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Old 12-09-2014, 02:08 AM   #21
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I've had first hand experience with piston slap in the FL120. After buying my Willard, I noticed what sounded like noisy tappets so had them adjusted but the noise persisted. The consensus was "piston slap", which is an out-of-round piston caused by overheating. On the FL120, the #6 piston is at the tail end of an anemic cooling system. (Btw, I understand there is an after-market fix available to improve fresh water cooling to that #6 cylinder.) Instead of rebuilding the FL120, I decided to repower with one of Bob Smith's American Diesel Corp's Lehman 6N140. These engines are "updated" with improved fresh water cooling to ALL the cylinders, increased fuel flow and return for better cooling of the injectors, and a maintenance free air-intake system. The cost of the new engine was only $5K more than a rebuild...and half the cost of a comparable JD or Lugger. The new engine has run flawlessly and economically for 8 years now, including a 2,400 mile round trip and tour of southeast Alaska in 2013. Hope this is helpful.
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Old 12-10-2014, 12:32 AM   #22
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Here's an interesting quote on how to determine whether the noise is piston slap. One would think that putting a .015-over piston in a .020-over bore would increase the likelihood.

James E. Harris, proprietor of Engine Restorations in Portland, Maine also disagrees with GM’s assertions regarding piston slap:

One way to check for piston slap: Remove three spark plugs, leaving number one in place. Crank the engine over until you feel the resistance of number one piston coming up on compression. Crank against compression until the piston is about half way up the cylinder. Now using the fan, rock the crankshaft back and forth and listen for a metallic knocking sound. If you hear a knock, you have piston slap and the only way out is to rebuild the engine.
reference:

http://www.forengines.com/enginetips.html

The Lehman pistons have long full skirts so would seem to be pretty resistant.
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Old 12-10-2014, 06:55 AM   #23
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Removing the spark plugs from an FL can prove troublesome.
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Old 12-10-2014, 08:04 AM   #24
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Quote:
Originally Posted by sunchaser View Post
Removing the spark plugs from an FL can prove troublesome.
And ain't that the truth..?

I repeat what I said in post 14. I think you are over-problematising this thing. Hey, I think I'll copyright that word...
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Old 12-10-2014, 11:40 AM   #25
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I would just slap it back....
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Old 12-10-2014, 12:26 PM   #26
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Pete, You might be right. The oil analysis will be here soon, I also have a mechanic that Caphead AKA Stretch has recommended will come by next week to take a look.
Thanks everyone for reading and posting, Mike
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Old 12-10-2014, 02:57 PM   #27
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Originally Posted by nwboater View Post
I decided to repower with one of Bob Smith's American Diesel Corp's Lehman 6N140.
These engines were based on a then-current model of Ford of England's diesel lineup. If memory serves, it's 150 hp. The nice thing is that it was a direct drop-in replacement for the FL120. I don't know if it was also a direct replacement for the FL135.

Unfortunately, due to some sort of problem-- supply, EPA regulations, or perhaps Ford's discontinuing the engine-- American Diesel stopped supplying this engine a number of years ago.
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Old 12-10-2014, 03:06 PM   #28
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.....problematising this thing. Hey, I think I'll copyright that word...
That's a great word, Peter. I think I'll start using it in conversation. It's right up there with one of my all-time favorite words that unfortunately I have little call to use, and that's "strategery."
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Old 12-10-2014, 03:13 PM   #29
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Marin,

I spoke with Bob at AD just 4 or 5 weeks ago and he told me they are indeed selling drop in replacement Ford block diesels, however only if that is the type of engine you have now. If I recall correctly the price was around 10k includes starter and manifold no coolers.


Still list it on their website
" In later years Ford up dated the 2725E engines to become the Dover-Tech series, our current model 6N140 engines that are still available today."
http://www.americandieselcorp.com/
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Old 12-10-2014, 03:17 PM   #30
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Scott- Thanks much for the update. I did not know they were still doing this, or had started doing it again. I was going off a discussion on the GB owners forum some years ago where the discontinuation of the replacement engine was announced.
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Old 12-10-2014, 03:25 PM   #31
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Scott- Thanks much for the update. I did not know they were still doing this, or had started doing it again. I was going off a discussion on the GB owners forum some years ago where the discontinuation of the replacement engine was announced.
I heard that as well (perhaps here on TF) that's why I asked him.

I think it's a no brainier to drop in a new and improved FL-120 instead of rebuilding one unless the shop is very well known, and then I would question it.

Bob has improved all the weakness out of the engine and as the old ones can and do go 10k hours plus the replacement unit would be the last time you did it.
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Old 12-10-2014, 03:58 PM   #32
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I wonder if the 6N140 engines will run gracefully at 80% load 24/7? That should be at least 2300rpm propped to 2500. Considering the source I wounder if anyone would have the inclination to do it. If I had one I would'nt be interested in running that hard but I'd sure want the engine to be capable of doing it. And if the boat needed the power I'd want to run it 2000 or 2100 as a normal cruise. And if it didn't need the power I'd be wanting a smaller engine. Re powering is a great place to be .... the only time one has the choice of how much power to employ.
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Old 12-10-2014, 04:10 PM   #33
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Understand that the 150 hp base engine that American Diesel is using is NOT the same Ford Dorset diesel that the FL120 is based on. The Dorset was taken out of production several decades ago. What AD is using is a modern, in-production Ford diesel that happens to have the same footprint and mounts as the designed-in-the-1950s Dorset.

So it's not like they've created an improved FL120. What they have is a brand new, marinized diesel engine that as luck would have it, has the same footprint and mounting system as the old 120 hp Dorset.

I believe, but I could be wrong, that the main motivation behind doing this was to provide a drop-in replacement engine for the owners of boats with two FL120s who'd had one of their engines fail catastrophically.

Several folks on the GB owners forum have done this in past years and according to them the 30 hp deference between the engines has no operational effect. I don't recall if there was any compensation reflected in the props.
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Old 12-10-2014, 04:32 PM   #34
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They are using the Ford Dover base in their ADC engine it is very similer (same crank,pistons rods, etc) some but not all part interchangeability. The blocks are named after the English city's they were manufactured in.

It is really an improved FL120 or Sabre 120 but the older Dorset block is not what was available when they bought out the remaining stocks the Dorset block was.

Bob told me they are for most intents and purposes the same, hey he is the guy that makes them.

As you know the 120 Dorset was first used in trucks and did not like the constant speed changes and lugging by bad drivers.

The Dorset was a 135 HP natural engine that found use in many places from pumps to power units and farm equipment.


Both engines are long out of production.

http://www.foleyengines.com/resource...dorset-engines

Manyboats, my Operators book says the continuous (24hr) rating is 92.8hp (68.8Kw) at 2500rpm for my 120hp Ford Sabre


Dover block


Dorset

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Old 12-10-2014, 05:30 PM   #35
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Good information, Scott, thanks. I had gotten the impression from Bob that he was using an in-production engine for the base engine of his 150 hp replacement. I didn't know he'd bought up an existing stock of the old Dover engines.
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Old 12-10-2014, 06:05 PM   #36
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Oh well I guess I should have said substitute injectors for spark plugs and # 1 cylinder for # 6.... It didn't seem that difficult.
A relatively cheap way to investigate the noise might be revealing, before throwing a bunch of money at a rebuild or repower.
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Old 12-10-2014, 09:27 PM   #37
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Scott,
That looks like a dyno statistic ... 93hp at 2500rpm. The equivalant running an under propped boat at 2500rmp. I had a Sabre 120 and they had good information. Thirty hp down (almost 30%) is (I think) considerably lower than most engines ... I should probably say most modern engines but I really don't know.

But that stat of yours may show that load is a much more limiting factor that rpm. Most trawler formers feel that rpm is what kills engines ... probably because rpm produces so much noise.
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Old 12-10-2014, 09:51 PM   #38
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Scott,
That looks like a dyno statistic ... 93hp at 2500rpm. The equivalant running an under propped boat at 2500rmp. I had a Sabre 120 and they had good information. Thirty hp down (almost 30%) is (I think) considerably lower than most engines ... I should probably say most modern engines but I really don't know.

But that stat of yours may show that load is a much more limiting factor that rpm. Most trawler formers feel that rpm is what kills engines ... probably because rpm produces so much noise.

Agreed, RPM won't hurt an engine (within working limits) in fact it puts less stress on it then high pressure and low RPM (Lugging) RPM is needed to make power and while noisy can lower temps, fuel consumption and wear.

I consider lugging an engine a crime, learn to down shift or prop it right.

The longest lived engines such as fixed RPM generator units run for years within a narrow RPM band at a constant power output, very similar to what our slow speed trawlers could be doing.
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Old 12-10-2014, 11:13 PM   #39
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When I bought my 6N140, I recall Brian (or reading somewhere) that ADC imported and registered a slew of engine block serial numbers. In this way they were able to get around the (then) new EPA requirements and still offer for sale their naturally aspirated engines. Plus, the 6N140 made sense as an affordable replacement for the thousands of FL120s out there in trawlerland.


Regarding this engine being "over powered" for under 40' displacement trawlers--I couldn't disagree more; Would you rather have a smaller engine running at 2200 rpm to make hull speed; or a larger engine capable of reaching hull speed at 1650 rpm? Besides, there is nothing like extra horsepower for running against a 3-knot current or having the "umph" to turn your bow into a 20 knot head wind. However, I do regret that ADC wasn't able to do with the 4 cylinder Super Lehman (rated@80hp) that they did so well with the old FL120.
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Old 12-11-2014, 05:09 AM   #40
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That's a great word, Peter. I think I'll start using it in conversation. It's right up there with one of my all-time favorite words that unfortunately I have little call to use, and that's "strategery."
You're welcome MarinÖfeel free. Just as long as you give me credit and don't attribute the word nucular to meÖthat I would object to. Actually, I like strategery, as it happens, (says Pete, fighting his laptop's attempts to correct the spelling), so I'll give you credit for that if I'm allowed to use it..?
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