Thx. I am putting together options for a repower from the 6BT to something in the 300hp range with more top rpm capability.
The easiest would be to stick with Cummins but I'm trying understand if another option is viable as well. Cummins seems to have the widest base, so any movement would likely be pushing the forward crossbeam aft a touch.
If this becomes more serious, I'll be sure to post progress.
I welcome any opinions.
Current options on table are
Cummins 370B mechanical. @3150 rpm top end. Easiest to install. Drop into existing mounts. Reuse all guages etc. Need to move sea strainer. Need larger exhaust size and outlet. Larger raw water hose.
Cummins QSB 330 or 380 - @2950-3150 rpm. Drop into existing mounts. Some guage changes. 24v/12v system is tricky to accomodate. New controls, transmission actuator or new transmission with electronic control. Exhaust size change, move strainer.
Volvo D6 330 - 3500 top rpm. Similar to QSB in install complexity, electronic engine, new controls, transmission actuator, guages etc. Forward engine mounts would need to move back. Exhaust size may not need to change (Unsure).
Yanmar 315hp 6lpa-ste or similar. 3800 rpm top. Engine mounts would need to move. Exhaust size change, move strainer, similar to mechanical B. Know boats with this engine and they have a good top end speed. 40-45kts
I favor Cummins. I know the engine well now. I like the community and ease of parts, working on it etc. The drawback is lower top RPM, more crushing low end torque. I still think you could imagine a 32kt fast cruise and a 40kt top end. Top torque lines up with the Konrad 520 specs.