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
