@tonytales
American was having fits with the Wrights. Curtiss put out a book for American crew and mechanics in 1957. Gov't reporting was 10 engine failures per day on the east coast west coast runs (Aviation and the Role of Government, pg 144). The Curtiss Wright book included:
BASIC THEORY OF OPERATION FOR WRIGHT TURBO COMPOUND ENGINES - 1965 reprint of 1957 manual based upon lectures to American Airlines DC-7C Flight Crews and Maintenance Staff.
This manual covers:
Effect of Airflow on Power
Effect of Mixture Strength on Power
Effect of Mixture Strength on Engine Temperatures
Detonation and Pre-ignition
Summary of Reasons for Using 10% BMEP Drop
Carburetion
Exhaust System
The Effect of Spark Advance
Cruise Mixture
Fuel Distribution
Manifold Pressure Limits
Carburetor Ice
Ignition Analyzer Policy with One Dead Cylinder
TC18 Tips
Have to wonder if the Connie had the same failure rate?
On a personal note, I remember dropping my Uncle off at Idlewild for his return trip to LA in the mid-to-late '50s. Gave me plenty of time to wander above the concourses and take in the sights. I soon centered on a SwissAir DC7C getting ready to depart. Passengers were on board and 3 4 and 1 were humming. 2 would not kick despite repeated tries. After what had to be 10 minutes, all the engines were shut down and ladders were moved up to number 2 for maintenance to work on. With the anticipated delay, passengers deplaned. Had to be an hour or so with portions of the cowling off and mechanics working away. At some point, ladders were moved away, cowling was still off and the captain got number 2 running. OK, shut it down, put the cowling back on and re-board the passengers.
Round 2 - 3, 4, and 1 running and 2 bolted back together but again would not kick. Engines shut down and mechanics back to work. This time no dice - engine still wouldn't fire. At some point, must have been a couple of hours now, air stairs were put up to the front cabin door and the captain came down to discuss with the ground crew. Once again the ladders were moved, cowling off, and as the Good Lord is my witness, the captain climbs the stairs and starts hammering on something in the engine. Climbs down, instructs the ground crew to bolt her back up and move the ladders and air stairs, clambers back on board and number 2 starts as if nothing had ever been wrong. 4 going and I'm wondering how the folks on board felt at departure if they had seen that.