Ford Lehman 120 Bad cylinder

Blackstone Labs.
416 E. PETTIT AVE. FORT WAYNE, IN 46806 (260) 744-2380 www.blackstone-labs.com

I just got mine done thru them.

I would guess that the piston damage followed the oil pressure issue, poor lubrication. Have you looked in your oil filter and your oil cooler? Perhaps they were plugged or impeded? I would expect to find the filter plugged now bu the oil cooler, I’d be curious about.

Untill you figure out what caused the engine failure it would be dangerous to just overhaul the engine.

A complete rebuild , total tear down ,tank clean the block and all passages , crank straightened & balanced etc would be only safe choice.

You might consider an upgrade by taking the engine after cleaning to a shop that does "speed shop" work.

The extra cost of matching the piston weights , the rod big & little end weights , and the rest of a balance job is very minor.

Even CC ing the combustion chambers is not expensive and creates a really smooth engine.

Like I said earlier, blueprinting.

Must Find Root Cause of Failure or it will repeat same issue again !

Mike,

I can't stress enough exactly what " FF " and so many others are saying above.

You must Find Root Cause of Failure or it will repeat same thing again !


Also remember there are small metal bits all through the engine. If they are not 100% cleaned out, that will cause future issues.

Remember, To dig in to that means spending significantly more money which is a much bigger major investment that will run your repair tab up a lot. The piston look bad, rings stuck in piston lands & the block needs hot tanking, crank needs major work & no telling what ELSE you will find.
I would not be surprised if it went to $ 10 K or more to do a 100% full rebuild & get everything corrected. So don't start spending $ or you end up down a road where you can't back out as your in to deep financially.

IMHO - A Recommended less expensive way to be 100% sure of not repeating this same issue - (if you don't find this root cause) - is to swap in a known good used motor that you can see & hear running, so it is a known quantity & full operational. Remember it should be the same brand ( Ford Leman) & model & HP ( 120 HP) so everything will bolt up.

If not the same engine - in this case a Ford Lehman 120 -, then most of the bolt on items will not bolt up & will require purchasing new stuff to make something else work, that would not be needed otherwise.

Your old engine will provide you spare parts for any future issue with either of your two Ford Lehman engines, so maybe you won't use it today, but may in the future, like the cylinder head or something like that.

Your having these spare parts is not a bad thing, & they work like insurance for any future issues. Plus, experience has shown many times if you have them, then you don't need them. If you dispose of them, then you do need them -- LOL ! Murphy's Law !

Come on over today if you want & we can go down to the boat & run the engine & talk boats. You have my number.

Keep me in the loop.

Thanks.

Alfa Mike

Let`s not be unfair. That engine does have a future. As a mooring block.

FF said:

Untill you figure out what caused the engine failure it would be dangerous to just overhaul the engine.

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This is what I am working on now. I am pretty sure we are going to find heavily diesel fuel diluted oil and perhaps some blockage. The pump has been checked and is perfect. I had stuck #2 rings on 3 pistons and also the #6 valve springs are coated with carbon which would seem to indicated the #6 exhaust valve was not seated properly.

FF said:

You might consider an upgrade by taking the engine after cleaning to a shop that does "speed shop" work.

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I've been thinking about this. I am wondering if could tell me more about the benefits of this?

BruceK said:

Let`s not be unfair. That engine does have a future. As a mooring block.

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Ha! I feel almost obliged now to redo the engine in order to show what nonsense this is

mplangley said:

Ha! I feel almost obliged now to redo the engine in order to show what nonsense this is

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I get that, and your loyalty to your engine is impressive. "Courageous", as Sir Humphrey Appleby(of Yes Minister/Yes Prime Minister) would say, perhaps even "character forming". It`s a challenge, isn`t it? Good luck, I hope it runs as smoothly as my mine after you work your magic with it.
A good one that runs, would slot in, now. You`d be back boating. Have you done the figures for overhauling yours,compared to a running replacement? Might be instructive. Mind you,the running replacement could stop running in a month....it`s not easy.

Youll spend less on a brand new cummins than you will for just a simple lehman rebuild. And thats not even considering the costs you are going to run into machining a severely damaged old obsolete engine back to use.

It should be simple to see, give it the watery grave it deserves. Dont forget to take the pistons out so the fish can use it for a condo.

Does a rebuilt cummins cost less than $12,000 ?

And a new transmission, motor mounts, wiring, plumbing, exhaust etc...

It would make sense to run the numbers at this point. OP has already done most of the work by removing and disassembling the engine. Now it's time to crate it up and send it to an experienced Lehman rebuild shop such as Bomac for a quote.

I personally would be heavily tilted to an off the shelf rebuild, but the numbers might go either way.

psneeld said:

Does a rebuilt cummins cost less than $12,000 ?

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I bought a rebuilt cummins from alabama boater for $5G, its in awesome shape. You can buy a new long block for $5G too which is why I went this way. Its way easier (availability) and a lot cheaper to replace (over a lehmans) if need be.

We have possibly 3 main (reliable) suppliers for lehman parts and rebuild vs. thousands of cummins suppliers.

My 6b bolts right up to my velvet drive, so I dont know why anyone would assume you need a different tranny. Fear of the "unknown" I suppose.

Edit: $5G for a rebuilt cummins is on up there in price, but this one came with everything to do a simple swap out, exhaust manifold, elbow, heat exchanger... etc. You can get a full rebuild kit for under $600. And they still make the engine.

what_barnacles said:

Youll spend less on a brand new cummins than you will for just a simple lehman rebuild. And thats not even considering the costs you are going to run into machining a severely damaged old obsolete engine back to use.

It should be simple to see, give it the watery grave it deserves. Dont forget to take the pistons out so the fish can use it for a condo.

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Well you might be right. That seems way overly pesimistic. I'm not so sure though. The quote I got for machining the crank was $350. Of course I could have everything machined, but even then, even with a new piston and new rings, gasket etc I don't see how the cost approaches that of a new engine (except the cummings we have been talking about - however I can't seem to find one). My estimate at this point I'd have about $1500 in parts and machine costs. Of course if I send things off to a "speed shop" that would add to it.

My biggest fear is that I'd rebuild the engine, not do a good job and then end up with something loud and smokey.

I think probably what I will end up doing is getting a another working engine and working on this this one as a project. That way by the time its done I"ll know exactly how much it cost to restore and if I ever want to sell the boat it will come with a spare engine.

For me the deciding factor would be that one cylinder pic that looks like it has a crack in it. Have you had that magna fluxed yet?




https://www.grainger.com/category/d...ding-chemicals/welding/ecatalog/N-nadZ1z0qac0

Maybe call these guys.
http://www.ebay.com/itm/NEW-for-Cum...m1eb7bfa42c:m:mYcoDrRTuUvNOEzxXi9cn-w&vxp=mtr

You could easily put together a full setup with a brand new block and head for less than 8G's. The plain ole 6b (non-turbo) comes in at like 130hp, you dont need a high output. I linked them as they do marine engines and could give you a better understanding of a swap.

The 1500 estimate is just repairing the damage and not doing a full rebuild?

The Cummins route makes sense if the OP is replacing a Cummins,but he`s not.
Replacing FL with FL avoids all the extra costs of extra changes that go with it.

Great thread, mplangley, any updates?

When I hear #6, the first thing that comes to mind is water intrusion through the exhaust.

Im hoping to post an update soon as the saga continues. I am working some things out. Because the opportunity presented itself I have acquired another FL which i plan on using for the boat hhowever I am still planning on rebuilding this engine and will post the details as soon as possible.

The latest news is that my crank was cracked and which is not what I expected. In sourcing a new crank and other thing I found another engine which I felt like I could'nt pass up however it sidetracked me from restoring this engine.

Engine knock brought me to this thread and I have to say it was fairly alarming/overwhelming to see what the possible issues might be. But also relieving to see such a great hive-mind group of supportive, experienced and informative people are out there to help.

Are there any updates on this project?

I haven't read this entire thread and I may be repeating myself but Industrial Engines in New Westminster BC rebuilds Lehmans, sells parts and I believe, short and long blocks. Also, Aiden Butterfield in Vancouver rebuilds Lehmans and blueprints them, he is a commercial rebuilder but he also does Lehmans. He is reasonable and is a friend of a friend. You can look up I.E. but if you want Aiden's coordinates, pm me.

The magazines Boats & Harbors and Rock and Dirt cater to the commercial users .

Many rebuilders of engines and trannys.

Very different pricing from "yacht yards".