jimmbo
Supreme Mariner
- Joined
- May 24, 2004
- Messages
- 12,976
At 60 mph, the old Land Yachts of the earlier 70s(Cadillac, Lincoln, Imperial) only needed about 40hp to maintain that speed.
Fuel distribution problems have plagued engines ever since a second cylinder was added. MPI reduced that to almost nil. DI 2 strokes, actually all DI engines, have had a rough development/refinement period. The changes to the way and when fuel is introduced to the Combustion Chamber and the resulting burn resulted in a very hard carbon soot forming under certain conditions. This soot is what did the earlier FICHTs in, and is currently wrecking havoc in todays auto/truck engines, especially those with turbos.
Marine engines would suffer less wear if the operating temps could be raised. Cylinders and Pistons wear is worst at lower temps and during the warming up. However, at temps above approx 140 F., the dissolved salts in water(fresh and seawater) start coming out of suspension. Eventually the cooling passages look like someone ran a batch of concrete through the block and let it cure. The higher the temp the greater the amounts and types of Particulates that come out of suspension. They will then attach themselves to the surfaces of the cooling system. With Raw water cooling the water is always fresh, fully loaded with these salts. On our cars this too happens, but only when there is fresh undistilled water added to the colling system. After a few hours the salts have come out of suspension and then with anti corrosion inhibitors in the antifreeze the system should stay clean. Adding a closed cooling system to marine engines would allow higher operating temps and use of gycol. The heat exchanger would then be the victim of deposit buildup on the raw water side. Of course the higher engine compartment temps might shorten wire and belt life and in theory lead to vapour locking, but fuel injection on the newer motors pretty much eliminated vapour lock.
Fuel distribution problems have plagued engines ever since a second cylinder was added. MPI reduced that to almost nil. DI 2 strokes, actually all DI engines, have had a rough development/refinement period. The changes to the way and when fuel is introduced to the Combustion Chamber and the resulting burn resulted in a very hard carbon soot forming under certain conditions. This soot is what did the earlier FICHTs in, and is currently wrecking havoc in todays auto/truck engines, especially those with turbos.
Marine engines would suffer less wear if the operating temps could be raised. Cylinders and Pistons wear is worst at lower temps and during the warming up. However, at temps above approx 140 F., the dissolved salts in water(fresh and seawater) start coming out of suspension. Eventually the cooling passages look like someone ran a batch of concrete through the block and let it cure. The higher the temp the greater the amounts and types of Particulates that come out of suspension. They will then attach themselves to the surfaces of the cooling system. With Raw water cooling the water is always fresh, fully loaded with these salts. On our cars this too happens, but only when there is fresh undistilled water added to the colling system. After a few hours the salts have come out of suspension and then with anti corrosion inhibitors in the antifreeze the system should stay clean. Adding a closed cooling system to marine engines would allow higher operating temps and use of gycol. The heat exchanger would then be the victim of deposit buildup on the raw water side. Of course the higher engine compartment temps might shorten wire and belt life and in theory lead to vapour locking, but fuel injection on the newer motors pretty much eliminated vapour lock.
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