Were there ever any two niche carmakers more in dire need of one another than AC and Bristol? That may be true on the face of it and from a distance of several decades, but back in the ‘50s, they had more differences than anything else. For a start, Bristol were a new outfit, utilizing BMW technology and affiliated with a major aircraft firm, while AC had been around since the early 1900s and were by then better known for manufacturing three-wheelers than anything else.
And yet, Bristol and AC collaborated pretty closely for a number of years, helping the former’s permanently-struggling sports car branch to keep its head above water just long enough to catch the eye of Carroll Shelby.
AC Cars is one of those businesses that went belly up, or just plain disappeared, a number of times. During one of their boom eras, just after the end of the First World War, one of the firm’s founding members, John Weller, designed a 1.6 litre OHC straight-6 that would serve as AC’s definitive engine for the foreseeable future. It was soon enlarged to 1991cc and a 1.5 litre 4-cyl. was developed from it, but the 2-litre AC overhead-cam six, thanks in part to its advanced design and because AC never had the money to develop anything else, just carried on, and on, and on…
Thirty-five years later, it was still there, now powering the newest AC creation, the Ace roadster. Slight asterisk about that: it actually wasn’t an AC creation. The all-independent Ace chassis was entirely designed by racecar engineer John Tojeiro in 1952. Tojeiro made several units, powered by a variety of engines, including Lea-Francis, MG and… Bristol.
The folks at AC got wind of these interesting specials and got Tojeiro to sign over the rights for a song (he received a cut of £5 per chassis for the first 100 units), put in their tired in-house 2-litre and launched the car at the 1953 London Motor Show. The car pictured above is the first prototype.
Initially, the straight-6 was only capable of 85hp, only 10hp more than when fitted in AC’s ancient 2-Litre saloons and tourers. The engineering department at AC managed to squeeze an extra 5 or so ponies out of the old block, but the car still felt underpowered, especially given how agile the chassis was.
Hence the Bristol engine returned into focus. It was also a bit weathered by then, having been designed by BMW in the mid-‘30s, and near identical in terms of displacement (1971cc) to the AC unit, but Bristol’s straight-6 was rated at 120-125hp out of the box and could be easily tuned to 150hp for racing. On their part, Bristol were not heavily invested into racing at the time, but were keen to see their engine get some track cred, and the AC Ace was exactly the right vessel to achieve that objective. The added revenue from selling extra engines was also pretty significant for such a small company as Bristol, who were also providing motors for a trickle of Frazer-Nash cars at the time.
The first AC-Bristol chassis, bodied as the Ace roadster or the Aceca coupé, were made in early 1956 and soon a number of cars found themselves on the track. From 1957 onwards, they were fierce competitors at Le Mans, winning the 1501-2000cc class in 1959. That certainly got the attention of the guy who won the race outright that year.
The Bristol six came with Bristol’s own 4-speed manual transmission, which was more user-friendly than the Moss boxes used on the AC-powered Aces. Those were still on the roster and were available until 1963 or 1964, but most clients preferred to pay the extra £200 (a tidy sum in itself, in those days) to have Bristol power under the bonnet. Front disc brakes became optional in 1957 and came as standard by 1959 — our feature car pre-dates that, so it has drums all round. The suspension is, just like all Aces since 1953, independent and uses transverse leaf springs both front and back.
These were expensive little machines, but that did not grant you much in the way of creature comforts. Mind you, power windows would not make sense on a window-less car, an automatic gearbox in this context is downright insulting (although a pre-selector, like a Wilson or Cotal, might have been acceptable) and even the best radio set of the period would have been rather useless in this environment.
With its tubular steel chassis and pretty minimal aluminium body, the Ace weighed all of 850kg, which was not a lot. This made performance rather brisk: 0-60mph in nine seconds and a top speed, depending on the state of tune or the presence of the optional overdrive, was around 115-120mph – a good 20mph faster than with the AC motor. Plainly justifies the presence of seat belts, I should think.
Bristol quit manufacturing their own (well, BMW’s own) engines circa 1962, so AC shopped around for another suitable six, ending up with Ford UK’s 2.6 litre block. Fed by three Weber carbs, those AC-Fords had 170hp on tap. But that experiment was short-lived, as the Ace was about to be re-incarnated as a V8-powered Anglo-American legend. Between 1953 and 1963, AC manufactured about 220 Aces with their own OHC engine and 37 with the British Ford 2.6, but the Bristol-powered variant (1956-62) was the more popular choice, tallying between 463 and 466 units. It is rumoured that some pre-1961 Bristol cars have had their 6-cyl. engines transplanted into AC-powered Aces well into the ’80s, so demand for this interesting combination of chassis and engine remained high, even long after the fact.
The only mystery about the AC Ace, be it Bristol-powered or otherwise, is who deserves to be credited for its simple but distinctive lines. The original prototype was allegedly bodied by Panelcraft and “inspired” by contemporary Ferraris, but the production version clearly had a different look, especially the front end. None of the sources I’ve scoured online over the past week or so care to shed any light on the matter. This, coupled with the many engines that powered it makes one of the most iconic sports cars of the postwar era quite an oddity. Even aristocratic thoroughbreds like this AC-Bristol are, at least partially, of unknown ancestry.
Related posts:
Curbside Classic: 1965 Shelby AC Cobra – Power To The Aristocrats
British Deadly Sins (High-Brow Hybrids, Part 1) – The Surprisingly Long Story Of AC
Very nice car. I think there was a period when Cobra prices were skyrocketing that you could still get an AC for a reasonable price. That is no longer the case although they remain a relative bargain.
What interests me is the evolution of the front end. The prototype Ace is very early 1950’s looking, but the moustache around the grille opening works better with the headlights than the production version. The Cobra did away with the moustache and an icon was born.
Lovely car and what a beautiful color, makes a striking combination with that burgundy interior.
And those lines – whoever it was who drew them, he really aced it! With those flowing curves it looks almost Italian, especially the front end that’s clearly cribbed from Ferraris of the era, right down to the egg crate grille.
I saw a Bristol 406 parked curbside the other day. Same era, same engine, but quite a different car. It had a (slightly stuffy) air of aristocracy about it, whereas the Ace is all curvy, sexy and racy.
The prototype had its headlights too low for US regulations, hence they were raised as the US market was as usual the most important sports car market at the time. This issue affected a number of other European cars, most notably the Fiat 500, which had silly looking raised headlights.
BTW, we have a Sports Car Illustrated vintage review of an AC-powered Ace that is scheduled tomorrow for a rerun. They were able to get it up to a 106 mph top speed. Not bad for an engine designed in 1919.
Very nice. The interior might not be full of luxury items but it does look very inviting. The blue exterior is quite eye catching as well.
Assuming those are standard-size Japanese plates, this AC is a smaller car than I thought! I guess this comes from years of looking at Cobras with differing profiles of bulging fenders – take the later bulges away and the resulting car is quite small.
Beautiful colours.
Always such a fine looker.
The Motor tested an AC-engined one and got it to 60 in 11.4 secs (and on to 103): not exactly shabby in 1954! The BMW-engined one was a bit over 9 for the former, and only 13 mph faster for the latter, but when you see the hilarious bore-stroke ratio of the old banger, its time was indeed up.
As to progenitors, I found this:
“Styling-wise, the Ace body was an in-house collaboration between Alan Turner and Eric George Gray.”
The latter name is mentioned in the current incarnation of AC cars on their website.
Whoever these mystery men were, they worked wonders. wonder if anyone here knows more.
(The author is a Ben Tyler – which name turns out to be uncommonly common – on some site I’ve never heard of).
https://supercarnostalgia.com/blog/ac-ace-aceca