The A311 Racing Hemi Program and Chrysler's Indy Effort
by Pete Hagenbuch
The A311 Engine program was first begun to provide Briggs Cunningham with an engine for his All-American attempt to win at Le Mans. Although he never succeeded in his quest he did come close several times. Failure was never due to his engines, though their extra weight certainly contributed to the brake problems which plagued him. This is a story in itself for later.
The A311 was a full blown effort to make the 331 cid Firepower V-8 competitive with the Jaguars and Ferraris at that famous Sarthe Circuit in the 24 hour race. It had a gear driven camshaft with roller tappets and some pretty wild overlap and duration figures. The compression ratio was around 12:1 and the racing pistons were all aluminum (without struts) and fit very loosely. Induction was Hillborn injection with tuned velocity stacks. I believe there were some multiple carburetor versions for Mr. Cunningham.
It goes without saying the ports were cleaned up and the much-discussed hemispherical combustion chambers were polished. Dual valve springs with surge dampers were used with special pushrods. Exhaust was welded from large diameter steel tubing. Later engines used a breastplate between the block and oil pan as very high output testing revealed a lack of stiffness in the bottom end.
The 331 cid tested earlier at Indy was so fast it scared all those established interests to death. They rapidly changed the rule which had allowed a larger displacement to be used on production-based engines. Mickey didn't get his until 1962.
The photos show a late model A311 of 271 cid (but still the Chrysler block) as tested at Indianapolis in 1952. Although competitive, the car was not a winner as the earlier test work with a 331 cid A311 had predicted.
In his history of the Chrysler hemi, Curtis Redgap wrote:
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by Pete Hagenbuch
The A311 Engine program was first begun to provide Briggs Cunningham with an engine for his All-American attempt to win at Le Mans. Although he never succeeded in his quest he did come close several times. Failure was never due to his engines, though their extra weight certainly contributed to the brake problems which plagued him. This is a story in itself for later.
The A311 was a full blown effort to make the 331 cid Firepower V-8 competitive with the Jaguars and Ferraris at that famous Sarthe Circuit in the 24 hour race. It had a gear driven camshaft with roller tappets and some pretty wild overlap and duration figures. The compression ratio was around 12:1 and the racing pistons were all aluminum (without struts) and fit very loosely. Induction was Hillborn injection with tuned velocity stacks. I believe there were some multiple carburetor versions for Mr. Cunningham.
It goes without saying the ports were cleaned up and the much-discussed hemispherical combustion chambers were polished. Dual valve springs with surge dampers were used with special pushrods. Exhaust was welded from large diameter steel tubing. Later engines used a breastplate between the block and oil pan as very high output testing revealed a lack of stiffness in the bottom end.
The 331 cid tested earlier at Indy was so fast it scared all those established interests to death. They rapidly changed the rule which had allowed a larger displacement to be used on production-based engines. Mickey didn't get his until 1962.
The photos show a late model A311 of 271 cid (but still the Chrysler block) as tested at Indianapolis in 1952. Although competitive, the car was not a winner as the earlier test work with a 331 cid A311 had predicted.
In his history of the Chrysler hemi, Curtis Redgap wrote:
Go from here to the main Hemi section
Home •
Engines •
Reviews •
Chrysler 1904-2018 •
Upcoming •
Trucks •
Cars
Spread the word via <!--Tweet or--> Facebook!
We make no guarantees regarding validity or accuracy of information, predictions, or advice - .
Copyright © VerticalScope Inc. All rights reserved. Dodge, Jeep, Chrysler, Ram, and Mopar are trademarks of Fiat Chrysler Automobiles.