Magazines:  Real Estate Shopping: Adult Costumes  |  Kids Costumes  |  Cars  |  Guitars |  Electronics
This Issue Archived Articles Blog About Us Contact Us
SEARCH


The Chrysler A57 Multi-Bank Engine

An amazing engine

by Julian Edgar

Click on pics to view larger images


This article was first published in 2008.

What do you do if it’s 1941, your country has just entered a war, and there’s an urgent need for an engine to propel a tank – an engine you don’t have? If you are the Chrysler Corporation, you develop a design that uses five of your six cylinder car engines, arranged around a common crankcase. The result was 30 cylinders, 21 litres and an output of 470hp at just 2700 rpm!

Click for larger image

If Chrysler had started from scratch to design a tank engine, they would have developed an engine that was nothing like the A57 Multi-Bank. But the need for speed – both in design and production – made use of existing tooling and design obligatory.

The starting point was the L-head, 4.12-litre in-line six. A slightly revised cylinder head reduced the compression ratio to 6.2:1 from the standard engine’s 6.8:1, but production Dodge carburettors were retained.

Click for larger image

The five engines were arranged around a cast iron crankcase, with each ‘sub engine’ being geared to a common ring gear. A single central shaft handled all the output.

Click for larger image

Using existing tooling and designs were the cylinder blocks, pistons, connecting rods, crankshafts and cylinder heads. Another advantage of the design was its compact shape; important in the rear-engine tank installation.

Click for larger image

The prototype engine had major difficulties with carburetion; the differing lengths of the intake tracts made carburettor synchronisation and fuel distribution problematic.

Click for larger image

The carbs were moved so that they all sat at the same level (also improving accessibility) and sheet metal guides were inserted in induction pipes to improve fuel distribution. The placing of the carburettors on the same plane also simplified the throttle linkages and air cleaner.

Click for larger image

The distributors, that on the original engines were positioned alongside the mid-point of the engines, were moved to the end of the camshafts. The camshaft of each sub-engine was driven by gears instead of the chain used on the donor car engine.

The prototype engines used five separate water pumps belt-driven from the crankshaft pulleys, but because of the lack of individual flywheels, the belts were subjected to alternating loads and belt life proved short. Given that a tank engine must be extremely reliable, the decision was made to use a single water pump driven by an accessory shaft located in the central crankcase.

Click for larger image

Dry sump lubrication was used with an oil cooler. Complete with radiator, cooling fan and clutch, the Multi-Bank weighed a considerable 5244 lb (2384kg).

The engine was used in the M3A4 and M4A4 Sherman tanks.

What an amazing piece of engineering!

Did you enjoy this article?

Please consider supporting AutoSpeed with a small contribution. More Info...


Share this Article: 

More of our most popular articles.
A dozen bits to find at the truck wreckers.

Technical Features - 29 August, 2008

Junkyard Dawg

Why an engine's peak power figure is becoming increasingly insignificant

Technical Features - 12 June, 2008

Forget the Kilowatts

How does Hz = stiffness?

DIY Tech Features - 12 November, 2013

Measuring the stiffness of structures by vibration testing

An auto trans cooler that will cost you almost nothing

Technical Features - 12 February, 2008

Cooling the Trans

Then the world's most powerful six cylinder passenger car diesel

Technical Features - 6 June, 2005

BMW's Twin Turbo Diesel

Electronic module that can sound high or low temperature alarms or warnings

DIY Tech Features - 30 June, 2008

The eLabtronics Pulser, Part 2

Designing structures so they won't fail

DIY Tech Features - 21 February, 2006

Making Things, Part 1

Dressing MIG welds made in car bodywork

DIY Tech Features - 3 June, 2014

Dressing MIG Welds

Important differences to intercooling petrol engine turbos

Technical Features - 10 January, 2008

Diesel Intercooling

One of the most significant cars ever

Special Features - 21 April, 2009

The Amazing Citroen DS

Copyright © 1996-2014 Web Publications Pty Limited. All Rights ReservedRSS|Privacy policy|Advertise
Consulting Services: Magento Experts|Technologies : Magento Extensions|ReadytoShip