Lehman 120 seized - where should I spend my next 10-20k?

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Ski in NC said:
If engine was running fine the last time you shut it down, I doubt it was a dropped valve or damper plate issue. Those tend to be noticed when engine is running.

If it won't move in either direction, I suspect coolant weeped into a cylinder and has the piston stuck. Sort of supported by the stuck valve.

I don't think the stuck valve has the whole engine stuck. Usually starter has enough grunt that a stuck valve will bend a pushrod or engine will still turn the other way.

Can also drain a qt of oil out of bottom of sump and see if there is any coolant present. If it got into a cylinder, some will drip past ring gaps. Only works if sump drain fitting is on the true bottom of the pan.

Since you already have the injectors out, try fishing a skinny poly tube down the injector hole and when it hits piston (actually might go in piston bowl), suck on it and see if you find coolant.

Can also get one of those cheap borescopes that plug into a phone. A skinny one can be fished into the injector hole.

Depending on what you find, I'm thinking pulling the head is likely.
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Yep - I think your on to it Ski. Can you tell from the pick if maybe the valve is sitting on the seat (as in not stuck) and has a bent push rod?. I suspect that you would have to compare it with another valve with clearance or spin the push rod. Either way I suppose it doesn’t help any with the diagnosis. Time to lift the lid and solve the mystery. I agree with you - most likely stuck piston.
 
Also, a diesel won't get a "stuck" valve when running. Piston comes very close to the valve even when valve is closed. If valve tries to stick open, piston will hit it and force it closed, or break something. With head off, often see wear patterns on piston tops from contact with valves. Can come from sticky guides but also errors in valve lash (too tight) or improper head machining (deck machined without recessing valve seats).

That stuck valve could also be from water somehow backing up the exhaust.

To the OP, try the stuff I suggested in that quoted thread above.
 
Warfdog I overheated my 120 but just ended up with piston slap in #6 Hopefully when you get the head off you can inspect all the holes and with the help of other members come up with a game plan. Get that head off first it’s heavy make sure you have help lifting it and keep us posted. I also would like to thank all the members who help me out with my 120
 
kchace said:
RT I was reading this and thinking to myself “of course I can hear what MY engines are doing” but then I got to the part about 300 monkeys shaking cans of marbles up and down and I think you’re onto something. That’s exactly what they sound like!

Ken
Click to expand...

What if one of the monkeys had a lisp? Could you hear it? We were maneuvering at low speed using the lower helm when with my one good ear I heard a slight whisp, whisp sound coming from the ER. I asked my near deaf mate if she heard it, no. By alternately advancing the throttle I determined it was coming from the port FL120. Examining the engine after shutdown revealed a drip of coolant on the bottom of the flywheel. Tracing that back upwards revealed a leak around the base of the coolant fill neck on the reservoir when the engine was running. It dried up with latent heat at shutdown making it invisible. Ground the area and applied MarineTex to solve it. No more annoying lisping monkey! Just another reason I liked to run the boat from the lower helm.
 
Busterbrown said:
Warfdog I overheated my 120 but just ended up with piston slap in #6 Hopefully when you get the head off you can inspect all the holes and with the help of other members come up with a game plan. Get that head off first it’s heavy make sure you have help lifting it and keep us posted. I also would like to thank all the members who help me out with my 120
Click to expand...

Solving my piston slap involved reboring the engine. Yours?
 
Ski in NC said:
If engine was running fine the last time you shut it down, I doubt it was a dropped valve or damper plate issue. Those tend to be noticed when engine is running.

If it won't move in either direction, I suspect coolant weeped into a cylinder and has the piston stuck. Sort of supported by the stuck valve.

I don't think the stuck valve has the whole engine stuck. Usually starter has enough grunt that a stuck valve will bend a pushrod or engine will still turn the other way.

Can also drain a qt of oil out of bottom of sump and see if there is any coolant present. If it got into a cylinder, some will drip past ring gaps. Only works if sump drain fitting is on the true bottom of the pan.

Since you already have the injectors out, try fishing a skinny poly tube down the injector hole and when it hits piston (actually might go in piston bowl), suck on it and see if you find coolant.

Can also get one of those cheap borescopes that plug into a phone. A skinny one can be fished into the injector hole.

Depending on what you find, I'm thinking pulling the head is likely.
Click to expand...
Your doubt is very authoritative and also very naive.
If you are wrong what does it matter to you, the OP spends his money.
Just because you doubt it does not make it so.

In my case, after a five hour run engines were allowed to idle to cool down, . Left with the yard for some work.
NEXT start it would not turn over for the yard. They barred both directions and concluded time to remove the head.
IT WAS THE DAMPER! Do the easier, cheaper work first.
 
Fair enough. It certainly can be the damper.
 
Greetings,
Mr. SV. I’m thinking that Mr. Ski’s “doubt” is based on HIS experience. Yours is a one shot occurrence. Just sayin.
 
RT Firefly said:
Greetings,
Mr. SV. I’m thinking that Mr. Ski’s “doubt” is based on HIS experience. Yours is a one shot occurrence. Just sayin.
Click to expand...
AND how I came to the conclusion was through this very TF forum doing searches on the issue and finding Brian at AM being quoted saying the damper is most often the cause. DUH.
 
Occam's Razor would predict that the two quite different failure modes are the
result of a common cause. As said before, the damper cannot cause a stuck valve.
 
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KnotYet said:
Occam's Razor would predict that the two quite different failure modes are the
result of a common cause. As said before, the damper cannot cause a stuck valve.
Click to expand...

and I agree with you.
Maybe I missed it, has the OP removed the valve train to find the valve stuck open.
 
Seems highly unlikely a damper plate would cause a stuck valve, unless a piece of the shrapnel worked its way through the air filter and got stuck under the valve...
 
KnotYet said:
In the original post he has an image of the offending valve with about .100 open lash.
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OK, I looked again at post 1 and see that picture showing what you are saying.
I admit I do not recall seeing that gap before. I will STFU now
 
OP here - let's all be courteous to each other out here. :flowers:

The stuck valve on #6 requires that the head come off no matter what is seizing the motor. It's not just open (about .20"- enough lash to remove the seated push rod) but it will not move.

All the other valves can easily be moved up and down with a gentle bar on the top of the spring with a long screwdriver. The stuck valve is solidly frozen. I didn't want to force it to see if it would loosen up but it is probably bent or seized in the guide. I'll check the push rod to see if it is bent but that is secondary for now.

If we are rigging up a lift to take the head out I will definitely be putting in a new damper in - so we shall see. Stay tuned I'll update this thread with a report when we get the head off in a few days... Waiting on a mechanic.
 
warfdog said:
OP here - let's all be courteous to each other out here. :flowers:

The stuck valve on #6 requires that the head come off no matter what is seizing the motor. It's not just open (about .20"- enough lash to remove the seated push rod) but it will not move.

All the other valves can easily be moved up and down with a gentle bar on the top of the spring with a long screwdriver. The stuck valve is solidly frozen. I didn't want to force it to see if it would loosen up but it is probably bent or seized in the guide. I'll check the push rod to see if it is bent but that is secondary for now.

If we are rigging up a lift to take the head out I will definitely be putting in a new damper in - so we shall see. Stay tuned I'll update this thread with a report when we get the head off in a few days... Waiting on a mechanic.
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Agree that if the valve is stuck open, the piston has maybe hit it and bent the stem. The head should come off and maybe that is all it is. If you had a way to try to turn it backwards, it should turn a little and that would prove it is valve piston interference. Maybe through the starter hole with a bar. If it turns a little backwards then not seized and go for the valve change. Don't turn it more than a few degrees. I don't see the damper falling apart while it was stored, running yes, stored no.
 
I'm curious. Aside from the engine issue, how are you going to fix the rotted stringer problem?
 
keep us posted

Warfdog,

you really have us going on this mystery. I am betting my nickel that your frozen engine has something to do with not starting it for 12 months and coolant leak producing rust in the cylinders and valve guides.

we have a boat down the street from you at he Redwood City Municipal marina.
who is your mechanic??

and let us know what you find.
 
This is a very interesting discussion but when I told my wife about it she didn't share my enthusiasm. I just don't get women. So my question is, why did Brian at ADC think #6 cylinder was in jeopardy and not any of the others? That's a key point that I don't understand.
 
Do mechanics/machine shops still perform an operation called “knerling”. This operation is/was done on pistons. Especially the piston skirt (lower) where large sideways forces are applied to the cylinder wall. The resulting ridges could aid oil retention and distribution on the piston.

Obviously not as effective as boring but much cheaper and easier to do. The piston is rotated on a lathe or lathe-like machine. They apply a tool that may have been a roller and it causes ridges to be formed on the sides of the pistons in a cross hatch pattern.

It was (to be sure) a kick the can down the road move. Burning oil and smoking exhaust was common in the day and knerling kicked the can well down the road. So if it’s still being done and one can remove the pistons w the engine in place (or slightly lifted) many old FL’s could be given a new lease on life.
 
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‘Stuck’ valve

I’d expect that at any point an engine stops at least one valve would be open: since you can’t move the crank how can you be sure the valve is ‘stuck’ vs. simply open by virtue of the camshaft position?


warfdog said:
Hello lehman experts,

I've been working hard on Voyager over the last year to rewire and refinish the interior, but at a slow pace as I have little time. As a result I have not taken the time to run the engine/transmission since a 50km relocating cruize 12 months ago.

I have great hopes for this great old boat...and now the engine is seized, the tanks are rusty, the engine stringer are rotten, the hull has blisters, the batteries need replacing, a windshield is cracked, the teak decks leak..I still love the boat.

Last year, on the most recent cruise, it ran well but tended to run hot between 200-220 indicated. Later, Brian at American Marine warned me that running it that hot would likely do havoc on #6. I thought 'good to know' and hope it didn't do any harm yet and that gauges were off.

Now, to my surprise this seems to have already turned into the worst case. I can NOT even bar it over one-degree by hand standing on a cheater bar, I verified the starter is kicking out a ton of torque and engaging/disengaging, but nothing can move the crank at all. It looks totally internally seized.

Fearing hydro-locking I pulled all of the injectors, but there is no sign of water in any cylinders. Oil was just changed before that last trip and it's still clean and clear. All of the valves move freely by hand except for the #6 exhaust valve which is frozen in an open position pic below.

Engine hours are less than 3,000 and the engine wasn't smoking or making any unusual noise. Given the weight of the head and my limited experience on the Lehman, I'm planning to have a mechanic come out and look at it. I don't think it's the damper. But I would love to see if anyone has ideas on what I did to it and how to utilize the mechanic. I'm willing to throw money at it but need to figure out where to start. :banghead:

Did #6 break off and drop a valve? Can a borescope see that through the injector port? Any chance when it overheated did I just melt piston #6 to the sleeve? Can a repair be done onboard or should I have it towed to a yard where the engine can be pulled? Should I have a mechanic pull the head where it is to inspect, or is it inevitable that the engine needs to come out to repair?

I know the answer lies in having an assessment from a qualified mechanic, but don't we all like to speculate where I should spend some boat bucks?

Figuring out next steps since I have to move the boat one way or another for dredging that is starting in about a week. I can haul it over to the guest dock and have a mechanic look at it, or I can have Sea Tow take it straight to a boatyard and pull the whole engine out for repair, rebuild or repower?

Thx,

Captain Warfdog
Westpoint Harbor
San Francisco Bay
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McDan said:
I’d expect that at any point an engine stops at least one valve would be open: since you can’t move the crank how can you be sure the valve is ‘stuck’ vs. simply open by virtue of the camshaft position?
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In the original post/photo, the valve is hanging open and not touching the rocker tip.
 
Albin said:
This is a very interesting discussion but when I told my wife about it she didn't share my enthusiasm. I just don't get women. So my question is, why did Brian at ADC think #6 cylinder was in jeopardy and not any of the others? That's a key point that I don't understand.
Click to expand...

#6 exhaust valve was frozen
 
GT6 said:
I'm curious. Aside from the engine issue, how are you going to fix the rotted stringer problem?
Click to expand...

TBD - probably lift the engine a few inches and refill the stringer under the engine with either a) coosa/marine-ply and thickened epoxy or b) sea-cast. I'm leaning toward sea-cast. Then cap with a strong fiberglass layup (either polyester or epoxy resin mix).

The whole area of compromised stringer(s) is very accessible and is only a portion of the overall stringer matrix.
 
Got the head and manifold off today. Signs of water intrusion in #6 and overheating in #4-5-6. After cleaning it up and soaking with penetrating oil I'll see if it can be moved without breaking something. Then I'll be able to see if the cylinder is damaged.

Hoping to be able to hone #6 and get everything unstuck and cleaned up. One picture for now. More after the weekend.

Any one know about a source for exhaust/intake manifolds for the 2715e? I heard somewhere that there was an improved aftermarket one available.
 

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Please let us know the outcome when head is off. There is something (probably corrosion) holding that valve down/open against the considerable push that the valve springs are giving trying to close it. Whatever did that (likely rust) has also likely rusted the cylinder wall and frozen the piston in the cylinder.
 
Albin said:
This is a very interesting discussion but when I told my wife about it she didn't share my enthusiasm. I just don't get women. So my question is, why did Brian at ADC think #6 cylinder was in jeopardy and not any of the others? That's a key point that I don't understand.
Click to expand...
Post 3 above may help.
 
sea water damge

Is the manifold higher than the exhaust /sea level, my Lehman got water in the sump and was pumped through the main bearings and when that dried out with engine heat, it grabbed the bearings and the motor wouldn't tun over until I removed the last main bearing. There was no engine damage as the water only circulated with the engine idling and not under load but I changed the bearings anyway
Have you check the sump for water at the bottom ?. If, like my motor, the water went in with out a long run, it will not have emulsified and also will not show on the dip stick as it will be at the bottom of the sump.

I had to modify the exhaust system so that it was impossible for it to happen againIMG_4359.jpgIMG_4361.jpg
 

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Steve Marcus,
I see no provision to control engine vibration in the loop.
Is the FL smoother than I think? I would like to see some bellows-like flex pipe in the vertical part closest to the exhaust man.
But maybe I missed your flex feature.
 
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