engine alignment

A special section just for steam engines and boilers, as without these you may as well fit a sail.
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SidWell
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engine alignment

Post by SidWell » Mon Nov 28, 2011 7:55 pm

I am trying to put together a process to align my engine to the propeller shaft. Considering a 3" x 5" x 4" compound engine is in the 400 pound range, and the work has to be done in the bilge, I am a bit overwhelmed. Any thoughts on how to make sure that nothing bad happens to either the crank shaft, propeller shaft or bearings after a hundred hours of run time?
87gn@tahoe

Re: engine alignment

Post by 87gn@tahoe » Tue Nov 29, 2011 4:43 am

Use some sort of flexible coupling, such as a lovejoy coupling, which will allow for some misalignment
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artemis
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Re: engine alignment

Post by artemis » Tue Nov 29, 2011 8:07 pm

Make sure you have a set of flat metal feeler gauges in that cover up to 0.250" in 0.001" increments (you should have these for valve setting anyway);
Use a proper marine engine-propeller-shaft coupling (flange type);
Make sure the engine has vertical alignment (leveling) screws - much easier than trying to insert shims;
Position the engine close (within 0.010") to the coupling flanges for "gross" alignment;
By means of a file or centerpunch, mark each flange rim at the "common" coupling bolt hole if this has not been done by the manufacturer. Much easier to reassemble coupling at later dates;
Sliding the propeller shaft in/out, use the alignment screws and a small "bar" to bring the flanges to within 0.004" max. separation of each other, measured at the rim of the flange and in alignment with the flange bolt holes;
Locate and drill mounting bolt holes. Use "engine hanger bolts" (lag screw threads on bottom, machine screw threads on top) for easier adjustments - now and later;
Finger mounting screw nuts;
Raise or lower alignment screws to maintain the correct flange alignment - faces should not vary more than 0.003" overall and insert metal shims between the engine bedplate and the engine bearers. I usually mount a strap of flat, 1/4" steel on the engine bearers running the full length of the engine bedplate; wide enough that the engine weight is carried entirely on this strap metal.

:idea: Most decent marine engine mechanics can show you/sell you what you need to do this. Trust me, a couple thousands off and you'll know.
Ron Fossum
Steamboating Magazine Editor
http://www.steamboating.org
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