Sorting Out The Anzani Twin-Cam Engines

We have received the following communication from Barry Peerless about Anzani twin-cam engines, which have been the subject of speculation in recent issues of MOTOR SPORT, We thank Mr Peerless for clearing up the points involved. W B

Re your article in the August Motor Sport on the R1 Anzani engined Frazer Nash, the following may be of interest. Firstly, The R1 (Ross No 1) was not a supercharged engine as designed and first produced. R1 was the original designation, which became R1A following development. The Squire supercharging development did not change the designation.

Designed in 1932 by Douglas Ross, it used the bottom half of the single o h c engine that had been made for and used in Archie Frazer-Nash’s “Slug”, Anzani intended sales to be to A F N and a letter from Ross in 1933 confirms this, but also states that different engine bearer-arms would be required. This is true: although seven such installations have been made without this modification they are a compromise rather than an engineering solution. The problem of modification is that the bearer-arms are cast as an integral part of the crankcase, as were those on the side-valve engines for A C, Horstmann and others, whereas Frazer Nash used a boll-on bearer which would have required extensive modification to the R1 crankcase patterns. Without firm orders from A F N this was never funded. In fact it was not until 1936, four years after the the engine had been announced that A F N tentatively declared themselves satisfied with it and offered the installation in their new Ulster 100 Frazer Nash, only one of which was made and, in fact, sold to a customer with a 4ED Meadows installed instead.

The Frazer Nash in your article, CML 208, was owned by a Miss Worthington of South Farnborough. When and where the installation was carried out is unknown to me. During the war the car was spotted by the side of the road in Battersea in a derelict state with a badly frost-cracked block. Later on the engine appeared in Frazer Nash AYH 33, a car known for some time as “The Slug”, which it patently wasn’t. I bought the engine from Ian Smith, the owner of AYH 33, when he installed an AC six engine in 1963/4.

The second Frazer Nash with an R1 was BMC 446, fitted by Peter Douglas-Osbourn. This engine later found its way into AMF 447, owned by Carmichael in Scotland, and it was from him that I bought this one also.

The third Frazer Nash was, and is, AMD 26. Bought new in 1933 by then Sub Lt Duff in, he had tried unsuccessfully to buy the car with an R1 installed by A F N but eventually separately bought their development engine and had it fitted by Whitfield Sernmence in 1938. This was the engine that had been fitted to the Ulster 100 in 1936 (FMC 120).

Of the two engines that I bought, well, they are a bit mixed up now as I have retained parts of both which went together to build one engine which is now fitted to my Frazer Nash Ulster 1, HX 3535, supercharged with p No 9 Cozette. The surplus engine has been sold to a Squire owner as spares. An interesting point about this installation is that at the same time as I bought the ex-Worthington engine from lan Smith, he included an unused front timing-case for skew gears driving a vertical Cozette supercharger from the crankshaft. As far as I know, this is a one-off by Anzani, not surprisingly unused as the skew gears are driven without bearing support on a 4in overhang from the front main bearing — which is not the way to treat skew gears! Nevertheless, it is part of the installation in my car as the configuration is the same as on the supercharged side-valve Anzani originally fitted, and it is a shame not to use it.

So, we have seven Frazer Nashes having been fitted with three R1 engines:

(Engine 1) CML 208 and AYH 33

(Engine 2) BMC 446. AMF 447 and HX 3535

(Engine 3) FMC 120 and AMD 26

None of these engines have engine numbers. Bob King in Victoria, Australia, has, as you say, a similar engine, no R1 62, in his Type 35 Bugatti. It was installed in 1938 by Lyndon Duckett, who believed it to be the last of 12 made. It is now supercharged with a bevel-driven vertical No 8 Cozette. D M R Adams installed another in his Type 37 Bugatti YU 2200; his has now been replaced by the correct unit, but where the Anzani went to I don’t know.

A quite comprehensive research was made into these engines by Johnathan Wood for Thoroughbred and Classic Cars between October and December 1974 for his articles on the Squire and this is well worth referring to.

Much more could be written about the small differences in the engineering of the pre-Squire engines, but basically they never had the development that was needed. Incidentally, whereas the Frazer Nash ‘Gough’ engine developed 56hp on 8.1 compression, the R1 developed 66hp on 7.71, both unsupercharged of course, so it would have been worth putting some development money into it before Squire came along. With the David Brown blower installation by Squire, 110hp was obtained at 10Ib pressure. Bob King is getting 120hp with 61b, and it would be interesting to know what Roy Palmer is getting with his Squire. It won’t be less than these. B P