A Club Sprint
"Those were the days. Drive to the event, pump up the tyres and off you go." How many club meeting rooms and saloon bars have echoed with those sentiments as nostalgia drifts across normal chatter? In racing terms our bar-room expert is right in all but a minority of formulae: even the classic saloons (pre-1957) tend is be trailer— mounted today, but when you get outside the realms of racing then things could be different, even in 1977. Sprints, driving tests and rallies still attract road-going machinery, with rallying as the last true bastion of the high performance car licenced for road use. A works team may put their vehicles on trailers to transport them, but the cars still need to be fully adaptable to normal public road puttering for most events.
In discussing the problems facing today's sporting motorist who wants to keep his car on the road as well as using it for competition, we decided it might be as well to find out how practical a project this is in 1977. We would run such a car ourselves. While we were at it there would be a better chance of finding out more about the basic levels and diverse attractions offered within motor sport today. Hillclimbs especially attracted our attention as we had written little about them in general terms recently, though we do have a resident expert who spoke in glowing terms of the courses and the people involved.
The choice of a saloon with civilised speed was a no-contest. There are Fords around every corner. We did not want to run a foreign car (not many Club men run BMWs and Alfas in competition) and Vauxhall's exciting 2.3 Chevette just does not seem to exist. So we plumped for a Triumph Dolomite Sprint, a car that just seems to have attracted the attention of club drivers with ambition to take advantage of the works involvement which has existed since 1973, when Broadspeed successfully contested the RAC Touring Car Championship.
From a journalistic point of view the Sprint would make a good story, for now there is a pretty full range of equipment to suit anyone from the road driver to the international race or rally contestant. In fact the car we have represents a bias towards rallying in its present form, owing partly to the fact that it was converted for our needs from a Sprint originally destined for the Caravan Rally, an event that would have been a Iot tougher than its title suggests.
Leyland Cars seem to operate their ST tuning parts system along a comparatively informal basis so far as dealerships are concerned, rather than the RS badging and so on promulgated by Ford. "Our" dealership has quite historic connotations: Penta Morris is actually the modern descendant of one of the original Morris Garages that sold the pre-war MGs. As the name implies, there is a big Chrysler network in the background, though you would never realise it when walking round their showrooms at Castle St., Reading. Here, surrounded by some imaginatively presented Leyland sporting produce, we realised that we had found a dealer with excellent paint spraying staff, who even boasted an ex-Abingdon num on the payroll.
Sprints and hillclimbs were our first objectives. Later we would like to assess the versatility of the Sprint in riskier branches of the sport: J.W.'s bank manager still shudders when rallying is mentioned! This has meant a pretty simple specification by current standards. The engine has only larger carburettors, mounted upon an appropriately modified inlet manifold. Though the exhaust system is altered, this is as much for the needs of rallying (for which it was designed) than for reasons of power. The chassis is is little more sophisticated, but let is examine the car's preparation in more detail ....
LOP 295P was entrusted to David Clifton at Perna Morris. He had the advantage of knowing most of the Leyland ST equipment from a fitting viewpoint, and the initiative to take a trip to nearby Abingdon to see what the factory are currently doing with the Sprint.
Mr Clifton began with the engine on our car. Instead of buying the ready-modified ST inlet manifold and mounting pad for the 2 in. bore HS8 SU carburettors, he machined out the standard inlet. The £49 labour charge for fitting the bigger carburettors thus includes this handwork and represents a saving - whether you are fitting the equipment or the garage, as the alternative parts cost £36 alone. David Clifton commented of the SC carburettor kit, "this is a very easy do-it-yourself job. The linkages are unmodified and you really can just bolt everything on."
The exhaust system is standard until after the engine manifold, when the two-box rally system incorporated, carrying a flexible tail pipe mounting. This Group I exhaust layout is suitably reinforced and quite acceptable for road use. You can tell that there is is heartier note, but it's quite tame compared with what has been accepted in the past.
The oil cooler was mounted with rallying in mind - as were many other details in the car, taking the opportunity to prepare it for as rigorous a future as possible! The cooler is quite small and neatly installed on its side, adjacent to the water radiator. The latter remains unaltered, though ST do offer an alternative.
For the transmission ST have two alternatives to the production 3.45:1 final drive ratio. Both are numerically higher at 4.1:1 and 4.55:1, the latter the ratio best suited for our needs and the original caravan towing spree. Racers will choose according to circuit, but there is still the question of gearbox options on the Sprint. There are actually three ways to go: - four speed, close ratio; four speed, wide ratio and OD on third only (to give five reasonable ratios) or the standard gears with a competition OD in action on third and fourth gears.
The Motor Sport Dolomite went to Brighton Speed Trials with six operable ratios, using (inevitably!) an unusual fourth option, the wide ratio gears with OD left in action for third and fourth. The 4.55:1 final drive is in very short supply at present and, at the time of writing, it was expected that we would have to use the 4:1. (In fact we used the standard 3.45:1 ratio. - C.R.) A new batch of 4.55:1s has been commissioned, but we are advised that those friendly with their Standard Vanguard Dealers should have no problem in obtaining this ratio!
Whereas a limited slip differential is quite expensive these days (£60), the competition modifications for the overdrive also transform the feel of the car's transmission abilities, but for the almost modest sum of £33. With stronger springing and higher oil pressure, for the pistons, the modified overdrive is faster than all but an F1 driver's gearchange, and extremely satisfying to use.
The limited slip differential is set normally to around 40% pre-load. For tarmac competition ST recommend up to 90% torque setting, or for rallying somewhere in the 50-60% region, according to event. The differential is slightly less noisy than we had expected, but it has not really done any work yet, so we will see what amateur dramatics are produced later. Penta-Morris reckon on 3 1/2 hours to install the LSD, so the retail customer is looking toward £200 (£184.50) inclusive of parts
The softer rally springing is pretty effective in tarmac use, providing very stable oversteer without the wheel-lifting often experienced in rival saloons equipped for rough road use. Where the racing spring rates are over 500 lb./in., the rally coils are almost soft at 189 lb./in. front and 182 lb./in. rear. Mated with Bilstein gas-filled shock absorbers (£28 each) there is the opportunity to alter the ride height at will, via the adjustable spring platforms provided on the damper bodies.
From the fitting side all that suspension work was simple, compared to the task of fitting the metal centre, hard rubber bushes to control the rear suspension components more directly
The bushes are installed at either end of the axle tie-rod; on each end of the twin radius rods, and there are also rigid competition bushes for the upper suspension arm on the double wishbone front layout. Clifton explained that the problem of squeezing in the bushes was made a lot worse by the absence of a suitable press, but a vice and grease eventually overcame the rear radius arm bushes' reluctance in the matter.
The interior was a lot more expensive than it need have been. There was a Halda Tripmaster left over from Abingdon's preparations, but we caused full harness to be fitted to both front seats (the Luke brand from Gordon Spice) and a full roll cage, including the front section. The cage costs a reasonable £60.60, but the labour charge for installing it was £42. Mainly this was through the need to weld plates to the floor at the rear: as with all Safety Devices cages the complete result fits in very well within the production interior.
Another needless expense for the immediate future was £14 labour charge for adapting and fitting the Leyland ST competition seat: the current ST seat costs £39.50 and comes complete with proper runners for the Sprint. Our Mr. Clifton spent some considerable time messing about, cutting the centre out of the frame supplied and widening it. Follow that with some brazing to secure things once more and the bill is no surprise.
The car already had many of the finishing details that actually consume so much time when you are converting a road car for competition use. An external battery cutout switch was needed, and we have installed a pair of manual fire extinguishers. I had an automatic extinguishing system in last year's Ford and was rather put off by the price (for the Dolomite it would be £98) and a little num who came round and demonstrated that rny system would not work, if the car was tilted at a certain angle in a ditch. He was selling a rival that did, of course!
Aside from the paintwork at Penta one very important handling asset came with the car. The asset was ST's "High-Geared Uprated Steering Rack" which reduces the turns from lock-to-lock from 3.8 to 3.28. Having enjoyed the privilege of watching Roger Clark trying to tame a rally Dolomite with the production rack, I know how worthwhile the quicker action is! We do not know what labour charges would be incurred to fit such a rack, but I do know the item itself costs £86.25.
Resting on the normal 175/70 Dunlop Formula 70 radials and 5 1/2 in. rirn alloy wheels, the car was taken to our normal test track for a morning session to sort out any bugs. No fundamental bugs emerged. We were particularly pleased that there was no fuel surge, leading to the frustrations of a dying engine in mid-corner. Most production saloons, cornered well beyond their normal limits after modification, exhibit this type of problem. Perhaps the SUs account for this splendid consistency under pressure? Most of the cars we can recall having real starvation symptoms - which can be impossible to legally sort out under many intrepretations of Group 1 regulations - have some type of compound carburettor.
The engine is still more than a match for anything in the 2-litre class around the World. Performance did not feel as brisk as one might have expected, but then the car is carrying full trim and the competition items as well. The substitution of a numerically higher differential and a set of ultra low profile racing Dunlops on a spare set of standard wheels can only help in this respect. Incidentally the Dunlops are of an exceptionally soft compound chosen with the idea of reaching full working temperatures within the 60s or so that will (hopefully) comprise most of our initial outings. There will obviously be more to say about them when we have some rnore experience. (A cautionary note: At Brighton we found the front racing tyres - the same size fitted to racing Dolomites - to be fouling the anti roll-bar mountings on lock and the inside of the nearside rear tyre to be rubbing on the wheel arch under axle torque reaction. We have yet to find the answer to this problem. - C.R.) Some fuel was lost through the standard cap, and that carries extra sealing as a result. The competition seat dug in to this driver as weil, but that is a matter of individual taste.
So we have a Dolomite built very much along the lines of competing in club sport while retaining full public road abilities. Now the job is to gather experience of the car in low key events and to measure the effect of the changes. I hope you will be able to read how it fared at the Brighton Speed Trials within the colour section. - J.W.
Leyland. ST parts.prices. Bodywork: front and rear roll , £60.60; sport seat £39.50. Brakes: Ferodo DS11 and VG95 friction material for stasndard front discs, rear drums, total £24.Suspension: Competition bushes for rear axlde location and front upper wishbones, £4.73; four rally specification coil springs, £24; four Bilstein shock absorbers, £116; competitions steering rack, 3.28 turns, £86.25; Engine: pair of 2-in. bore SU carburettors, £90; air cleaner, casing and element, £30.60: Group 1 rally exhaust system, £65.70; oil cooler kit, £49. Transmission: limited-slip differential, £160: solid piston assembly for overdrive, £33. Total, £783.38.
Sample of Penta-Morris labour charges for Dolomite Sprint conversion work (£7 per hour); install carburettor kit, including machining manifold instead of buying replacement, £49; fit oil cooler kit, £28; substitute Bilstein dampers (four), £35; mate and hang exhaust onto existing system, £21; insert all suspension bushed, £49 (rear), £10 (front); fit front ad rear roll cage, including welding, £42; install seat harness (two) of four-strap pattern, £21.
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Cavalier stays Opel-powered
Vauxhall inform us we were incorrect in our story that the Cavalier, when assembled in Britain, will adopt the Vauxhall s.o.h.c. engine in place of Opel high-camshaft unit. This is a story that has been circulating amongst motoring journalists for some little while and we had also heard it from one or two, what we thought were unimpeachable, sources close to the industry. But we doubt that Vauxhall would take the trouble to deny it (very politely) if we had been correct. It's a shame really - the Cavalier could be an even better car with the torquey Vauxhall engine.