Adjusting engine bearers

[gunnarsilins]

I have now 4 brand new engine bearers and I will spend the easter aligning the engine.
How do I know that the engine weight is evenly distributed on the bearers?
Is height measurement th best, or only way? These beares are quite hard, so nothing much seems to happen when they take the load of the engine.

Also, is it normal that the alignment need to be checked/readjusted after a while when installing new bearers? How long can I expect this 'running-in time' to be?

 

[chippie]

If the engine is attached to the bearers by the engine manufacturers mounts at their correct mounting points that is about as good as you will get in terms of weight distribution.
Having got it all aligned to your satisfaction, it would pay to check after your first trip out and then in a couple of weeks time .
If by bearers, you mean what we call mounts , you get the flanges lined up along a central axis and then check with a feeler guage around the edge and between the flanges to ensure alignment in the other planes.

 

[gunnarsilins]

Sorry, I mean mounts!

Bearers is the reinforced part of the hull on which the mounts are bolted?
But what I meant is, let´s assume I have the flanges aligned perfectly in all planes. Still, the the weight of the engine could be uneven distributed on the mounts.
I realized this when removing the old mounts, the engine balanced perfectly well on only three of them, so one single mount took basically 50 % of the engines weight, instead of 25 %.

 

[AndrewB]

Assuming, as Chippie says, you mean the mounts, I've never heard it suggested that the load on each should necessarily be equal. Indeed on many in-line engines, the forward mounts are intended to take more weight than the aft. What matters for adjustment is that alignment is perfect. And it can be a fiddly job inching the engine up, down and sideways!

Alignment must be done with the yacht in the water. It isn't usually necessary to recheck unless there is a knock to the sterngear or the stuffing gland suddenly starts leaking badly. I like to give the mounts an occasional glance to check they haven't worked loose from the setting.

Alignment is impossible if the shaft isn't true. If possible also check that before launching.

 

[brian_neale]

As I remember, in the case of Yanmar engines, the mounts are actually different fore and aft, because they take different amounts of weight. If the mounts are the correct mounts, the alignment is correct, and the engine is not tilted beyond the manufacturer's limits, then the weight distribution is also correct - and correct does not necessarily mean equal on each mount.

 

[gunnarsilins]

AndrewB!

I totally agree that the forward engine weight surely differs from the aft.
But I´m thinking sideways, or athwarthships, so the AFT PAIR of mounts take a equal share of the weight, and of course the same applies to the forward pair. I think it might be possible to align the engine with a very low load on one mount, so the other one one in that pair will be overloaded.

 

[david_bagshaw]

If the mount/ engine heights are adjusted by a nut, it is quite easy to feel the stiffness with the spanner & hence the load on each foot, if by shims, then you get an idea by using a lever on a mount bracket, and the same amount of force is applied to lift each of the front pair and the amount the engine deflects is noted, which hopefully will be the same, followed by doing the same with the back pair. This is best done with the shaft slid back if it is possible. Obviously the front back deflections will be different as in many smaller installations the back mounts take gear box weight as well.

David
www.euroboating.net

ps height measurement is not the way, after all one engine bed might dip down or up

 

[Guest]

All engine mounts have one set of slotted holes to allow you to move the engine to stbd or port which ever is necessary for alignment. They normally have about 1/4" movement to either side of center.They have a nut upon which the motor mount actually rests. by raising or lowering the nut you change the face of the engine coupling with the face of the shaft. The trick is to get the faces as nearly parallel as possible both up and down and to have them centered so that the bolt holes are identical. I just spent 2 days getting mine done properly and within 3 thousands.
Good luck!