Questions for Bob Smith about Lehman 120's

[kolive]

I am finishing Bob Smiths Trawler Fest Diesel class today. Does anyone have a question or two they would like me to ask him today when/if I have time? We are disassembling and reassembling the Lehman 120 today.

We went thru a lot of information today and I went back to my boat and took a bunch of photos al around my engines to get a better idea of what is going on with them.

No guarantee I can get all questions asked, but I would be wiling to try. No doubt they are things I would most likely need to know as well.

 

[RT Firefly]

Greetings,
Mr. k. If you remember, ask Bob what the oil change interval on the injector pump is. At one point (Mystic Trawler Fest) he advised me the 50 hrs. was a misprint in the manual and the actual time frame was 100 hrs. Thanks

 

[Nomad Willy]

Ask him what is the maximum continuous rpm for a 120 Lehman propped to 2500rpm at WOT.

 

[kolive]

RT,

Yesterday he said there were three different intervals published in different manuals but this is what he does, monitor the oil for any diesel in the oil and change the oil at the same interval as the engine, around 100.

Eric, he did say the governor is set for max 2500 rpm at wot.

He showed a graph about rpm's and full load, 1/2 load and another setting. I did not get a copy of that but will see if I can get it later today.

 

[RT Firefly]

Greetings,
Mr. k. Thanks so much for the confirmation. I used to change pump oil at the 50 hr. mark but after what I'm sure Bob said in Mystic I switched to the 100 mark BUT since so many in another thread were adamant about 50 hrs. I started to second guess myself. 100 hrs. it is.
With a previous Lehman I did detect the odor of diesel when changing oil @ 50hrs but no evidence, thus far, in the current Lehmans even @ 100 hrs.

 

[Captain K]

My FL 120 manual suggests lube oil and filter change interval of 200 hours (page 24 in my copy). Does Bob recommend doing that at 100 hours instead, or did I misread your post #4? Thanks.

 

[Nomad Willy]

Keith I'm not talking about full "idle" speed.

I would assume one would assume WOT in gear. And I've heard the assume = u n me many times.

I wanna know how strong the Lehman guru thinks his favorite engine is.

 

[DavidM]

I remember Paul Foulston (admittedly a biased Cummins guy) saying on boatdiesel that the Lehman had a marginal cooling system and should never be run continuously at or near wot. My guess is that 2,000 rpm would be a safe number if propped to 2,500 at wot.

 

[kolive]

Captain K,

100 hours is what he recommended.

 

[kolive]

Eric,

Bob says, if everything is adjusted as it should be the motor should be able to be run at 2500. He told a story of running his Defever for 4 hours in storm conditions with. 26" prop and 2 1/2 to 1 tranny at 2450. He reiterated this is what it should be able to do if everything is checked out and adjusted as it should be. Not the average engine adjustment of the average boater. He feels it will run as rated when taken care of properly.

 

[kolive]

RT, in a discussion this afternoon. Bob said the oil change interval could go to 200 hours if you use the boat more on longer runs as opposed to short hops. He said you could go to 200 hours if you run it from 200-500 hours per year. Keep checking it for smell and lubricious. So it appears to be a little dependent on how you use the boat. Shorter runs equates to more frequent changes, longer use longer between change...to a limit.

 

[kolive]

Another oil tidbit from this afternoon. Bob said to not add oil until it is 1 to 1 1/2 quarts low. Basically develop a oil maintenance scheme developed by the habits of your particular engine, they all respond a little differently. Adding 1/2 quart low might result in burning oil, but actually waiting and adding at 1 to 1 1/2 quart low and finding the pattern of oil consumption would be better for the performance of the engine. Find out your engines habits and feed accordingly.

 

[RT Firefly]

Greetings,
Mr. k. Thanks for the information. Could be I'm overfilling my particular engines as they seem to be using a quart every 10-15 hrs. sometimes. Several marks on each of my dipsticks. Did the requisite full drain and add 12 quarts deal. Maybe I'm using the wrong mark.

 

[Nomad Willy]

Thanks for asking Keith and I'm not surprised he'd drop the ball. So he ran his at 2450 for 4 hrs. If there was/is no continuous rating I wonder why he didn't just say so.

Then he says "Basically develop a oil maintenance scheme developed by the habits of your particular engine, they all respond a little differently"
and
"Find out your engines habits and feed accordingly"

He sounds like he's talk'in about taking care of a bunch of barnyard animals or middle school kids.

Must be talk'in about the dipstick fiasco.

As I recall he did (some time ago) recommend the Lehman be propped to 2500rpm. Glad he was specific about that.

 

[motion30]

when I have 120 I did over fill it do to a faulty mark on the dipstick. I found it would just spit out the out the oil it did not want until level was acceptable

 

[Xsbank]

Motion30 that's exactly what happens and exactly what Bob means.

 

[kolive]

Eric,

Not sure what you mean by "not surprised he'd drop the ball on this one", but I do not feel like he dodged the question or issue at all. Was your question through me intended to do something else? Now I feel a bit set up and sorry I even asked. Sounds to me like you have something against Lehman's and Bob Smith. If so, that is your issue and not mine and I would prefer to be kept out of that argument. I asked the question for you in good faith and it seems like you did not like the answer. I found him to be straightforward, knowledgeable, experienced and very capable. He knew his stuff from experience. I prefer that over theory anytime.

Why don't you call him and talk with him yourself? He is easy to reach. I know he does not post on forums but is more than willing to talk with people about their particular issues. Heck, drive over to Trawler Fest and sit down with him on the docks and chat, he is here now. He is a no BS kind of guy.

 

[Larry M]

[QUOT]...Must be talk'in about the dipstick fiasco...[/QUOTE]

I hope this can be read. It is from our factory Ford Lehman manual. The last sentence addresses why the dipstick needs to be recalibrated. I'm not sure I'd call it a fiasco though. If nothing else, it's something boat builders should have addressed since they are installing the engine (s).

 

[kolive]

Larry, the different engine installations styles are exactly why the remarking is needed. He spoke to that point specifically. Thanks for the post.

 

[Nomad Willy]

Post # 3 Keith.

"Ask him what is the maximum continuous rpm for a 120 Lehman propped to 2500rpm at WOT."

Continuos output. Pretty straight fwd. That's ok it probably dosn't exist as the engine was first produced in the 50s and they may not have rated them for continuos output at that time. As far as I know all modern engines have a continuos rating that usually is a few hundred rpm less that maximum power.

No I'm not impressed w the Lehman but maybe other 60 year old engines are worse. If I had a 47 Chris Craft engine in my boat it may not have a continuous rating either.

Bob Smith obviously has a great bedside manor as everybody seems to like him. And I'm sure I'd like him too if I met him. And most of his comments that I've heard have been ok too.

Larry,
Lehman marketed the 380 Ford engine as modified by them for marine service. Most all marine engines destined to be prime movers operate at an incline as determined by the propeller shaft. Boats have various p shaft angles. How do other engine manufacturers account for that difference. Putting the dip stick in the middle of the engine fore and aft should accommodate most installations and variations. I've not heard of this problem on any other engine.
OK .. Call it a f##k up or oversight then.
Could be the norm and I'm just not aware of it. Should I question the oil level showing on my dipstick Larry? I have a 10 yr old Mitsubishi.

 

[kolive]

Eric, drive over and talk with him instead of making an assumption. I do not have your answer, but I'd be willing to bet you would get the answer if you talked directly with him.

I don't know what you have against Lehman's nor do I really care because they are the engines we happen to have and are pretty good engines from what little I have talked with people over the years. They are still in service in a few thousand boats so they must have something positive about them. I must admit I am curious though on how many years you had a boat or boats with Lehman's in it.

 

[kolive]

RT,

To clarify my last post about oil change could go to 200 hours. That was engine oil, not injector pump oil. Sorry for any confusion.

 

[nwboater]

Keith, did Bob discuss improvements made to later model Lehmans? (i.e. American Diesel Corp's N6-140). My understanding is the cooling system was improved (particularly concerning the #6 cylinder, which had been a weak link in overheating problems), also, the injectors I'm told have a greater "return flow through" for better cooling, and lastly, the air-intake is maintenance free. Personally, I like these engines for their economy, reliability, and overall ease of maintenance and availability of parts. What more could you ask for in a recreational power plant?

 

[jleonard]

I've not heard of this problem on any other engine.

Not to be argumentative but his is a common issue in marine installations.
It is discussed often on "boatdiesel". When I did my repower years ago with a new Cummins 6BTA, I went thru the dipstick calibration procedure.

 

[jleonard]

Personally, I like these engines for their economy, reliability, and overall ease of maintenance and availability of parts. What more could you ask for in a recreational power plant?

I started off not liking the Lehman, but it seems to be growing on me. Their downside is the injection pump because it is intolerant of any air in the fuel, plus those oil changes are a PIA in my opinion, however I have now changed to a 100 hour schedule (was 50 per the manual) and that's tolerable.

Bob Smith is very old school, sometimes his attitude is a little tough, but he sure knows his Lehmans and I respect that. I suppose if I had to answer the same questions for 50 years I'd have a tough attitude as well.

 

[kolive]

North Star,

Richard,he did not discuss any of the American Marine engines. He focused on the 120 & 135's. Feeling pretty comfortable about adjusting valves right now. A few of us are going to get together and help each other do our boats. Rob from Saga will join us, he took the class as well.

With Rob's help we noticed that my oil hoses are in backwards. They currently go from the block to the cooler and then to the filter. It should be the opposite, block to filter then cooler. Plus they are the High pressure lines with a smaller I.D. So I will be replacing those along with the breather tube on the valve cover. I currently have the copper tube like Rob had when it fell off and killed his engine. Simple fix, replace with hose!

I learned a lot and had a great time with everyone in the class.

 

[motion30]

North Star,

Richard,he did not discuss any of the American Marine engines. He focused on the 120 & 135's. Feeling pretty comfortable about adjusting valves right now. A few of us are going to get together and help each other do our boats. Rob from Saga will join us, he took the class as well.

With Rob's help we noticed that my oil hoses are in backwards. They currently go from the block to the cooler and then to the filter. It should be the opposite, block to filter then cooler. Plus they are the High pressure lines with a smaller I.D. So I will be replacing those along with the breather tube on the valve cover. I currently have the copper tube like Rob had when it fell off and killed his engine. Simple fix, replace with hose!

I learned a lot and had a great time with everyone in the class.

when I change the oil hoses to the larger diameter I picked up 10 pounds of oil pressure. I never would have thought that was the case

 

[kolive]

Motion 30,

That is exactly what Bob said would happen, an increase in oil pressure. Easy enough to do and reasonably priced from American Diesel too.

 

[Nomad Willy]

Keith we actually drove by there today. Went to Mary Ann's Kitchen for lunch. Wanted to use the marina rest room and then saw all the tents. Went elsewhere. I've been to Trawler Fests and a lot of boat shows but at this point I'd rather work on my own boat.

How many Lehmans have I had? And I suppose you'd tell me I don't know anything about children if I hadn't had any .. right? None of either but Wash state and the providence of BC thought I knew enough to teach high school.

I had a Sabre 120 that used the same base engine as the Lehman. It was reported to be blueprinted and I liked the engine. That was before I got on TF so at the time I knew little about them. The Lehman reminds me of the Buick straight eight except the Buicks were smooth and quiet. There's a lot of old Lehmans around the trawler world but the fact that many survived may be a tribute to their durability. More likely though it's that most all trawlers got the Lehman engine and replacing them is difficult now for people that can only afford an old boat. I saw one (Lehman) the other day at Harbor Marine priced at $15,000 ($13 w core). If it was me I'd buy an Iveco or some other new engine.

If I had a boat like yours Keith I'd be very keen on taking very good care of the engines too. I had an old Perkins and replaced it w a new Mitsubishi. I think the wonderful thing about the Lehmans is that they can run on for years and years given decent care. And a lot of trawler guys have Lehmans and good maintance costs little? So by that yardstick ther'e great. But as an engine among engines I think they are just average.

Bob Smith now he certainly is'nt average. Way above as evidenced by his strong following.

 

[kolive]

Eric,

Too bad you did not stop and try to find Bob. He is an interesting guy that I think you'd have great conversations with. My question on how many Lehman's you had owned was purely based on what you might have experienced with them. Nothing to do with children or teaching. Bob talked some about the Sabre engines too, but I really did not know them so I did not really tune into that discussion much. I do not have enough experience myself to judge one engine over another and the thought of repowering with twins is out of the question for us. I walked down the docks there this morning and had no interest in going aboard the boats for the reason you mentioned, I have a boat I like and am enjoying working on it. But I will confess that only two boats caught my eye, a Bill Garden boat and an Alaskan 46. I went aboard the Alaskan and it was beautiful. They spent a huge amount of money and the boat shows wonderfully. They even actually use it 4 months out of the year which was nice to hear. Both boats I liked were actually wood boats. Classic lines and character.