New Engines for an Old Boat

Engines, engines engines...

Jim,
I have a 55 with 8V71's, while I like them, the entire 71 series is very old technology with the basic design about 1937 and moderate updates since then, mostly more cooling, bigger injectors and higher blower pressures. They are very fuel ineffecient as well as being heavy as ****.

The Ford 275's I believe are American Diesel Ford Lehman engines, if so, you are at the top of the horsepower range with them as they were originally designed as 120 HP normally aspirated engines. The higher HP ratings are (as are the 71's) at the cost of service life.

I'm having a bit of trouble believing that the boat has 454's unless they are the result of someone repowering the boat in the past as most 47 Chris Crafts had Ford 427's as gas engines. A perusal of the Chris Craft Commander site will give you a lot of information on those engines as the Commander owners swear by them. You may want to post the boat serial numbers to Jim Wicks as he has data sheets on every Roamer that Chris Craft built.

Personally, I'd forget about the 4-71's and would consider the Ford 275's after a good inspection and compression test. However, if it was my boat I'd run the gas engines until they gave up the ghost. I'd love to repower my boat with something a little more efficent, but the dollars and cents just don't support a repower until the 71's give up and as I just turned this side of 60 and based on the rest of my family will have an active life into my 90's, I don't think I'm going to live long enough to wear them out.

Jim Bauer
San Ramon, CA
1973 55 Aluminum

Gas Engines

Jim,

I understand exactly what you mean. There are a few rules to be followed with gas engines that can be ignored with diesels. First - Venting the engine rooms. Bilge blowers must be installed, working properly and run well before starting your engines. On my gas boats, I always opened the hatches and sniffed before I ever started them. Second, buy and install fuel sniffers, they are electronic sensors that are sensitive to hydrocarbon vapors, they need to be installed in the engineroom and the fuel tank compartment, they'll alert you to any leaks in the system. Follow the Coast Guard reccomendations for fueling your boat, hatches closed , no smoking etc.. You shouldn't have any fears about a well maintained safe installation and operation of gas engines.

On another note. Use a good high quality synthethic oil in your engines and change as per the manufacturers instructions. Those 427 Ford engines are almost as expensive as a set of diesels.

Good luck, Jim Bauer

Jim,

I am "assuming" that the engineroom has an installed fire suppression system, either halon or CO2. This is your first line of defense against fire. I've had 2 fires in my boats, one, a transmission cooler line failed and sprayed hot oil on a hot exhaust manifold and the other involved a turbocharger clamp failing and the hot exhaust gases set the hatch cover on fire. Both triggered the fire suppression system and neither involved fuel, either gas or diesel. Both fires were out before I even got to look at them.

My Roamer has a 50 lb CO2 bottle in the corner of the engine room with a heat sensor in the center of the room as well as a 25 lb Purple K bottle outside the engineroom door and numerous Halon, CO2 and dry powder bottles scattered throughout the boat. I'm well prepared for a boat fire, either mine or my neighbors.

Ventilation is the answer for fuel fumes, with proper ventilation either forced or natural, they will probably not build up to an explosive level. It's also a good policy to run the blower after shutdown do get rid of any fumes from the carbs percolating as the engines cool down.

PS, we won't even discuss electrical fires.......

Buy it and enjoy........

Jim Bauer