Tickin Time Bombs?

[ohiohatteras]

Considering this 1989 38......

http://www.yachtworld.com/boats/198...tates?refSource=standard listing#.WpL-LejwZPY

Got a couple Detroit buddies that said to run away quickly! The engines in this boat are tickin time bombs cuz the horsepower is turned way up.
What do you guys think? And does anybody know this boat?

Thanks!

 

[Boatsb]

A customer in Daytona had 3500 plus hours on a pair before he rebuilt them. They were starting to lose a hundred rpms at wot and a bit of extra smoke.

 

[bobk]

Some of my friends back in Baltimore had these TIBs on larger boats which probably meant they worked harder. Their view was expect 2000 hours on them. My son had them in a 46 Silverton and they were tight, no smoke. I'm not sure of the hours, but could find out if you want.

Bobk

 

[fissioneng]

A dockmate had a pair in an Ocean 45. Seemed to run fine, but very sensitive to HX fouling/overheating. My friend was constantly cleaning them.

 

[MVCaprice]

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At least they aren't 53s. Our old 871 TA's only made 485 per side. Those are definitely tuned! I'd check the coolant and see how much they smoke if your seriously looking at the boat.

BTW, All Detroits are ticking time bombs IMHO. Haven't been made in many years. Hard to find service shops. They all smoke. Uggh!

 

[MVCaprice]

A dockmate had a pair in an Ocean 45. Seemed to run fine, but very sensitive to HX fouling/overheating. My friend was constantly cleaning them.

That makes sense. HX probably was designed for +-300HP and now its 170% of capacity.

 

[kelpy]

The only Detroits that are "ticking time bombs" are the ones that have not been taken care of with regular and proper maintenance. If you see nasty oily engine spaces full of nasty oily rusted engines, the owner is not taking care of the machinery no matter who manufactured them. Those are the "ticking time bombs" you want to stay away from.

The 485 TIBS are at the edge. I would have to know the detailed maintenance history and, just as important, how much fuel has been run through them before I would commit to a set.

Just my opinion. YMMV

 

[MVCaprice]

The only Detroits that are "ticking time bombs" are the ones that have not been taken care of with regular and proper maintenance. If you see nasty oily engine spaces full of nasty oily rusted engines, the owner is not taking care of the machinery no matter who manufactured them. Those are the "ticking time bombs" you want to stay away from.

Jimmy lovers!

I have just been getting spoiled by new Volvo IPS and MTU powered boats lately so It's hard for me to want to crawl back into our 37 year old engine room!

 

[kelpy]

One should be able to walk around, crawl around and lean over the machinery and not get dirty. The age of said spaces and machinery should not make much difference.

Those 2000 and 4000 series MTUs are spectacular engines. Volvos not so much due to a bad experience with them a number of years ago.

 

[racclarkson@gmail.com]

One should be able to walk around, crawl around and lean over the machinery and not get dirty. The age of said spaces and machinery should not make much difference.Those 2000 and 4000 series MTUs are spectacular engines. Volvos not so much due to a bad experience with them a number of years ago.

I second that.

 

[jim rosenthal]

I don't agree. The reason they made millions of Detroit 2-cycle engines is that they sold millions of Detroit 2-cycle engines. Like any mechanical device, their life is proportional to how they are used and how they are maintained.

If you like the boat, make an offer you can live with, and if accepted, get a good Detroit guy (Tom Hugg, around here) to survey them. If they pass muster and the hull survey likewise, buy the boat and go boating. If not, keep looking. I'd worry a lot more if they were Cummins 370s or 903s- those are really hard to get parts for, from all I've ever heard. And very expensive when you find them.

 

[mike.s]

The 671 TIB is a great motor. Very reliable and once its running it will keep running as long as it has fuel and air. My family had a 56 Ocean Cockpit motor Yacht from 2001 until 2017, it bounced back and fourth between my parents and my wife and I. We ran the boat hard all the time and would run it at 2,250 rpm cruise. It went 2,200 hrs before the 1st rebuild and about the same or a little more before the 2nd rebuild. My mechanic said if we would back it down to 1,950 to 2,000 rpm we should get 3,000-4,000 hrs between rebuilds. If you find a good independent mechanic to work on them you can have them rebuilt for $2,500 a hole. I Bought a 61 Davis last August with 1292 ta's if you read and believe the internet they are junk and will only run 2,000 hrs between rebuilds. I didn't waste my money on a motor survey and probably never will again. The broker talked me int one on my last boat and I felt very ripped off after, i was cautious about the motors because they were MAN's. All you need to do to tell a Detroits condition is start them cold. If they start quickly and the smoke clears quickly, plus they hit rpm they're good to go. I bought my Davis with 2,300 hrs on one of the motors and have put 200 hrs on it at mostly cruise rpm, and thats a motor that a lot of people will tell you won't go more than 2,000hrs. If you like the boat and the motors start clean buy it and enjoy it, and put the money you save from not doing an engine survey in a repair account.

 

[MVCaprice]

I don't agree. The reason they made millions of Detroit 2-cycle engines is that they sold millions of Detroit 2-cycle engines. Like any mechanical device, their life is proportional to how they are used and how they are maintained.

They also made millions of 6.5L GM Diesels. To me that means that they were common and pushed into a widely used platform and maybe most importantly all that was available at the time. I agree with your point about service making or breaking them over time. I just think that emissions, parts availability and the availability of service for a very old platform has a lifespan. It will be interesting to see how long that is.

 

[MVCaprice]

If you find a good independent mechanic to work on them you can have them rebuilt for $2,500 a hole.

This!!!!

 

[Walter P]

The 71 series engines (71 cu in per cyl) go back to before WW 2 and were originally set up to produce
less than 200 hp. I think they were rated at about 160 hp. They gained their reputation for reliability
and longevity during the period of time that they were set up for about 300 +/- hp. Johnson and Towers
marinized versions were rated at 310 hp which was considered high at the time they came out. All those
lower HP 71's seemed to last forever and as was commonly accepted, give them clean fuel and lots of
air and they would run with thousands of hours on them. It was/is not unusual to find plenty of 71 series
engines in the commercial boats with upwards of 10,000 hrs on them. Simple physics ..... the more
stress anything is subjected to the less longevity. That seems to apply to most things in life including
ourselves. The 6-71 TIB @485 is very stressed but they were still very good engines and perform very
well but they need to be overhauled more frequently than the lower HP engines. I believe that even
requiring overhaul more frequently than the 300 hp engines they are still a bargain even today in the
age of modern computer regulated engines.

If the engines in most of our boats are worn out, but we're satisfied with their normal rated performance,
then it is worth the cost of the rebuild every couple of thousand hours. If as stated in an earlier post
on this thread they cost $2,500 per hole and they only last 2000 hours and the average boater on
this forum does the recommended maintenance and runs about 100 hrs/yr, that would equal 20 years
divided into $30 G = $1,500 yr. Not bad at all. And the numbers can be a lot better if you lower your
cruise RPM's a bit. Those estimates are for the 485 hp engines. The 310 will probably double that
figure or well less than one thousand dollars per yr for the pair of engines.

Now all this does not mean that I don't salivate over some of the new engine technology, especially
the Cummins B, C and QSM-11 engines. They have many advantages but if you do the math the
cost of changing them out far exceeds rebuilding the Detroit engines. If you're satisfied with the
lower speed from the detroits, as well as the greater fuel consumption rate and extra weight and you
slow cruise slow most of time then IMO it's a no brainer to stick with the old iron.

Walt

 

[wndsr]

IMHO......Most people that are afraid of Detoits or consider then ticking timebombs just don’t understand them.

 

[MVCaprice]

IMHO......Most people that are afraid of Detoits or consider then ticking timebombs just don’t understand them.

Or maybe they have an appreciation for modern, clean burning, 4 stroke, direct injected common rail diesel technology. Just saying. But simplicity and mechanical injection does have its benefits.

 

[luckydave215]

My 12-71's are rated at 1000hp/side (think 6-71's at 500 hp).
Run sensibly with good care they went 7500 hours before being rebuilt, I now have ~2000 hours - also running sensibly with good care.
They run like new, start instantly with zero smoke in 40F weather without block heaters, and have practically no leaks (stupidly designed tach drives excepted lol).
Sure, if wishes came true I would have a shiny new pair of 1800 hp C-32's, but in reality, at 61 I probably won't live long enough to wear out these 12-71's.
BTW - My friend Capt Andy Cates got 100,000 hours out of a set of naturals (triple engines) in the 105 ft Red Rooster 111. The 6 cyl Luggers he replaced them with have 80,000 hours and are still running strong.
The notion that well cared for diesel engines wear out every two weeks is nonsense.
You can kill anything by running 'em on the pins all the time, use your brain.

 

[mike.s]

Or maybe they have an appreciation for modern, clean burning, 4 stroke, direct injected common rail diesel technology. Just saying. But simplicity and mechanical injection does have its benefits.

I can honestly say I didn't notice any advantage with modern common rails over old Detroits. I've had boats with Man's, MTU's, Detroits, And Cats. All of them served me well and gave me very few problems, I usually put between 300 and 500 hrs a year on them. I will say unless it's a deal I can't pass up I will never own another boat with Cats. I like the motors but hate the service and the specialized tools required for each series. My motors of preference are Detroits though for one reason, they are simple. I have seen boats with modern diesels get towed in because a relay or some $50 electrical part failed. I was at Pirates Cove inside Oregon inlet when a sport fish with Detroits came in with a rod sticking out the side of the block of one of the motors but it was still running. That was a rough day and I wouldn't have wanted to come in on one motor.

 

[Scarlett]

Dave where did you find 40 degrees in San Diego. I can confirm that Dave’s engines don’t even produce a puff of smoke on start up. John