Ford Lehman 120 Bad cylinder

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MPL

According to your first post, over a year ago a reliable mechanic told you the engine had a bad piston /cylinder. What was the recommended action at that time?
 
bummer.

disconnect the shift cable and see if you can move the shift lever through the gears easily. make sure you feel it pass thru the detents. Then put it in neutral and see if the engine rolls over.

The #4 looks like it has rust, and thats not good. If the engine hydrolocked while under power it could have bent some connecting rods.

If you cant roll the engine over in neutral then you have to beat the siezed pistons out. Then if you have enough sleeve left to bore out its time for that.

Me, personally, I wouldnt stick another nickel in it. Replace it with a cummins natually aspirated. Way cheaper, rugged, and parts are everywhere for far less than lehmans. I am putting this one in my boat. I pet it everytime I am at the storage.... :)

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http://www.trawlerforum.com/forums/s9/cummins-6b5-9-m-diesel-29258.html

I think (hope) the rust on #4 is a result of my inexperience and some procedural mistakes. I had not fully drained the coolant prior to loosening the head bolts. I was reminded of this as soon as I noticed water in places it should not be. I then waited a week..........

As for the cummins - A great idea. I'll be hanging out a donations basket. Thanks for your other tips. Im going to be looking at the transmission issue this evening as I continue to dismantle the engine. At this point I'm just going to have it taken out for sure no matter what as AlfaMike suggests Im not sure how good a job I (or professional help) can do in the boat anyway. Also I want to change the engine mount, clean the bilge and find out what is hiding down there.
 
MPL

According to your first post, over a year ago a reliable mechanic told you the engine had a bad piston /cylinder. What was the recommended action at that time?

I actually had two mechanics look at it. One said it may run forever as is. The other said I should deal with it immediately.
 
Amazing you got it to run for all this time. I think it is number 6 - very well-known failure. Lots of information on that, number 6 fails and rubs on the cylinder wall, destroying the piston and the cylinder wall. I would pull that piston out, dollars to doughnuts its only number 6 and that's why it seized.

Did you call Industrial engines? They will sell you a long block and you get to buy it with Loonies.

You still don't know if its the engine or the transmission but its rare to be that. Better find that out first, the transmission will have to come off anyway although you can haul it out with it attached. Did it overheat or just stop? Yes, you can rebuild it in place but if you haul it up into the salon it will be much easier to manipulate. And, if you get it into the salon you can just slide it out the rear door and get it done in a real shop. Or replace it.

Loonies? What are Loonies? Also Industrial engines?
 
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The more common failure for an unexpected lockup is the dampner plate.

I researched this thoroughly and it seems to be pretty common.

Sure, if other symptoms other than the plate keep looming.. But usually a free turning tranny with good oil and an engine with no real symptoms, the the plate becomes suspect no. 1.
 
A Loony is a Canadian Dollar, or Northern Peso if you prefer.
 
Could be a failed damper plate. The springs fail and get jammed between the plate and block. You need to slide the trans back to check it out. You just need enough room to get a mirror in there. If you have the head off and can't turn the crank I'd bet on the plate.

Well I got down to the boat and realized I had no clue about how to remove the transmission for an inspection of the damper plate. How would I go about "sliding" it back". I imagine it would have to be unbolted from both the engin and the prop shaft for any sliding to take place. I think Alfamike also mentioned I'd need to support it.

I also gave it another shot with a hefty 1 in wrench and bar on the crankshaft with absolutely 0 resulting movement. Thats after soaking the piston heads/rings in PB Blaster.

By the way. I am not sure what it means but I am also able to spin the prop shaft whether the transmission is in gear or not. Maybe that is normal.
 
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When I had my failure years ago my transmission was bolted to the engine bed not hanging on the bell housing by itself. I was able to support the bell housing and slide the trans to the rear. I was on the hard. I assume your trans is only supported by the bell housing. Yes, you need a way to support the trans and still be able to slide it a few inches.
 
Remove two of the bolts and replace them temporarily with threaded rod and you will be able to slide the tranny back without having to lift it.
Will also help with reinstallation.
 
Several engine guys said if it was internal engine stuff.....there was a high likelyhood I could get some movement of the crankshaft.

With the flywheel locked tight by 3 little pieces of spring....not even 0.000000001 of an inch movement.

As they told me, before starting to tear down the engine, check the dampner plate first. One said if all else is too much, just drill a tiny inspection hole in the bell housing and stick in a micro USB camera.
 
MPL- since you have head off, take a measuring tape and measure how deep each of the pistons are relative to block deck. 1 and 6 should be identical. 2 and 5 should be identical. Same with 3 and 4. If any of the pairs are different, something broke regarding con rods.

Thinking drive plate like the others. Debris jamming flywheel.

What did engine do as it seized? Any change in noise? Any rattling or squealing?

Wipe a heavy layer of motor oil on the cylinder bores to limit corrosion til you can get this sorted.
 
Well the saga continues.

Thanks to advice received here I managed to remove the transmission however I do not see anything obviously wrong with the damper plate. I have attached a few images and a shareable link with others if anyone wants to take a look. I guess my next step is to remove the bell housing to get a closer look. I don't mind because ultimately if this is a transmission issue then I'll still have to solve the excessive smoke issue which was the problem I first reported. So I think Im taking the engine out anyway or at least brake it down so the pistons can be worked in the boat if there is some issue there.

One thing I notices was that there is a little bit of oil at the bottom of the bell housing. I figured that is normal and lubricates the damper plate?

The other thing @psneed I measured the pistons and 1&6, 2&5, 3&4 were identical. At least with in I'd say a 1/16 of an inch. I just used a regular tape measure to check.

Also to answer your question, when the engine seized I was on the flybridge so I did not hear a lot. I first noticed that a drop in rpms, then things returned to normal for a few seconds exept for a large quantity of thick black smoke coming out the exhaust. Then the engine seemed to be dieing so I shut it down. I thought I shut it down before the engine stopped on its own. I was surprised that it would not turn over once it was off. On thing is my son though he had heard some sort of noise (as if gears were shifting) about a few minutes prior to this.

https://drive.google.com/drive/folders/0BwwOgMXRX4WvZ281RzVvU0pJMEE?usp=sharing
 

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Oil leaking from the rear main seal is common enough that one of the rebuilders puts a disclaimer in their paperwork about it.
 
Plates looks ok but you might as well pull to be sure. It will have to come off anyway.
 
Might as well pull flywheel too after pulling plate.
 
Have you pulled the starter. Could the gear grinding noise your son heard be the starter engaging then freezing up?
 
You can get a perfectly good bore from a boring bar (with someone that knows how to use it). The big boring machines will get the cylinders perfectly in line and parallel, but it really doesn't matter in most engines. If the engine is apart, I'd do all cylinders the same. Besides, that's how engine kits come, unless you're going to buy one piston.
But the lock up damage may change your options. If you stay with the engine, you can probably improve the heat problem with the last cylinder by drilling a port in the block and bringing a small line 3/8 -1/2" from where the coolant exits the heat exchanger and put cooler water on the heat. Maybe to the head depending on the flow direction.
When working on a single engine under a hatch, you can put a beam across on rollers or casters, lift the trans with it and roll it back. Also, sometimes when doing the bearings and pistons, it's often easier to lay the engine on it's side when working on the bottom end. Also use a assembly lube that dissolves in oil for initial startup.
 
Have you pulled the starter. Could the gear grinding noise your son heard be the starter engaging then freezing up?

I'll check this evening. But why would a starter problem prevent me from manually turning over the engine with a wrench? The starter is definitely engaging but the engine is not moving.
 
Have you pulled the starter. Could the gear grinding noise your son heard be the starter engaging then freezing up?
I`d put a dollar on this being a possibility. If the teeth of on the starter have jammed with the teeth on the flywheel - this could cause a lock up
 
Number 6, number 6, number 6...sorry, its my sense of humour...
 
Well since I could not find any problems with the damper plate or starter which may have prevented the engine from turning over I returned to the brute force method and finally got the engine to budge (to turn over). I did so by hitting a few of the pistons with a rubber mallet and then repeatedly hitting the starter which caused movement at about the rate of a 1/16 of an inch each time. I hit it about 20 times or so and finally was able to expose the #6 cylinder which I expected to have damage. I could not see any (Hopefully I did not damage the starter or anything else in the process.)

Unfortunately (as far as solving the riddle) there was no damage. In fact to my untrained eye except for excessive carbon I don't see any damage to the cylinders at all. There is a bit of scoring on the #5 but it seems minor to me (is there such a thing as minor scoring of a piston wall?). I tried to get a close up of it (last attachment) but its not very visible.

Also I removed the flywheel and did not see any damage there either.

The other thing is now I am at the final stages of pre engine removal. I was planning unbolt the bottom half from the top and then attempt to lift the top out with my beam and pulley system. The problem is the engine mounts are attached to the top half of the engine such that if I remove the bolts the bottom will fall about 6 inches until it is stopped by the oil catch pan under the engine. I guess I'll put some blocks under it and hope the pan is strong enough to support the engine. Otherwise I'll have to figure out how to support the bottom half while I am removing the top.
 

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It's pretty hard to tell from those photos but is that rust around the top of number 5?
 
A couple of tricks: First, each piston has a few thou oil clearance between bore an piston, you should be able to wiggle piston in bore and visibly detect the motion. If all but one wiggle, you found one binding.

Also, put big wrench on crank pulley bolt and wiggle it cw/ccw. Check for the slightest motion on the outside diameter of the damper/pulley. All the bearings also have oil clearance so if there is motion that will tell you that the crank is not seized in a bearing,. If zero motion, then could be a main seized.
 
I would pour some kerosene or other light penetrating oil in each cylinder and let it sit for a few hours. Maybe a stuck ring. Also I believe the pan is aluminum so you don't want to put any weight on it.
 
When replacing my Lehaman 120 the center of the lift was about 2' behind where the engine needs to be mounted. Used a 20" 2" x 12" board and hydraulic floor jack to roll it into and out of position. The oil pan can hold the weight just fine if it is distributed across the entire area.
 
Don't those 6 cylinder Fords have wet liners, with the pistons out they should press out, if not a block of hardwood and a sharp crack with a hammer.
Personally having checked the transmission was free I'd lift the engine and make it my winter job to completely overhaul it, then look around and find a race shop and get it race balanced.
Overhaul the fuel pump and injectors and with strict servicing you'll have an engine good for 30 years. Don't forget always, always use anti-freeze all year round, it does way more than stop the engine from freezing.
 
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