Afterthoughts

After two years and about 200 hours of engine time, I've had a chance to evaluate the installation. I'm pleased with the engine choice. I'm glad that I rejected the Westerbeke engine. It is already out of production. This leaves only the Cummins or possibly the naturally aspirated version of my Yanmar as alternatives. The last two choices would be less expensive. Given the substantial cost of the entire rebuild project, it doesn't make sense to scrimp on the engine. The engine bed, exhaust system, V-Drive installation, and engine instruments all worked out well. The engine runs reliably and is quiet and smooth at cruising speed. I initially had some minor vibration problems at some engine speeds, but was able to eliminage this by careful re-alignment. It now runs as smooth as silk at all reasonable throttle settings. As far as I can determine, fuel consumption is similar to the old W60 at similar engine speeds; about 1gal/hr at cruising speed. I think the propeller may be slightly undersized as indicated by the sea-trial checklist. It is close the the correct size however. At high engine speeds, the wheel pulls to the right, enough so that the engine can overpower the autopilot. This becomes significant at engine speeds that exceed the 2500 RPM / 7.3kts cruising speed. There is no reason to drive the engine this hard except for occasional short periods as dictated by the owner's manual. The only important issue I have with the installation is the common-rail mount that I bolted to the front of the engine for the second alternator and refrigeration compressor. As my research indicated, it is common for them to develop problems. I thought I was overdesigning them by using 1/4" plate steel, but I found that the horizontal mounting plate would vibrate. I welded a reenforcing plate to the underside of this to eliminate the problem only to have the side plate crack and break shortly after making the initial repair. I suspect that the crack developed before the repair was done. It broke next to the weighted disc on the front of the engine where the side rail is only two inches wide. I have yet to repair the bracket. My plan is to jack the engine up off the aft engine mounts using a cable winch, remove the engine mounts and side brackets and weld additional steel to the side brackets. I also have a minor issue with soot on the transom. Yanmar suggested adding an injector cleaner to the fuel tank to clean out the injectors. I have not yet had a chance to see if this fixes the problem.