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Etwenty1

Anyone marinized a m20?

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I have a good m20b20 and a 16 foot boat hull with no motor. The idea of a 6cl fuel injected in-board sounds pretty cool but i know some engines are more suitable than others. Thinking a prop rather than a jet. Any comments?

Major issues i guess would be mating it with a suitable gearbox/drive, a heat exchange/cooling system and modifying the electrics/sensors as required. Anyone know what the weight of these engines is minus the trans?

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bmw made quite a few marine engines based on teh M30 3.5L lump 220hp on twin carbs

, have also seen diesel 2.5l units 6cyl and 2l 4cyl m10 type in think

i think i might have seen a 2.5L petrol (maybe m20 based but could be m30 type)

the main thing with a boat motor is power to weight ratio .

so i think a m20b25 or m20b27 would be better.

you want a heat exchanger unit built around the exhaust manifold.

http://www.trademe.co.nz/motors/boats-mari...n-477128257.htm

http://www.trademe.co.nz/motors/boats-mari...n-477518018.htm

how about a 4L or 4.4l V8 have seen a few done for jet boats etc

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Yeah BMW actually had an entire marine division back in the 70's & 80's. A friend of mine has an M30B35 (I think) in a ski boat with the BMW stern leg (EFI, tuned length water cooled stainless headers etc). They actually make a bloody nice setup and their stern leg was light years ahead of the mercruisers. Sophisticated and quiet - but having said that a 540ci injected big block on dry pipes does make a certain statement.

You still see the occasional BMW around but they are pretty rare now. You may also need marinised valve guides - they tend to run hotter as they are under constant load and if you use std valve guides they can seize a valve (seen it on small block chevys) with ugly results....

You might be better using a Lexus V8 as they are very commonly marinised for jetboats with plenty of support and parts.

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...a 16 foot boat hull with no motor. The idea of a 6cl fuel injected in-board sounds pretty cool...

Is the hull built for an inboard? If not, there will be a lot of work to put in engine bearers etc. Also, 16ft of boat is not much length to start with. Put in a straight 6 inboard and do you have room left for people?

Whether it is a good idea depends on what you want to achieve. If it is a cool old boat it might turn out pretty neat in a retro style, but it will never be a cheap way to have a good performing boat.

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