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Old 08-17-2012, 03:33 PM   #81
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Any other Lehman's out there with EGT's? If so, it would be interesting to know what you're running.
It is important to know where the temperature is taken if comparisons are to be made.
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Old 08-17-2012, 03:45 PM   #82
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Our EGT probes are mounted in the exhaust elbows just aft of the connection to the exhaust manifold and prior to the water injection point. Our EGT sensors and gauge are by ISSPRO.

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Old 08-21-2012, 11:02 AM   #83
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This summer the after cooler on one of our Perkins Sabres developed a leak allowing sea water into the induction air. I bypassed the after cooler and ran about 1000 miles with no ill effects on either EGT or a variety of engine temps as measured with an IR gun. On advice of the designer I limited max RPM to an EGT of 600 F or about 80% of full rated load equating to 2000 RPM. 2000 RPM I never hit anyway with normal cruise about 1750 RPM and 400 F EGT.

This issue caused me to once again visit the belief that unless a marine engine can achieve max rated RPM without over heating, something is amiss whether in engine health or prop size. For sure, one of the boxes to be checked when buying or selling is "Max rated RPM achieved OK?"

In my pre-retirement years, the last big diesels I bought were 4000 HP and rated for full RPM at 15,000 feet for a 30 minute climb out of an open pit. This is how the engine designers have built most diesels for decades if not 70+ years or more.

So my thoughts, run them hard now and then to assess engine well being. The next owner sure as heck will prior to finalizing a purchase decision.
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Old 08-21-2012, 11:38 AM   #84
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When I repowered I made a big deal of getting sea water off the engine completely. Never regretted it.
Wish you were down the street so we could swap sea stories Tom.
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Old 08-21-2012, 03:57 PM   #85
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Originally Posted by sunchaser View Post
This summer the after cooler on one of our Perkins Sabres developed a leak allowing sea water into the induction air. I bypassed the after cooler and ran about 1000 miles with no ill effects on either EGT or a variety of engine temps as measured with an IR gun.
___________________________________

Have you had any issues with the engine since leaking salt water through the air intake?

I had a dripping exhaust elbow joint over the air intake, 6.354 n/a, that went undetected for several weeks on a trip. After the joint was repaired, everything was fine for a while. Then we started hearing a slight compression hiss at idle. Thinking it was a head gasket, we pulled the head and found two of the hardened valve seats on the intake side had severe pitting.

Anyway something to watch for.
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Old 08-21-2012, 07:08 PM   #86
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Thanks Marin. That is one for sure.

So anyone with an FL120 should follow your advice.

It seems that it is going to be an as per engine.

The Cat dealer is of a mind that it is a good thing to do once in a while.

Any others?

SD
SD, we don't run up to WOT because we can achieve a nice hot EGT at around 1750 rpm, and while there may be a reason to put a greater load on the engine, I don't know what that reason would be. So we cruise around 1375 - 1400 rpm at 550 degrees EGT (out), which probably means around 700-750 degrees inlet temperature, and 775 to 800 degrees (out) and probably 1100 degrees inlet temperature at 1750 rpm. I get a little visible smoke when I first spool up (which I do every 4 hours or so for 15 minutes), but that dissipates to being almost invisible after 5 minutes or so of loading. I don't know if this is the best way to manage the engine, but it seems to match what most experts recommend.
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Old 08-21-2012, 07:47 PM   #87
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Talking to my local commerical guys, They refered me to a manual one of them had with the specs that the perkins should operate at 80% of max rated RPM during use. I know that all our military equipment " diesel " crank and after about 45 seconds runs up to almost WOT. Some times for 10 days at a time to provide power for the FOB's. they would fuel them and about every 10 days they would shut them down check coolant, Check the oil, Take a sample of the oil, Service it if hours were in range then fire them up again. i Never seen any of them fail running WOT one was at a FOB i worked at on two deployments so it had been there over 3 years doing its job. So i guess it's all in what the MFG says about the 80% range .
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Old 08-21-2012, 11:11 PM   #88
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honeybadger,
Are you sure they spec'ed 80% of rpm? That would seem a dangerous thing for them to do as many boats are'nt propped right. The load on an overpropped boat would likely be WAY overloaded at 80% rpm. Also 80% of rated rpm on a correctly propped boat is about 50% engine load. This is a very low load for a max continuous rating. A 37 Plymouth could probably do that.
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Old 08-22-2012, 12:43 AM   #89
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Don't forget that he makes a living selling engine parts.

A freshly washed car always seems to run a little better too.

Don't start rumors now.
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Old 08-22-2012, 01:05 AM   #90
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The Yanmar FAQ area on the web says this:
Q- What is the definition of a LDC (Light Duty Commercial) application?


A- Any engine used in a revenue producing, government service or rental use is considered a non-recreational craft application and is not covered by the Yanmar Recreational Limited Warranty policy. Rental use is defined as a vessel used for pleasure charter, typically sailboats, sailing catamarans, power catamarans and trawlers. For an engine to be considered for a Light Duty Commercial application it must fall within the following guidelines:

• Engine is operated at maximum output for less than 5% of total operation hours.
• Standard operation is at less than 90% of the maximum output RPM.
• Wide open throttle RPM’s, under load, must reach rated speed in any operating condition. post rpm is max 3000 max load ,Continuous rating rpm listed as 2900. So as i say Who knows ??
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Old 08-23-2012, 01:14 PM   #91
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the last big diesels I bought were 4000 HP and rated for full RPM at 15,000 feet for a 30 minute climb out of an open pit. This is how the engine designers have built most diesels for decades if not 70+ years or more.

These were industrial duty engines.

Many "trawlers" have lawn implement or converted taxi engines , a far far different base engine .

IF there is NO MFG 24/7 power rating , caution is the watchword

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Old 06-08-2018, 08:12 PM   #92
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I read this post 7 years ago when I came into possession of a 26 foot Groverbuilt with a 120 Lehman with 2500hours in it.

I put about 6k worth of parts into it including injectors, head gasket, exhaust manifold, injector lines (no rebuild on injector pump.)

I am religious on maintenance and follow every one in the manual. (Once you do it a half dozen times, you get quick at it)

The engine now has around 5k hours on it.

About 80% of that time has been at wide open throttle. I run it 2500 RPM for hours at at a time. (I make annual runs from NYC to Nantucket, fully loaded with my wife and three of her friends)

All I can say is that it runs like a sun of a bitch and it’s been 7 years of WOT.

Might not last until 10k, but she is gonna run at WOT until the day she dies. (And I will keep doing all the maintenance, on schedule, on her until then)

Just wanted to give an update. I decided to do this based on the continuous rating and the fact it’s naturally aspirated and I don’t have to worry about turbos etc....
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Old 06-08-2018, 08:17 PM   #93
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Greetings,
Welcome aboard speedy.


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Old 06-08-2018, 08:40 PM   #94
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I've had her at WOT one single time and she did 22kts. But she wasn't happy about it AT ALL. (51 year old 327f's)
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Old 06-08-2018, 08:50 PM   #95
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That should be interesting for those afraid to go over 1800rpm.
And even more so those that think higher rpm wears out engines fast.

Got to admit I would have thought the Lehman couldn't do that. But it shows that running properly loaded (prop wise) that running 1900 to 2200 should not be problematic.

Alisske are you sure you're tell'in the truth here? Sorry but 5000hrs at 2500rpm is really work'in that engine!
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Old 06-08-2018, 10:36 PM   #96
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Yes, lol. I’m being straight up honest. To be frank, I had a great paying job until a month or two ago. I enjoy working on the Lehman, and if it blew up, I had the dough to repower.

BUT, things changed recently and the dough dried up, so I started thinking about WOT again, lmao. (Hence googling wide open throttle)

I am going to dial it back to 2300 or something because of my finances. (Got a new job, but 3/4 the pay, so repowering the Groverbuilt needs to wait.

But I did ride that thing WOT for 2 hours today. (Thats when my current dilemma dawned on me)
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Old 06-08-2018, 10:37 PM   #97
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And I’m going to block island from NYC this year, not Nantucket. (Can’t get two weeks off with new gig)
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Old 06-09-2018, 05:34 AM   #98
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All diesels are NOT the same , sure they work in a similar fashion but the loads they can accept are not the same.


Big Detroits , Cats ,MTU and many others are industrial sourced and can function at WOT , full rated power and RPM on a continious basis.


Big truck engines are similar , just need a few hundred RPM pullback for all day service.


Car , light truck, taxi and farm implement sourced engines can only stand WOT , full power for a very short period of time.


The web site for your engine will usually have 4 power ratings , all are time factore


Should there be no rating , the engine is probably not industrial and WOT operation for a long pei would be avoided.od riod of time should be avoided.
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Old 06-09-2018, 07:57 AM   #99
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We have had the boat for fourteen years. While we use it year round, my work and other interests pretty much confine us to weekend or three-day trips except for one longer cruise a year. So the boat gets used a fair amount but not for a lot of hours. Most of our weekend trips are three to four hours out and the same amount back.

The engines do not run any differently today than they did fourteen years ago. There is a bit of blue smoke at startup, there is the typical sheen of unburned fuel out the exhaust whent the engines are cold, and that's it. They start as soon as the starter starts to turn them, they run smoothly throughout the rpm band we use, which is idle through an occasional 1800 rpm but mostly 1650. The one time we took them to WOT they did so without protest. The engine temps (coolant temps) are where they are suppose to be at 1650 rpm. We have EGTs and they are marked for the normal temperature at cruise and that's where they continue to indicate at cruise (about 600 degrees IIRC). We have never had to clean soot off the transom, swimstep, or swimstep-mounted dinghy.

The engines use no more oil today than they did fourteen years ago, which is less than one quart per engine every 100-150 hours which is our oil change interval.

All this isn't to say they both won't explode next week but so far the engines have not changed at all.
That fuel oil sheen on the water, is that something the USCG would see and become very upset and then fine a person for?

Years ago, a guy ran his diesels in the marina harbor for hours and filled the surface of the water with sheen and soot. Of course no official saw this, but at the time I was wondering if they would have considered it a violation of the clean water act.
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Old 06-09-2018, 09:49 AM   #100
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Originally Posted by Alisske View Post
I read this post 7 years ago when I came into possession of a 26 foot Groverbuilt with a 120 Lehman with 2500hours in it.

I put about 6k worth of parts into it including injectors, head gasket, exhaust manifold, injector lines (no rebuild on injector pump.)

I am religious on maintenance and follow every one in the manual. (Once you do it a half dozen times, you get quick at it)

The engine now has around 5k hours on it.

About 80% of that time has been at wide open throttle. I run it 2500 RPM for hours at at a time. (I make annual runs from NYC to Nantucket, fully loaded with my wife and three of her friends)

All I can say is that it runs like a sun of a bitch and it’s been 7 years of WOT.

Might not last until 10k, but she is gonna run at WOT until the day she dies. (And I will keep doing all the maintenance, on schedule, on her until then)

Just wanted to give an update. I decided to do this based on the continuous rating and the fact it’s naturally aspirated and I don’t have to worry about turbos etc....
What are your speeds at WOT compared to 2/3 and/or 3/4 throttle?
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