they would have gone through to arrive at those conclusions.
As I understand it from the previous posts, the bearing problem was cured by using a harder material, and there was a harder grade still to be tried. Being careful not to use hindsight: by the end of the 1970s, BMEP had soared, due to the influence of turbochargers and “high torque-rise” engines. The bearing materials for those engines would have been in the experimental stage at least, I would imagine. Without using hindsight at all, the 1967 Mack Maxidyne straight six engine’s dimensions were 4.875x6" and its peak torque was 1228Nm. If someone can do the calculations while I go and do some real work 
, I predict that we will see that the Mack’s mean piston load was considerably higher than the AV801’s. I bet its rod end bearings were not significantly bigger than the AEC’s. If someone can find those dimensions, we can compare the two engines’ mean bearing pressure. Again, I would not expect the AEC’s figure to exceed the Mack’s. In other words, bearing to fix the problem were on the shelf.
I do not think a change in cylinder spacing would have been affordable. It would have meant new casting patterns and forge dies for all the main bits.
The noise issue would have been an excuse to kill the engine, as cav551 says, nothing more. There were plenty of engines with bigger bores and similar maximum engine speeds around at the time. Unic had their 15.6 litre, 138mm bore engine on the drawing board, and the only thing that stopped that going into produciton was parent company Fiat’s even bigger one taking its place!
Incidentally, I found this:
archive.commercialmotor.com/arti … tish-built
[zb]
anorak:
As I understand it from the previous posts, the bearing problem was cured by using a harder material, and there was a harder grade still to be tried. Being careful not to use hindsight: by the end of the 1970s, BMEP had soared, due to the influence of turbochargers and “high torque-rise” engines. The bearing materials for those engines would have been in the experimental stage at least, I would imagine. Without using hindsight at all, the 1967 Mack Maxidyne straight six engine’s dimensions were 4.875x6" and its peak torque was 1228Nm. If someone can do the calculations while I go and do some real workYes, correct, different bearing metals had been tested with good results.
I do not think a change in cylinder spacing would have been affordable. It would have meant new casting patterns and forge dies for all the main bits.
New drawings had been prepared for a slightly longer engine block and wider crankshaft big end journals but because of the cost of re-tooling the idea was not approved
The noise issue would have been an excuse to kill the engine, as cav551 says, nothing more. There were plenty of engines with bigger bores and similar maximum engine speeds around at the time. Unic had their 15.6 litre, 138mm bore engine on the drawing board, and the only thing that stopped that going into produciton was parent company Fiat’s even bigger one taking its place!
Once again as mentioned previously AEC played by the rules. The V8 engine fitted under the cab without any rear end protrusion, even if it had been made 12 inches longer there would have been minimal protrusion outside the cab, so noise encapsulation would still have been good. Compare AEC’s adherence to the rules with Gardner’s approach and its 8LXB. On a day cabbed Atkinson, ERF, Seddon, and Guy
Incidentally, I found this:
archive.commercialmotor.com/arti … tish-built
It isn’t possible to redesign an engine in a couple of hours even these days, so let’s not get too ■■■■■■■ in the minute details, but running all the figures through today’s design technology was an interesting if pointless exercise, especially in light of ‘gingerfold’s latest post.
I asked them to run the basic calculations based on a slightly ambitious maximum design output of a reliable 450 bhp (projected 100’000 mile overhaul in line with Perkins engines of the day - AEC usually substantially exceeded this).
All the initial AEC V8 design constraints had to be observed, so the outside width and hight dimensions of the engine remained unchanged. The AV801 bore dimension of 135 mm remained with the 114 mm stroke, with turbo charging applied. As far as was practicable, the calculations were based on the recommended oil specification available in 1968, and the Glacier ‘SB’ bearing material used for the later production run (the ‘SC’ material was developed post production).
The valve lift, inlet and exhaust valve head sizes and connecting rod cross section were all found to be satisfactory, as were (surprisingly) the main bearing journals of 95.184 mm diameter and 43.70 mm (front), 56.00 mm (rear), 47.65 mm (centre) and 47.72 mm (intermediate). This gives a combined projected bearing area of 235 sq.cm. Adequate.
The original big ends were inadequate by some margin because the calculated oil film pressures developed on the bearing surface were excessive. The original design used a crankpin diameter of 88.9 mm with a bearing shell width of 28.5 mm. The minimum requirement for the proposed power needs an increase in area of 21%, which keeping the 88.9 diameter could be achieved with a width increase of 6.2 mm per bearing. This would take the combined projected bearing area upto 247 sq.cm, just 2 sq.cm over the absolute minimum calculated requirement. This would require a crankshaft 49.6 mm longer than the original.
Obviously a longer crankshaft requires a longer cylinder block, heads and all the ancillary components. A 50 mm longer block would allow a 16.5 mm increase in the cylinder spacings - and according to the information available, that would be enough to improve coolant circulation dramatically. Just visually judging the thickness of the block cylinder wall (from photos of the sectioned engine), and the block deck coolant passages, they suggested that there looks to be slightly too much material present. An experienced eye suggested that 5% could safely be removed from this area, further opening up the coolant passages. We did discuss the AV740 engine and it’s 2.5 mm thicker block cylinder walls (on the piston side, of course), and the consensus was that at full load, with the pistons being so short, they probably would not be able to transfer enough heat through that thickness of iron into the coolant.
But then we knew that!.
The pistons of the AV801 at it’s original rated capacity and design would be able to transfer enough heat, but teeth were sucked when turbo chargers and increased BMEP’s were mentioned. The theoretical 5% material reduction was considered enough with the improved coolant circulation of the extra block length and cylinder spacing to comfortably allow enough actual heat transfer to take place. All theory of course.
But the pistons are another matter. They say there is no way that the original design of piston could possibly operate at 450 bhp to be reliable in service. Oil galleries cut into underside of the piston crown and piston cooling oil jets would help, but they still said that in 1968 the aluminium piston capable of handling the proposed power at the original piston dimensions was probably not available. Composite pistons, or special lightweight cast iron pistons were a possibly, but hugely expensive back in the 1960’s.
It is interesting to note these findings, and does demonstrate just how very close Keith Roberts and his team came to developing a successful engine. I was perhaps a bit ambitious proposing 450 bhp, 350 bhp was the figure that the AV810 engines were tested at, but I think the conclusions are interesting all the same.
To summarise the above, 450bhp, 100,000 mile overhauls and SB bearings with the oil of the day would need a longer everything and pistons made of unobtanium.
[zb]
anorak:
To summarise the above, 450bhp, 100,000 mile overhauls and SB bearings with the oil of the day would need a longer everything and pistons made of unobtanium.
- Would the SC bearings allow the 450bhp, I wonder? What would the expected overhaul interval be then, disregarding the piston issue?
- What about 350bhp? With the SC bearings, the 5% thinner cylinder walls and the oil galleries in the pistons, what would the overhaul interval be?
When Keith Robets initially designed the V8 he wasn’t designing a 450 bhp engine. I pulled that figure out of thin air just to see if anything within the engine had been designed with the potential for that sort of output, and I was amazed to find that some of it had. With the above modifications to the AV801 design and original Wellworthy aluminium ‘Alfin’ pistons, they said it should run totally reliably in turbo charged form at 300 to 350 bhp, which is exactly where AEC envisaged it.
Overhaul periods with the modifications are difficult to calculate because of all the variables, but with the correct oil and regular oil changes at intervals in line with AEC six cylinder engines, bearing life should be comparable. Glacier ‘SC’ material proved to actually give the big end bearings an acceptable (100’000 mile) life at their original width, so if applied to the longer crankshaft design they would perform even better. The bearing material modification from ‘SB’ to ‘SC’ was achieved for TL12 development, not specifically the V8, and as I understand it the bearing surface material was changed - not to make it harder, but to improve it’s oil retention ability so that the oil film could be retained at higher loading pressures.
My own conclusion, based on all of my involvement, is that making two capacities of V8 engine from exactly the same block casting was a step too far, and the AV800 and AV801 should have been the only engines produced. Big end issues apart, the AV740 engine was always going to be challenged by it’s thicker cylinder walls and protruding liners requiring the head gasket fire ring to seal around the outside of them. The AV691 engine suffered exactly the same liner and head gasket problems due to this design.
The AV800 and AV801 cured the liner and head gasket problems in the same way the AV760 did, with thinner cylinder walls and by pressing the larger diameter liners fully home into the block counterbore, sealing the head gasket fire ring onto the liner top. You can see that in the sectioned AV801 photos above. If the original engine design had been drawn up with the same 25%+ margin built into the big ends as was applied to other parts of the engine, instead of working at the absolute engineering limit of those components to make the engine as light and compact as possible, I have absolutely no doubt that in AV800/801 (and turbocharged) form the engine would have been an outstanding success.
But then Keith Roberts knew all that.
At the end of the day they were testing prototypes, that’s all.
They had done all the difficult work in getting the combustion process honed to produce exceptionally good power and torque characteristics from the engine, sorting out the shortcomings of the basic design had been shelved for a rainy day with extra funding, but the call to put the flawed engine into production came first. Producing drawings and new casting patterns for all the slightly longer components was a big task, but it was bread and butter work to these people. It’s such a shame they were not given the time, funding or opportunity to do it.
Without doubt it was an outstanding effort and as ERF says you don’t design an engine in minutes.The conrod/big end bearing size issue which to a degree is a problem on vee engines could have been addressed in the same way Deutz approached the problem and that was to off set the big end of the rod towards the front or rear and like wise remove material from the crankshaft to enlarge the width of the journal.
My main worry at 350hp would be piston failure,more so without piston coolers being fitted and the inefficiency of the dry liner set up.At a time when most were using wet liners,i wonder why AEC choose dry,maybe for block stiffness?
Sorry ment width of journal,my mistake.
Block stiffness was definitely an issue.
Even today they say that a V8 Diesel engine of the AEC’s bore, stroke and physical dimensions could not be built as a wet liner design without seriously compromising block stiffness.
Just in case anybody is interested, these are the comparisons in ‘SA’, ‘SB’ and ‘SC’ bearing materials from the Glacier catalogue…
