This thread was brought to my attention lately, and I'm generally not a fan of posting in long forgotten threads but when its so specific and I can somehow contribute, then I do so.
It was asked what were testing procedures of Japanese engines and how much they had to endure before acceptance (with remark that most likely they would not be able to pass US tests. I have my doubts with last claim, at least some of them like Sakae engines should have no issues in passing those since they were incredibly reliable. Ask GregP how many problems they had with their Sakae in A6M5 in Planes of Fame museum
)
But ad rem, I received lately a document titled "Regulations for Acceptance Tests of Aircraft Engines. Administrative Equipment Order (Nairei hei) No. 83" from October 1942. Document was captured on Saipan in July 1944 and translated under Item No. 9777 position (Cincpac-Cincpoa special translation).
The document lists exact definitions of terms used in testing aircraft engines at the Air Technical Deport. Document sets forth the specific conditions, procedures and objectives of those engine structural and operational tests and in addition gives the minimum government specifications and performance requirements.
Document is revision of similar Orders given on January 1927, then revised subsequently on June 1933, August 1934, May 1939 and January 1939.
As you may see Japanese had set their own regulations and requirements from the very moment they became capable of independent manufacturing of aircraft engines (albeit first ones were licensed engines from various European companies).
Sidenote - I will not quote whole document but only parts of it, as it is way too long. But most important things should be here to give you a point. Also, first will be given explanations on terms and only after the procedures. I think that way you will be able to distinguish differences easier.
"
Chapter I - Introduction
Item 1 - The following specify the regulations which concern aircraft engine acceptance tests.
Item 2 - The purpose of aircraft engine acceptance tests is to assess the practical value of the engine's construction, performance, reliability and endurance.
Item 3 - The OinC (Naval Air Headquarters) will specify separate regulations, based on the present ones, for the acceptance tests of special type engines which are not adequately covered by these regulations.
Item 4 - Besides these regulations, separate regulations for aircraft engine construction and repair tests should be used.
Item 5 - Details of test procedure will follow procedures established separately by OinC.
Item 6 - When tests are to be carried out according to these regulations, the OinC, will notify the departments concerned.
Item 7 - Acceptance tests conducted under these regulations will be made on the following engines :
1) Experimental engines
2) Engines which are judged to need acceptance tests after modifications.
3) Others which are judged to need acceptance tests.
Item 8 - Acceptance tests will be subdivided as follows :
1) Structural tests
2) Operational tests
Item 9 - The entire acceptance test procedure is to be followed for experimental engines.
(...)
Item 13 - Instruments, machines, equipment, and units of measurement used during tests and inspections must be approved by the OinC.
Item 14 - Tests of experimental engines will be conducted on engines for which tests have been completed at the factory. These tests will follow the procedure for tests of engine performance and second operational tests on the same model engine as determined by these regulations.
Chapter II - General Rules
Item 18 - The rated output of an aircraft engine is the output at rated altitude and rated horsepower (HP). For engines with variable speed superchargers, the rated output at first rated altitude and at rated HP.
Item 19 - When the rated output of an engine is 300 HP or less, multiples of 5 HP will be used, and when greater than 300 HP, multiples of 10 HP will be used to indicate output.
Item 20 - To indicate various manifold pressures, multiples of 5 millimeters will be used.
Item 21 - To indicate various revolutions per minute (RPM), multiples of 20 or 50 RPM will be used.
Item 22 - To indicate rated altitude, multiples of 200 or 500 meters will be used.
Item 23 - Terms used in the regulations are defined as follows :
1. Manifold pressure - The difference between absolute cylinder intake air pressure and standard atmospheric pressure (measured in mm of mercury).
2. Rated Manifold Pressure - The maximum pressure permissible for a period of not more than 30 minutes continuous operation.
3. Take-off manifold pressure - Maximum manifold pressure permissible for not more than one minute continuous operation during take-off. In emergencies, three minutes continuous operation is permissible.
4. Normal maximum manifold pressure - Maximum manifold pressure permissible for continuous operation over several hours.
5. Engine RPM - Crankshaft revolutions per minute
6. Rated RPM - Maximum RPM permissible for not more than 30 minutes continuous operation.
7. Take-off RPM - Maximum RPM permissible for not more than one minute continuous operation during take-of.
In emergencies, three minutes operation is permissible.
8. Normal maximum RPM - Maximum RPM permissible for continuous operation over several hours.
9. High speed RPM - Max RPM permissible for glide or dive operations.
10. Idling RPM - Minimum practical RPM
11. Altitude - Height measured in meters under standard atmospheric conditions.
12. Rated altitude - Max altitude at which rated manifold pressure can be maintained at rated RPM.
13. Horsepower - One horsepower equals work done at rate of 75 kilogram meters per second.
14. Rated HP at sea level - Shaft HP developed at rated manifold pressure, rated RPM, under standard (sea level) atmospheric conditions.
15. Take-off HP - Shaft HP developed at take-off manifold pressure and take-off RPM under standard (sea level) atmospheric conditions.
16. Normal maximum HP at sea level - Shaft HP developed at normal maximum manifold pressure and normal maximum RPM under standard atmospheric conditions.
(...)
26. Rated operation - Operation at rated manifold pressure and rated RPM.
27. Rated HP operation - Operation at sea level rated HP and rated RPM.
28. Take-off operation - Operation at take-off manifold pressure and take-off RPM.
29. Take-off HP operation - Operation at take-off HP and take-off RPM.
(...)
33. High speed operation - Operation at high speed RPM with output of 50% or less of sea level rated HP.
(...)
46. Cruising permitted cylinder (or coolant, lubricating oil) temperature. - Highest temperature permissible during sustained operation over several hours.
47. Cylinder (coolant, lubricating oil) temperature permissible for 30 minutes - Maximum temperature permissible for 30 minutes sustained operation.
48. Permitted maximum cylinder (coolant, lubricating oil) temperature - Maximum temperature permissible for not more than five minutes sustained operation.
Item 24 - As a standard, take-off HP is greater than rated HP at rated altitude.
Item 25 - As a standard, normal maximum manifold pressure is no less than 85 % of the rated manifold pressure.
Item 26 - Take-off RPM is greater than rated RPM.
Item 27 - High speed RPM is no less than 110 % of rated RPM.
Item 28 - Idling speed RPM is no more than 25 % of rated RPM.
Item 29 - Oil temperature permissible for continuous operation is 70 degrees or above at oil pump inlet, while the oil temperature permissible for 30 minutes operation is 85 degrees or above.
Item 30 - Coolant outlet temperature permissible for continuous operation at sea level, using plain water, is 80 degrees or above at engine outlet, while the coolant temperature permissible for 30 minute operation is 90 degrees or above.
Chapter III - Structural Tests
Item 34 - Structural tests based on the various charts, documents and on the actual engine which the manufacturer submits under the stipulations of Item 15 will be made concerning the following points :
1. Suitability of the plans.
2. Suitability of the materials and effectiveness of heat treatment.
3. Ease of handling.
4. Adaptability to airframe.
Chapter IV - Operational tests
Item 35 - Under operational tests, assessment of the performance, reliability and endurance of the engine will be made.
Item 36 - Operational tests are divided as follows :
1. Engine performance test.
2. 1st Operational test.
3. 2nd Operational test.
4. Practical Operational test.
Item 37 - Under engine performance tests, assessment will be made of the items mentioned in the following paragraphs. The details will be determined by the OinC :
1. Sea level performance
2. Altitude performance
3. Suitability of the limits of use of alternate fuels (Translator : Probably refers to use of high octane gasoline for take-off and low octane gasoline for normal flights. [ Hiromachi : Correct presumption, in case of D4Y1 manual it is stated that for take-off is used 100 Octane gasoline and for the rest of the flight a lower grade Av gas. ] ) Suitability of prescribed fuels and lubricants.
4. Various operational conditions, fuel consumption rates, etc.
5. Permitted temperature for a long periods, 30 minute permitted temperature, permitted maximum temperature, and permitted minimum temperature for cylinders, coolant and lubricating oils.
6. Cooling data :
a) Amount of air flow necessary to cool cylinders, area of openings proportional to this amount, difference in air pressure in front and to rear of cylinders, and amount of heat radiated (air cooled engines).
b) Amount of coolant circulation and amount of heat radiated (liquid cooled engine).
c) Amount of lubricating oil circulation and amount of heat radiated.
7. Coolant and lubricating oil circulation in various positions and altitudes.
Item 38 - Engine performance test results, aside from the rate of fuel consumption, will be corrected to standard atmospheric conditions, and recorded in graphic form.
(...)
Item 40 - The practice will be to take readings for engine operational tests, other than during take-off and similar special cases, after the throttle has been kept at a given setting for three minutes or longer.
Item 41 - 1st and 2nd operational tests will be conducted with the full complement of accessories and with a propeller or brake which has an equivalent braking power.
Item 42 - The 1st Operational test will comprise the following essential tests :
1. Dissasembly, measurement and inspection.
2. Manifold pressure operation.
3. Accelerating, starting and stopping operations.
4. Endurance tests (140 hours, adding changeover operation of 20 hours for engines with two speed supercharger, and of 30-40 hours for engines with three speed superchargers).
a) Take-off HP operation (20 hours)
The following tests, lasting ten minutes, will be repeated 120 times :
Idling operation - Five minutes
continous
Take-off HP operation - Five minutes
b) Rated HP operation (25 hours) - An engine equipped with a two speed supercharger will be run the first fifteen hours at low blower and the last ten hours at high blower.
c) Normal HP operation (50 hours)
d) Cruising operation (25 hours)
Five hours at 7/10 of rated HP at SL
Five hours at 6/10 of rated HP at SL
Five hours at 5/10 of rated HP at SL
Five hours at 4/10 of rated HP at SL
Five hours at 3/10 of rated HP at SL
e) Rated HP operation at temperature permissible for 30 minutes ( 10 hours ) - 30 minute permissible temperature for cylinder, coolant and lubricating oil will be maintained.
f) Rated HP operation at permitted maximum temperature (5 hours) - 60 tests, each for five minutes will be made.
g) High speed operation (5 hours)
h) Changeover operation (conducted only on engines with variable speed superchargers) :
Engine with two speed supercharger - 20 hours
Engine with three speed supercharger - 30 or 40 hours
Notes :
1. Tests a, b, c, d, e and f will be conducted at temperature permitted for long periods.
Item 43 - The 2nd operational test will be comprise the following essential tests :
1. Manifold pressure operation
2. Endurance test :
a) Take-off HP operation (10 hours)
The following ten minute continuous tests will be performed 60 times.
Idling operation - Five minutes
continous
Take-off HP operation - Five minutes
b) Rated HP operation (25 hours)
3. Disassembly, measurement and inspection.
Item 44 - The 2nd operational test will be conducted on the same engine which has undergone the 1st operational test.
Item 45 - OinC, may on occasion, order a practical operational test to be conducted on a different engine of the same model instead of an engine which has qualified in both structural and operational tests. "
The document is not complete, I also did not have all the graphs attached and it seems there were subsequent revisions later but this should be enough to give everyone a basic view on the testing procedure.