Ford Lehman 120 Bad cylinder

[Xsbank]

Why did those bearings fail? Have you had the pistons out? Did they seize? It looks like at some time in the past this engine was run out of oil or the oil failed, perhaps it was never changed enough? Anyway, the name I gave you rebuilds Lehmans and sells all the parts too. Also, there is a builder here who blueprints Lehmans when he rebuilds them, if you would like an even better engine than new.

 

[RT Firefly]

 

[Ski in NC]

There should be oil holes in each rod journal. If not visible it might be clogged up with melted metal. Oil holes go through to an adjacent main journal where oil is supplied.

Also, journals might have gotten hot enough to screw up the original heat treatment. I'd be hesitant in grinding and reusing that crank. Talk to AD.

Need to find out why you lost oil pressure. Did you have a functioning oil pressure alarm? Did it sound?

 

[mplangley]

There should be oil holes in each rod journal. If not visible it might be clogged up with melted metal. Oil holes go through to an adjacent main journal where oil is supplied.

Well you were exactly right Ski in NC. The holes got clogged up with melted metal. I put a long rod diagonally from the adjacent main journal and tapped gentle and out came a molten plug.

But now I am wondering if the "scoring" i see on the journal is actually the smeared molten metal from the bearing which has formed a thin layer over the journal and who knows if the journal itself is scored at all. Wouldnt the bearing be a substantially softer metal in the first place? Also the scoring color. bright silvery, seems more like the color of the bearing than of the journal itself . The other thing is, I took out a set of vernier calipers and measured each journal. The two "scored" journals do in fact appear greater in diameter. If this is true it might indicate this same thing, namely that what we are seeing is layer of melted bearing material.

Anyway I'll put a call into AD in the morning and see what they say.

 

[alfamike]

Engine internal failures - More issues will be found !

-- Important considerations:

When you have engine internal failures like you have experienced there is a tremendous amount of small metal bits caused by this issue & are now spread through the entire engine & it can damage other parts of the engine.

Every oil galley, every oil passage in the cam & crank, every where oil goes now has the metal contamination. For example, Cam & lifters can be damaged as well, cylinders can be scored, etc.. list goes on.

This metal contaminating that is now all through your engine block & head MUST be 100% removed & cleaned.
That usually means you hot tank the block & that also means replacing all welch plugs, all seals, all gaskets, and don't forget cam bearings, etc., etc. - the list goes on.

Also when a bearing seizes like this the side loads on connecting rods & main webbing of the block, crank shaft, etc. get a huge amount of stress on them. So checks of the straightness & conditions of the rods & crank needs close scrutiny. Sometimes the bearings can even spin in the mains webbing & big end of the rods -- all causing more & different additional damage.

May need complete rod reconditioning or even replacement of connecting rods - pistons need checking too. Also don't forget, Align hone block as a minimum is usually needed on mains where the crank shaft rides.
I have seen cams & lifters & rods & pistons & bushings & bearings all damaged in some way or at some level as well from this type of issue.

Your Crank passages also will have all kinds of mental contamination in them. Oil Pump will have some damage. Crankshaft Will have to be machined as a minimum. Damage to Heat treating of crankshaft could be a big issue. And that is just a start to other possible issues.

NOTE: Heed this warning -- SKI in NC and jleonard are both absolutely correct in what they said regarding the crank as well.

I ask the rest of the knowledgeable engine guys here in TF - Would you agree ? -- that the metal contamination should be completely & thoroughly cleaned out ?

IMHO - If you don't get it all cleaned out 100% - then you will have future issues.

as Xsbank has also said -- So you have had this failure - but still do not know the root cause of failure ? There are more issues to be found.

It is not normal for an engine to have this type of issue.
It is caused by something as of yet not found.

Deeper & possibly more expensive issues are yet to be found that will also need repairs. If that is not found & corrected - the issue will repeat it self.

Do not get stuck in this money pit damaged engine trying to fix it again. It was tried previously & happened again. Not a good omen !

So what do you do ?

Listen to BruceK his recommendation is on target & the best way to go.

As always I am local to you & happy to assist in any way possible if I can.

Good Luck.

Alfa Mike

 

[SoWhat]

Why did those bearings fail? Have you had the pistons out? Did they seize? It looks like at some time in the past this engine was run out of oil or the oil failed, perhaps it was never changed enough? Anyway, the name I gave you rebuilds Lehmans and sells all the parts too. Also, there is a builder here who blueprints Lehmans when he rebuilds them, if you would like an even better engine than new.

Original mechanic diagnosed excessive blow by. This could dilute oil to the point it was no longer lubricating. Could have been a result of worn rings or running engine a long time at idle resulting in cool combustion chamber thus poorly seated rings.

Either way, pistons should come out and at a minimum light hone to the walls and new rings. Crank looks like toast. Bomac should be able to source a used one for you.

 

[High Wire]

This engine has come a long way from the original dead cylinder issue.
Curious what type lube oil you use.

 

[Larry M]

What are your plans now? With what looks like some pretty serious damage to internal parts, are you going to rebuild or repower? Swapping out your core and parts for a warrentied rebuild maybe an easy way out. Just asking.

 

[Bob Cofer]

I have the engine Bob Smith used for his Trawler Fest engine classes sitting in my garage. Send me a pm if you’re interested.

 

[Xsbank]

Boy THAT engine was very well looked after. He sure put on some great lectures at Roche Harbour. The highlight of the Rendezvous (well, maybe the wine and dinner...hmmm) was hearing Bob talk Lehmans. What an enthusiast.

 

[Bob Cofer]

He was quite a character.

 

[mplangley]

Boy THAT engine was very well looked after. He sure put on some great lectures at Roche Harbour. The highlight of the Rendezvous (well, maybe the wine and dinner...hmmm) was hearing Bob talk Lehmans. What an enthusiast.

I wonder if anyone made recordings?

 

[jleonard]

If it were mine, I would not bother trying to rebuild this engine.
As alfamike pointed out there is too much possibility of contamination that will never be completely cleaned out.
Time for a complete repower.
Embrace it as a positive thing.

 

[Irish Rambler]

Loads of people offer great advice.
In our business we had a n/a Ford 6 cylinder driving a bulk powder blower, when it needed overhaul we fitted a main shaft for turbo diesel version of the engine as it was cintrided (specially hardened). The engine was still running when I retired.
Just my two cents to the discussion.

 

[sunchaser]

MP
Aside from the advice you've received, a new/rebuilt engine with a transferable warranty would go a long way in helping sell the boat. PM Larry on Hobo for details of his recent professional rebuild of his Lehman.

 

[Comodave]

I have adjusted that engine. It was a great seminar.

 

[mplangley]

So for what its worth I talked to both AD and Bomac marine about the crank.

Both assured me that these crankshafts can take a significant amount of grinding. Bomac in fact used rather colorful language when I referred to the specially hardened "heat treat zone" on the journal. He said "that is a crock of $h!%!" He said these cranks can be ground down to 60 under. I found this a bit ironic since I don't if that was a round about way implicitly confirming the existence of the heat treat zone that is actually fairly deep or for some other reason. Obviously there is some limit at 60 under.

Anyway I took my crank to the machine shop for an initial inspection and he said it journals appeared to be standard and perhaps were the original and never had been turned. The bearings also indicate standard (STD) so that may be a good thing in my case. I wonder if the crank was new 1800 hours ago when the engine was rebuilt.

Something else which Bomac talked about that seemed relevant is the fact that these are low RPM engines. "This is not a racing engine we are talking about. If it were we'd have a whole other set of concerns but its not....." so he said the heat and other stresses were much lower.

Of course as Alfamike pointed out there are many other things to think about. But I thought people would be curious as to what AD and Bomac had to say about the crank. AD carries bearings in increments down to .040.

 

[mplangley]

I asked about a new crank when we had our FL SP135 rebuilt. $2,500.

I got a quote for $2800. How is that for a few months inflation? "Has to be ordered from Europe". Thankfully it does not look like I'll need a new crank.

 

[Larry M]

I got a quote for $2800. How is that for a few months inflation? "Has to be ordered from Europe". Thankfully it does not look like I'll need a new crank.

The reason I looked at a new crank was I was warned that the rear seal may leak on a refurbished crank. Our SP135 has a 2 piece rope seal. After the rebuild it leaks. The leak is only while underway but a disapointment . Just a heads up if your rear seal is similar.

 

[Ski in NC]

If crank turned easy with main caps on and rod caps off, then it is not warped. A good thing. Have the machine shop go over it carefully.

I don't see any bluing from hot journal damage. Heck I don't see any bluing from heat treatment. Maybe that thing is not hardened at all. Most diesel cranks are heat treated at the journals and you see bluing in the area. And burn up a bearing and that can heat it past the bluing temp which is sorta a kiss of death.

I'm not too worried about the debris in the galleries. They can be opened up and cleaned, just need to be thorough and methodical.

Still don't know what the cause of the train wreck is. Looks like classic loss of oil pressure.

 

[mplangley]

If crank turned easy with main caps on and rod caps off, then it is not warped. ......
.

I could spin it easily so hopefully you are correct.

......

Still don't know what the cause of the train wreck is. Looks like classic loss of oil pressure

Afraid to go down that road too far for fear of finding owner neglect at the other end of it.

But actually, yesterday I measured the oil I drained from the engine before taking it out and it comes up to 10 quarts. This does not include some I had spilled into the engine pan and not including any that remained in the oil pan. I thought the capacity was 12. If that is the case I think then I was about a quart short. I don't know what the quality of the oil is though. Its possible as someone suggested above that diesel fuel worked through the rings and contaminated my oil so that what I think is 10-11 quarts of oil is actually 10-11 quarts of oil/diesel mix.

 

[BruceK]

A slight drift, rather than a fresh thread.
Brian Smith/American Diesel Corp now have an actively monitored general mailbox <lehmandiesel@gmail.com>.
Hopefully most TF Lehman aficionados are checking this thread

 

[SoWhat]

Its possible as someone suggested above that diesel fuel worked through the rings and contaminated my oil so that what I think is 10-11 quarts of oil is actually 10-11 quarts of oil/diesel mix.

If the oil is contaminated with diesel you should be able to smell it.

 

[jleonard]

I stand strongly by my comments regardless of what Bomac may feel.
Perhaps the Lehman crank has deeper heat treat that some others, but as an engineer I have lots of experience in heat treat.
And like I said, many Perkins cranks do not last after grind.

 

[Larry M]

A slight drift, rather than a fresh thread.
Brian Smith/American Diesel Corp now have an actively monitored general mailbox <lehmandiesel@gmail.com>.
Hopefully most TF Lehman aficionados are checking this thread

Thanks for posting that. I’m glad Brian/Ameican Diesel are staying in the game. The amount of time that is spent on the phone vs what they sell in parts, the margins have to be pretty tight.

 

[FF]

If the oil is contaminated with diesel you should be able to smell it.

Perhaps , but if the diesel fuel load is minor simply placing a couple of drops (usually from the dip stick) on a paper towel will show.

IF the oil spot grows rapidly and clear , it may be fuel in the oil.

Do it sometime to see how normal lube oil grows on a paper towel.

 

[C lectric]

An oil sample sent to a lab would also answer the question about fuel contamination/dilution and to what % which may help sort out the cause. $35 approx.

Diesel fuels do not have the strong odour they used to have. That odour used to be almost unmistakable, not so any more once the sulphur was reduce to its current low level.

 

[Gmarr]

this is a good one and why I like TF!

 

[Ski in NC]

MP- being a couple quarts low should not cause any problem. Most of these engines can run low on oil and pump suction stays way below oil level and all is fine.

Oil dilution is a possibility. Either the paper towel test or lab sample is a good idea. Oil diluted enough to cause damage is usually obvious as being super thin and watery. I can tell right away by sloshing it in a pot or stirring with my finger.

Did you notice a lack or oil pressure or get an oil pressure alarm? Did your alarm work?

I'd be looking hard at oil pump and also make sure oil lines at filter head were not somehow reversed.

 

[mplangley]

An oil sample sent to a lab would also answer the question about fuel contamination/dilution and to what % which may help sort out the cause. $35 approx.

I will definitely send out a sample but I am not sure where. I figured there would be a local place but have not found anything. Where do people usually send these?

I did the smell test on the oil and all I can say is that it just smells burnt. It does seem thin unfortunatly though so I suspect diesel contamination is an issue.

Attached are pictures of the pistons. My biggest disappointment and surprise was to find the #1 piston fairly heavily scored. The other surprise about this is that the #1 cylinder is not scored. All of the cylinders seem fairly good to me. FWIW I can see some lines but cannot really feel any defects with my fingers/fingernails in the cylinders.

The second interesting thing were that the second rings on #2,#3 and #5 were all partially stuck at one of their ends. Some more than others around the circumference but one end on each are definitely stuck and probably not making contact with the cylinder around the entire circumference.

Im wondering what the symptoms/impact would be the impact of a stuck #2 Piston ring? Would this account for all the smoke getting into the valve cover area?

The third interesting thing was that you can see all the pistons have both a lacquered glaze that developed around their skirts as well as shiny spots on each side. Are the shiny worn areas from Piston slap?