Toyota Type A engine

Type A
Overview
Manufacturer	Toyota
Production	1935–1947
Layout
Configuration	I6
Displacement	3,389 cc (3.4 L; 206.8 cu in)
Cylinder bore	84.1 mm (3.3 in)
Piston stroke	101.6 mm (4.0 in)
Block material	iron
Head material	iron
Valvetrain	OHV
Combustion
Fuel system	carburettor
Fuel type	Gasoline
Output
Power output	62 PS (46 kW; 61 hp)

The Type A engine was Toyota's first production engine, being produced from 1935 through 1947.

This engine was a 3,389 cc (3.4 L; 206.8 cu in) pushrod, overhead valve, 6-cylinder, three bearing engine copied from the 1929–36 Chevrolet Gen-1 3 bearing Stovebolt L6 OHV engine. By virtue of a modified intake manifold it produced 62 PS (46 kW), while the Chevrolet engine produced 60 PS (44 kW). GM used a number of local Japanese suppliers for the smaller engine parts (e.g. carburettors) while the Osaka Assembly location was open until appropriated by the Imperial Japanese Government.[1] Toyota was able to use the same suppliers for its cars. The parts were identical enough that pistons, rods, valves, etc. could be used in both the Chevrolet and Toyota engines interchangeably. There are several recorded instances of parts intended for one being used to repair the other.[2]

Toyota had initially considered copying the Ford flathead V8 engine because it was the most popular engine in Japan at the time. However, the machining of two separate banks of cylinders would add too much to the production cost, so the Chevrolet engine was copied instead.[2] The Ford Model T was also being manufactured in Japan beginning in March 1925,[3] followed by the Ford Model A in 1927; both used the flathead Ford Model T engine.

Other references to the Chevy engine claim different power figures. Different manufactures used different measuring techniques (e.g. with or without the generator/alternator connected), engines differed from year to year and that some manufacturers simply lied. In this case, Toyota did back to back comparisons using the same techniques, so it is likely that the Toyota engine did in fact produce slightly more power than the Chevy engine on which it was based. Also, the Chevy engine was likely to be a year or two old, so the current Chevy engine may have produced even more power.

The 3,386 cc (3.4 L; 206.6 cu in) Type B was a more technically advanced version of the Type A. Production commenced in November 1938 with the opening of Toyota's Koromo plant.[5] The design was based on the Chevrolet 207 engine, and built under license but with metric dimensions and minor revisions to suit the local market. It had a four-bearing crank and shaft-mounted rocker arms, as did the Chevrolet engine. The type B engine remained in production until 1956 at least.

The original output was 75 PS (55 kW) at 3000 rpm. In January 1940 this was increased to 78 PS (57 kW) at the same engine speed. Another bump, to 82 PS (60 kW) occurred at the time of the BM truck's introduction in March 1947.[5] A 1944 prototype for a large passenger car called "Toyota Large B" also received the B-series engine, although with a higher 6.9:1 compression ratio and producing 85 PS (63 kW).[6] This was also the output of the improved engine fitted to the 4-ton BA and 2.5-ton BC trucks which were built until February and July 1956 respectively.[7][8]

The Type B was complemented and eventually supplanted by the similar 3.9 L Type F which first appeared in 1951. The Type F is based on the larger OHV GMC Straight-6 engine built from 1939 until 1963 in the same way that the Type A and Type B were based on the Chevrolet engines of their times. There was also an experimental 4-liter version called the Type D.

An unrelated four-cylinder diesel engine introduced in the 1970s was also called the Type B.

The 2,259 cc (2.3 L; 137.9 cu in) Type C was produced from 1939 through 1941. It was formed by removing two cylinders from a Type A engine.

The 4,052 cc (4.1 L; 247.3 cu in) Type D was a larger version of the B engine developed in early 1944, featuring an increased bore while retaining the same stroke. It was a direct response to a national order issued in 1940, instructing Toyota to develop a higher output engine based on the B.[5] It did not enter series production, with Toyota instead developing the somewhat smaller Type F engine after the war. Output was 100 PS (74 kW).[5]

The 585 cc (0.6 L; 35.7 cu in) Type E was produced in 1938 only for the prototype EA sedan. It was a copy of the two-stroke engine used in the DKW F7.

Type S
Overview
Manufacturer	Toyota
Production	1947-1959
Layout
Configuration	I4
Displacement	995 cc (1.0 L; 60.7 cu in)
Cylinder bore	65 mm (2.6 in)[10]
Piston stroke	75 mm (3.0 in)
Block material	iron
Head material	iron
Valvetrain	side valve
Compression ratio	6.5:1
Combustion
Fuel system	carburettor
Fuel type	Gasoline
Output
Power output	27 PS (20 kW; 27 hp)
Torque output	98 N⋅m (72 lb⋅ft) @ 2400 rpm
Chronology
Predecessor	None
Successor	Toyota P engine

The 995 cc (1.0 L; 60.7 cu in) Type S was produced from 1947[11] through 1959. It was unrelated to previous Toyota overhead valve engines, being designed by reverse-engineering a 1930s Adler Trumpf Junior's engine, and used the less sophisticated flathead engine design which was short lived.

Wikimedia Commons has media related to Toyota Type A engine.

• List of Toyota engines
• Toyota AA passenger car
• Toyota G1 truck