Sigmadrive engine alignment

[Supertramp]

Looking for advice on engine alignment when a Sigmadrive Sd55 is fitted.

Beta 60 rear engine mount has sheared. I have never replaced an engine mount but it looks straight forward, access is OK and will use a jack and blocks to replace each mount in turn. Will plan to do all 4. Boat is afloat.

My question is about aligning the engine with a Sigmadrive SD55 coupling. Does anyone have experience of aligning the engine with one of these? I have read the instructions but it's not clear to me whether to unbolt the 4 M10 nuts holding the gearbox coupling or to remove the 8 M6 Allen bolts and withdraw the tapered collar on the shaft end. Separating the 4 bolt gearbox flange looks the most logical to me.

And having separated whichever of these from the engine, how do you align? While the sigmadrive deals with some angle error, the ends of the shafts must align. My only thought at the moment is doing it by feel - finding the point where the shaft slides on and off the coupling with ease. Bit crude and not likely to meet 000" tolerance. Or is that OK with a sigma drive?

YouTube video says refit the old flange to align (not an option) and I belive Sigma drive are not trading at the moment.

 

[NWSailing]

Looking for advice on engine alignment when a Sigmadrive Sd55 is fitted.

Beta 60 rear engine mount has sheared. I have never replaced an engine mount but it looks straight forward, access is OK and will use a jack and blocks to replace each mount in turn. Will plan to do all 4. Boat is afloat.

My question is about aligning the engine with a Sigmadrive SD55 coupling. Does anyone have experience of aligning the engine with one of these? I have read the instructions but it's not clear to me whether to unbolt the 4 M10 nuts holding the gearbox coupling or to remove the 8 M6 Allen bolts and withdraw the tapered collar on the shaft end. Separating the 4 bolt gearbox flange looks the most logical to me.

And having separated whichever of these from the engine, how do you align? While the sigmadrive deals with some angle error, the ends of the shafts must align. My only thought at the moment is doing it by feel - finding the point where the shaft slides on and off the coupling with ease. Bit crude and not likely to meet 000" tolerance. Or is that OK with a sigma drive?

YouTube video says refit the old flange to align (not an option) and I belive Sigma drive are not trading at the moment.

Did you go ahead with purchasing a Sigmadrive? If so can you give any feedback on how it has been?

 

[Supertramp]

Did you go ahead with purchasing a Sigmadrive? If so can you give any feedback on how it has been?

I already had the Sigmadrive. I replaced the mounts, removed the Sigmadrive completely and then aligned to get the vertical, horizontal and angle as good as I could - the Sigmadrive allows a 3 degree tolerance. But over the first 100 hours the rear mounts dropped a mm, so had to do it again. The Sigmadrive allows for angle misalignment but not if the shafts are off centre, if you follow.

Last winter I replaced with an Aquadrive thrust bearing. Much more expensive but a much better solution.

 

[SailingSabino]

I know this is an old thread and you used another product later. I’m working at aligning my sigma unit on my sailboat new motor mounts. Did you try using the sigma blocks when aligning yours if so did they work? Freshly painted shaft and dripless coupling so I’d prefer not completely removing sigma to align. Thanks

 

[Supertramp]

Yes, I used the blocks to ensure the prop shaft coupling flange doesn't move around. I could move the shaft and then line it up with the coupling and adjust the engine mounts until everything lined up. Although the Sigmadrive allows a 3 degree angle you still need to be sure the shaft end is vertically and horizontally lined up with the gearbox flange, and I adjusted until the shaft slid freely into the coupling, aiming to use as little of the 3 degrees as possible.

I've heard of people using two Sigmadrives to remove this requirement and create a sort of CV joint that will take thrust (seems nearly as complicated as a thrust bearing arrangement to me).