Pentz AC Ace Bristol: Latin twist

By Martin Buckley

| 25 Jan 2023

Classic & Sports Car – Pentz AC Ace Bristol: Latin twist

In his oversized peaked caps and self-aggrandising military garb, General Marcos Pérez Jiménez, President of Venezuela from 1952 to 1958, was your prototype dodgy mid-20th-century South American military dictator.

Short and tubby in appearance, his hobbies included embezzlement, election-rigging and ruthless suppression of anyone who questioned his regime.

All of which is pretty standard stuff for this turbulent part of the world.

And yet, looked at in its entirety, the legacy of Jiménez shows that nobody is all bad.

Three special-bodied AC Ace Bristols were built in German garage owner Karl Pentz’s workshop

In light of Venezuela’s subsequent history of military coups d’état and political assassinations, his years in power look almost stable: even the populist lefty Hugo Chávez, president from 1999-2013, is on record as thinking highly of Jiménez.

True, he reputedly lined his own pockets to the tune of $200m while in power, but ‘PJ’ also used Venezuela’s oil-producing wealth to develop the local economy with huge public infrastructure projects for roads, schools and hospitals.

And, like almost every other 20th-century despot from Mussolini onwards, Jiménez had an eye for fancy motor cars.

Triple Solexes top the Pentz AC Ace Bristol’s cross-pushrod straight-six engine

He was an enthusiastic Mercedes 300SL owner who even took racing lessons from his friend Juan Manuel Fangio, so few were surprised when el presidente decided to put his name to a scheme to promote sports car racing in Venezuela.

These were not to be purpose-built circuit events – there were then no such venues in the country – but hardcore road-races and hillclimbs modelled along the crowd-pleasing, death-or-glory lines of the recently banned Mille Miglia and Carrera Panamericana.

Period images, clammy with humidity, show makeshift tracks dotted with palm trees, with nothing but sandbags and hay bales between cars, spectators and tragedy.

The sensational Bristol engine, here in C2 spec, perfectly suits the character of the lithe and focused AC Ace

The hot, gearbox-breaking 6.2 miles of closed-road circuit earmarked for the Caracas 1000 Kilometres was close to the Fuerte Tiuna military base.

It attracted all the big factory teams – and most of the star drivers – although it was only in the final, 1957 meeting that the results counted towards the World Sports Car Championship.

There was a presence from Porsche and Aston Martin, but it was the Italian equipes that dominated proceedings: Fangio and Stirling Moss won aboard works 300S Maseratis in 1955 and 1956 respectively, while Peter Collins – partnered by Phil Hill – took the laurels in the scrappy 1957 race in a Ferrari 335S.

BEX148’s first owner, Dr Oscar Lupi, chases a rival Ace in the Trofeo Shell – La Trinidad, a race he contested in 1958 and ’59

This brutal six-hour event famously marked the end of Maserati’s top-level works efforts when all three of its 450Ss crashed.

By then the nature of the grid was changing, with the occasional ‘civilian’ car entered to trade blows with the pure factory racing machinery.

For wealthy local privateers looking to prove themselves, the recently introduced AC Ace Bristol was rapidly emerging as a machine that would go the distance, with a good chance of honours in the under-2-litre class.

That was mainly thanks to the efforts of a certain Juan ‘Jack’ Fernández, a Caracas garage owner and sometime works-supported Ace driver.

Lupi on the front row of the grid at the Trofeo Shell – La Trinidad

Venezuela was fast becoming one of Thames Ditton’s most successful overseas outlets: Fernández found homes for an impressive 41 cars – four Aces, 31 Ace Bristols, five Aceca Bristols and a single AC-engined Aceca – among the oil-enriched Caracas elite.

Six Aces, all but one of them local cars, entered the 1957 Venezuelan Grand Prix.

One failed to qualify and Hap Dressel’s Ace Bristol (car 54) was cut in half when it became involved in an accident with the Stirling Moss Maserati 450S.

BEX148’s snug cockpit matches that of the standard AC Ace Bristol

The Equipo CADV Ace of importer Fernández was a DNF on lap 18, but the remaining three ACs were placed 16th, 17th and 21st.

It is at this point that the German garage owner Karl Pentz enters the Venezuelan Ace Bristol story, because the latter two finishers had been modified in his workshop to extract more speed – mainly by way of improved aerodynamics – for owner/racer Renny Ottolina and Colombian driver Antonio Izquierdo.

Chassis BEX148 (B for Bristol, EX for export), the AC pictured here, did not take part in the Caracas 1000 but is the only one of the three Pentz-modified cars – which were all slightly different – to survive.

A long gearlever operates the superb Bristol ’box

Sold new to Dr Oscar Lupi, BEX148 left the AC factory in April 1956.

Upon its arrival in Caracas, the Pentz modifications included a full undertray – hence the large wing vents to relieve underbonnet pressure – and slightly flared wheelarches accommodating wider 6.00x16 tyres, instead of the standard 5.50x16s.

The most obvious change, other than the lowered windscreen, was the Maserati/Ferrari-style nose, complete with faired-in headlights.

The Pentz-modified Ace retains original AC floor-mounted pedals

BEX148 received perhaps the prettiest rendition of a frontal treatment that, as well as improving its aerodynamics, allowed the little British roadster to look perfectly at home among beefier opposition.

It also made the Pentz Ace a foot longer than the standard item.

Dr Lupi appears to have been active from the start with BEX148, managing fourth place in the under-2-litre class at the Estado Carabobo Trophy held in Valencia in 1956, and a ninth at the 1957 La Montana Hill Climb alongside the Aces of Fernández and Fredy Brandt.

BEX148’s modified bodywork, including a new nose, helped to improve the AC’s aerodynamics

Painted red and always wearing the number 139, it was often to be seen mixing it with much faster, purpose-built sports-racing cars: one image shows Lupi jostling for position with at least eight Ferraris.

The Trofeo Shell – La Trinidad was a big meet in Venezuela featuring a main Formule Libre race along with class events.

Lupi and his Ace came seventh in 1958 and second in 1959.

After another seventh, this time on the Vuelta de Aragua in 1960, Lupi took delivery of a new Ace Bristol and BEX148 was, apparently, retired.

Although standard 5.50x16s are fitted up front, slightly flared rear wheelarches accommodate wider 6.00x16 tyres

It had two local Venezuelan owners who used it as a road car before going into long-term storage in the 1990s.

When Tim Isles, the AC Owners’ Club’s registrar for the model, found BEX148 some 20 years ago it needed, in his words, “A bit of help.”

With marque specialist Nigel Winchester overseeing the restoration, Tim was determined to reuse every original part he could, and maintain the Pentz modifications.

This one-of-three Ace Bristol has always worn the number 139

BEX148 was ready to race again in time for the Fordwater Trophy at the 2013 Goodwood Revival and it was Nigel himself – clearly a handy driver – who brought the car home well ahead of the other Aces in the race.

After that it stayed with Tim in Yorkshire for several years, but has recently been sold to a collector in Germany by Pendine, based at Bicester Heritage, which is becoming a bit of an AC specialist.

The standard Ace looks so right from every possible angle that it’s hard to view modifications to its graceful profile as anything other than lily-gilding, although the lower nose must have reduced the frontal area to get an (unspecified) higher maximum speed.

At 128bhp, or up to 170bhp in race tune, the Pentz-modified Ace has more than enough power to loosen the tail

Hopping in through the dinky cutaway doors, you immediately sense that you ‘wear’ the close-fitting but comfortable Ace, regulating its movements through smooth-acting floor-hinged pedals and a man-sized steering wheel that gives lighter and more direct control than its large diameter might suggest.

The cranked gearlever seems to promise ponderous changes, but it is the Bristol gearbox that came with the engine, which means you can whip it around its well-defined gate with a nifty precision that is more firearm than automobile.

The crisp and fruity BMW-derived Bristol straight-six – handsome but half lost in its spacious quarters – has hemispherical heads and triple Solex carbs for a full-bodied bark that is exactly equal to its considerable bite.

The low windscreen provides little protection from the British weather

It is fussy-sounding but never less than expensively well-bred in tone, pulling smoothly and evenly from 2500rpm but feeling at its strongest from 4500rpm, where most other ‘sixes’ of its era were running out of breath.

If they were willing to fit colder plugs and richer jets, competition-minded owners could get the full benefit of 6000rpm change-up points that gave a 70mph second gear and a near-100mph third.

The suspension, on the hard side of firm but not in a way that rattles the fillings, adds to your confidence in the total stability of the Ace, with its roll-free cornering and neutral steering.

Following an outing at the 1960 Vuelta de Aragua in Venezuela, BEX148 was apparently retired

It does not require huge amounts of physical or mental effort to put it where you want it on the road and you guide the car, its steering lightening with speed, adding near-instinctive precision.

There was probably nothing to touch the Bristol-engined Ace in the world of showroom-available ‘pure’ sports cars in the second half of the 1950s.

It’s very easy to see the attraction for buyers such as Dr Lupi: here was a road-friendly, 120mph, 20mpg two-seater that gave well-heeled, competent drivers who couldn’t stretch to a Ferrari or a Maserati a good chance of track success simply by turning up.

‘The crisp and fruity “six” has hemi heads and triple carbs for a full-bodied bark that is exactly equal to its considerable bite’

As for what happened to Dr Lupi, I can’t tell you. Likewise Pentz or even Fernández.

Their fates are as obscure as those of the sister cars to BEX148.

Izquierdo’s Ace, BEX149, has not been heard of since the mid-’60s.

Arguably the least attractive of the Pentz-modified cars, it was much campaigned in period: after Caracas, its next outing was in Nassau for Bahamas Speed Week, but Izquierdo sold it upon his return and bought a new Ace (BEX460) direct from the factory.

At the expense of improved fuel efficiency, competition-minded owners could fit colder plugs and richer jets to maximise the AC Ace Bristol’s performance

He raced it throughout Europe that summer before shipping it home to continue competing in Colombia and Venezuela in late 1958 and ’59.

That car still exists, in excellent condition, in a collection in Colombia.

Ottolina’s Ace was replaced immediately after the Caracas 1000, when he upgraded to a Maserati 200S that ended up as a V8-engined drag car before being scrapped in the ’80s.

The standard AC Ace Bristol chassis offers sweet balance

The fate of its first owner was equally grim.

As well a former crooner and talkshow host, Ottolina was a man-of-the-people 1978 presidential candidate who died in a plane crash shortly before that year’s election.

If you thought motor racing was a dangerous sport in Venezuela, it was often safer than politics.

Images: Will Williams

Thanks to: Pendine; Tim Isles

Factfile

Pentz AC Ace Bristol

Sold/number built 1957/3
Construction tubular steel chassis, aluminium body
Engine iron-block, alloy-head, ohv 1971cc straight-six, triple downdraught Solex carburettors
Max power 128bhp @ 5750rpm (up to 170bhp in race tune)
Max torque 128Ib ft @ 4500rpm
Transmission four-speed manual, RWD
Suspension independent, by upper transverse leaf spring, lower wishbones, telescopic dampers f/r
Steering Bishop cam steering box
Brakes Alfin drums
Length 13ft 8in (4165mm)
Width 4ft 11in (1500mm)
Height 4ft 1in (1245mm)
Wheelbase 7ft 6in (2290mm)
Weight 1793Ib (813kg)
0-60mph 8.7 secs
Top speed 121mph
Mpg 18-27
Price new £2165
Price now c£350,000*