SigmaDrive - Opinions?

[HeywoodJ]

We put two of them on our cat with Volvo D2-40 engines. Tremendous improvement. Have had them for two years. I'd estimate it's about the same as 500 rpm, maybe more (i.e. the level of vibration we get at 2500 rpm is what we used to get at 2000). At cruising rpm (1800-2000) now you can barely tell the engine is running, used to be pretty obvious (in case you can't tell, I'm a convert )

Was always careful before about alignments, but mounts compress, hulls shift a bit. Get the Sigma aligned well so you start out in a good place, then you don't have to sweat the minor changes.

[Jon Neely]

We have 1000hrs on ours. Still love it. I took it apart last time we hauled and repacked it with grease, very straightforward.

[Paradox111]

I got tired of crawling over the engine to align the driveshaft flange to the transmission flange whenever a vibration appeared. BTW the cost of a Sigmadrive SD55 was the almost the same as a professional charges for an alignment. I could not be happier with the smooth results.