Etwenty1 45 Report post Posted May 25, 2012 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? Quote Share this post Link to post Share on other sites
BM WORLD 1282 Report post Posted May 25, 2012 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 Quote Share this post Link to post Share on other sites
elmarco 56 Report post Posted May 25, 2012 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. Quote Share this post Link to post Share on other sites
turbolizard 38 Report post Posted May 26, 2012 ...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. Quote Share this post Link to post Share on other sites
