Originally Posted by charliehows
was looking through old threads on converting auto/tractor engs for boat use - anyone thought about/tried converting any of the new small car engines now popping up on the market - last time i asked i was quoted $10000 for a new yanmar
30hp 3 cyl eng and trans, gotta be able to do a conversion for half that...
The short answer to this question is that you can pretty well convert any engine
, petrol or diesel
, to work in a boat and because of their lightness recycled auto engines are a good choice.
The requirements are being able to safely supply the engine with fuel
, keep it cool and transmit the output power to the propeller
or other drive system.
is the easy bit but can get a little complex if you want high reliability
I have a cleaning
(polishing) system consisting of a gear
pump, paralleled by a priming pump with a check valve bypass which feeds to a filter made out of a spaghetti storage
jar and then returns to the fuel tank
. The spaghetti jar contains a felt bag filter element I sewed up on the boat with my sail repair sewing machine
. I built it this way because I could not find a suitable off the shelf item. It cleans the fuel very effectively. The fuel feed to my engine includes two series connected paper fuel filters one of which is upside down so that it acts as a bleed-able air trap. I cannot see that supplying clean fuel to any diesel
engine aboard a boat should be a problem.
Whilst I would not particularly want a modern common rail electronically controlled fuel injection system (primarily because of the complication) I cannot see any reason why one should not be used on a boat particularly a power cruiser where the lower fuel consumption
these provide would result in a significant fuel saving.
How one would keep it cool depends on whether it is air or water
cooled. I'm sure someone out there has built an air cooled system for marine
use but I have never seen one. I found there is nothing to difficult or complex about making the parts to implement either the first exchanger-in-manifold arrangement or the extant raw water
On connecting the engine to the prop. After I had made the decision to bin the cast iron bell housing and techno plate I found this to be one of the easiest parts of the project
. The two starter motors I installed will allow me to implement two entirely separate starting systems, I was able to use the existing motor
beds, and the hand made alloy bell housing is about 1/4 the weight of the cast iron ones. I had no problems adapting the marine gearbox
I chose and even managed significant improvements whilst doing so.
Having done a conversion using nothing but a drill press and hand tools I am now confident that I could pretty well adapt any diesel to marine use and am fairly confident that in doing so improve on many of the commercial