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AC Ace and Aceca (1953 to 1963)

By Jon Cosson · Last checked 14 October 2026

The AC Ace roadster and Aceca coupe (1953 to 1963) were hand-built at Thames Ditton with AC, Bristol or Ford Zephyr six-cylinder engines. Engine identity, originality and history matter most. The Greyhound and the V8 Cobra are not covered here.

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Buyer's guide

AC Ace and Aceca buyer's guide

What to check, the test drive, buying at auction and selling.

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Why?

Our long-form buyer's guides live on joncosson.com, an independent, ad-free site from the same editor. This site keeps its focus on Thornton-le-Dale, the village and Mathewsons.

At a glance

Years: 1953 to 1963 (Ace shown October 1953, production from 1954; Aceca coupe from October 1954; Bristol engine from 1956; Ford Zephyr 2.6 "Ruddspeed" from 1961; production ended 1963)
Body styles: two-seat open roadster (Ace); two-seat fixed-head coupe with tailgate (Aceca)
Engines: AC 1991cc overhead-cam straight six; Bristol 1971cc pushrod straight six (100B, 100C, 100D and D2 types); Ford Zephyr 2553cc straight six tuned by Ken Rudd
Built in: Thames Ditton, Surrey, England

Why people buy one

A light, hand-built British sports car with an aluminium body and independent suspension at both ends, which Motor Sport called a first for a post-war British sports car.
The Bristol-engined cars had a strong competition record, including a 2-litre class win at Le Mans in 1959.
The Aceca adds a closed GT body with a tailgate and a rubber-mounted differential for a quieter ride.
The Ford-engined 2.6 cars are rare (37 Aces and 8 Acecas, according to the AC Owners Club), and Ken Rudd's tuned Zephyr engine gave up to 170bhp.
The AC Owners Club keeps registers for these models, which helps when checking a car's history.

What to weigh up

Engine swaps are common, so a car sold as a Bristol may have had its original engine replaced, and AC-engined cars have been given Bristol identities.
Sources disagree on production totals: about 223 to 229 AC-engined Aces and 463 to 466 Ace Bristols, with 151 AC and 169 Bristol Acecas.
Many Aces were modified, re-bodied, raced, or converted towards Cobra specification, so a car's present form may not match its build record.
Replicas exist, for example glassfibre Ace Bristol replicas from Hawk Cars using MGB parts. Read the V5C description carefully.
The AC engine dates back to 1919 and Supercar Nostalgia calls it the Ace's weak spot; the Bristol engine is complex and its carburation is notoriously hard to set up.
Restoration of the aluminium body and the Aceca's timber framing is skilled, specialist work.

Where they rust

The two large main chassis tubes along their length, especially underneath and near crossmembers, where water can sit.
The fabricated box sections at each end of the chassis that carry the suspension and final drive.
The small-diameter tubular frame that supports the body, including the scuttle hoop behind the dashboard and the windscreen and door hinge mounts.
Aluminium panels where they touch the steel tube frame; look for bubbling, white powdery corrosion and cracks.
Lower edges of the doors, wings and rear body, where damage and repairs collect.
On the Aceca, the ash framing in the doors and tailgate structure; dropped doors or a sagging tailgate point to rotten wood.
On the Aceca, the glassfibre bulkheads and footwells, for cracks and poor repairs.

Mechanical weak spots

The AC engine is a mostly aluminium wet-liner six with a chain-driven overhead camshaft; check for coolant in the oil and water leaks around the block.
The Bristol engine is a cross-pushrod design based on the pre-war BMW 328 unit. It prefers to rev, and Hagerty UK notes its centre main bearings suffer if it is laboured at low revs.
The Ford 2.6 is a Ford Zephyr six tuned by Ken Rudd in several stages (Motor Sport gives 120 to 170bhp); ask which stage is claimed and whether it is documented.
Gearboxes vary: AC cars used a Moss box at first and later a TR3-type box, while Bristol cars had Bristol's own close-ratio box; Laycock overdrive was an option from 1956.
Brakes were drums at first, with front discs optional from 1957 and later standard (Supercar Nostalgia says 1960, Wikipedia 1958). Some owners prefer drums for historic racing eligibility.
Transverse leaf springs and wishbones are used front and rear; Motor Sport noted that suspension and mechanical parts suffer when a car is laid up for years.

At a Mathewsons viewing

Find the chassis plate in the engine bay on the left-hand footwell box and check it against the V5C; Sports Car Market notes the last three digits are repeated on the door and boot hinges. AE and AEX numbers should mean an AC engine, BE and BEX a Bristol engine, and RS a Ford 2.6.
Read the engine number on the plate and casting and check that it suits the chassis prefix. Ask whether the original engine is still fitted and whether the AC Owners Club register agrees.
Look for evidence of a Ford 2.6 car: a smaller front air intake and slightly flared wheelarches, as described by Motor Sport. A Bristol car should have a Bristol engine with three carburettors.
With a torch, look underneath along the main chassis tubes and at the suspension box sections, and check the panel edges for corrosion. On an Aceca, try the doors and tailgate for drop.
Open the bonnet and look for oil and coolant leaks and untidy wiring, and if staff start the car, listen for knocks and watch the oil pressure; do not assume it will be started.

Parts, specialists and clubs

Specialists who restore Aces and Acecas can make body and chassis parts, while parts for the AC and Bristol engines are specialist items. The AC Owners Club covers all AC models and keeps registers for members, which can help confirm a car's original specification before you bid.