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Old 01-10-2013, 10:16 PM   #61
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There's a lot of people out here in the real world that don't write books or spend a lot of their time promoting themselves on websites. That doesn't mean they aren't just as "expert" as the writers.

To say many or most modern diesels go bang at 600 hours...well let's just say that's ridiculous...

Here is one of his statements that should be in CAPs..

"....but you have to understand that the AVERAGE includes high performance diesels, as well as those folks who do not maintain their engines at all; the ones who run them until they stop."

Boy...I wish could make a living at stating the obvious...unfortunately I'm not such a great/prolific writer.

Touring engine shops for repair statistics is like touring hospitals for the healyhy vs sick...how about fitness centers instead?

I know a boatload of charter sportfishemen who would laugh at that 1100 hour average...they would be out of business if they planned for major rebuilds that often...so would most any commercial operator...and there may be the difference...the way engines are run and maintained...not who makes them or what rpm they are designed to run at.
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Old 01-10-2013, 10:48 PM   #62
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Pascoe is an excellent resource for getting one point of view on a topic, be it a particular make or model of boat or an engine. And he makes a lot of points about boats that are worth heeding or at least being aware of.

But he is incredibly biased, incredibly opinionated, loves the sound of his own voice even more than I do, and plays favorites like you wouldn't believe. So it's best, I think, to take pretty much anything he says with a big grain of salt and treat it as a single data point to be added to whole bunch of other data points that you get from a whole bunch of credible other sources.

Since he's not here to tell us, it's hard to know the specifics of his claim of such short lives for modern diesel engines. Is he basing it on the repair records of specific engine makes and models? Is he basing it on warranty claims? Is he basing it on insurance claims? Is he basing it on the collected and verified records of diesel shops across the country? Is he basing on the fact that "he knows a guy" who's Yanmar blew up at 600 hours?

No way to know at this point.

Like psneeld I find it very hard to believe that a blanket claim of such short service lives for modern diesels is valid. If it was, you would think the boat manufacturers would be falling all over themselves NOT to use these kinds of engines in their boats.

Because any deficiency in the engine reflects on the boat even though the boat manufacturer had nothing to do with the design and manufacture of the engine. People don't say "My John Deere engine blew up." They say, "The engines in my two year old Grand Banks blew up," and the damage to GB's reputation is done.

Psneeld said that commercial operators would not accept engines with a TBO of 1100 hours. I don't think recreational boat buyers would, either. A Grand Banks 47 costs well in excess of $1 million. So does a Flemming 55. A big Eastbay is getting right up there toward $1 million bucks if not more. All of these are relatively fast boats with big, powerful engines and their owners tend to run them at speed because they can afford to.

I cannot conceive of a person able to afford this kind of boat who would plunk down that kind of money and expect to re-engine or re-build the engines at 1,100 hours.
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Old 01-10-2013, 11:01 PM   #63
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I suspect that when Pacoe refers to "go fast" diesels, cranked up much higher than 1 HP per CID, he is thinking of the offshore racing or cigarette crowd that hangs out down in Florida. He refers to engines blowing up at 600 hours that have "never been maintained". That's not hard to imagine if you think of some guy draped in gold chains, trolling for women half his age, and speeding around in his "substitute". Yeah, why not just drop a couple of million to buy the boat, run it until it breaks, and then throw $40,000 fixing up the engine in order to get another couple of years until it croaks again.

It's very unusual for diesel engines to fail at 1000 hours, or 2000 hours. I've only had one diesel engine failure, at 3600 hours, and that was due to water ingestion into a cylinder rather than being physically worn out. In the typical pleasure boat application it can take 8-10 years to run up 1,000 hours. In my opinion, the jury is still out on the longevity of the newer, high-rev diesels compared to the older larger displacement mills. How many of the smaller engines have accumulated 2,000 or 3,000 hours, (in sporadic, pleasure boat service)? Enough to draw solid conclusions?

I have long subscribed to the displacement/HP ratio generally described by Pascoe at the end of his remarks. That's not an idea that's original with him. I've heard it from several old time diesel pros over the years. Doesn't make it right, just commonly believed. :-)
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Old 01-10-2013, 11:07 PM   #64
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Are you sure?
. My IH diesel truck engine has 1649 hours at 79000 miles and most consider it just broken in. No one would buy these trucks if they didnt go at least 3000 hours and i don't know of a single one that has needed rebuilding before that unless they had the hosepower jacked way up. 600 hour engines would be totally unacceptable to most consummers i would think. Now i am talking truck and farm diesel engines not marine and i always thought marine engines were made to last even longer.
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Old 01-10-2013, 11:10 PM   #65
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Chuck said: In my opinion, the jury is still out on the longevity of the newer, high-rev diesels compared to the older larger displacement mills.
Yes, the high-performance, racing-type engines excepted, it would be interesting to know definitively how the higher-speed, turbocharged diesels used in many "normal" boats today compare in longevity with the Ford Lehmans, Perkins, Detroits, etc. from the 60s, 70s, and 80s.

There are a lot of opinions out there, most of which seem to come down on the "new stuff won't run as long as the old stuff" side of the fence. But so far as I know there has not been any factual study done with a lot of credible data to back it up.

The only numbers I have heard bandied about for the engines in our boat (FL120s) is that it is a "12,000 to 14,000 hour engine in recreational service assuming proper operation, servicing, and maintenance." I've heard those numbers from a wide range of sources.

I quote those numbers myself simply because I've heard them from so many sources. But I have absolutely no idea why---- or if---- they are actual, credible numbers based on something real.

They sound good, though.
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Old 01-10-2013, 11:13 PM   #66
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I wonder if we've demoralized and depressed the original poster to the point of rejecting the thought of buying a boat entirely.

I don't know of any diesel marine engine that turns so fast that it is killing itself prematurely. Some run around 4000 rpm. I had one that made maximum steam at 3450 rpm (Yanmar) and it wasn't new and it performed very well cruising at 2750 rpm most of the time.

There's been lots of talk about twin engine trawlers having a very serious problem w lack of space in the engine compartment to do simple owner type maintenance. If the same boats had 4000 rpm turbocharged engines there would probably be much more (or plenty) of space for all activities normally encountered. AND the boat would be much lighter and thus higher performing. Perhaps significantly.

Having a big heavy old slow turning slugger of an engine is nonsense. Just because our boats go slow is no reason our engines should go slow. And now a turbocharged engine is no longer considered a high performance engine because it has a turbocharger. All an engine is doing is powering a boat. What engine speed it's done at is of no matter.
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Old 01-10-2013, 11:15 PM   #67
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The boats i have been looking at are all older and most have 2-3500 hours on them which i am told is nothing for a perkins or FL. I would like to see some real numbers but havent found any. Seems to me the boats are wearing out before the engines in most cases. So with the new ones its diferent? humm....
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Old 01-10-2013, 11:21 PM   #68
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dont you think those tiny turboed engines turning a kazillion rpms to make the boat move at displacement speed is making a bit of a racket? My experiance with those high revers has been they are very load and sound like they are ready to gernade at any time. Isnt the clatter of an old DI engine at maybe 15=1600 rpm but a murmur compared to the scream of the teeny turbo monster
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Old 01-10-2013, 11:26 PM   #69
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Eric--- I think most of the boats that people in this discussion have in mind when they talk about twin-engine boats vs single engine boats are boats like mine. Old or old-ish, and made at a time when things like FL120s and FL135s were the accepted engines. Higher power engines were things like Cats and Deeres and Cummins, but they were still "old and slow" compared to the new lightweight, high speed diesels I think we're talking about here.

While I understand your own philosophy with regards to twin engine boats, the manufacturers who made single and twin engine models simply created a twin by putting two of the same engine they put in the single into the boat. Sure it was heavier, sure it perhaps resulted in more power than was necessary (unless the hull form was such that it could make use of the extra power like a GB). But this meant you just had to stock one kind of engine, one kind of mounts, one kind of transmission, etc. etc. etc.

The realities of the production world sometimes don't match up to the realities of the "scientific" world for want of a better term.

This production philosophy held on for a long time and perhaps even today. When my wife and I were chartering a GB36, we chartered a 1991 model with a single engine. The engine was a 210 hp Cummins. In that same year, Grand Banks also offered a twin engine GB36. Standard--- if not the only-- engines available for that boat were....... two 210 hp Cummins.

So it's been going on for a long time, in the case of GB since 1966 clear on up in the late 90s and, for some boats, until today.

So given that production philosophy, the engine space in a twin engine GB36 is a lot more cramped than the engine space in a single engine GB36.

Your notion of using one big powerful engine in place of the two less powerful ones to create, in essence, a single engine version of the twin engine boat is valid with respect to the power and space in the engine room.

BUT....... you still have a single-engine boat, and I refer you to the infinitely long single vs twin thread for the reasons why some people (like me) really want two engines.
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Old 01-10-2013, 11:31 PM   #70
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I think everyone wants twin engines they just don't wish to pay for the initial cost of or the maintenence of the second engine system when its only really useful at the marina or for spare parts
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Old 01-10-2013, 11:40 PM   #71
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I think everyone wants twin engines they just don't wish to pay for the initial cost of or the maintenence of the second engine system when its only really useful at the marina or for spare parts
Could be. I know from our brief experience with the chartered single engine GB36 (which had no generator, either) that getting around in the engine room to check things out was WAY easier than it is in our boat. Having only one engine also made more space for things like a proper diesel heating system, a good sized hot water heater, sufficient battery banks, and so on with still plenty of space left for crawling around.

Add in the weight benefit and the other factors you mentioned in your post, and I think single engine boats have a legitimate appeal even to people who could afford otherwise.

To turn this back into something the OP might be more interested in if he's still around is what would be the smarter buy in a used boat? One with "old generation" diesels like Lehmans, Perkins, older Cats, Deeres, Cummins, etc., or something fitted with one of the newer, lightweight, more efficient, high tech, higher speed diesels?

Which will give him the most value for the money? And not just purchase money but money spent over the time he owns the boat.
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Old 01-11-2013, 12:04 AM   #72
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Floyd I can see your concern about the noise. And about that I really don't know. But I've had some thoughts on noise over the years. I think basically most any engine we would use could be made very acceptably quiet w what ever amount of sound insulation was required to do the job. I should address that issue myself. At my normal cruise of 2300 I consider my boat plenty quiet enough. But at 2500rpm for an hour or more I get a bit tired of the extra noise. My boat has little sound insulation and I'm sure lots of my noise is coming from the air intake. So I need to make an intake silencer like the cars of the late 40s had.

But just how much noisier a high rpm engine is ..... I just don't know. I do know though that the higher the engine speed and the more cylinders the engine has the less vibration. And vibration is a huge source of noise. Many more strokes of less force and energy produce much less vibration unless there is a significant part of the boat like a bulkhead that is resonant to the engine frequency. Soft engine mounts absorb low amplitude higher frequency vibration well.

The sound of a diesel engine is frequently not an indication of how "happy" it is. I think the engines are "happiest" at a relatively high rpm and normal load.
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Old 01-11-2013, 12:35 AM   #73
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Quote:
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The Lehman drive coupler was designed by Bob Smith and he's the one who told me what I'm about to tell you...

The drive coupler is not a good design... and is the only Lehman component to have ever had a factory recall (according to Bob

So the real solution is to toss the whole thing, Lehman drive coupler and the Jabsco water pump, and replace them both with a brand new, one-piece Johnson pump that is a bolt-on replacement.

This is what we did on both our FL120s when the removal of one of the Jabsco pumps for overhaul revealed a failing tang on the drive coupler. So we had the couplers and pumps on both engine replaced with 1" Johnsons.
Do you have a Johnson part number you can share with other FL owners, for the replacement pump?
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Old 01-11-2013, 01:05 AM   #74
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No, I don't have it offhand. I might have it on the boat and our diesel shop obviously knows what it is. And if you join and post your question to the GB owners forum there are people there who probably have the number memorized. Or you can search for it in their archives--- it's been talked about plenty of times.

The pump normally recommended for the FL120 is the 3/4" pump. The pump recommended for the FL135 is the 1" pump.

However at the time we discovered our drive coupler problem Johnson was temporarily back ordered on the 3/4" pump and we had a cruise to do. So on the recommendation of both our diesel shop and Bob Smith at American Diesel, we had the 1" pump installed on each engine instead.

And this is actually beneficial because the 1" pump moves more water. While this does not change the engine temperatures due to the thermostat, it does drop the transmission temperatures down a very noticeable amount (by feel, I haven't measured it). And as far as I'm concerned, the cooler a transmission runs the better.

So the part number I would have if I have it is for the 1" pump. But this is a really common conversion for FL120s so I would think any diesel shop on the planet that has experience with these engines would know the pump and the part number. Or you could call the Smiths at American Diesel.

One thing to be aware of--- the Johnson pump is much shorter than the combined drive coupler and Jabsco pump. Also, the Johnson pump has the inlet and outlet on opposite sides of the pump body. This means the outlet comes out of the top of the pump so you need a 90 degree elbow right there to turn the flow aft. No problem, right?

Well, the position of the elbow puts it right underneath the drain plug for the Minnemec/CAV/Simms injection pump. You can get a wrench and fingers in there to remove the plug okay but there is precious little room below it. I've come up with a system using a split section of water hose to catch the oil and funnel it out to the bottle I use to catch it. You can also cant the pump inboard (rotate it counterclockwise a bit) to give you a bit more working room under the injection pump. I haven't bothered to do this since our system works fine.

If we're at the boat this weekend I'll try to remember to take a picture of the installation.
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Old 01-11-2013, 06:59 AM   #75
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....... At least 99% of us will never wear out the engine w the shortest engine life expectancy. Lots of engines get killed but not worn out......
I agree.
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Old 01-11-2013, 08:08 AM   #76
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The origional service for the engine must be considered .

The big truck or industrial based engines have little problem operating at or near their rating for long periods of time.

A Toyota or BMW (Yanmar) engine built for a passenger car may have a huge HP rating , but that is no where near a cont rating.

The old concept that it takes about 3 CI to make a hp, "forever" should be a guide .
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Old 01-11-2013, 09:54 AM   #77
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Our boat has two Perkins 6.354's....they were built in 1977. So far as I can tell by the mound of paperwork that came with the boat...they have never been rebuilt, and have only had a few repairs...and regular maintenance.

They work well, they are fuel efficient, the parts for the most part are readily available, except that it appears that the fresh water pump for their "contra rotating" engine is difficult to find, though TAD can rebuild them...

If you look at a boat with Perkins...and it is a newer make...it is possible that the engines rotate the same, but the transmission turns the prop contra rotating....

Having experience with "new" diesel engines...with all of the electronic gadgets they have hung on them....I personally would avoid them at all cost. The cost of EGR valves and turbos is high....very high.

For instance....I owned a Dodge P'up with a Cummins 6 diesel...vintage 2004. I never had a bit of trouble with it...not even with the turbo. On the other hand...I talked to owners who had the newer versions of that engine...that included the EGR valve... and those have been a nightmare. And the ECM's.....fun times.

I prefer my old 6.354's that are 100% mechanical......
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Old 01-11-2013, 06:22 PM   #78
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Several have asked if the OP was still here and yes I am... and learning a lot from many of the posts. The discussion has been very helpful and most of it was exactly what I was hoping for. The discussion between the "old slow" diesels vs the "new high rev" diesels is very interesting to me. I'm a mechanical engineer and that was the first thing that jumped out at me as I started looking at used trawlers. I've asked many of my boating friends about the pros and cons of each but most of them are not technically savy so I was hoping to get some insight into that subject in this thread. Philosophically I am leaning towards the lower reving engines with less "stuff" but i'd like to continue to listen to the experiences many of you have had with each of them. Thank you all so much for the info and i'm happy to continue to listening!
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Old 01-11-2013, 09:28 PM   #79
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Quote:
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Most important point made here yet, I think.

As a point of information for the OP, the FL120 has the reputation of being a 12,000 to 14,000 hour engine in recreational boat service ASSUMING the engine is operated, serviced, and maintained properly.

This 1950s-designed engine is a little more maintenance-intense than other engines if for no other reason that the fuel injection pump has it's own oil sump as opposed to being lubed by the engine's lubrication system. And for a reason more detailed than is worth going into here, the lube oil in the pump should be changed every 50 hours. It's not hard, it only takes a few minutes, but it's something that should be done that most other engines do not require.
I asked Bob Smith (American Diesel, former Lehman head) last year how long the 120 was good for and he said he knows of two that have passed 80,000hrs and have not been rebuilt yet!
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Old 01-11-2013, 09:42 PM   #80
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I haven't heard the 80,000 hour figure. The one Bob told me a number of years ago was some 25,000 hours in service with the Washington State Ferry system. I assume running pumps or generators or something. And of course, they would have been run every day and gotten very close attention, service, and maintenance. So probably not really relevant to the engine's longevity in typical recreational service.
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