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.