OBSERVATIONS ON THE AUSTIN SEVEN "NIPPY"
ON THE AUSTIN SEVEN ” NIPPY ” OBSERVATIONS
THE •• N. ii ipy Austin Se Veil seems to be a rather humble motor car about which to write in the pages of AIOTOR SPORT, but the following few notes are inspired by the recent sight of my faithful ENE 603 standing, fortunately undamaged, amid the remains Of a flybombed garage.
The “‘Nippy ” was bought in the spring of 1938 to replace a ” 12/40 ” Lea-Francis which was getting rather long in the tooth to provide reliable daily transport to my place of employment, without an extensive overhaul. As I was at that time quite a firm supporter of the vintage-type of car, I viewed the newcomer with a certain amount of suspicion, which was in no way alleviated by the loss, after some weeks of ownership, of two big-ends on the way home one evening, and the consequential ignominious end of that run on a tow rope. Since then, however, the ” Nippy ‘ . has endeared herself to me and has been responsible for converting me into a very keen Austin Seven enthusiast. For those readers who are not familiar with the ” Nippy ‘s ” speeilicatiori, it generally follows well -I rieil Austin Seven lines, but quite a large proportion of the parts are different from the standard type of that time. The front axle beam is dropped as in the ” Ulster ” model, and a reverse-camber front spring is used, with rear springs that are flat, to lower, the car. At the time that the ” Nippy ” was designed, vintage ideas as to the functions of road springs were still ruling at Longbridge, as the springs have the same number and thicknesses of leaves as the 5-cwt. vans. The steering gear is lowered by using the same steering-bOx as was used on the “Ulster,” Which rakes the column and drops the wheel into the driver’s lap to give a very comfortable driving position. Brakes are exactly as on the standard car, and so is the rear axle, except for a crown wheel and pinion giving a final drive ratio of 5.625 to 1 instead of the usual 5.25 to 1. The gearbox is known as a close-ratio box, but as the box ratios are 1, 1.49, 2.87 and 3.79 to 1, It must be taken that this is Capt. John Moon, a very capable student of design, as “Motor Sport” readers .know, and a keen member of the 750 Club, writes of his experiences with, and modifications made to, a 1935 model —the size of sports car many
people will run after the war.
meant as a relative term only. The getarboxes fitted to the “
Nippy models varied from year to ye:ii iii the same way as they did for the standard cars. In 1933, towards the end of which season the “Nippy ” started life as the Austin “5,” the boxes had no synehro-mesh, but constant-mesh third gears ‘only. For 1934 there is synchro-mesh engagement for third and top, and second gear is in constant mesh, but is engaged by plain dogs. In 1035 and onwards, the top three nit ios are all constant-mesh and are .synchro-,111.sh engaged. Ratios are swapped hv means of a long, cranked gearlever, which is not very satisfactory, as its knot) is still some way from the steering Wheel. and quick movement with one’s arm outstretched is not an easy matter’. This point I have now attended to by fitting an enclosed type remote control of my own design and construction. The engine follows the design of that of the standard car quite closely, but, nevertheless, it manages to differ from the standard engine in all its component parts except the timing case, the flywheel, and sundry minor parts. The crankshaft is a very massive affair, machined all over and with bigends, but oil feed to these big-ends is still by means of two jets in the side of the crankcase, which squirt oil into rather shallow pockets milled out of the webs’ of the shaft and which lead into the journals via drilled oilways. This lubrication system is, to my Mind, the chief snag with the ” Nippy ” and has been the cause of nearly all the trouble which I have had with my car ; but more of this later. A few ” Ninnies ” of ’36 and ’37 vintage are fitted with the ” Speedy ” engine, Which has pressure feed to the big-ends, through the front end of the crankshaft, which is more reliable. This engine cost an extra £25 when fitted to the ” Nippy.” The connecting rods are also machined all over and have fullyfloating gudgeon pins which bear in an unbushed little-end in the rods. The connecting-rod caps are retained, by two bolts, whose nuts are locked by locking plates and not by the usual split pins. The cylinder block is cast in Chromiditun, but in other respects does not differ from that of the standard Seven. The head is the same as that fitted to the earlier ” Ulster ” models, and, I believe, gives a compression ratio of about 7 to 1 with a normal-thickness gasket and a bit more with the correct ” Nippy ” gasket, which is soniewhat thinner than the standard one. The valve gear is the same in design and layout as that of the standard Seven, though all parts are different, starting with the camshaft, which gives a lift of about 1-in. and an overlap of 20″. Tile tappets are adjustable, which I always feel is rather a mistake, as valve bounce is generally the limiting factor on the ” Nippy ” due, I think, to the short valve springs which the adjustable tappets necessitate, and also to the not inconsiderable reciprocating weight of the tappets themselves. The light, hollow tappets with hardened buttons and the longer springs of the ” Ulster” never give trouble in this direction. The camshaft is driven by a pair of steel gears, whereas the normal Seven has east-iron timing wheels. The induction manifold is an aluminium casting carrying the 30-mrn. downdraught carburetter, which feeds down into a bored horizontal passage and thence down into the two siamised inlet ports in the block. The inlet manifold bolts to the exhaust manifold to give a hot spot directly below the carburetter. This exhaust manifcild is of a somewhat peculiar shape, but the negligible improvement resulting from the substitution of an ” Ulster ” outside manifold suggests that it must be of fairly efileient layout. The
carburetter is :4 Zenith VEI, which differs from those Zeniths fitted to larger Austins and most other cars in having a rather larger selection of holes and jets drilled in it. The ” Nippy ” generally takes a 21 choke, and I have used quite a variety of jet combinations at different times, with, curiously enough, different results !
The crankcase has grooves cast in it to accommodate the large big-ends. The sump is quite a deep affair, cast in aluminium, with ribs on the bottom. The instruction book and all other sources of information give the oil capacity as four quarts, but I have never been able to persuade mine to take more than three.
As I am one of those who dislike the Le Mans style of body with a flat tank at the rear, I approve of the ” Nippy ” body for a car of its type. There is very comfortable accommodation for two, with reasonable luggage space at the back of the seats under cover. If more space is required, quite a lot can be piled on the opened cover of the spare wheel compartment of the tail, though, as this is really abuse, a certain amount of discretion is needed. I have once even gone as far as to carry a complete wheelbarrow in this position, though not without having a very guilty conscience. Very early ” Nipples ” had aluminium-panelled bodies, which are very liable to split in various places, but the steel panelled bodies, as fitted to the 1935 and later cars, are quite free from this trouble, and last remarkably well considering that the chassis frame stops short in front of the rear axle and that the body supports itself and the petrol tank from there back. The hood gives quite good weather protection in spite of the absence of side
screens on 1935 models. Like all smallcar hoods, it is complicated to erect, and possesses an astonishing propensity for tying itself into knots when being erected during a thunderstorm. It stows away quite neatly on top of the folded hoodsticks behind the seats when eventually it is dismantled. The windscreen is quite a solid affair, some 1 in. higher on 1936 models than on the earlier ears. Unfortunately, it only opens upward, but I have in mind a simple conversion to enable it to fold flat, which I shall probably effect after the war. The single screen wiper had. advantageously been replaced by a dual one, with the motor on the near side, so improving visibility over the near-side wing with the screen open for blackout driving.
The dashboard instruments are rather meagre and not too good, no rev.-counter being fitted, while the speedometer is of the horrible ribbon-type which were being produced by Smith’s at that time. I have added a thermometer and a second oil pressure gauge, which does not have such a depressing tendency to read zero as the original one has, and also lets me know what the oil pressure actually is when the car is being warmed-up.
Perhaps the most valuable modification which I had carried out was a tonneau cover which fits over the hood-sticks but under the furled hood, the latter being enclosed in its original cover held down by additional press-studs. The tonneau cover can also be used when the hood is erected, so preventing the seats from being wetted by rain blowing in at the sides. The brakes I found to be reasonable, provided that One used the hand and foot controls together and pulled hard. This
was rather beyond a girl friend who used to drive at the time, so I forestalled disaster by fitting a set of the longer cam levers which were fitted as standard to the 1936 cars. The 1936 front-type levers fit both back and front on Austins with flattened rear springs, but where the rear springs are not flattened, the 1936 rear-type levers have to be used, together with new brake cables with fork-end instead of ball-joint connection to the levers. By this modification, Austin brakes are improved in power, but the snag of unequal application of the front ” stoppers ” remains. I do not trust the so-called self-lubricating camshaft bushes, and shall drill mine through for greasegun lubrication when I get an opportunity. One front brake seized on, once, due to these bushes. External brakepull-off springs are well worth fitting, as the brake shoe springs easily get tired. The final answer to the brake problem is, however, to my mind, enclosed-cable operation for the front wheels, and this again is a modification which is on the waiting list. All the steering rod joints require watching and lubricating frequently. Later models have grease nipples for the pushand-pull-rod joints, and these are well worth fitting, as otherwise it is a job for a force-feed oilcan. The springs that load these same joints are very liable to col lapse, so causing steering backlash.
The 1935 propeller-shaft (front half) is a Hardy Spicer, but not of the needleroller variety. Mine developed a certain amount of backlash, and was advantageously replaced by a needle-roller type as fitted to 1936 and later cars. This entails changing the coupling flanges also.’
I have had a certain amount of trouble with the engine, and so have all the ” Nippy ” owners that I know (and that covers quite a large ‘mintier of cars). The crux of the matter. to my mind, is this. The spit-and-hope ” method of big-end
I ubrication is perfectly satisfactory for t he standard I -in. crankshaft, especially with the quite sizeable oil pockets forged in the crank. hut the rather small pockets machined in the ” Nipp ” crank seem to collect only the barest sufficiency of oil for the larger 11-in. journals. As soon as there is any interruption in the oil supply, such as a partially-hlocked jet, the big-ends run short of oil and start to lose their white met II in small fragments. This is a cumulative process, and unless the oil is ellaitged very frelpiently, one gets pieces large enough to completely block the jets. and then its all over very shortly. All the ” Nipples ” that I have known have suffered the loss of one or more hig-eials, .2-cia•rally Followed by the loss of other, -41(,rtly afterwards, caused by failure of the repairer to strip the engine completely 1( )r cleaning out the white metal. This must l)e done exceedingly thoroughly, even to the extent of removing all the brass plugs; screwed and riveted into the end of the drilled oilways. If this is done and the big-ends are fitted with the correct clearance. the engine run-in earefully. and the oil changed conscientiously every 1,00() miles. I think that a ” Nippy ” engine will give good service aml will he reliable. There are, however, two attend lives. The first is to use a pressure-fed crankshaft (as used in the ” Speedy ” or ” 75 “
model, and in one or t NV() ” Nipples-) in which the oil is fed info the drilled crankshaft through a white-metal-hued bush which runs on a parallel portion of the starting-handle dog.
Unfortunately. to convert an engine in this way takeS a In Mt £20 w(irth of new parts parts that one is not likely to be able I» pick from a breaker. citli(1.. The second alternative is to use a tuned standard engine with the 1 crankshaft and spit-and-hope big-end lubricat ion. I did this during the early part of II e war when the main bearing races of tlie ” Nippy ” engine worked loose on the crank. (This is another playful little I rick that these engines play.) This engine was built up with the erankease out ()I’ an Austin Seven van, and the rehored block, rods and crank of an earlier engine that I had by me, and was alisohility standard except that the “Nippy’s” m downdraught (st rburetter and manifidds were used. This engine gave ccellent pulling at low speeds. but maximum speed, and acceleration in the higher ranges, were considerably eurlailed. It mail(‘ a very satisfactory war-flute hack, however, as it stood up to a terrible caning and never gave any trouble at all. After some months I fitted the higit-compression head from the ” Nippy engine (I was advised not to do this as the elarimtype little-ends of I he standard rods were said to ohje(‘t). This larsel?,restored the mu it X iuiui ant, hilt not the acceleration, It, I lie tr)i, )ii level. Thc 140wer is still so good that I think she will easily poll a higher gear, and I have a .-1.2.1 14) axle ready to use when I get the chance. The reduction in urge at higher speeds is,
of course, due to the limited overlap of the standard camshaft compared with a ” Nippy ” one, which also explains the absence of the usual ” Nippy ” bark front the exhaust, which led the Editor to describe •my car as ” fast but silent.”
am not at all sure that the extra ” bite ” at high speeds is worth the bark and wear and clatter from the high-lift cants, hut if I do want it, the high-lift eattishaft can be conjuced into the standard crankcase b?,, grinding small clearances from the centre cams and by using non-standarddiameter rollers for the centre bearings. Alternatively, I have been told that the standard crank can be used in the “Nippy” crankcase, but this needs checking carefully, as the ” Nippy ” oil jets are slightly differently situated, and may not spit in quite the direction for the standard crank. .kettially, I am convinced that an engine built up in this way with all the ” Nippy ” features except the crankshaft would perform far better titan a ” Nippy ” engine, due to the reduced friction resulting from the smaller crank. If the ultimate performance is required, then a pressure-fed evil ilk is ticcessary, but I still think that a tly I h fig larger than the 1 –in. crank is tni(lcsirmtble in an tuiblown engine. When I disinantled the standard engine for a top overhaul after some 5,000 miles’ bashing, I found everything in good order except the exhaust valves, which needed refacing. As these are only 3 per cent. nickel steel and cost 2s. 2d. each, I think this cannot be considered an expensive item. Incidentally, when using the ” Nippy ” engine I found that it paid to lift the head and lightly grind-in the exhaust valves about every 1,000
A further experiment has been to try out an external exhaust manifold of the ” Ulster” type, with an outside Brooklands silencer and a rather curly exhaust pipe leading under the near-side door and back underneath the body. The principle advantage gained is a few inches more ground clearance. The increase in. power is almost imperceptible, and a larger compensating jet is required to make up for elimination or, rather, considerable cutting down, ‘of the hotspot.
A hand ignition advance has been fitted to supplement the automatic device, but it bias not really paid for itself. Incidentally, it is operated by a knob marked ” choke, ” which rather foxes strangers, as the choke itself is not marked. A Lucas high-voltage coil has proved to be well NVOrt h tilt Mg. The gear change, operated by about three feet of gear lever, worried me for a long time. For some reason no satisfactory remote control for the 4-speed Austin box has ever been marketed, but I eventually designed and made up one that has been very satisfactory. I had to use a welded-up steel easing, and it is necessary to use a (list aitee piece smite A-in. thick between the remote control rasher, and the gearbox itself, in order to accommodate the interlock arm, which is H minded above the face of the gearbox easing and which swings sideways into a recess milled in the original gearbox lid, right tip to one of time setscrews securing the lid. The only modification required In the box itself is the filing out of the htdtom of the slot in the reverse-speed selector. which acts as the reverse stop in aornial circumstances. This, unfor
tunately, means taking the gearbox out of the car. Incidentally, the reverse stop On the remote control was arranged to be operated by pressing the lever downwards, which is very convenient for quick changes into reverse.
A very minor but valuable alteration was the boxing-in of the headlamp brackets, by welding a strip in the hollow of the U, which completely cut obt the headlamp dither which beettme apparent when we had to fit heavy lamp masks. A pair of fat Michelin RH’ wheels and tyres (I think the size is 140 by .10) for the rear wheels have improved steering. roadholding and comfort enormously :nal make the car look much less spindly. They were fairly well worn when I bought them, and do not seem to be much smoother now, which is a good thing, as the cost of replacing them will be considerable. I think that a lot of the success of the Michelin tyres is due to their thin and flexible sidewalls, which explains why the same advantages do not accrue from the use of normal tyres of large section. I have tried 4.5-in. by 17-in. tyres on the front, but they are rather too large, and 4-in. seems about the best sect ion for the front wheels. In order to stiek to the same running radius for all NO eels, this indicates 18-in. rims, which I let ve not got at the present, but which are lilted lo so me
vans. Nothing larger than a ?cetiOn tyre can be fitted into the conmart ment at the back of the body, so that the size of the spare is restricted. Anyway, we are getting to the days at which we can leave our spare tyres at home—a puncture is a very rare occurrence.
So much, then, for the ” Nippy,” with her snags and little peculiarities. I I er perft/mance on paper looks ntost uninipressive—about 30, and 45-plus on second an), third, and about 03 on top, with a p ret t y steady 40 m.p.g. wherever you go and however you drive ; but there are not many ears as handy in thick traffic and for short journeys in built-up areas.
Just before embarking for Service overseas for the second time, I took her out for a short journey. She still performs as faithfully as ever but begins to get somewhat tired, which is not surprising considering that she was laid up for two years with no other preparation than to change the sump oil and then to squirt engine oil into the carburetter while she was running, until one could not see for blue smoke. After that two years she was started and driven off without even a check over. She is now laid up again, but as soon as I return I intend to give her the f)verhaul that she deserves. A new rear axle will be fitted, the gearbox will get new bearings, and various chassis rivets will be tightened up. If I can see a convenient way in which to extend the front wings, a wider front axle will be fitted to improve the roadholding, and I think that a new dashboard with new instruments is indicated, while if I can afford to risk impairing her reliability. I think that a very moderate boost is an idea to be adopted. All this may sound a waste of money, but I think that after seven years I know all her soags. and that nothing I am likely to be ;title to larv after the war or. in fact, anything less than a Type 328 13,Al.W, or something similar, would tempt flue to 1:trt wit Ii her, and even then I t kink that she would make a good second string.