Proper Performance Engineering

[ThePHNX]

Sounds like we'd get along just fine. Had to form my own company cause the only time people would put up with me is when I paid them to!-)
Guess with tyme we'll git over the speling thing?
Hope you all (I'm in the South now) had a great thanksgiving.
HBH

[Bigshrimpin]

Phnx - I was just reading about the 1957 Mercury Mark 75 (first 6 cylinder outboard and first mercury tested at Lake X).

In 1957 that motor set the world endurance record propelling a runabout over 50,000 miles in 68 3/4 days of continuous day and night running. Refueling on the run . . . the boat maintained an average speed of 30.3 miles per hour.

[Ed]

Tim,

That's impressive esepcially considering it was 1957. If my math is correct, that is about 1,632 engine hours, no?

I wonder if a modern day 4 stroke or maybe the ETEC could run constantly for 68 days?

-Ed-

[Bigshrimpin]

They were twins 60hp Mark 75's pushing a decent size boat 30.2mph. I am guessing that they were running it continuously above 70% throttle to average 30+ mph over 68 3/4 days. The drivers had to eat meals, go to the bathroom, rotate staff, pickup fuel, etc. So 1632 hours is remarkable for that kind of load on a two stroke.

[Bigshrimpin]

Ed - What's more impressive is that the motors ran 1600+ continuous hours (50,000 miles) WITHOUT changing water pumps, fuel pumps, gear oil, decarbing the motor, or any of the other routine maintenance items.

[spareparts]

the truth to that feat was reveiled in a magazine article a while back( Powerboat, I think), apparently they did swap out lower units( with water pumps) on a regular basis, they were also allowed to change plugs and decarbon the engine. Due to the fact there were no spray decarbonizers available at the time, the were allowed to pull the head and scrape the chambers, because this took some time to do, they would install another stand by power head to continue while the other one was being serviced so the event could go on. There was some speculation that the decarboned powerhead that was returned wasn't even the same one that was removed. Fred Kekifer was a marketing genuis. During the test, one of the test drivers fell asleep and was killed when he ran into the trees, they decided to continue with the marathon, changing drivers more regularlly. I wish I could remember exactly which magazine it was in, the article was great, explaining some of the wars and compitition between Mercury and OMC, with the industry greats trying to one up each other.

[Bigshrimpin]

Funny how that information doesn't make it into the film or the merc site. To me running continously means "continously". In the film they show them stop at 25,000 miles and disassemble the motors (check the specs) and state that it was reassemble using all the same parts. I wondered about the miracle water pump, plugs, lower unit gear oil, lack of carbon build up, etc.



************************************************** *********
In 1957, the company began operations at a 1,400-acre undeveloped Florida lake - a new testing area away from prying eyes. To keep the location a secret, Carl Kiekhaefer referred to it as "Lake X" when speaking with outsiders, and the name stuck.

" That same year, the Mark 75 was introduced, the industry's first six-cylinder, 60-hp outboard. At Lake X, two Mark 75s set a world endurance record, each propelling a family-sized runabout over 50,000 miles in 68 3/4 days of continuous night-and-day running. Refueling on the run, they maintained an average speed of 30.3 miles per hour."

Spares - If you find that article . . . let me know what issue it was in . . . I'd love to read it.

[spareparts]

i wish I could find it, it was a great article, had a lot of other stories about the early days at Lake X, had some great photos.It must have been about a year and a half ago, could have been trailer boat, boating, or yachting( they are the magazines we get at the office)

[oldbluesplayer]

hmmm, well, returning to the core of this post...

As most Mercruiser IO powerplants are GM, I would bet you could get the torque / horsepower / rpm curves from them - I know in my old hot-rodding days these numbers were available - and often were published in the factory shop manuals (not the owners manual), but the last set I have of those is for old Ford V-8's (think Boss 302.... yeah, I'm an old fart)

quite true on horsepower to get to plane, vs horsepower to maintain - same with a car, what it takes to accelerate to 60mph, vs, what it takes to cruise at 60mph - much lower.

Phnyx, sounds like you have heavy aircraft background - safety requirements called for many more guages to monitor in-flight condition of engine - on small, pleasure type boats you will mostly see fuel flow, maybe voltage, temp, oil pres if an inboard or IO - but would probably get more involved on a big bucks sportfish with diesels. My experience on manifold pressure, is only on piston engine aircraft, and military / commercial vehicles, with turbo or superchargers (and hot-rods with same)- so the boost point kick-in, and max pressure, could be monitored. Any other old farts out there, with any Army experience, remember the M551 Sheridan light tank - had a 6V53 Detroit Diesel, with twin turbos, and a supercharger - on full boost it was quick - I worked on that puppy at the Detroit Tank Arsenal.

stray thoughts...

Bill

[spareparts]

Bigshrimpin, for what its worth, i just changed out a set of impellers on the water taxi, twin 150 four stroke Yamahas, 2005 model, 1900 hours, they were worn, but they were still pumpin'