by KENT KARSLAKE WHEN some time ago 1 was seeking to arrange insurance cover for an Ilis-panoSitiza car, I was informed that the underwriters, specialists in motor insurance, were not particularly keen to accept the risk, as " they had never heard of an Hispano-Suiza." was rather disc/imaged ; hut it is in consequence all the more heart-warming that. My somewhat, .0:at.Txu efforts to write• a history of the marque should have brought me a post-bag of letters not Only from this country but also from as .far afield as Spain, Holland, Australia and the United States, and should have led me into a " friendly debate '' with no less an authority on motoring matters than Colonel Clive Gallop. My only regret is that if the debate is to revolve around the stroke of the Monza engine it will not, on my side, be a very spirited one. Ever since I first drove PP 1181, which was a year or two after it passed out of Colonel Gallop's possession, and until Mr. Briand measured what 'appeared to be its engine a few months ago I have believed its stroke to be 150 Min. lam still as anxious as anyone to think that I have driven a car with this rare engine feature. I confined myself in June to saying that "in the absence of any evidence to the contrary, the • long-stroke Monza' engine must be dismissed as a myth " ; and I still await the contrary evidence with as much. impatience as does. Colonel My preoccupation with the length of the engine stroke sh-ould not in any ease have led me into saying that "I cannot ascertain that the Monza model ever made a public appearance on the then new Italian track." I could have ascertained it perfectly well, if I had not been incompetent in the matter, and perhaps I may now till in this gap by stating that in the Gran Premio .d'Auttinno, lam on October 22nd, 1922, Andre Dubonnet's Hispano-Suiza covered 40 laps ofthe complete Monza circuit, giving a total distance of 400 kilometres, in 3 hrs. 2 mins. 57i sec., thus winning the over 3,000-c.c. class at an Average speed of 82.1 m.p.h. from Conelli's Baflot, NiceOlini's

and Galliani's Mercedes. It is when we get back to the 85 by 130 mm. " Barcelona" engine illustrated in the June Issue, however, that the plot really thickens'. I am comforted by Colonel Gallop's view that certain features in the kg) pea ranee of this engine are "very suggestive of rockers," because that is what I thought myself, although I did not quite have the courage to say so. And yet I think that we wore. both wrong, although, I Suspect, for a very good.. reason. Writing from New York, Mr. Alec Ulmann, whom I have already quoted in connection with questions ofHispano-Suiza history, .points out that I failed to make reference to the so-called " de hum" models announced in 1918 for the 1914 season. These. .models had four-cylinder engines made in three sizes, with dimensions of 80 by 130 nun., 90 by 150 mm„ and 100 by 180 nun., respectively, and in each ease there was an offset -vertical •shaft driving a fan on

the ‘.entre he of the engine as well as an .?‘..-rhead eamsluift, also on the centre ine of the engine, which operated inclined overhead valves by means of rockers. The line drawing reproduced herewith shows the layout of the engines of this type. It may be noted that, by measure mem, the dimensions do not correspond with any of those mentioned by Mr. Miami, but would exactly fit the Type 8 engine, of 70 by 120 nun., mentioned by Le. Catalogue. des Catalogues as having been manufactured from 1914 to 192(t. Externally these engines must have closely resembled the 1922 85 by 180 mm, engine already illustrated ; but before jumping to the conclusion that the layout of the latter was also similar, we ought .perhaps in any case to have been warned by Mr. Dale's evidence, quoted on page 271, that as early its 1914 MT. Birkigt had redesigned the 100 by 150 tam. 'l'-head engine and had provided it with overhead valves operated by an overhead camshaft direct. In any case Mr. Dale 110W writes of a 1922 85 by 180 nun. " Barcelona " model owneduntil recently by Mr. Lyndon Duekett of NIelbourtie, and with which he is most intimately familiar, that " the camshaft was carried on the centre line of the cylinder head . . . and operated direct on the top of the valve stem just as the later French cars did." But, he adds, "the drive for the camshaft is via skew gears with the camshaft-drive from the crankshaft offset to the near side of the car." SO that it. seems that we can now trace three stages in the development of production model overhead camshaft Hispano-Suiza car engines, as follows :—

1 70 , 120 nun. 1 • 80 ,‘ 110 nun. 1, Met vortical shaft, 1914 •1 90 x 150 ram rockers. 100 x 180 mut ? 1915 55 x 130 mom. I OffSet, vertical shaft, direct

1100 x 180 Mil. I operation. 1919 100 x 140 nun. Centre-tine vertical shaft,

8-cylinder , direct. operation.

The models:in the first group appear, on the face of it, to have had a very limited life and it would be very interestingto hear of any reader Of Moron SPOkt who has had personal experience of rockers On an Hispano-Suiza engine.