- 5,287
- Sick_Cylinder
As well as being jaw droppingly beautiful this car has special historical significance for many reasons (Le Mans competitor and three time SCCA production class champion 1957-59) and deserves to be added to the roster of classics in the game.
The engine is of very unusual design being a 1971cc straight six hemi-head designed in 1935 by Fritz Eidler when he was engine design chief for BMW and was originally used in the pre-war BMW 328 sports car. After the war he went to work for Bristol cars who used this engine design and also supplied units to AC. The engine has 18 pushrods - one for each inlet valve and two for each exhaust - one is vertical and the second operates across the head resulting in what LJK Setright called "a forest of pushrods".
It was capable of 170bhp at 7000 rpm in race trim or 130bhp at 6200 rpm in road trim.
The inlet ports are unusual in that they are arranged vertically with the mixture passing straight through the centre of the head rather than from the side as in a conventional design.
Above picture shows cross head exhaust pushrod tubes and vertical through head inlet tracts.
Triple carbs without filters fitted.
Above photo shows the engine as installed in the AC Ace Bristol. Engine efficiency was excellent thanks to the short, straight inlet and exhaust path - a truly remarkable engine!
When Bristol decided they needed a bigger engine they switched to Chrysler V8 power - AC realised that their supply of engines was about to dry up. As a stop gap they started using Ford Zephyr 2.6 litre straight six motors fitted with Ruddspeed heads designed by F1 engine designer Tony Rudd.
Ford were developing a 260 cubic inch V8 for a new pickup truck range which was very lightweight for the time because of its short cylinder block skirt design. Carol Shelby was searching for a suitable lightweight british sports car into which he could slot an american V8 - a practice that he was familiar with from his past experience with J2 Allards which were supplied to the USA without engines and were often fitted with Cadillac V8's. First Shelby approached Chevrolet, but was turned down as they already had the Corvette.
Ford supplied a 260 V8 to Shelby and AC provided an AC Ace without an engine and a marriage was made in heaven - the AC/Shelby Cobra was born!
The engine was enlarged to 289 cubic inches and extensively tuned and Shelby conducted much development work solving the teething problems.
We already have the 427 cobra, it would be nice to get the 289 cobra, but please PD give us the father of the Cobra - the AC Ace!
NB please feel free to add extra information or videos, photos etc - I think this car is sufficiently important that it deserves to be kept at the top of the suggestions list (subject to no breach of protocol of course!)
Don't forget to also like the son of this car - the Shelby Cobra MK 1:
https://www.gtplanet.net/forum/threads/shelby-cobra-mk1-1962.302857/
Don't forget to also like the father of this car - the Tojeiro Bristol:
https://www.gtplanet.net/forum/thre...grandfather-of-the-cobra.310397/#post-9719611
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