Alvis Speed 20
{{EngvarB|date=February 2018}}
{{Use dmy dates|date=February 2018}}
{{Infobox automobile
|name = Alvis Speed 20
|image = 1933 Alvis Speed 20 SA IMG 2773 - Flickr - nemor2.jpg
|caption = 1933 Speed 20 SA sports 4-seater by Vanden Plas
|aka=
|manufacturer = AlvisThe Olympia Show. The Times, Thursday, 22 Oct 1931; pg. 18; Issue 45960
|production = {{ubl |1932–36|1165 made{{cite book |last1=Sedgwick |first1=Michael |last2=Gillies |first2=Mark |title=A-Z of Cars of the 1930s |year=1993 |publisher=Bay View Books |isbn=978-1-870979-38-2}}}}
|wheelbase = {{ubl |SA {{convert|123|in|mm|0|abbr=on}}|SA option {{convert|132|in|mm|0|abbr=on}}|SB-SD {{convert|124|in|mm|0|abbr=on}}Cars Of 1934. The Times, Wednesday, 27 Sep 1933; pg. 5; Issue 46560|SD option {{convert|130|in|mm|0|abbr=on}}{{cite book |last1=Culshaw |first1=David |last2=Horrobin |first2=Peter |title=Complete Catalogue of British Cars |year=1974 |publisher=Macmillan |isbn=978-0-333-16689-5}}|3½-litre {{convert|127|in|mm|0|abbr=on}}The Motor Show. The Times, Tuesday, 22 Oct 1935; pg. 9; Issue 47201 }}
track {{convert|56|in|mm|0|abbr=on}}
|length =
|width = {{convert|65|in|mm|0|abbr=on}} SA
{{convert|66.5|in|mm|0|abbr=on}} SB-SD
|successor = Alvis Speed 25
|predecessor = Alvis Silver Eagle
|class = Mid-size
|body_style = {{ubl |4-door sports saloon|4-seater drop head coupé|sports 4-seater|chassis for bespoke body}}
|layout = Front-engine, rear-wheel-drive
|engine = {{ubl | SA & SB {{convert|2511|cc|cuin|0|abbr=on}} | SC & SD {{convert|2762|cc|cuin|0|abbr=on}}Cars Of 1935. The Times, Thursday, 13 Sep 1934; pg. 8; Issue 46858. |3½-litre {{convert|3571|cc|cuin|0|abbr=on}} }} Straight-6
|transmission = 4-speed manual transmission
|weight = {{convert|3528|lb|kg|0|abbr=on}} (4-door sports saloon)
| sp = uk
}}
{{Infobox automobile engine
| name = Speed Twenty and 3½-litre
| image = Alvis Speed 20 SC Lancefield Drophead Coupe (8514289680).jpg
| caption = 1935 Speed Twenty SC
| manufacturer = Alvis
| aka =
| production =
| successor =
| configuration = straight-six
| displacement = {{ubl | SA & SB {{convert|2511|cc|cuin|0|abbr=on}} | SC & SD {{convert|2762|cc|cuin|0|abbr=on}}|3½-litre {{convert|3571|cc|cuin|0|abbr=on}}}}
| bore = {{ubl |SA to SD {{convert|73|mm|in|abbr=on}}|3½-litre {{convert|83|mm|in|abbr=on}}}}
| stroke = {{ubl |SA & SB {{convert|100|mm|in|abbr=on}}|SC & SD {{convert|110|mm|in|abbr=on}}}}
| block = 4-bearing balanced crankshaft with torsional vibration damper
| valvetrain = pushrod overhead valves camshaft drive by duplex chain patented multiple valve springs
| compression =
| supercharger =
| turbocharger =
| fuelsystem = 3 SU carburettors supplied by double petrolift hotspot and dual ignition
| management =
| fueltype = petrol
| oilsystem = forced lubrication to main and big end bearings, rockers and pushrods
| coolingsystem = water, thermostatic radiator shutters, centrifugal pump
| power = {{ubl |SB 95 bhp @ 4,000 rpm|3½-litre 102 bhp @ 3,600 rpm|SA to SD 19.82 tax horsepower|3½-litre 25.63 tax horsepower}}
| specpower =
| torque =
| length =
| width =
| height =
| diameter =
| weight =
}}
The Alvis Speed 20 is a British touring car that was made between late 1931 and 1936 by Alvis Car and Engineering Company in Coventry. It went through four variants coded SA to SD.
In October 1935 the Speed 20 was supplemented by a 3½-litre car initially sold alongside their Speed 20 SD and named 3½-litre SA. After their Speed 20 was dropped from their catalogue the 3½-litre car was given a shorter wheelbase and named Speed 25 SB.
Speed 20 SA
The car could be fitted with a variety of coachwork. Standard bodies were a four-door sports saloon from coachbuilders Charlesworth, a four-seater sports coupé or four-door tourer by Cross & Ellis, but some cars were supplied in chassis form and carried bodies by coachbuilders such as Vanden Plas. The 4-speed gearbox had constant mesh on the top two gears.. It used a single plate clutch, central change lever, open tubular propeller shaft with metal joints (arranged in a straight line), and a spiral bevel fully floating back axle.
Approximately 400 of the SA cars were made.
Speed 20 SB
The SB launched at the October 1933 London Motor Show had a new cruciform braced chassis, slightly longer at {{convert|124|in|mm|0|abbr=on}}, with independent front suspension using a single transverse leaf spring with a long solid anchorage in the centre.Specifications, Latest British Products, Models For 1935, Cars and Commercial Vehicles. The Times, Tuesday, 2 Apr 1935; pg. 63; Issue 47028. Steering was improved using new designs employed for racing Alvis cars since 1925. Road shocks were not transmitted from one wheel to the other nor did they affect the steering wheel and the gyroscopic effect was eliminated. Rear springs damped by Hartford Telecontrol dampers are long and underslung. The engine remained the same but the new all-silent gearbox, the first of its type, had synchromesh on all gears and was mounted separately from the engine. A built-in jacking system was fitted as standard.
As with the SA, a wide range of bodies were fitted to the cars. Large Lucas {{convert|12|in|mm|0|abbr=on}} P100 headlamps became standard, adding to the sporting appearance of the car.
| File:Alvis Speed Twenty - Flickr - mick - Lumix.jpg]]
|File:1934 Alvis Speed 20 SB "flat-back" 2-door saloon by Vanden Plas, rear right.jpg]] |
=Road test=
The Times motoring correspondent tested and after describing its technical features in detail reviewed the car. Salient comments have been summarised as follows.
The four-seater saloon was described as "distinctly fast in acceleration and speed" with a comfortable body such that a passer-by looks twice at it. A third person could be squeezed into the back seat. The four windows in the four doors allowed a good view all round. It was noted that each front wheel was independently steered and sprung in the manner introduced on the Alvis Crested Eagle and used on Alvis's racing cars since 1925, the aim being to provide good directional stability, road-holding and comfort.The Times, Tuesday, 3 April 1934; pg. 3; Issue 46718.
The steering and suspension was a star feature, the steering action exceptionally steady and light. The car does not heel or roll and there is little wheel bounce. The best speeds on second and third gears were 48 and 68 mph, 90 mph should be possible in top. Providing on the road such rapid acceleration and high rates the engine ran fairly quietly and with smoothness yet displaying exuberant spirits. The action of clutch and new gear change was pleasing.
| File:1934 Alvis Speed 20 Vanden Plas Saloon 2762cc 20hp.jpg]] |
Speed 20 SC
For 1935 the engine grew to 2762 cc by increasing the stroke to {{cvt|110|mm|in|2}} and the range designation became SC. Modifications were also made to the complex steering gear, and the front damping was improved. Twin electric fuel pumps were provided. At the rear the chassis was stiffened by having side members above and below the axle.
| File:1935 Alvis Speed 20 SC Lancefield Drophead Coupe (8513232845).jpg |
Speed 20 SD
The final SD version for 1936 was similar to the SC but had a larger fuel tank and slightly wider bodywork. A {{convert|130|in|mm|0|abbr=on}} wheelbase version became an option.
| File:1936 Alvis Speed Twenty 10135340186.jpg]] |
3½-litre engine
File:Alvis 3.5 litre 1935 Castle Hedingham 2008.JPG]]
As with many cars of the time, bodies were getting more luxurious and hence heavier. Five weeks after their 30 August 1935 announcement of minor improvements to their Speed 20 Alvis announced a new additional 3½-litre 26hp engine fed by triple SU carburettorsCars Of 1936. The Times, Thursday, 3 Oct 1935; pg. 10; Issue 47185 naming it 3½-litre SA. Twelve months later, given a strengthened engine with seven main bearings, it was renamed Speed 25.Cars Of 1937. The Times, Wednesday, 26 Aug 1936; pg. 8; Issue 47463
References
{{reflist}}
External links
{{commons category}}
- [http://www.alvisoc.org/ Alvis Cars Owners Club website]