New Lehman in our Defever 41

[ralphyost]

I havent been around posting here for a while but wanted to share with you pictures of replacing the Lehman 120 in our Defever 41 2 years ago.
Here is the old engine: found antifreeze in the cylinder.
OldEngine

And here is the new engine:
NewEngineApr1,2011

Now have only 800 hrs on her after doing 2/3 of the Great Loop.
But we have the boat up for sale this year as we are cruising north from Florida. Will probably head to Chesapeake Bay, Atlantic City, then perhaps New England.
Say Goodbye FOR SALE

 

[DavidM]

Ralph:

It looks like you repowered your Lehman with a long block. What did you do about all of the add on marine and non marine parts (whch might have been the source of the antifreeze in the cylinders)?

David

 

[ralphyost]

antifreeze in the cyl

We determined that there was severe scoring in the cyl walls. Suspect that antifreeze was coming in through the cyl. walls.
During late summer I noticed the AF overflow bottle level was down a but. Refilled it. Month later same thing. Hmm...where is this going? Hauled out in October. Removed the injector pump and injectors for rebuild while the boat is on the hard. Came back three weeks later and cyl 1 had AF up over the hole in the head where the injector goes....all occurring within 3 weeks. In order to remove the fuel inj. pump you have to align the engine which places cyl 1 at the top.
ALso had "block slag" which was mud accumulating in the AF overflow bottle.
We removed the head, hoping to find a breach in the head gasket, but it was fine. Then we saw the scoring in cyl 1. Also determined that someone else had the engine apart before....missing washers, etc.
I lost confidence in the old block between the AF leak and the block slag, I didnt think it was worth rebuilding.
So I opted for a long block which was faster and probably cheaper in the long run. I removed all the bolt on stuff: electrical, hoses, complete fuel system, water pumps, heat exchanger, etc. Hire a very good mechanic to do the removal and replacement as he had the lift. I prepped the inside of the boat for him and we worked together. Replaced the motor mounts while we were at it. I came back and put all the bolt on stuff back on. So I did most of the labor, saving me thousands in labor costs, and got to the end of the project faster because I could devote more time to it than the mechanic could.
So now I have a very nice old boat with new power in her ! Only 800 hrs on it right now.
R.

 

[FF]

Only 800 hrs on it right now.

And ALL the post install / break in checks have been done?

Torque head , adjust valves , inspect hoses , re check alingment , snug engine mounts and what ever da book sez?

Remember the antifreeze leak was probably caused by not changing the antifreez or a loose cylinder head.All PM.

 

[ralphyost]

All maint is done

Yes, all the post install maint was properly done BY THE BOOK (or by Da Book) as you say !
Did a strict engine break in period.

Previous engine was owned by several owners before me and had been taken apart before. I found other evidence of an unknowledgeable person work. The didnt know how to put the bleed off tube on correctly. In doing so, they cross threaded the bolt through the bleed off tube into the top of the injector. DUh! They also obviously didnt know you are supposed to air pressure test the bleed off tube after installation to ensure it is sealed. The lack of seal meant that bleed off diesel was leaking into the engine lube oil, diluting it. The good news is that the Lehman 120 has a very low bleed off - 1/2 pt in 10 hrs. Still, it was a bad installation before me.
Remember - this is my OLD engine that has been replaced . See the URLs below for the pictures of the crooked bolt into the top of the injectors.

Cross threaded bleed off bolt 1
Cross threaded bleed off bolt 2
Top view of bleed off tube

Of course when I reassembled the new engine, I did the air pressure test and verified that the bleed off WAS installed correctly by measuring no pressure loss.
Also found that the injectors were set to the wrong opening pressure...by about half. That effectively changes the timing of the combustion by making it mist the diesel early. The amazing thing was when operating the engine, you couldnt tell any of this. Sounded good, started right up, ran good, and did the full throttle test well also.
If you start at the beginning of that album and look at all the pictures, you will see how badly the injectors were burnt and covered in oil.

 

[Brooksie]

Lovely looking installation, nice to have something new in ones bilge.
With all due respect to you and your mechanic, I agree with David that the likely cause of the coolant in a cylinder is not one of the longblock parts if not the head gasket. Cylinder scoring would never be a cause of coolant ingestion & your cylinders were hardly worn.
So I have to ask also if the exhaust manifold, end cap, & elbow were pressure tested as a unit, assuming FW cooled ? Was the cyl. head crack checked and checked for flatness along with the top of the block.

 

[ralphyost]

Cyl head was removed and checked out OK. Head gasket was in tact so that was not the problem. The scoring in the cyl was deep enough that you could catch your finger nail on it. The pictures dont do justice to the real visual inspection and condition.
The head bolt threads were rolled indicating improper torque technique.
The engine is a parent bore engine which does not use sleeves.

We did not spend a lot of time on forensics of the engine. We concluded that it needed to be rebuilt internally, but I did not have confidence in continuing use of that block when I considered the block slag (very fine rust) that was accumulating in the overflow bottle.
When we removed the exh manifold, it was in very good condition. We did clean it up before reinstallation and I used new gaskets.

My theory is that the lube oil was thinned by the leaking diesel fuel from the improper bleed off tube connection, which led to improper lubrication in the cyl. walls. The resulting antifreeze leak was from tiny holes in the cyl. walls that occurred while the engine was at rest.
R.

 

[Brooksie]

Sounds like you have covered all bases. The leaking injector connection into the engine oil, and all the extra connections necessary to put the injectors under the valve cover seem an unnecessary pita on this engine.
Good luck

 

[ralphyost]

Its all a trade off

Life is a trade off. Boats are a good example of that. And although the bleed off tube is a quirk, I really love the simplicity of the Lehman 120. Its a very easy engine to maintain and there are lots of smart folks around who can help if one needs it.
The good news for me is that I took Bob Smith's engine class and learnd about the few quirks that exist on this engine. Thats how I knew about the bleed off tube pressure test.
Here are pictures of the class. About halfway down is the pressure testing of the bleed off tube
Bob Smith's Engine Class
The class is held at TrawlerFests around the country. I thought it was expensive but I got my money back for the things I learned that allowed me to do the labor on this engine instead of paying a mechanic. It also allowed me to maintain the engine better than if I had not taken the class.

 

[FF]

The lack of seal meant that bleed off diesel was leaking into the engine lube oil, diluting it. The good news is that the Lehman 120 has a very low bleed off - 1/2 pt in 10 hrs. Still, it was a bad installation before me.

This should have been found with the first oil sample sent to a lab.

 

[ralphyost]

Agreed! But it wasnt. All the oil samples from the old engine are "acceptable".
R.

 

[FF]

All the oil samples from the old engine are "acceptable".


Be sure to select a DIFFERENT lab for the new engine.

 

[ralphyost]

Great Loop 2012 Trent Severn Waterway & Georgian Bay

The new engine in action -

https://picasaweb.google.com/1173918...51367172655234

https://picasaweb.google.com/1173918...51466227466386

https://picasaweb.google.com/117391835980828093465/GreatLoop2012TrentSevernWaterwayGeorgianBay#589375 1168629728802

 

[Nomad Willy]

I don't need to go to school to keep my Mitsubishi engine running.

But many do like this old engine and spend much money on them. Having to change oil in the fuel injector as well as the engine is much like having to change the points in your car engine every 10k miles. Puts a dent in the "easy to maintain" theory and the fact that more oil changes are specified than for newer engines makes maintenance not only more time consuming but more expensive too.

I personally don't mind maintenance like oil changing oil but w twin Fords it's a seven gallon affair.

But simple is good. My Mitsu is 7 years old now and is no more complicated than the Ford as far as I know except for thin wall casting techniques and probably better metallurgy in the crankshaft and other hard to notice modern improvements. Oh yes the valve cover is cast aluminum instead of stamped sheet metal.

But it's a known fact that the Fords do last quite a long time.

 

[ralphyost]

Its all a trade off

All boats have trade-offs. I agree (who wouldnt?!) that for the Ford Lehman 120, changing the fuel injection pump oil every 50-100 hrs is a real downer. But I really do love the simplicity of the rest of the engine. And I like the fact that something like 30,000-40,000 of them were sold. My guess is its the most popular engine in trawlers of the late 70's and all of the 80's. (I include the Lehmn 135 which replaced the 120 in 1986). They are known to last for 20,000 hours.

American Diesel Corp in Kilmarnock VA provides any part you need for it at a very reasonable price. And you can call them and get real engine repair advice FOR FREE......and/or you can email Bob Smith personally for the same.
That was part of my calculation when I was trawler shopping in 2007 and made it my preferred engine.