The Chevrolet Stovebolt engine is a straight-six engine made in two versions between 1929 and 1962 by the Chevrolet Division of General Motors. It replaced the company's inline-four as their sole engine offering from 1929 through 1954, and was the company's base engine starting in 1955 when it added the small block V8 to the lineup. It was completely phased out in North America by 1962, but GM continued to build it in Brazil until 1979. It was replaced by the Chevrolet Turbo-Thrift engine.

First generation: 1929–1936

"A six for the price of a four"

The new six-cylinder engine was introduced in 1929 Chevrolet cars and trucks, replacing the company's first inline-four. The 1927 Chevrolet Series AA Capitol had sold very well—over a million units sold as compared to about 400,000 of Ford's Model T—but Ford had introduced a new model in the autumn of 1927: the Model A. The Model A, with its improved four-cylinder, compared favourably to the Series AA Capitol, and sales of the Model A surpassed Chevrolet by 1929. Chevrolet had been considering switching to a six-cylinder engine since 1925, and the ascendency of the Model A precipitated the switch. Chevrolet had long been known for its "valve-in-head" design in the previous four-cylinder engine, so General Manager William S. Knudsen and marketing executive Richard Grant insisted that the new six-cylinder design also use overhead valves. The new engine was mockingly called the "Cast-Iron Wonder" and "Stovebolt Six" for its seemingly old-fashioned design,

  • 1930 Chevrolet Series AD Universal - @ 2600 rpm, @ 900 rpm

Applications:

  • 1933 Chevrolet Series CA Eagle / Master - @ 2800 rpm, @ 1000-1800 rpm
  • 1934 Chevrolet Series DA Master - @ 3300 rpm, @ 800-2200 rpm
  • 1935 Chevrolet Series EA/ED Master - @ 3200 rpm, @ 1000-2000 rpm
  • 1935 Chevrolet Series EB/QA/QB/QC/QD Commercial Utility - @ 3200 rpm, @ 1000-1400 rpm
  • 1936 Chevrolet trucks - @ 3200 rpm, @ 900-1500 rpm

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A version with a bore and stroke was also introduced in 1933, in the lower priced Series CC Standard, and used again in the 1934 Series DC Standard. It made a peak at 2300 rpm, and peak torque of at 1200-2000 rpm. The compression ratio in the 1933 model was 5.2:1, and was increased to 5.35:1 in 1934. Production of this version ended after 1934, and the Standard used the 206.8 cubic inch engine thereafter.

Second generation: 1937–1962

The Stovebolt engine was significantly re-engineered for the 1937 model year, distinguished from the earlier 1929-1936 engines by having a redesigned crankcase with four main bearings in lieu of the older engine's three bearings. It is often known as the "Blue Flame" engine, although that name was only officially applied beginning in 1953, and then only for the 235ci version coupled to the Powerglide automatic transmission (including in the Corvette).

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This engine had a displacement with a bore and stroke of . A four-bearing crankshaft was added, along with 6.5:1 compression pistons, for . A new cylinder head in 1941 increased output to , and 6.6:1 compression gave the 1949 model . This generation did not use a fully pressurized oiling system. The connecting rods were oiled using an "oil trough" built into the oil pan that had spray nozzles that squirted a stream of oil at the connecting rods (which were equipped with "dippers"), thus supplying oil to the rod bearings.

Rod bearings were made of babbitt cast integral with the rod. The bearing was adjustable for wear by removing copper shims placed between the rod cap and connecting rod. In this way specified oil clearance could be maintained. If the crankshaft were to be turned undersized, or if the bearing was damaged or worn out, rod and bearing were replaced as a unit, typically at the dealership.

This engine was also used in GM's British Bedford truck. In the late 1930s rival Austin decided to get into the 2-3 ton truck ("lorry") market and in a crash program based the design on the basic architecture of this "Stove Bolt" engine, except that they added detachable shell main and con-rod bearings and pressurized lubrication. That Austin engine, in six-cylinder form, post war known as the Austin D-Series, went on to power cars such as the Austin Sheerline and Princess, and the Jensen Interceptor and 541. Austin also lopped off two cylinders to create the BS1 engine and in that form various versions, with various capacities, powered cars such as the Austin 16, A70 Hampshire and Hereford, A90 Atlantic, the Austin-Healey 100-4 and the Austin Gipsy, a generation of commercial vans, as well as some models of the iconic London black taxi (FX3 and FX4).

{| class=wikitable

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!Year

!Compression Ratio

!Power

!Torque

!Notes

!Reference

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|rowspan="2"|1937-1940||rowspan="2"|6.25:1|| @ 3200 rpm|| @ 1200 rpm||passenger cars||rowspan="2"|

</references>

  • FAQ Stovebolt.com — What is a Stovebolt?
  • Chevrolet "Stovebolt" Six by Jack Nerad — The story of the Chevrolet "Stovebolt" Six.
  • Classic definition of a Stovebolt — by the Mid State Antique Stock Car Club
  • Sheridan's 1946 Chevy Truck — 1941–46 Chevrolet truck photos; much information.
  • Stovebolt.com — Online information resource and discussion forums for pre-'73 Chevrolet & GMC trucks.
  • chevytrucks.org — Specializing in information on 1941–59 Chevrolet trucks; how-to articles, pictures, history, etc.
  • "The Art Deco Series" — This site is dedicated to the history and preservation of the Chevrolet & GMC commercial haulers that were produced just before, during, and just after World War II, 1941–46.
  • OldTruckNetwork.com — The No. ? online information resource for old trucks and politics.