[C320-list] Transmission Reduction Ratio for Perkins M30

[P.F. Ross]

Jeff,

My tranny has the same ratios as shown in the manual: A (opposite engine
rotation) = 2.05 and B (same as engine rotation) = 1.85.

I believe the A direction is forward, however you should double check me on
this.

Regards,

Frank
#206

On Thu, Oct 28, 2021 at 9:18 AM Jeff Smith <svsailmates512 at gmail.com> wrote:

> Frank,
>
> Perfect. Thank you for the link. I live four hours from the boat so I can’t
> easily check. Now I see it will have the ratio stamped on a tag on the
> transmission.
>
> Jeff
>
> On Wed, Oct 27, 2021 at 8:56 PM P.F. Ross <pfrstl at gmail.com> wrote:
>
> > Jeff,
> >
> > There is a Hurth owners manual on the 320 website here:
> >
> > https://c320.org/filemgmt/index.php?id=130&query=hurth
> >
> > I recall seeing this nameplate on my tranny but don't remember what my
> > ratio is offhand, it is dark now but I will go out and check in the morn.
> > I also have the M30.
> >
> > Regards,
> >
> > Frank Ross
> > Beta Wave #206
> >
> > On Wed, Oct 27, 2021 at 2:48 PM Jeff Smith <svsailmates512 at gmail.com>
> > wrote:
> >
> > > Can anyone tell me how to determine the transmission reduction ratio
> for
> > a
> > > Perkins M30? Watching the conversion about the right prop, I emailed
> PYI
> > to
> > > find out what pitch I should set for my prop and to confirm my
> settings.
> > > They said it is a function of prop diameter and the reduction ratio. My
> > > manual says Perkins M30 has either 2.05:1 or 2.73:1. I believe I have
> the
> > > latter but I want to confirm before I haul the boat to change the prop
> > > pitch. The Max-Prop Classic has two settings and I now think I missed
> > each
> > > setting by one tooth, causing my prop to have a 14 degree pitch instead
> > of
> > > the recommended 24 degree pitch.
> > >
> > > Thanks,
> > > Jeff
> > > ’94, #121
> >
>