Читать книгу Aston Martin Engine Development: 1984-2000 - Arthur Wilson L. - Страница 11

In 1972, I was offered a position in the experimental department on engine development, primarily on engine test bed development and carburetion. I would be working for David Morgan, who was chief engineer on engine development reporting to Harold Beech, who was head of design. You can imagine how pleased I was, although it did mean a drop in earnings and any overtime was to be unpaid but expected.

This was a very exciting time for me working directly for David in the experimental department at AML and later on within Aston Martin Tickford (AMT). Also during the Tickford days I was fortunate to work closely with Alistair Lyle, who was chief engine designer for AMT. I learned a great deal from Alistair in the process. They were busy times and it would not be possible to cover it all in this book, but the following is a taster.

The early part of my time in the experimental department was mostly taken up with the move to carburettors on the V8 engine and, in particular, the USA version.

Contrary to some of the more fanciful stories that I have read, the reasons for moving on from the Bosch mechanical injection was no more than the normal process of product development by both parties. Bosch was going away from mechanical injection and we would have been the only people using it (if Bosch would have been prepared to produce and support it for such a small volume). The complete system was also quite heavy and it was quite complex and time-consuming to manufacture and set up when compared to a carburettor installation. Carburettor technology of the time was not standing still and it was possible to achieve a good balance of power and emission control using four Weber twin-choke 42DCNF carburettors. Drive ability was improved, performance was at least on a par and fuel consumption was slightly improved – the only downside was the need for a power bulge in the bonnet. From an engine development point of view, it was much easier to make changes to the carburettor calibration in-house, whereas any changes to the calibration of the Bosch metering unit meant Bosch involvement. Again the question of continued Bosch support has to be considered, taking into account that they were going away from the mechanical system and our small-volume manufacture.

Times were hard for the UK motor industry as a whole during 1973/4, and just before Christmas 1974 we were all taken to a meeting at the local cinema and told that the company was going into receivership and that we would be made redundant. This was a bit of a shock to say the least. Somehow I had to earn a crust, so I started up working for myself rebuilding race engines and tuning carburettors, etc. on various exotics including Astons. I was doing pretty well but when, in 1975, the call came to go back to AML, I couldn’t resist – it just gets into your blood. When I started back in what had been the production rectification area there were two other guys already there, Bill Harris and John White. Roger Date re-joined a week after me. We were putting together cars that were part finished and I was required primarily to set the engines up but we all pretty well tackled anything on the car. I still had jobs in progress at my workshop, so for a while I worked all day at AML and at my workshop in the evenings.

Eventually things began to pick up and AML was reborn as AML (1975). And as departments slowly started to regroup I was invited to re-join the experimental department by Mike Loasby, who was now in charge of the department. Harold Beach was retained as a consultant.

Thus began a very busy period as the go-ahead for the new William Towns-styled Lagonda had been agreed. There was a huge enthusiasm and spirit within the revived AML, which was just as well because the target for the new car was set for Earls Court, October 1976. Every effort was put into that car, with everyone doing whatever was needed, whenever it was it needed, I even did coach lining. We made it, just. I think that I fitted the last bit on the stand at Earls Court, the solid silver motif atop the grill. There were some other memorable Lagonda moments as well. Dennis Flather was able to make special arrangements for a Lagonda to enter the 1977 London to Brighton run and I was given the privilege. I believe that this was the first time a modern car had been allowed to enter.

The Lagonda was a completely new car and chassis with a very low bonnet line and a new engine bay. The new engine bay layout would allow us to lower the engine but would require a smaller oil sump capacity for ground clearance and a new oil pump. But even then, the low bonnet line would still restrict the air intake system. To offset this, the compression ratio was raised and larger 2.1" inlet valves were fitted along with new camshafts to boost mid-range torque. Much work was done on the intake system to optimise the limited space available above the carburettor intakes. Various attempts at smoothing the flow by shallow trumpets and different air entry points to ensure even distribution resulted in a gauze dome or flame trap over the carburettor intake being the best, combined with a side-entry air box. The gauze domes really work, particularly in the mid-range. Top-end power was always compromised by the low bonnet line up to the introduction of the 1985 injection engine cars, which used the same engine as the V8 Coupe of the time, so had comparable power.

A higher performance version of the V8 engine was to be developed for a new, more performance-biased version of the V8 Coupe, a return of the Vantage name last used on a six-cylinder car. The engine was developed using 48 IDF carburettors feeding through 1.5" inlet ports to 2.1" diameter inlet valves, new pistons and camshafts and higher compression ratio. A twin four-into-one manifold and exhaust system was developed specific to this engine. It produced 370 bhp at 6,000 rpm with 350 ft/lb of torque at 5,000 rpm. During the road and track development stage we had a real problem with keeping the spark plugs clean on this engine specification, although the heat range was correct for full power running. MSD ignition helped but the eventual cure was to use NGK BP6EV spark plugs, which worked very well. Thus began a long and happy association with NGK and I have always specified NGK plugs ever since.

The car was also extensively changed aerodynamically, with front air dam, blanked radiator grill, Perspex covers on headlamps and a flip tail rear spoiler. All of which resulted in a remarkably low drag factor for such a large frontal area car. This had involved considerable night-time testing in the wind tunnel by the engineers responsible. Night time testing was cheaper. We also did track testing with short lengths of wool attached to the front and side bodywork. I can remember driving the development Vantage down the timing straight at MIRA at an indicated 170 mph, with guys at the side of the track taking photos. The suspension was developed after extensive track and road work to include Koni shock absorbers and Pirelli CN12 tyres on 7" rims.

In those days we had no shortage of good analytical test drivers within the department. We also used the services of people like Ray Mallock and Bill Nicholson. I once had the pleasure of going testing with Bill Nicholson. For some reason I had been off work unwell. I was still feeling a little second-hand when I returned to work, only to be told ‘you are going brake fade testing with Bill, that will sort you out’. Brake fade testing is not pleasant for the copilot at the best of times, with repeated hard braking from 100 mph upwards. I survived but I have to say that I have never been driven so relentlessly hard for every inch of road between Newport Pagnell and MIRA. Compared to the trip to and from MIRA, the brake fade testing was a breeze, Bill could really drive a car. Bill also did a lot of the durability and chassis development driving on the Lagonda. If it was going to break, Bill would break it. I remember that he knocked off a number of engine oil filters while landing the other side of a particular humpback bridge on the test route before we tucked it up far enough out of harm’s way.

The first customer V8 Vantage cars were converted from standard V8s from the production line. They were passed over to experimental to be converted individually in a small area of the experimental workshop. I was made responsible for this process and the sign-off after testing. From memory, I think that the rolling road sign-off required something of the order of 300/310 bhp at the rear wheels. All cars had to achieve an indicated 170 mph on level ground. The cars were then returned to the production line for final finish and valet. One very keen customer had his car delivered straight to Silverstone circuit to enter it in an Aston Martin Owners’ Club (AMOC) race, which he won.

USA certification was looming again and eventually I had to go out to the EPA facility in Ann Arbour, Michigan with David Orchard, who was in charge of the safety and legislation department at AML, to certify the USA specification car. This was my first trip abroad for the company but luckily David knew his way around, having been there many times before. There were a few hiccups, not the least of which was the shipping company at Detroit airport losing track of the container with our certification car in it. But they eventually found it some days after it had arrived. After we had successfully certified the car and had our fill of Ann Arbour’s buzzing nightlife, we were invited to stay with Peter Sprague for a few days so we drove upstate, stopping off at the Niagara Falls on the way just to have a look. We enjoyed Peter’s hospitality in what is a stunningly beautiful part of America. Over the years I have had many enjoyable trips to America on company business.