Converting a car/truck diesel for marine use

Hi,

I am looking at finishing a 42foot steel yacht that already has a motor that is not fitted.
The motor is a light pickup truck diesel 4 cyclinder 1,7Litre motor from ISUZU/OPEL/General Motors.

I saw in another formum regarding engine life that it would be advisable to restrict a car motor down to about half the RPM/Horse Power, to give it comparible engine life that for marine use.

I am looking for advice on how to convert this motor reliably for Marine use, in an application where I might be doing considerable cruising for a few months.

Exact info I need is:

- How to build a gearbox/marine drive?
- Cooling - I see keel coolers for motors are riliable, what about a raw water marine exhaust that has a fresh water converter. Ie the engine uses fresh water that has a converter to raw water. What pumps are used.
- How do I muffle the engine. I want to get the engine noise down to almost not audiable. Yachts that achieve this are so much more pleasant.
- How do I restrict the RPM on this motor and what other conversions can I do for long life.
- How do you know when a diesel needs an overhaul or replacement?
- How do I decied on a final drive ratio for the propeller? And is it possible to build a gear box that has a high power gear and a lower RPM longer distace gear. the low RPM gear would be used if for example there is no wind for 2 days at sea, one would set the engine at 2000RPM and chug along.
- Under emergency conditions during a storm for example, would a car diesel be faster to fail/overheat?
- Do you get good alarms that would sound if oil pressure, water pressure, raw water, rpm, heat, pinging goes out of spec?
- How do people use auxilliary power. do they attach the power unit to the gearbox or simply install an outboard bracket.

Your answers will assist me in decieding to buy the semi complete boat, or choosing to put a different motor in from the start.

 

The simplest is to look on the various eng mfg web sites , and see if the truck engine is used in boats.

Observe the rating , you need what a work boat needs cont use , not ski boat numbers.

Cheapest is to pick an engine that will operate at or near the torque peak , producing the hp you need at that rpm.

Find out what the boat weighs in pounds , divide by 2240 (one ton) and multiply that number by 3 .

This will give all the hp you will want to pay for at normal cruise.About 7K.

Purchasing a used marine gear box is FAR FAR simpler than designing one and having it cast , machines and tested.

Dry stack and keel cooling are simplest and best methods for any cruiser.

FF

 

I am looking at finishing a 42foot steel yacht that already has a motor that is not fitted.
The motor is a light pickup truck diesel 4 cyclinder 1,7Litre motor from ISUZU/OPEL/General Motors.
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I have recently installed an Isuzu engine into a 41' 0" Steel yacht.

If you can give me the specific model number (eg. 4JB1 67Hp naturally aspirated) I may be able to give you definitive information. For info I have a friend in Capetown who has just installed one as wing engine in his trawler.