Best Gearbox brand TM 93 VS PRM 500

[stefano_ita]

Hi all
I was wondering, wich is the more reliable gearbox's brand ( i know it's a kind of difficult question)

For the same price, for a beta 75 hp at 2500 rpm, would you get a TM 93 2,4:1 ratio or PRM 500 with 2,57:1 ratio?
Obviusly with a bit bigger propeller(1-2 inch diameter) in case of the PRM.

The heavy duty rating of the TM 93 is 103 hp at 2400 rpm, while the PRM 500 is 5,9 hp every 100 rpm so 147hp at 2500 rpm...

Maybe the bigger and stronger PRM 500 could live more and when i will burn out the first engine (let's say 20 years) i could keep the gearbox, and just buy a new engine bobtailed?

Wich is the more known worldwide? Just in case of break down...

Thanks all
Stefano

[stefano_ita]

P.S.

And also for a little bit more (about 400 euro) between the beta 75 naturally aspirated, indirect injection and the beta 90, same engine (only +2mm bore,) but direct injection, and NO glow plug...

Just talking about reliability, i guess the 75 is better...I would need about 40 hp at the shaft for cruise speed, meaning 2/3 of the 75 and about 50% load of the 90 hp engine...But in case of adverse condition for long time, could be, according to you 15 hp make the difference for a 50 ft, 22 ton steel sailboat?

[shakey doug]

Easy choice, for a 50' Steel 22 Ton vessel I would not go past a slower turning larger Prop, best value 400 euro you will spend!


PRM boxes are a well proven, easy to work on reliable Design.

[stefano_ita]

Thanks for the answer

Yes i would think to go for the 90 too but the direct injection ( higher injection pressure, more sensible to dirty and water in fuel) is stopping me...even i thought to get a 10 microm thrn 5 microm, before the original fuel filter (5 microm again)

And the missing of flow plug for cold start...
What do you think?
I've read some thread here about DI and IDI....