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patzfan4eva 09-11-2011 08:28 PM

Ford Lehman Runaway
Scaring event today, I finished the installation of two new fuel tanks, new filters, and new line.* Bleed fuel system to remove air and started engine normally.* 10 seconds after starting motor ran-away! Pinned tach and was running on light water level as I was going to top off after thermostat opened. Ran away*for about 3 - 4 minutes and got very hot.* Turned newly painted exhaust manifold dark red with a few darker spots at the leading edge.* Don't think it got above 250 degrees, but water level was low so I'm not sure.*

How hot can the engine get before real damage occurs and for how long?

Pretty sure run away was caused by new oil*under valve cover from oil*change and new breather hose to air filter caused vacum*which drew oil into intake.

Any*expierence or advice*is greatly appreciated.

FF 09-12-2011 03:50 AM

RE: Ford Lehman Runaway
How hot can the engine get before real damage occurs and for how long?

Each engine is different and how steam pockets that form vary.

Just X your fingers and go for a ride.

RickB 09-12-2011 05:24 AM

RE: Ford Lehman Runaway
If it was running on lube oil as you described then the excess heat was probably limited to the exhaust valves and manifold since lube oil burns slower and would exhaust while still burning. You may have stretched the valves which will cause problems for sure. The overspeed is a biggy and could have caused damage to rods and crank that might not show up for a few more hours.

Was the engine wound up like a turbine? How fast do you think it was running and how did you stop it? Did it stop by itself when it ran out of excess oil? Did it wind down slowly or shudder to a stop? What did it sound like as it stopped? Any funny noises?

If you can get it started, do like FF suggested, go for a ride. Run it at the dock for a while first just to make sure it doesn't grenade right away. I suspect you will be low on power at the very least. I would have very little confidence in that engine until it was inspected in a manner that might cost more than it is worth.

patzfan4eva 09-12-2011 06:30 AM

RE: Ford Lehman Runaway
Thanks guys,

Rick to answer your question, I disconnect the breather tube to the basket and shut the fuel valve so the motor ran out of "gas" it slowly ran out and don't think it got aobe 3300 rpm. as it was cooling down only one strange sound about 4 minutes later which sounded like a ball peen hammer being tapped against the engine block. Was thinking a head bolt or connecting rod bolt popped?


sunchaser 09-12-2011 07:24 AM

RE: Ford Lehman Runaway
I've heard of several runaways where sucking lube oil from the crankcase was the culprit. As is the case with many OM breather systems, a vacuum break (after market puke bottle concept works too) is used. What year and how many hours on your engine?

RickB 09-12-2011 08:29 AM

RE: Ford Lehman Runaway
You may have dodged a bullet if it didn't run long and didn't wind up too far.

Before starting it, turn the engine over by hand so you can listen and feel for anything unusual. Check the oil for metal, and check to make sure it holds coolant.

You can put a length of*clear plastic tube into a cooling system pressure test cap and run the open end up to the flybridge and put about*.4 psi of pressure per foot on the system that way and have a good indication if there is an internal coolant leak.

patzfan4eva 09-12-2011 08:31 AM

RE: Ford Lehman Runaway
I believe its 30 years old as its the original engine, has only 1200 hrs and I think the oil on top of the head from the oil change was the cause of the run away

patzfan4eva 09-12-2011 10:52 AM

RE: Ford Lehman Runaway
Alot of people are looking at this thread but no one is adding. Love to hear alot of ideas, opinions and perhaps examples from other members - PLZ!

jleonard 09-12-2011 11:52 AM

RE: Ford Lehman Runaway

patzfan4eva wrote:
Alot of people are looking at this thread but no one is adding. Love to hear alot of ideas, opinions and perhaps examples from other members - PLZ!
*My suggestion is to call American Diesel Corp and talk with Bob Smith the Ford-Lehman "guru" about this. I'm sure he has run into this before.

My only "runaway" was with my old VW diesel Rabbit pickup. It would suck the crancase vent into the intake manifold...the manifold would hold oil in the crevices, then once in a while, always while going uphill with my foot to the floor (it was there often with that vehicle) it would suck in the oil and runaway....wouldn't hurt anything though as it would last only 20 to 30 seconds and then all the oil would be burned up. It was under load so the rpm stayed in check.

So you are theorizing that the oil got sucked into the enigne via the valve stem seals?


RickB 09-12-2011 01:27 PM

RE: Ford Lehman Runaway

patzfan4eva wrote:Alot of people are looking at this thread but no one is adding.
Are you looking to purchase an indulgence ... go forth*skipper, runaway no more and everything is alright sort of a response?

If your engine "ran away" and pegged the tach for several minutes at some unknown rpm then there is only one way to determine if the bearings are wiped, the valves are stretched, the*crank is cracked, or a rod or piston is about to fail and that is take the engine apart to visually inspect it and do a dye penetrant or mag particle inspection.

Even the Pope can't help you out of this one.

bobofthenorth 09-12-2011 02:56 PM

Ford Lehman Runaway
I'm looking but not responding because I have nothing to add.* My father always told me if I had nothing to say then it was best to say nothing.* However I would like to hear what Brian/Bob Smith have to say about this.* Runaways are a known problem on 2-strokes but this is the first 4-stroke runaway I have heard of.* I'd like to know whether it is something I should be worried about.

If you want my opinion then I'd say you likely spun a bearing, based on the statement that when the engine stopped it sounded like a ball peen hammer was hitting something inside.* I hope that isn't the situation.


-- Edited by bobofthenorth on Monday 12th of September 2011 02:58:41 PM

patzfan4eva 09-12-2011 03:06 PM

RE: Ford Lehman Runaway
Whateva! THe truth shall set me free!! I spoke with Bob at AD and sure enough i was given the holy pass on the engine issue. Fuel Pump Baffle was the likely cause. I have electric fuel pump that feeds the engine system which probably pushed the fuel into the crank case and thinned the oil to the point it passed the rings and entered the cylinder. It created excessive fuel in the combustion chamber thus creating a run away.

Will replace mechanical pump (OLD) and remove electric fuel pump, change oil - should fix issue!


AND YES Rick!! I was looking for someone to hold my hand and tell me it would be alright!! Where were you on that one? lol

RickB 09-12-2011 03:35 PM

RE: Ford Lehman Runaway

patzfan4eva wrote:AND YES Rick!! I was looking for someone to hold my hand and tell me it would be alright!! Where were you on that one? lol
*I must have been checking my oil level or something.*

Besides, I am not likely to ever suggest to someone that their engine is just peachy swell after experiencing a runaway event.

Besides, the oil level thing sounds fishy, surely you checked it before starting and after adding oil? Did you check it after it quit?

If it was running on*a crankcase full of fuel diluted oil then it is unlikely that simply shutting off the fuel supply would stop it since the governor had long since reduced the fuel delivery to virtually nil in its attempt to slow down the engine.

That is why very few are willing to bless your engine. I am surprised BS takes such a casual approach but then again he sells engine parts so doesn't havwe much too lose.

Phil Fill 09-12-2011 03:44 PM

Ford Lehman Runaway
If the fuel pump seal fail it will pump diesel directly into the oil pan.* We had the 671 fuel pump seal fail which pump diesel into the oil pan.*the new low sulfur diesel can damage older seals.* *Luckly I notice the oil level abov the full mark.*** If the oil level is above the full mark. So when checking the oil level check if its to low or to HIGH.***

-- Edited by Phil Fill on Monday 12th of September 2011 03:46:55 PM

capt jerry 09-12-2011 05:51 PM

RE: Ford Lehman Runaway
the noise might have been a fuel knock???????

FF 09-13-2011 04:37 AM

RE: Ford Lehman Runaway
RICK is right , about the damage that might happen to a real industrial duty engine.

However most Ford Econ power and Perkins have light truck backgrounds.

30-40 years ago automatic trannys were not common in light trucks,

SO the engine had to be able to accept modest over speeds from a driver going down hill in the wrong gear.

Stuff happens , and scraping an engine that was merely abused would not be acceptable.

patzfan4eva 09-13-2011 10:55 PM

Ford Lehman Runaway
Unfortunate result is a fried exhaust manifold! Need to replace, probably will replace head gasket as well. Need to talk to Bob again and follow his suggestion.

-- Edited by patzfan4eva on Tuesday 13th of September 2011 10:55:57 PM

RickB 09-14-2011 11:24 AM

RE: Ford Lehman Runaway

patzfan4eva wrote:Unfortunate result is a fried exhaust manifold!
*Ugh.* Now a bit more to think about ... if that large hunk of water cooled iron got hot enough to fry, what do you think happened to those skinny little lightweight uncooled exhaust valves that were the first items exposed to the fire?

sunchaser 09-14-2011 01:04 PM

RE: Ford Lehman Runaway
As smart as the Smiths may be from long distance, insure you have some capable hands and eyes on things as they come apart. On an overheat and runaway, I'd be suspicious of everything including block, pistons and crank shaft.

Now may be the time to price out a rebuild vs a new engine.* There was a long thread earlier this year (Larry's Krogen?) on rebuilding/replacing a Lehman.

Larry M 09-14-2011 01:24 PM

RE: Ford Lehman Runaway
David:* Here' the link to the thread that Tom refers to about rebuilding/replacing a Ford Lehman.* You can a get a good rebuild for ~10K.

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