Extract from an article entitled “The Enigma of the AEC V8 Engine - Why was it ever Produced” written by Bob Fryars, Chief Engineer of AEC and Leyland Truck & Bus, for the AEC Bulletin, June 2014.
Extract:
Why did AEC in the mid-1960s put considerable talent and investment into designing and manufacturing a new engine and accompanying chassis models that were in direct competition to highly successful units already in production? I believe I can throw some light on this puzzle.
Previously I have explained the background to Guy Motors’ bankruptcy, their acquisition by Jaguar, and the attempt to entice ■■■■■■■ to manufacture their V6 and V8 engines in the old Meadows factory next door in Wolverhampton. Sales of loose engines to such as Dodge and Guy had become an important part of AEC’s business, so John Bowley, AEC’s general manager must have wasted no time in telling Lofty England of Jaguar / Daimler that AEC could match ■■■■■■■■ So the concept of making a V engine was launched.
This was in 1961 when discussions on AEC becoming part of BMC were well advanced. I had found that our two truck ranges were a good fit together. It was clearly ACV’s strategy that to meet the coming threat from big continental manufacturers in the Common Market, AEC must become part of a big group for economies of scale. So when John Bowley requested a V engine study he clearly had in mind also broadening the range of industrial engines AEC could offer. The dry-liner version of the AV690 to become the AV691 and the 760 was well in hand as were plans to do the same for the AV470 to meet rising demands on power output.
When Keith Roberts and I obtained copies of the ■■■■■■■ V engine patents we found these cleverly covered the best cylinder bore to stroke ratios. To avoid the patents meant either a long stroke tall V, or a squat over square V engine. We quickly decided a V6 would be a very rough unit at the 90 degrees V essential to fit in a chassis - and ruled out that option. So we were looking at a very over-square V8, one well outside any known direct injection combustion chamber relationship. Then there was noise. Theo Priede, than at CAV, had recently come up with an empirical formula linking diesel engine noise emissions to the square of cylinder bore diameter and to rotational speed. An over-square diesel would be a very noisy unit, which added to the difficulties.
John Bowley proposed a compromise. To deal with technical aspects we should make a short-stroke in-line research engine. We should only scheme a design for a V8 and check that it could be accommodated under BMC’s new FJ cab. Bowley had his V8 brochure by the late spring of 1962 (but no engine!) - a time of turmoil in the motor industry with a disastrous outcome for the future of AEC.
Late in 1961 Rolls Royce had complicated matters by proposing how a tripartite arrangement could be made with ACV. This was soon discounted and ACV merger talks with BMC continued, only to be discontinued when financial forecasts for BMC were shown to be dire. By then ACV had discounted possible mergers with such as Scania, leaving Leyland, reluctantly as the only possible partner.
But the AEC board may not have been aware that at the very same time Leyland was in serious difficulty with its purchase of Standard Motors that could become a catastrophe big enough to bankrupt Leyland itself. Chrysler had arrived on the scene intending to buy a share in Leyland.
August 1962 and the “merger” with Leyland was quickly concluded, much to the dismay of middle management at AEC. I had to make a presentation to the new group board about the development of the 760 and 520 engines, which was scaled back to become the 505. The V8 project, still a brochure at this stage, was mentioned in passing, but nothing more was heard about it for more than two years.
Following this presentation and policy meeting, much later I discovered that in total secrecy Stokes had ordered all further AEC engine development to be stopped in favour of new Leyland designs - The Tattersall Engine.
Norman Tattersall from Leyland Motors had designed, working in secrecy, concept tank engines, based on the Leyland L60, which incorporated “throw-away” cylinder blocks, and with all gear-driven accessories to eliminate belts. Sight unseen of any actual engine Stokes persuaded the board to approve building and equipping a new facility to produce 300 Tattersall engines weekly. But when the 700 (as it was called) prototype engines were tested they suffered major structural failures within hours. But the unusual shape and weight precluded its installation in any Leyland Motors Truck or Bus model. (Except an old bonneted Beaver).
Donald Stokes instructed Dr Albert Fogg to salvage something from this impending disaster, and with input from Ricardo the Tattersall engine was re-designed to at least run satisfactorily. But it was still too big to fit in any normal chassis. This concept was dead in the water, so a scaled down version which became the 500 Series was designed. Naturally aspirated it would produce 160 - 170 bhp, but not powerful enough for the proposed 32 tons legislation impending for 1965.
So why, in this quite dreadful scenario of a failed secret Leyland engine strategy, did attention suddenly turn to the AEC V8? A new updated concept paper was demanded urgently to show a V8 installation under the new Ergomatic cab.
What objective had Donald Stokes and Bertie Fogg in mind? I do not think we shall ever know for certain, since Stokes never put on paper a record of the verbal instructions he gave. Bertie Fogg would never, ever discuss the question. I had to assume that his job would have been on the line if he had ever breathed a word about this Leyland Motors disaster. The AEC V8 “brochure” engine was rapidly rushed through development and into production. The later V8-810 version with Mac Porkess in charge of development at Southall was showing great promise as a turbo-charged unit at 350 bhp, but noise was still a problem and I had to pull the project in favour of the TL12, which at 280 bhp fulfilled our immediate needs in the mid-1970s.
In conclusion I believe the V8 only ever came into production as a second string solution to the almost unbelievable shambles that that the highly secretive Tattersall engine concepts had produced at Leyland. So I have always been proud of how well AEC people designed and developed the V8 and walk-through Ergomatic cab.
But an over-square V8 was never going to be capable of meeting noise, and later, emissions regulations. On both counts, diesel engine bore-stroke relationships would optimise at very conventional ratios for all vehicle applications.
End of Extract.
There is plenty more in this article worth reading, so I have selected what I think are the relevant parts. Suffice it to say… one disaster begats another disaster.
