Engine Mount Installation

[Richard E Smith]

Several threads in the past on mounts, but not specific to this which I'm receiving conflicting information both from otherwise reliable sources.
When installing engine mounts one source advises the height adjusting bolts must be parallel to the drive shaft/engine (assuming engine and drive shaft are on the same plane) and perpendicular to the base of the mounts. Another says the adjusting bolts should be verticle, still perpendicular to the base of the isolation mounts which would be horizontal and the engine feet parallel to the base of the mounts (in this the feet rotate on the engine brackets/bolts to allow the engine to slope to the angle required to align with the shaft). The latter allows the engine weight to load straight down (perpendicular) while the first has the engine load tilting slightly aft, the amount equal to the angle the shaft leaves the boat.
Which is proper and/or how much of an angle/tilt can the isolation mounts accept?
I am replacing mine and note the engine bed/logitudinal stringers tilt aft slightly less than 4 degrees and the shaft exits at roughly 6 degrees. The current forward mounts have the engine feet set higher on the adjusting bolts than the aft mount height bolts to adjust for this difference.
Comments? Thanks

[James S]

When I installed my new engine I bolted the mounts to heavy angle bars on the longitudinal stringers that ran parallel to the engine at the same angle as the engine/shaft about 3.75%...this puts the mounting plates on the engine in the same plane as well.
this is the only way I have ever seen these done.
I can imagine that if the angle is very great than installing all in the vertical may add life to the mounts....but 4% is not much at all...I've seen this same senario up to about 6%.
What does the manufacturer of your mounts recomend?

[Richard E Smith]

Instructions back on boat, but they (Trelleborg) indicate the engine feet and the base of isolation mounts can not be more than 5mm out of parallel. Will confirm this with them on Monday and post that. Just curious as to what others have done/found.

[mikereed100]

My Kubota manual permits mounting up to 15 degrees from horizontal. No mention is made of rotating the mounts to vertical and I have never seen this done. Best of luck.

Mike

[Richard E Smith]

The design engineer for the isolation mounts indicated that, assuming properly sized mounts, in my application, with relatively low incline, the mounts are forgiving enough to be mounted with either the base horizontal or perpendicular to the engine/driveshaft. More critical is not allowing the engine feet to be too high on the height adjusting bolts, the maximum height determined by the amount of thrust load applied.

[artisthos]

This is just the tread I need to add too.

3YM30AE Yanmar Install in "Clio" 32B sailboat




Images of the engine space, jig and rail extensions. Making them out of aluminum, 3/16” for the jig, 3/8” for rail extensions.
About half the engine sticks out into the cabin and the rail extensions (that are being made with 3/8" aluminum with as many gussets as possible) attach to the complete length of the original rail 23” and then goes into the cabin 7”

An old mariner suggested using angle iron to reconfigure the old rails into the new rails. A Yanmar install specialist recommended making the "L" bracket out of aluminum for salt water. I am waiting for him to approve my drawing. "Just use as many gussets as you can." he said.

Any ideas?

This is my first install so be easy.