Graphic: back to OSCO IndexOSCO Engine Failures

A former OSCO engineer recently wrote the following: ...those engines fascinated me, and seemed like they could run forever. I guess you proved in the case of Oahu Sugar, that wasn't really true when those blew up. I once spoke w/ the people at HC&S as late as 1976 or so, and their purchasing guys told me they preferred the old Corliss.

Ted Vorfeld responds:

The failure of the Oahu Sugar engines is an interesting story. Crank pins were made out of steel and pressed into the crank disk, and peened over on the back side. There was a shoulder where the pin bottomed in the crank disk hole. Past practice was to remove the crank pin every five years and replace it with a new one. Since this was laborious, somebody decided that ultrasonic inspection would do the job better and detect any cracks before the pin broke.

When I arrived at Oahu Sugar this was still the practice and it was a crank pin that broke on the first engine. Closer inspection revealed that the geometry of the pin and shoulder prevented the ultrasonic waves from seeing the most vulnerable part, which is where the thing broke. So much for modern science. The second engine broke at a crack in the crankshaft bearing box, a place that seldom got any attention at all. Repairing these engines is a separate and long story of lost skills.

I was probably the last person in Hawaii who could actually set the valves on these engines. I learned how to do it in college at Oregon State by an old "hands on" professor who taught us how to make engine indicator diagrams and all of that now-obsolete stuff.

The Corliss engines would have run forever if we could have been able to afford the labor to open them up every off season and install new rings. Occasionally they needed to be bored out and that was a real involved process since the bores were 30" or so and about 5' long!

Unlike steam turbine drives, everything about these engines was big and required a crane to work on.

With regard to the pump you talked about, it was Pump 5, not Pump 6 that was in a deep shaft. Pump 5 was near Ewa and mauka of the now H-1 freeway. And, yes, the original pumps were below ground and were driven by Corliss engines. But when I was there they were driven by electric motors. Most of the steam pump stations were actually fired with coal originally. I never heard of them being fired with wood. Then the boilers were shifted to Bunker C oil as it became more available.

Pump 6 was built like Pump 5 but was at a much lower elevation and needed only a 40' deep pit to house the pumps and engines. When I was there the pit flooded with great regularity because the roof leaked so badly and we had to pump it out and dry out the motors and switchgear. Process took about two weeks. I finally had a new roof put on that pretty much stopped the flooding.


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