Perhaps it is a function of how flexible is flexible. If both are relatively solid i could see it working. In my case both were quite flexible (Volvo engine and chain coupler) the two started whipsawing against one another. The solid coupling I replaced it with was still trouble free 35 years later.
Don Newman C&C 44 > On Dec 11, 2013, at 17:54, Rich Knowles <r...@sailpower.ca> wrote: > > Hmmm. Interesting but I have to tell you I have had regular flexible mounts > and a Drive Saver flexible coupling on my boat for 15 years with no problems. > Others may wish to comment. > > Rich > >> On Dec 11, 2013, at 18:47, Don Newman <donrnew...@gmail.com> wrote: >> >> Good post Rick, but one quibble. >> If an engine has flexible mounts then it must have a solid not flexible >> coupling and vice versa. >> >> I made that mistake when I repose red my last boat and the coupling >> destroyed itself with extreme prejudice in a couple of hours of running. >> Everything was aligned but the two components worked against each other. >> >> I learned later that this is an inflexible rule ;-) sorry I can't provide a >> reference but my painful experience bears it out. The original had a solid >> mount and flexible coupling and the new engine had flexible mounts so I used >> the very substantial coupling. >> >> >> Don Newman >> C&C 44 >> >> >>> On Dec 11, 2013, at 14:45, Rich Knowles <r...@sailpower.ca> wrote: >>> >>> Josh: >>> >>> I just had a look at mounts on the PYI site: >>> http://www.pyiinc.com/index.php?section=rd_marine&action=engine-mounts&sn=1 >>> >>> Their widget allows you to insert the dimensions of your existing mounts so >>> you can receive new mounts that should simply replace the existing units >>> with no drilling or other fiddling. I trust you completed that exercise and >>> have received the correct units. Note, they are not stainless but zinc >>> plated. >>> >>> Many of our boats came with some sort of metal members in the engine >>> mounting system and I suggest leaving well enough alone unless you have >>> good reason to make changes. If you do one mount at a time, you should be >>> able to simply undo the bolts, back off the positioning nuts, remove and >>> replace the old mount and, after all have been replaced, adjust the mounts >>> to position the engine correctly. >>> >>> Well before you start, I suggest soaking the mounting bolts and nuts and >>> your propeller shaft flange connecting nuts and bolts with one of the >>> proven rust busters previously discussed on this forum. >>> >>> Also, before you undo the existing mounts or make any changes to the >>> adjustment nut positions, I suggest you measure and record the distance >>> between the underside of each engine mounting bracket to the top of the bed >>> under it and use that measurement to set the top of the bottom nut of each >>> of the new mounts. Even if an old mount has settled, it will give you a >>> reasonable starting point to start aligning the engine. >>> >>> Aligning the engine after installing the new mounts will be another chore. >>> This involves undoing the bolts connecting the propeller shaft flange to >>> the engine shaft flange and fiddling with the nuts on the mounts until the >>> shaft is centred in the shaft tunnel, the flanges are concentric and the >>> engine is aligned so the clearance between the flanges is equal or within >>> .001 - .002" all around. This can be a tricky job and will test your >>> patience, but needs to be done as best as possible. After this is done, the >>> system should be reasonably vibration free. Ideally the final alignment >>> should be done after the engine has settled on the new mounts for a few >>> days and the boat is in the water. >>> >>> To reduce alignment and vibration problems further, I highly recommend >>> installing a flexible shaft coupling which will absorb most of the >>> remaining shaft coupling misalignment which is inevitable, especially when >>> the system transitions from a static state to an operating, loaded >>> condition. >>> >>> See: http://www.pyiinc.com/index.php?section=rd_marine&action=shaft-coupling >>> >>> Google will reveal many discussions of shaft alignment on the web. One of >>> the simplest illustrations is: http://www.ebasicpower.com/faq/alignib.htm >>> >>> I also suggest checking your cutless bearing while you are fiddling with >>> the drive train. Note the spelling, it's not a sword:) >>> >>> Good luck. >>> >>> Rich Knowles >>> INDIGO LF38 >>> Halifax, NS. >>> >>> >>> >>> >>> >>> On Dec 11, 2013, at 7:33 AM, Josh Muckley <muckl...@gmail.com> wrote: >>> >>> Hey Folks, >>> >>> I'm in the process of replacing my engine mounts on Sea Hawk, equipped with >>> the original Yanmar 3HM35F. I purchased mounts from PYI. They look to be >>> quite high quality mounts and appear to be made of SS. Unlike OEMs, they >>> are positively captured so your engine won't go flying lose if the rubber >>> separates. >>> >>> The previous mounts were not OEM either. In fact it appears that the PO >>> may have over loaded them or installed used mounts because the forward pair >>> appeared very compressed, almost a 1/2 in shorter and kind of inverted on >>> themselves. At first glance I thought they were different designs from the >>> aft pair. Because they were short it looks like the PO had to build up the >>> forward foundations with some 5/8 or 1/2 inch starboard (polyethylene) >>> blocks. >>> >>> Sitting between the engine mounts and the glassed in foundation of the boat >>> there are 1/2 inch thick aluminum plates. They run the full length and >>> width of each port and starboard foundation rail. Because of the clearly >>> redesigned nature of the situation I began to question if these aluminum >>> plates should be there or if they too were part of the PO's engineering. >>> >>> I'm looking for thoughts and advice regarding the engine mount replacement >>> task as well as the appropriateness of the aluminum plates. It would also >>> be helpful if anyone has torques specs or design details of the fiberglass >>> foundation. >>> >>> Thanks, >>> >>> Josh Muckley >>> S/V Sea Hawk >>> 1989 C&C 37+ >>> Yanmar 3HM35F >>> Solomons, MD >>> >>> _______________________________________________ >>> This List is provided by the C&C Photo Album >>> http://www.cncphotoalbum.com >>> CnC-List@cnc-list.com >>> >>> _______________________________________________ >>> This List is provided by the C&C Photo Album >>> http://www.cncphotoalbum.com >>> CnC-List@cnc-list.com >> _______________________________________________ >> This List is provided by the C&C Photo Album >> http://www.cncphotoalbum.com >> CnC-List@cnc-list.com > _______________________________________________ > This List is provided by the C&C Photo Album > http://www.cncphotoalbum.com > CnC-List@cnc-list.com
_______________________________________________ This List is provided by the C&C Photo Album http://www.cncphotoalbum.com CnC-List@cnc-list.com
