CD 25D engine mounts and shaft aligment

[Mike Harrison]

I have just replaced the shaft and cutless bearing on my CD25D. I now need to align the shaft. But the Yanmar engine mounts are missing the adjustment nut! These nuts were presumably left off to allow the engine to sit lower. If I were to install adjusting nuts the engine would be too high. I have investigated replacing the engine mounts with ones made by Bushings Inc. as these will adjust down to a height of 2-3/8 inch (I need about 2-1/2 inch). However, the holes on these mounts don't match the holes in the engine bed (4 inch versus 5 inch). Has anyone found engine mounts for a 1GM that match the CD 25D engine bed and will go as low as 2-1/2 inch? Also, how have you aligned the shaft and engine coupling as there is not room the swing a dial gauge, and feeler gauges will only tell you if the 2 halves of the coupling are parallel (but not that they are the same height and same left-right)

[barfwinkle]

Good morning Mike

What mounts are currently installed? When I replaced Rhapsody's (years ago) I just ordered 1GM Yanmar engine mounts and got the wrong ones. I had to call them back and after describing the mounts they sent me another (the correct ones) set.

The first ones they sent looked like this:



The correct ones (at least on Rhapsody) are shown below are part # DF 265 according to the receipt total cost $220 (set of 4) at the time.



Hope this helps. Fair Winds

[Mike Harrison]

Bill, thanks for the reply.

Your first picture is the type of engine mount that I have. The problem is that the advertised minimum clearance is 3-5/8 inches (92mm) and I need to go down to 2-1/2 inches. To get around this problem the engine was installed without the adjusting nut that goes under the engine bracket.

Your second picture is the engine mount manufactured by Bushings Inc. of Michigan (sold by Toad Marine at $48.28 each). The minimum clearance of 2-3/8 inches would work fine for me. The problem, however, is that the hole centers are 4 inches apart, and my engine bed is drilled for the 5 inch (126 mm) centers of the other mount! I have spoken with Toad Marine and Bushings Inc. and they cannot supply this mount with 5 inch hole centers. I have thought of make an adapter plate to be attached to the mounts with 4 inch center holes and to the engine bed with 5 inch center holes. But the thickness of the adapter plate would increase the minimum clearance above the required 2-1/2 inch. (Also, the there would be a problem with the 5 inch hole centers being at the edge of the 5 inch long mounts).

The existing mounts are attached to the engine bed with 1/4 inch x 3-1/2 long machine bolts (measurements from memory, but close). I imagine that these bolts screw into a metal frame deep inside the engine bed. It would be extremely difficult to drill and tap this frame to match the 4 inch center holes of the mount in your second picture.

Unless I can find another engine mount with 5 inch hole centers and a minimum clearance of <2-1/2 inches, I can only think of using brass shims between the engine mount and engine bracket (where the adjusting nut would normally go) to adjust the height. I would still have the problem of side-to-side adjustment. My thought here is to elongate the holes in the engine brackets (If I can get the frozen bolts to come out of the engine!)

Thanks again,
Mike

[tjr818]

Mike,
Can you make a clamping bracket out of some aluminum plate or channel that would fit over the top of the Bushings mount? It would need to have a hole large enough for the "post" part of the casting to fit through. Then in the clamping plate you could drill the holes you need for the 5" centers. The Bushings bracket could either be drill out or ground out for the 5" centers or, possibly it could just be rotated 90 degrees to get those flanges out of the way.

[Mike Harrison]

Tim,
Thanks for the idea. As the hole for the "post" part of the casting would have to be 2-3/4 inches diameter, the clamping bracket would need to be at least 3-1/2 inches wide (to have 3/8 inch left in the bracket both sides of the hole). The current mounting is 1-11/16 inches (50mm). So the new clamping bracket would be 1-9/16 inches wider than the current mount. I will check next week to see if there is room to do that.

Thanks again,
Mike

[Jim Evans]

Hi Mike,

I believe you'll find the engine mounts from Bushings Inc are rated for engines that weigh up to about 800 pounds. I have those very same engine mounts on my CD33, supporting a Yanmar 3GM30F that my P.O. had installed by a reputable installer 15 years ago. These engines weigh about 350 pounds, and I expect your 1GM weighs a lot less than that. At any rate, the shop encountered similar issues to what you are going thru - and their solution was to have a machine shop remove about half of the material from the base of the mount in order to lower the rear of the engine to accommodate the alignment. So, as a result, the ears (where the mounting holes are) have about 1/2 of the original thickness. The thought of this made me cringe, but after 15 years, and over 3500 engine hours, the mounts are doing fine.

So, what I'm saying is that you might consider machining the base of your mounts to reduce the thickness - and that would give you some room to install an adapter plate to accommodate your mounting configuration. It's certainly not an ideal solution, but I think the only ideal solution is to rebuild your engine beds. Any other solution will be a compromise to some extent.

[Mike Harrison]

Jim,
Thanks for sharing your experience with the reduced thickness of the engine mount base. I hope to get my hands on a Bushings mount later this week so that I can determine have much material would need to be removed and whether, or not, this will be an option.

If reducing the thickness to allow an adapter plate to go under the mount looks feasible, I have received a suggestion for the adapter plate. Instead of trying to place the 5 inch center holes in the plate 1/2 inch both sides of the 4 inch center holes in the mount, I could have the front hole of the adapter plate line-up with the front hole of the mount and then have the back adapter hole 1 inch behind the back hole in the mount. This would avoid the problem of the adapter and mount holes running into each other. It would mean that the engine would be moved forward in the boat by 1/2inch. Any one see a problem with that?

To change the engine mounts, I will have to, at least, raise the engine and maybe even remove the engine. As there is no direct access immediately over the engine for a lifting sling, what other methods have been used? I have thought of a lifting under the oil pan with a scissor jack or inflating a basketball under the oil pan. All suggestions would be appreciated.

Thanks

Mike

[Doug Jesseman]

Mike, I welded together a very tall "C" shaped channel iron bracket to remove my engine. I drilled holes for eye bolts, two in the bottom and one on top. The "center of effort" is the key. Once the engine is up off of its mounts you swing it back and then up and out, slowly. Patience is important, but it will work. Do any tranny improvements while you are at it. And paint the bilge just for fun. Good luck!!!

[Noel Heslop]

Mike,
I can only comment for when you are about to instal, but I will add my knowledge now for the future, as the bit about engine handling may help you now.

I only observed (I did help minimally) Bruce the mechanic to re-install Yanmar 1GM in Breezy my CD25D. Sorry, I did not observe the removal in the first place. Bruce told me he has done similar a thousand times. He was excellent.

Bruce placed a solid timber beam across the top of the open hatchway, at the stern most edge, with padding under to protect teak. The washing up plastic basin covering top was removed. Bruce attached a smallish compact chain to the beam, and the chain hanging down (through wash basin opening into engine bay) had a neat hand size handle on a rachet type of winch.
Bruce (I may have helped?) lifted yanmar into engine bay opening, sat it temporarily, then attached chain to motor, then rachetted up to suspend motor, which he could then push out on an arc (from memory) to sit over the 4 engine mount bolts, and drop down over them.
I cannot remember how chain was attached to yanmar, so I think it was minimal, as I just cannot remember.

Bruce used about 3 or 4 long tyre type levers (say 2ft long) to lift motor as necessary to tighten engine mounts, working mostly from the cabin, and a little from the port locker. He seemed to work by feel alone. Very impressive.

IMPORTANT. Bruce did the final engine alignment in the water. Seems the boat shape changes a little. Bruce seemed to concentrate on both flanges meeting perfectly, and only then did he actually bolt up the flange to finish the job. My memory from 3 years ago was that the final alignment took 1 hour or more, including running the engine and going for a motor in the lake to test vibration and shaft temperature. There was minimal vibration (and still is after 3 years), and I had thought vibration from the 1GM was the norm. I am still a novice here.

Perhaps someone on the board can give a name to the rachet type of double acting winder on the chain that I do not know what it is called. I can phone Bruce tomorrow if needed and repost?

Hope this helps. Noel