Aircraft Engine manufacture in WW2 days in US

[PWR4360-59B]

From everything I have seen (video's etc.) and read, back in the war days, all aircraft engine manufactures, assembled the engines 2 times. First the initial assembly and then a test run, then a tear down and inspection then another assembly. I'm not sure but I think there would have been a final proving test run after the final assembly before shipment. Can you imagine the cost and time to accomplish that? I guess back then at pennys an hour for pay the cost was minimal for the man hours.
Does anyone else here know more about this practice in the day? Did this still go on into the 50's and early 60's to the end of reciprocating large aircraft engine manufacture?
Oh and not only the tear down, but the cleaning of parts, the oil used for tests etc. I suppose the oil was re purposed for other uses.

 

[yosimitesam]

You are correct that there was a run-in, tear-down, inspection, rebuild, and then 2nd run-in. As an engine model matured (fewer faults found) the 2nd run-in was shorted (I believe to 2 hours in the R-2880 B-type.) The power generated in all the run-in's was "captured" in generators and provided a significant amount of electrical power to the engine factory. Large amounts of av-gas were burned.

 

[PWR4360-59B]

You are correct that there was a run-in, tear-down, inspection, rebuild, and then 2nd run-in. As an engine model matured (fewer faults found) the 2nd run-in was shorted (I believe to 2 hours in the R-2880 B-type.) The power generated in all the run-in's was "captured" in generators and provided a significant amount of electrical power to the engine factory. Large amounts of av-gas were burned.

Do you have first hand experience working on them in the day?

 

[PWR4360-59B]

It would be interesting to know what the rejection rate was for the various engines and the plants they where built in. How many never passed the first run in, and how many left an oily mess of parts in the dyno room that sort of thing.

 

[Ryanjames17]

For Rolls royce it was enough to turn reject merlin parts into tank engines

 

[Shortround6]

There were quite a number of inspections of individual parts along the way. Along with a paper trail of which machine operators did what and which inspectors signed off on the inspections. Not saying they never blew up an engine but it wasn't common.
Sometimes a rejected part could be reworked and pass inspection and sometimes it couldn't, it was just scrap.

Blown up engines would be torn down and carefully examined to determine what failed and how.