Charles Griffin , Director of Engineering at the Austin Morris Division , discusses the Austin Maxi with the Editor .
Charles Griffin – This car has been a general talking point for a long time in that the big market place outside has been shouting at us to produce a 1½ litre car to fill the fairly large void in the Austin/Morris range between the 1100 series and the 1800 . Of course we have been conscious of the gap – although the void was very much greater when the ADO16’s had 1100 engines than it is now they have 1300 engines .
Editor – Was another front drive vehicle explicit in your original thinking about the car ?
Charles Griffin – The thought that it might not be front-drive never entered our heads . Or that it might not be Hydrolastically sprung . It was only a question of how we were going to apply these proven techniques . This new 1 ½ litre car is the latest thinking we’ve got on the front drive , transversely mounted Hydrolastically sprung concept .
Also we had to meet the criticism from some quarters that the only thing wrong in our high volume specification is that accommodation for luggage is a bit on the light side . We felt that to exploit the specification to the full , the right logical solution was a five-door vehicle that would give the total envelope over to luggage – or such proportions of it as the operator might care to use , down to a normal boot . In other words , it is an estate vehicle with the appearance of a normal saloon .
Editor – Can we talk about the engine and the transmission ?
Charles Griffin – You know , of course that the engine has an overhead camshaft ?
Editor – Yes…..but why ?
Charles Griffin – Because this is the right way to make an engine . It is right to try and get precise followings between the camshaft and the tappet , and to get the right message to the valve timing . And it’s very much more accurate when you’ve got the direct mechanism of an OHC than when you’ve got pushrods and rockers and things . We are , probably , ahead of the main race in this . On the Continent , of course , they’ve got OHC engines coming quite rapidly – and there are one or two competitive engines in this country . We have a head start .
Editor – Are there any problems for the man behind the wheel ?
Charles Griffin – No problems , but perhaps a change of habit . The big point about this engine is that the driver hasn’t got to worry about the use of engine speed , he can use more revs . We have here an engine that is very happy up to about 6500 rpm or more , but it does , of course , look a very big car for a 1 ½ litre engine . But if you start to use the engine and gearbox as they are supposed to be used , you get real performance . There’s no problem at all in winding up to very high speeds on autobahnen , autostrade , and motorways .
We have a 70 limit in Britain , of course , but there are plenty of places where people go for holidays where it is still a free for all , and they are going to get a lot of enjoyment out of using the very long legs we’ve given this motor car . They’re going to get the performance with durability that we think they are going to expect .
Editor – How long has it taken you to reach production ?
Charles Griffin – We produced the research engine something like six years ago . The engine that is coming in on the car has been developing over about the last four years .
Editor – Can you tell us about the testing ?
Charles Griffin – Well , as we are talking it’s away in Finland – it was there last year too – taking advantage of the extremely low temperatures that obtain just inside the Artic Circle . We are testing down to the order of 50 degrees of frost . From the time we started out on the project our total experience on the engine and gearbox is in excess of three quarters of a million miles .
Editor – Why did you use a five speed box ?
Charles Griffin – The short answer is : somebody had to take the initiative in this . Once again , as with front drive , we’ve done it . You can’t talk about this without bringing in overdrive . The real objective of an overdrive is to increase the relationship between road speed and engine speed . The normal fourth speed , depending on the power to weight ratio , lies somewhere about 15 ½ -mph per 1000 rpm for the normal family saloon . Now overdrive lifts all that up to about 19 ½ -mph per 1000 rpm . People buy an overdrive because they just don’t like fuss when cruising . We have therefore built this feature into our car with a fifth speed , replacing the need for an applied separate unit .
Editor – What you’ve gained , then , is smoothness of the engine at cruising speeds ?
Charles Griffin – Yes . Very low revs on an engine that doesn’t mind high revs and , in consequence , more durability for high speed cruising . Mind you – having driven the ADO14 for many miles myself – I use fifth speed almost continuously . I find myself not waiting to get onto a motorway to go into fifth speed . When I want to listen to the radio at 50 mph , that’s the time I enjoy fifth speed . The noise level comes right down , and you’ve got something very nice and refined .
Editor – Has it , for some reason , been difficult to produce a five speed box till now ?
Charles Griffin – Gearboxes are things that tend to go on and on in production , and you’ve got to make this decision at the start when designing a new gearbox – a difficult decision on a high volume production motor car . All the time you are trying to keep the price down , of course . Our big advantage was that we were starting with a brand new factory – no problem of carry over materials , you see – and a brand new car . What we can say is that we have the advantage of an overdrive built into the price of the car .
Any person who is really comparing the ADO14 with a competitive ‘buy’ at the same price should look down the brochure and say ‘Well , I must compare this with the overdrive version of the competitive vehicle’ – because this is what the ADO14 is . On that basis we are very attractively priced . There is no more maximum speed in fifth than fourth , except on a very long road with a fair following wind . We don’t think that this part of it is very important . What is important is that when a man has reached the speed he wants to cruise at he is able to slip into fifth speed , rest his engine , and live a quiet life .
Editor – You said earlier on that Hydrolastic was an automatic choice for the suspension .
Charles Griffin – Yes , but it wasn’t quite a straight forward transfer of units – in this case the ADO16 size – to the new car . As I said , the ADO16 size Hydrolastic units are used for the total suspension – which tells you the amount of reserve in them . You know , we’ve got something like 1½ million road testers out on the 1100/1300’s who have proved the systems durability . How do I know ? Because we’ve really no service business !
On the ADO14 we’ve given the units different damping characteristics and so on . Let’s take the front suspension . You could call it an embryonic sub-frame with a cross-tube , something like the 1800 , but ‘rubbed off’ from a joint study of the 1100 and the 1800 series . It is a definite contribution to the vehicle structure . Instead of being fluidly mounted through rubber it is bolted to the structure – which means that the car itself doesn’t have to carry the additional structural weight burden which goes with fluid mounting . Here’s another example of what I would call ‘incremental progress’.
The lower control arm of the suspension is in an A-type bracket that is rooted into the very rigid part of the structure at the base of the toe-board – instead of forward mounted to the more flexible structure at the front of the motor car . The sub-frame , as I said , has a cross tube , something like the 1800’s but here’s the difference . We take the Hydrolastic hoses out through the bottom of the cross-tube and run them straight under the floor instead of out into the engine cockpit and then going back .
The important gain here is more free space round the engine for doing normal service operations . The rear suspension has its two displacers mounted at the inboard end of the trailing arm , and these are on small separate mountings attached to the heelboard and floor . All the forces that actuate the spring – big forces , something like five times the wheel load – are contained on a common axis . The inboard end of the trailing arm is gimballed – it’s on a ball that is on the centre line of the displacer so that all the forces are contained and simplified . The outside end – the wheel end – almost in the plane of the wheel , is the rubber support bearing which supports which recognises only wheel loads . It hasn’t any of these multiplication loads , loads that are contained with the Hydrolastic unit .
Editor – And this adds up to what ?
Charles Griffin – Good fore and aft compliance and refinement . This has deleted the need for a sub-frame at the back of the car .
Editor – Can we round of this interview with a general summing up ?
Charles Griffin – We think that a very wide variety of operators are going to find that this is exactly the sort of motorcar they are looking for because it is very much more useful than an ordinary car . For instance ; until now , if you wanted the station wagon facility , you had to have something that didn’t look like a motor car . In the UK this is the first time really that we’ve given the best of both worlds .
Our ultimate motivation is based on the fact that a motor car is essentially an extension of a person ; motoring is a very personalised activity . We have tried to give the customer what he wants – what we feel he wants – an entirely new car with enormous carrying capacity , easily and economically serviced , and attractively priced .