Finnøy Gear pressure

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Bilge Dweller
Posts: 2
Joined: Thu Feb 20, 2020 6:34 pm
Currently located: British Columbia

Finnøy Gear pressure

Post by Mikeneave »

Hi everyone, new to this but I have a technical question regarding a finnoy gear box I have onboard my vessel and was hoping someone would provide me some answers.
Finnøy gear driven by medium speed diesel MaK engine gear pressure normally runs around 21 bar I had the clutch slip out of gear the other day underway with L.O alarm gear alarm sound. Pressure reads 21 bar at start up but drops when you activate the clutch in. Regulates but still 1 bar lower than under no load. Then once I give it approx 800 rpm (my normal docking RPM) and put some pitch to the propeller the gear pressure drops to approx 16.5 bar. Should the gear pressure drop at all under load? My thinking is that pressure should rise under load? Am I wrong? Any ideas?

Deck Plate Wanderer
Posts: 27
Joined: Fri Jun 28, 2013 3:19 am

Re: Finnøy Gear pressure

Post by Vegman »

Hi Mike, not familiar with that Finnoy gear set up, Is the oil pump driven off the gear box and therefore the faster the RPM , that faster the pumps spins? or is it a separate electric driven pump? But I would say no, the clutch pressure should not drop at all under load , providing the oil temp doesn't increase much.

But one possible cause is that when you are activating the clutch in command you are pressurising a new part of the circuit that you were nt when you had clutch out, possible that part has a relief valve on it and that relief valve may be lifting.

Does it happen every time or is it intermittent? Anyhow if you have solved it , please let us know.

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