1931 Hispano-Suiza J12

1915 type 153

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Fellow Frogger
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Christchurch
Before WW1, Delaunay-Belleville were the undisputed makers of the world's best cars. After the war, the cars designed by a Swiss living in Spain took over at the top of the heap. This is an abridged version of the story I did for the latest Classic Driver on the only J12 in regular use anywhere in the world.





Idling up to the traffic lights in top gear, the big Hisso drops down to 10 mph and yet still the driver makes no move for the chrome plated lever by his right leg. It might only have three speeds but right now only one is required. The lights go green and as the throttle is opened we gather speed instantly. Cars around us are staying level with us, some pulling ahead then losing ground as they change gears.
With 9245 cc of V12 lurking under the cream and blue bonnet, we have no need for revs or gears, 220 hp and seemingly unlimited torque means we accelerate like a turbine and in almost complete silence. At the 100 km/h speed limit the Hispano is nowhere near getting into it’s stride and is attracting plenty of attention from the Friday afternoon commuters looking forward to getting home. Then we come to the hill. Cars around us start to slow but as the head of the stork mascot, once worn proudly on the side of French WW1 fighter ace Charles Guynemer’s Hispano-Suiza powered Spad XIII points onward and upward and not only are we holding 100 km/h as we start to climb, as we need to overtake slower tin boxes, as soon as the throttle opens the big tourer leaps forward and the only way the occupants know of the increase of speed is the movement of the white needle on the OS speedo and a little more breeze coming into the front of the car as we have the top of the hood furled in the 3/4 position and front windows down, in effect making the driver’s compartment (only ever intended for the hired help while the master rode in comfort in the rear). This is truly what the term “Grand Routier” was invented for.
Spying a suitable photo location at the last minute the massive, mechanical servo-assisted brakes (which Rolls-Royce also used under licence to Hispano-Suiza) slow us down every bit as impressively as we had just been accelerating and we pull off the road. At walking pace, second gear is selected and we swing into to driveway. Even at this slow speed the driver doesn’t seem to need to haul hard on the wheel to make the tight turn despite the massive size of the carriage he is conducting. As chauffeur he is still feeling fresh, unflustered and ready to tend to any of the master’s instructions.
Yet things were not always so happy with this car. It had a problem from new in that it overheated. And Persia (now known as Iran) is not the best place for a car with a suspect cooling system to live. Within a year of arriving at the Shah’s palace the bonnet had grown extra louvres in the top, and the sides were replaced by new ones featuring doors, mimicking Chevrolet or Cadillac from 1932 in an effort to get hot air out from the sealed engine bay as efficiently as possible. Yet none of this made any difference at all and the car saw very little use.
In the early 1960s the Shah finally sold the car to (of all people when considering the politics of the region) an Israeli dealer who passed it on to a collector in the USA. Making landfall on the east coast of the USA in 1963 the car was driven 1500 miles to it’s new home in Tulsa. Apart from overheating issue, it behaved perfectly.
Fast-forward to the 1980s and in New Zealand the late Roy Southward had obtained a J12 engine and he was seeking a Hispano-Suiza H6 chassis (the six cylinder predecessor to the J12) to build a car around. Contact was made with a Hispano contact in the USA who had a better idea. Instead of trying to concoct a car which would always be a ”bitza”, if Roy wanted a J12 why didn’t he buy the whole one in his garage instead.
It was discovered that despite no longer having to cope with the desert heat of Persia, it still ran hot, did not seem to perform as it should and seemed to lose power the further it was driven. At idle it would run slower until eventually stalling, then would refuse to restart, the carbs would flood and the radiator boil. Clearly there was something amiss and the car was entrusted to Bristol Motors in Upper Hutt where Dave Wilkens and Neale Ryder were told to fix it, no matter how long it took.
It took some time. The cooling system was checked, the radiator seemed fine, the twin water pumps (one for each bank of 6 cylinders) were both operating as they should. The problem was not there. The next possibility was a build-up of silt around the cylinder. The decision was reached that a full strip-down of the engine was going to be the only way to look deeper into the issue. The engine consisted of a pair of alloy blocks with integral heads bolted to an alloy crankcase, pistons working within 100mm nitralloy liners screwed into the blocks. In the interests of silence, instead of engineer Marc Birgkit’s normal aviation practice of overhead cams with associated drive gears or chains, the J12 used pushrods and roller tappets for valve operation, with the exhaust valve stems filled with sodium to aid cooling.
With the blocks removed it was immediately obvious that despite the low mileage, things were not at all well inside. The pistons were scored badly and a look inside the bores revealed severe scuffing. Clear evidence of the pistons seizing, but was the as a result of or the cause of the overheating? But what would have caused such serious markings on both surfaces? It did not take long to discover the reason. It turns out the problem was an engineering issue from the factory itself. The bore was 100mm and so was the piston! So as soon as the pistons got warm and started to expand, they were binding in the bores. Basically, the engine was trying to seize but the large capacity meant that it kept running (just) and of course, once it had been switched off and allowed to cool for while, the pistons contacted and it would re-start, all 220 hp should be on tap, briefly.
As the liners are nitrided they can’t be bored in the usual manner so they needed to come out. In typical Hispano-Suiza style they are screwed into the bottom of the blocks. It sounds simple but... there are no holes or castellations in the bottom of the sleeves to get any sort of tool to grip on. A plug was made to slip inside the cylinders and a clamp to go around the outside. With a ¾ drive socket and bars on increasing length, including a behemoth from the local bus depot, there was still no sign of movement. More head scratching took place before a novel method was tried. With the alloy blocks being heated with a massive gas heater, liquid nitrogen was dropped down the bores. In theory with the blocks expanding and the sleeves contracting the grip would break and allow the unscrewing to begin. In practice, nothing changed
The socket drive was dispensed with and a bracket bolted to the clamp which would take (very) long lengths of bar. It took a 20 foot long piece of pipe, Dave on one end and Neale on the other before they would then unscrew, effortlessly. As an experiment on the next cylinder, the bar was reduced to a mere ten feet. No chance of anything unscrewing then, so back to 20 feet and it worked. Finally! With everything out it was now possible to fix things.
Under normal circumstances it wouldn’t not a big job to fix it. In the day, new blocks from the local Hispano service agent. That wasn’t an option so the best bet would be to bore the liners, add a new set of pistons and problem solved! As boring wasn’t an option the sleeves were instead ground true while Denco in Christchurch were entrusted with make patterns and casting new pistons of the correct, this time the correct size but the opportunity was taken at the same time to increase the compression ratio.
With everything back together it was time to start the motor. Success, it fired up immediately and ran well, but the good news was the temperature sat exactly where it should. The bad news was the carbs were still flooding and the on-road performance was still not what was expected. Much fiddling with float levels, jets and fuel pressure not only sorted the flooding but also brought the fuel consumption up to the quite reasonable figures of 12 mpg at 100 km/h and 11 mpg at 120 km/h. The twin Scintialla Magnetos which provide the spark to the 24 plugs (one on the inlet and one on the exhaust side of each cylinder) has also been overhauled but it was discovered that they had slightly differing advance characteristics. Fortunately the owner at the time, Roy Southward was able to source a matching pair and with these overhauled and fitted, for the first time in it’s life, the Hispano actually delivered it’s full quota of power and was transformed into the effortless high-speed cruiser which it should always have been. Then...
On it’s maiden outing, going better than it ever has before, disaster struck when it dropped a valve seat! The block had to come off again and it was discovered that this early engine (the first one made) had seats with tapered seats. This must have been a known weak point in the motor as later ones have conventional parallel sides. There was no realistic option other to remove the other block as well and replace all 24. Quite a tricky operation this with this having to be done with arms inserted into the cylinders from the bottom. Non-detachable heads are very fortunately now very much a thing of the long-distant past!
With this done, the Hispano now performs faultlessly and reliably, just requiring routine maintenance as would be expected from an 80+ year old car. This car was the subject of a test by The Autocar in October 1931 who commented on the power, torque, great roadholding, outstanding braking and light, precise steering steering. They recorded a maximum speed of just over 100 mph and a 0-60 mph time of 12 second, outstanding figures for the day. Intended to be Hispano-Suiza’s equivalent to Bugatti’s Royale and costing as much as 75% more than a Rolls Royce Phantom III, the type 68 was intended to be the absolute epitome of the Grand Tourer.
 
Ah yes, the joys of non-detachable cylinder heads.
Any mention of the brakes? I was lucky enough to experience an H6 when in France in 2007 - apart from the GO, I couldn't believe the WHOA - thanks, of course, to the mechanical servo-assist system which was good enough for Rolls-Royce to use under licence.
Yeah .. what a car!
 
Panhard went to its grave still using one piece cylinders with an integral combustion chamber and then there was Bugatti ......
 
Fantastic write up of a brilliant machine! I'd never heard of it before, but I'd love to know more! Any more pictures available? Perhaps internal shots and engine bay?!
 
I will find a couple which I didn't use in the magazine and put them up in a day or so...

Fantastic write up of a brilliant machine! I'd never heard of it before, but I'd love to know more! Any more pictures available? Perhaps internal shots and engine bay?!
 
Panhard went to its grave still using one piece cylinders with an integral combustion chamber and then there was Bugatti ......

Indeed. Want to change a valve on a Bugatti? Start by removing the back axle if I recall. I have a vague recollection of Porsche 918 engines having the heads welded in place too.

Great Hispano-Suiza story for which many thanks. What a truly superb car.

Years ago a Hispano-Suiza pulled up at an Adelaide motel near where we lived. I was not sure what model as I was about 18, but I did know of Hispano-Suizas. It looked to me like a 30s car, dripping oil a bit, totally unrestored and with Victorian plates. Clearly it had driven from Melbourne. it had Isotta-Frascini wheels what's more. It was a large car and a huge WOW.
 
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A nice story and a lovely car, Thanks for sharing! It's handy to know even Hispano Suiza used to build "Monday" cars!:)
 
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