Volvo 290 max torque/HP

[duggy]

What is the max HP/Torque a 290SP will handle?I have searched around and cant seem to find any specs.I am doubtful if it will hold up as it is in my new boat.
Regards Doug

[KnottyBuoyz]

I've looked in the factory service manual and there's no mention of max hp. I'm thinking I've heard 325 as the max for a 290. Mine is a 290DP with an AQ271A (275 HP).

[baeckmo]

There are no official figures for maximum torque (which is the limiting factor, not power) for the 290 SP. However, there have been factory models with slightly over 400 Nm input torque, and I have personal experience from a VM diesel 250 hp (shaft torque at max power is 481 Nm) running fine with a 290 SP drive (later rebuilt with a DP "wet part").

Depending on what setting your iron has, it will deliver roughly 460 to 480 Nm to the drive, so provided everything is in good order (shifting cones correctly set aso) and treated well, you should be reasonably safe. ("Reasonably" since I dislike the I/O drives from the depth of my heart.....).

The next factor to consider is the output torque, and here the limits depend on what transmission gearing you have got; it should be the 1.61 to 1 version, giving an output torque of ~750 Nm, which is on the (reasonally.....) safe side torquewise.

The boat you have shown in the other thread would probably have been better off with a 290DP (rebuilding is possible) or a Bravo ll with a 19" prop. But estimating its weight to some 3500 kg, I would suggest that you start with a Volvo 16 x 19 HS left hand propeller, and for all sakes keep the weight down as far as possible; good luck!

PS Btw, do you have any documentation on the engine (owners manual or similar)? I have one of these beasts standing in a corner of the workshop; a "leftover" from a customer and I am a bit curious about it (fuel system in particular), any info is of interest! DS

[powerabout]

504 has the PT fuel system like any other cummins from that era
504 will only have about 400ftlbs/500nm so about same as big block chev

[duggy]

Okay so I have taken your advice and got hold of a 290 duo lower unit with a 1.65 ratio,now just needing to sort out a starting point for props.What sort of performance improvments did you experience after the swap?
doug