FWIW when I did mine I left the alignment to a professional. IMHO...money well spent.
David F. Risch 1981 40-2 (401) 419-4650 (cell) From: r...@sailpower.ca Date: Wed, 11 Dec 2013 15:45:45 -0400 To: cnc-list@cnc-list.com Subject: Re: Stus-List C&C 37+ engine mounts 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
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