Bolwell Nagari: The ultimate all-Australian ProdSports racer
03 January 2014
The conspicuously large number of Bolwell Nagaris that competed in production sports car racing (ProdSports) in the 1970s highlights the broad appeal and affordable race-winning performance of this proudly Australian-made, V8-powered super car.
Although less than 120 were built by Bolwell in Melbourne, the thundering fiberglass-bodied Nagari was a common sight in both coupe and roadster body styles on Australian race tracks, where it was competitive at club, state and national level motor sports.
Many were prepared and driven by part-time weekend racers with limited funds and technical resources, who appreciated the Nagari’s mechanical simplicity and tried-and-tested Ford V8 drivetrains that ensured power-packed performance with good reliability and parts back-up.
The Nagari never won the nation’s premier sports car title - the Australian Sports Car Championship - but that was largely due to technical rules which for the majority of the ASCC’s near two-decade existence (1969-1988) catered primarily for Can-Am and Le Mans-style Group A cars designed and built purely for competition use.
These magnificent hand-built machines, like Frank Matich’s SR4 Repco, John Harvey’s Bob Jane Racing McLaren M6B Repco, Phil Moore’s Elfin 360 Repco and Garrie Cooper’s Elfin MS7 Repco-Holden, were the cars to beat from 1969 to 1975.
As a result, production sports cars designed primarily for road use like the Nagari didn’t stand a chance of winning the title until 1976, when the Group A thoroughbreds were dumped in favour of Group D Production Sports Cars – two years after the Nagari had ceased production.
While the incentive for such a change may well have been to encourage more road-legal makes and models, which in theory would be more affordable to buy, cheaper to run and which spectators could better relate to, the end result was nothing but an embarrassing Porsche benefit.
During the ASCC’s six year production-based period, the German thoroughbreds galloped away with every title thanks to star drivers like Pete Geoghegan, Allan Moffat, Alan Hamilton and John Latham and a smorgasbord of the latest factory race cars like the Carrera RSR, 930 Turbo and 934 Turbo.
Even so, it was during this production-based era that the Nagari came as close as it would ever come to winning Australia’s most sought after sports car title.
A rule change for 1978 made Hamilton’s 934 Turbo ineligible and Nagari driver Ross Bond came within a handful of points of claiming the ASCC, after winning two of the four rounds and finishing equal second to championship winner Ross Mathiesen in his Porsche Carrera.
To bring an end to the German marque’s domination, the championship returned to purpose-built competition sports cars in 1982. Although Bernie van Elsen’s wild-winged, K & A engineered Nagari roadster continued to be seen in the result sheets, the 1970s Aussie-made super car - and sports car racing in general - were clearly past their peaks.
With dwindling fields and a general lack of spectator and media interest, the championship was cancelled after the 1988 ASCC.
Even so, the Bolwell Nagari’s widespread popularity and success in Australian production sports car racing during the 1970s shows how good the basic product was in its prime. It had its shortcomings like any car, but clearly for many competitors those beautiful flowing lines combined with simple, affordable and brutal Ford V8 performance far outweighed any negatives.
Bolwell Nagari: Born to race
When the Nagari went into production in 1970 as a ‘turn-key’ production car, on paper it seemed to have all the raw ingredients required for a low maintenance, high performance competition car which would respond well to performance upgrades.
A robust backbone chassis fabricated from 14-gauge sheet metal provided torsional rigidity calculated at 678 Nm per degree of twist and left a hefty margin for extra performance and cornering forces. The front of the chassis embraced race engineering principles tying in the Ford Windsor 302 cid (4.9 litre) small block V8 with the front suspension cross-member. The transverse chassis member at the rear, which located the body mounts and rear suspension, allowed further development.
The compact Windsor V8 was set so far back in the chassis that its location relative to the front axle line was described at the time as “almost mid-engined”. Because the Windsor V8 had been racing in everything from GT40s, Mustangs to AC Cobras, proven performance parts were widely available. The chassis of later cars were re-engineered to accept the larger and heavier Cleveland V8 with all its race bits.
Even if the production wishbone front suspension was dictated by a mix of Bolwell and Ford parts, it was a good starting point. The heavy live rear axle, located by lower trailing arms, radius rods and coil springs, also left room for development. Steering was via rack and pinion and brakes were power-assisted front discs and rear drums.
On top of this rolling chassis was a wind-cheating lightweight fibreglass body, initially available only as a coupe before the stunning roadster became available in 1972. The coupe’s roof was about the same height as Ford’s iconic GT40 Le Mans racer.
With all that V8 grunt on tap in a car that weighed just over 900 kgs, the raw sub-15 second 400m performance in standard road-legal trim was shattering for its day. The mind boggled at its potential, attracting plenty of budding production sports car racers keen to unleash the new Nagari on the race track.
Case study: Steve Webb’s Bolwell Nagari
One of the most successful Nagaris to compete in production sports car racing in the 1970s was owned by Sydney-based Steve Webb, whose son Jonathon now competes in V8 Supercar racing with the Tekno Autosports team he established in 2011.
Steve’s immaculate bright blue Nagari roadster was typical of the 1970s ProdSports breed. A regular visitor to meetings at his local Amaroo Park and Oran Park circuits, Webb enjoyed considerable success which included winning the ARDC/Better Brakes production sports car series at Amaroo.
Like many Nagari racers, Webb was a ‘weekend warrior’ who had to finance his racing through other activities during the week. He worked on his car after-hours and on weekends with the help of friends and also bought and sold Bolwells. The profits he made from rejuvenating tired and tatty Nagaris were pumped directly back into his motor sport activities.
The production sports car rules were similar in philosophy to those that applied to touring car racing at the time. Standard chassis and drivetrain elements had to be retained, but there were allowances for modifications in key areas to make road cars into better race cars.
Webb is well placed to comment on racing Nagaris in the 1970s, as he competed in both coupe and roadster versions and developed an intimate technical knowledge of the breed through hands-on involvement in development and routine maintenance.
"I’ve heard people refer to the Nagari as a larger V8 version of the Lotus Elan which in some ways I think is a fair comment,” he told Shannons Club.
“I’ve restored a Lotus Elan and obviously spent a lot of years working on Bolwell Nagaris, so having played with both I think it’s fair to say that even though the Nagari had a live rear axle the inspiration for its design certainly came from Lotus.
“The Nagari had most of the ingredients you could want for racing, except for the wheelbase and track dimensions. The wheelbase was too short for the track width of the car; it was too square which didn’t give it enough directional stability and made the handling a bit twitchy.
“The standard front-end (suspension) geometry also left a lot to be desired, but we sorted those things out over time. We started with something that was pretty ordinary and just kept making it better.”
As a teenage car enthusiast Webb was knocked out by the Nagari on its release as a production car in 1970 and like many enthusiasts wanted to drive one on the race track.
“I started with a coupe in about 1971. The NSW agent for Bolwell at the time was Fleetwing Garage at Lakemba and the proprietors were John Edwards and Neil Stevens.
“They’d just traded-in a doctor’s car on a new Nagari, so I bought it. Apparently the good doctor had been using it as a call car (home visits etc). It was lime green with a Windsor V8. It had dodgy gel-coat and a few other things that needed attention, so it was nice and cheap for a young bloke like me who couldn’t afford anything better.
“We set about putting those ugly factory guards on it (wheel arch flares), painted it black and raced it a few times in Sydney. At first I used IDA Webers but I had to cut a hole in the bonnet for clearance which the scrutineers didn’t like, so I changed it over to fuel injection.
“Later on I took it down to a race meeting at Hume Weir (near Albury) but I ended up going nose-first into a wall and demolished the front of the car. So when I brought it back home to be repaired, I figured it was also time to make some improvements.”
Neil Stevens, who played a pivotal role in the development of Webb’s Nagari, hand-fabricated a new front-end that rejuvenated the Nagari’s wayward front suspension by using proper competition parts hand-made by Rennmax racing car manufacturer, Bob Britton.
These comprised elegant upper and lower wishbones, lightweight uprights, huge brakes and other items; all one-offs originally built for a Mustang sports sedan that was wrecked in a crash. Webb bought all the undamaged front-end components from that car which were adapted to the Nagari. The standard steering rack was also replaced with a Rennmax component.
“It gave us a nice, adjustable racing car front-end that we could work with because the biggest limitation with the Nagaris - be they road Nagaris or race Nagaris - was always the front suspension,” Webb revealed.
“Those early cars suffered from terrible bump steer, which is why you’ll find a lot of the later Nagaris were modified by Neil Stevens. They put late model Torana front ends in them which got rid of all the geometry problems that those early cars had.
“We also strengthened the car’s rear-end because they used to flex quite a bit around the T-intersection of the rear chassis.”
Although Webb’s car was originally a coupe, extensive body damage caused by the Hume Weir crash prompted him to update to the roadster body. This offered several advantages in terms of lighter weight, less frontal area (with the low profile windscreens of the era) and much improved open air driving comfort.
“Don’t underestimate the coolness issue,” Webb said. “When we ran it as a coupe it was incredibly hot inside, particularly as I was silly enough to paint it black which made it even worse.
“They had poor ventilation and your feet would get fried because they were right beside the engine and the exhaust pipes. The switch to the roadster body solved those problems.
“I bought the last roadster body that they (Bolwell) had sitting on their factory floor. I drove down to Melbourne overnight in my little truck from work, picked the body up early in the morning and drove back to Sydney with it the next day.
“I never liked the look of the factory wheel arch flares they made for racing. I thought I could make some much nicer ones that blended better with the shape of the car, so we set about moulding up some new flares which we then mounted on the new body on the newly rebuilt chassis.
“We also simplified the wiring loom and attached the body to the chassis using only eight bolts so that when we had to work on the car we just had to undo those bolts and a few things then lift the body clear off the chassis and place it on some stands. It made working on the car so much easier.”
Like most racing Nagaris, Webb’s car was powered by the wonderfully light and compact 5.0 litre small block Windsor V8, as the larger and heavier Cleveland unit fitted to later model Nagaris (and trialled by some competitors in 351 cid/5.8 litre form) resulted in inferior handling.
Webb’s race engine, built by Neil Stevens, utilised the much stronger Boss 302 cylinder block developed for US Trans-Am racing with rugged four-bolt mains for high rev tolerance. Dry-sump lubrication and competition-grade crank, rods and pistons completed the small block Ford’s stout bottom end.
A high performance solid camshaft was matched with fully worked 302 Windsor heads, topped with high quality valve gear and fed high octane racing fuel via a Hilborn constant flow mechanical fuel injection system. Hand-made exhaust extractors snaked their way rearwards through the tight confines of the engine bay to a booming open exhaust system.
Webb said he never had the funds nor the inclination to run any numbers on a dyno, although he suspects his healthy little Ford V8 was producing around 400 bhp.
He also never put the car on a set of scales, so power-to-weight ratio clearly was not considered the most important measure. “It was either a good car to drive and won races or it didn’t, simple as that,” Steve said with typical pragmatism.
A competition clutch and Ford top loader four-speed gearbox proved to be rugged and reliable. Steve’s top loader was a special race version from the US, equipped with a more precise shifting mechanism.
Power went to ground through a stronger nine-inch live rear axle sourced from a compact Fairlane. This featured Ford’s bulletproof nine-inch crown wheel and pinion, thicker fine-spline axles and a Salisbury clutch-type limited slip diff that was adjusted to suit Steve’s driving style.
Although this type of LSD required constant adjustment, Webb said its consistent and predictable power delivery was a much better option than the brutal in-or-out engagement of the Detroit Locker given the Nagari’s handling traits.
“All I ever ran was the Salisbury clutch-type LSD because if you kept the (clutch) plates screwed up tight it worked fine,” he said. “How guys like Peter Warren drove them with a Locker I will never know, because the Nagaris were very twitchy with their short wheelbase and wide track dimensions.
“I recall in the early days I actually borrowed Peter’s Locker diff and put it in my car to test it out at Amaroo Park. I came through the left hander there (Honda Corner) and when I hit the throttle it locked when I didn’t want it to, suddenly turned hard left and drove me straight up the earth embankment that ran all the way down the back straight.
“I almost drove the entire length of that embankment at 45 degrees before I could get the thing back on the road again. It was scary. I drove straight back to the pits and said ‘pull that bloody thing out!’”
Under the ProdSports rules, the Nagari had to retain its standard front disc/rear drum arrangement which wasn’t a problem for Webb as the Rennmax front-end upgrade featured huge ventilated disc rotors clamped by powerful Girling four-spot racing calipers.
These were more than adequate to meet his braking requirements without having to worry about the rear drums overheating or locking up. “We just adjusted the brake bias so that the rear drums virtually didn’t work. They were just there to hold the rear wheel in place and not much else.”
Webb’s Nagari initially ran Mawer lightweight composite racing wheels in the maximum allowable 10-inch width before moving to wheels tailor-made for the car by Tony Simmons.
Suspension tuning was fairly straightforward, in keeping with the relatively basic and simple design of the car. Finding the right balance of coil springs, adjustable competition dampers and anti-roll bars resulted in a fine handling race car that was fast, predictable and satisfying to drive.
“It was a very successful car, particularly at Amaroo Park which was just around the corner from where I lived at Parramatta,” Webb said. “It was my local circuit so I spent a lot of time driving around there and the car was very well suited to that track.
“The late (motoring journalist) Barry Lake tested the car and did a write-up on it for one of the motor sport magazines at the time. He said he couldn’t believe what a good handling motor car the Nagari was, but having said that it was very un-Nagari like in terms of things we had to re-engineer on the car to make it that way.”