Detroit Diesels

[rickalan35]

A Detroit Diesel question. At 2400 hours, with probably an history of average maintenance are we looking at rebuilding? Engines are 1986 vintage and I'm assuming are 92's.

[rickalan35]

Guess they're 6V71's

[prowlersfish]

If they are high output quick answer is yes , 671 or 6V71 at 450-485 hp is high output as is a 6V92 at 550 hp . When you get in to the lower HP they can last many more hours . a 671 at apox 250 hp can be a 10,000+ hour engine . How they are taken care of and how hard they are run is a big factor .

Do you have more exact info ?

[rickalan35]

Well, I just received more info but not sure how accurate.

These Detroit's are in a 1986 Gulfstar49 located in Florida

Allegedly, the engines are 175 horsepower each and both have 2100 hours. 3 blade props. That's about all I got at this point.

[prowlersfish]

Not making much sense . While the did make a 671 at 174 hp is a old one . a quick look at the 49' show most around 350 hp and most are Cats .

[rickalan35]

Hi Prowler, Yeah, Gulfstar put Perkins diesels in the early ones and then later on Cats, but it appears that during the final two seasons (86 and 87) they put Detroits in some of them. But like I said, the info is unreliable because the guy says they are V-drives too - which is impossible. I think it is probably 350 hp per engine.

Lets pretend they are indeed 350 hp units. Does that mean that they might run out until 3,500 or 4,000 hours before major work was required?

I know they are Detroits because I had a non-boater friend down in Florida go over and confirm this fact. But he didn't get much else for me except to say "They're really big."

[prowlersfish]

Taken care of and not run on the pins yes . The made the 671 in a lot of ratings 350 would be a odd one ( to me anyway ) . Brokers have been know to get engine info wrong . Can you get some photos ?

[rickalan35]

Probably not, because of the logistics. (The boat is far away) The owner will be emailing me tomorrow and I'll ask him some questions. He's mid eighties.
I may be able to get some info from the marina as they are currently changing out the exhaust hoses.

[prowlersfish]

would be nice to know why they are changing the exhust hoses . Could it be from a over heat water flow issue ?

[rickalan35]

The reason given was that one was discovered to be perforated.

[rickalan35]

As part of the operation, the marina repair team apparently weighted one side of the boat down to incur a severe enough list to drain certain hoses. I'm not a diesel guy. Does this operation make sense?

[Patriciamarie]

Check the air box drain tubes for any oil under load, being marine app they are most certainly returned possibly to fuel tanks, is the fuel black midway down if so the rings are worn or cracked, do you have an oil consumption issue. You could sample the oil for testing,or check the rings directly pull the covers and bar the engine over and push on the directly if their is no spring to the they are cracked.A good rule of thumb in the truck trade was 10,000 gallons of fuel used indicates in frame considerations
Steve