petrol to diesel conversion.

[bluetooth]

I don't recall charging you £2k for the transom work.....

I do. Must be the GRP fumes !

 

[ulyden]

Hi
I replaced a 3,7 165hp mercruiser with a ford fsd 425 tci 12 years ago. Runs on a alpha one drive. Cost about 2,5k£.
I still have the boat and engine. Runs 3000 to 4000rpm all time. Never had any issues.

But the connection to drive needs some work. I replaced the turbo to a larger wo bypass ,bigger nozzles,bosch fuel pump an fitted a bowman intercooler. Bowman also had a combined exhaus manifoild and heat exchanger. Also mounted a large oil cooler. Seawater pump in the drive. Power about 130hp

 

[prv]

So you could have a two rad compact set up .
Open duct or scoop on the side (s) or front ,under a seat -air first passes through the sea water cooled rad then fanned through the hot engine rad ,and a suitable gril at the back high up to let used air escape

Sounds hugely inefficient compared to just putting engine coolant and seawater through a normal heat-exchanger. Physically much bigger too.

I have actually encountered a small boat that used a water/air heat exchanger like this, in order to make use of a small air-cooled diesel (6hp or so at a guess). It did basically work, but the system was bulky, complicated (the water pump and fan needed to be arranged to run-on after the engine stopped), prone to overheating, and tended to shake loose bits of the sheet-metal air ducting.

Pete