When it comes to rallying, the late 1970s and early ’80s were, without doubt, the heyday of the sport. And one of the most genre-defining cars of the era was the Vauxhall Chevette HS, and subsequently the HSR, created when Dealer Team Vauxhall switched from circuit racing to rallying.
How to win rallies? ‘Put a big engine in a small car.’ DTV’s solution was to shoehorn the Magnum’s 2.3-litre slant-four engine, complete with 16-valve twin-cam head, into the baby Chevette. With a Getrag five-speed gearbox, multi-link rear axle and a deep front air dam, the Chevette HS was born.
To comply with FIA regulations, Vauxhall had to produce 400 roadgoing examples, so a dedicated line was temporarily installed at the Luton factory and work began. The first batch of 150 cars rolled off the line in 1978, followed nearly two years later by batch two. There is some confusion over exactly how many were actually produced – Droop Snoot Group resident HS/HSR expert Terry Cobbold (above) reckons around 300 original cars can be confirmed, with 100 left in existence now.
Nevertheless, DTV got its FIA paperwork and the cars hit the showrooms, priced at £5000, when average house prices were around £17,000. Soon after, DTV decided to head into Group 4/Group B territory and needed 40 examples of a more extreme car, the HSR. Each would begin as an HS but a new kit of parts, including body modifications to increase downforce by 40%, would result in the £7200 road car.
The works rally cars were very different from the road cars and, by the time the DTV engineers had finished with the engine, it was pumping out 260bhp, and turned the Chevette into a giant-killer, beating the Escort RS1800s and Fiat 131s at their own game.
Production was short-lived though. By the early 1980s, DTV had moved on with the Manta 400, and the Chevette HS and HSR passed into the realm of legend and the hands of aficionados. Tracking one down now won’t be easy, but it could be a canny investment – and will fulfill your tailsliding stage fantasies.
Because of the limited number of cars produced, few come up for sale – and those that do tend to stay under the radar. A decent HS could be had for as little as £7000-8000 while, if you are lucky enough to stumble across an HSR, you’ll be looking at closer to £15,000-18,000, depending on its history. And if a genuine ex-works car becomes available and takes your fancy, you’ll need to find around £80,000.
IN A NUTSHELL
All HS chassis numbers should include the letter ‘R’ but the plate is only riveted on, so check for evidence of tampering. Terry also recommends checking the build date, which should be stamped into the bulkhead and read 1978 or ’79.
Road cars tended to suffer from several inherent engine issues, but ‘…they should have been dealt with on pretty much all cars by now,’ says Terry.
The first is the amount of heat generated by the engine. The original radiator was woefully inadequate, so the best upgrade is a three-core replacement with twin nine-inch electric fans. The original oil cooler was a VX4/90 automatic transmission fluid cooler and fills with sludge, so the fix is a proper 13-row cooler and thermostatic take-off.
The biggest issue, though, is the twin Stromberg carbs originally fitted. ‘Under-bonnet heat would cause fuel vaporisation, which was bad enough, but the design meant they had to run rich at the bottom end to prevent leaning-out at full speed,’ says Terry. ‘As a result, they were hideous to drive in traffic, with plugs fouling and engines cutting out. An instant fix is fitting a pair of 45mm or 48mm Dellortos, curing the running problems and adding 15bhp out of the box.’
Cylinder head problems are expensive to rectify, as there aren’t any replacements, so repair is the only option and a set of vernier valve pulleys is essential, since the originals ran the cams for emissions, not driveability. Also, anyone attempting an engine rebuild needs to be extremely careful, since there is a host of specialist knowledge needed: for example, to ensure the head bolts go into the right location, as some carry oil to the top end, and welding shut the bypass valve in the oil filter housing to stop it jamming open and letting unfiltered oil through to the crank. If the engine has been rebuilt, make sure it’s by a specialist.
The transmission is relatively robust, particularly if it’s treated with respect. However, the lack of a positive detent on the selectors means the slightest knock on the lever will pop it out of gear and, once that starts, it’ll only get worse. One way to help this is uprated engine mounts to prevent the engine and transmission rocking but this is an engine-out job.
The standard car came with a normal differential but limited-slip options were available – £500 at the time but they improve the driving experience. The factory suspension was also inadequate; Terry says increasing the front spring rates to 500lb and using the smaller anti-roll bar of a standard car will help to get the rear end sliding, the best way to drive an HS.
The original brakes were appalling, so the best conversion is a four-pot caliper and vented disc set-up from Wilwood (around £400; parts only). For all but the most extreme use, the rear drums will be OK but track-day cars can benefit from a disc conversion using parts from the Ford, Peugeot and VW bins.
The DSG has secured original moulds for the HS and HSR bodykits, reproduced the tartan trim and commissioned other specialist parts, such as the Kent Cams vernier pulleys.
As perhaps the rarest homologation specials around, these hot Chevettes tend to be few and far between but, when they do come up, they aren’t silly money.
If you’re serious, then the best course of action is either to contact the DSG or to get along to the Vauxhall Bedford Opel Association national day at Billing, Northamptonshire, in July, and have a chat with the experts – including Terry, naturally.