Stuck Valve, Ford Lehman 120 - a bit dire.

[01kiwijohn]

Is the valve just partially stuck open, or did it somehow have the old "kiss of death", with the piston and make a clattering noise as it got destroyed?
If the former, you may be able to free it up by putting it on TDC, so you don't drop the valve into the cylinder, removing the overhead gear, and working on it from above.
If the latter, you really can't do much without removing the head and evaluating options from there.
If you elect to run it on 5, it will continue to inject fuel into that cylinder so it would be prudent to route the injector line back to the excess fuel return line.

[RABenko]

Please consider contacting American Diesel Corp:
https://americandieselcorp.com/

It is run by descendants of those who built your diesel engine. I have a Hudson Force 50 with an 80 hp Lehman. They've been great in supplying parts and advice!

[Scrimshaw4]

I definitely would not pull the fuel line and crimp it. The pressure to the injector is VERY high and would probably blow fuel thru a crimp. If your going to bypass a cylinder, which could lead to rough running (vibration related issues to the engine, mounts and shaft), you should mechanically close off the end of the line with some form of non-destructive butt cap fitting. JMHO

[pelicans]

We did the head on our 120 on the Gold Coast some years back. Cost about 2k from memory and didn't take long. If you do some of the muscle work yourself I'm sure it would be less. Took us around the world and back and never missed a beat since. Wonderful engine well worth the care and attention.

[NorthCoastJoe]

I would pull the head. It should not be too dificult a job. I used to rebuild engines if it is only a stuck valve a machine shop should be able to do a total valve job on the head for about $600 USD if you bring it to them. As long as everything else looks good reassemble and torque it down. Be careful taking out the exhaust manifold, bolts may break but if they do the machine shop should be equiped to deal with that. Just get it off and take it in.

I would not run on 5 unless it was a total energency. And if you did I would not crimp the line but put rubber tubing over the end of the line and dirict the flow back to the fuel tank. I would also pull the injector so that there is no compressoin in that cyclinder, and remove the rockers so that valve does not move.

The last thing you want to happen is that valve to hit the piston. At high rpm I have seen valves go through the piston and out through the side if the crankcase.

[Boatguy30]

Is the push rod bent? I've used a large drift to "loosen" and replaced the bent push rods on those motors before..

[billgewater]

Just did the head rebuild (total overhaul -reseated valves, new stem guides, serviced injectors - the lot) Aus cost about $1400 AUD. but installation labour and other stuff ended up at a total of a bit over $3000. AUD) The engine was an even older 6 cylinder Ford 590 E series. Shop around for a head gasket. I found a tractor company that had lots of them. $140 for the head gasket kit (everything needed plus block head cleaning advice, copper injector seats, rocker cover gasket etc. and torque setting sequence and loadings.)
Just be grateful you don't own a Yanmar or Volvo where parts - according to legend, can be grossly expensive. e.g. the head gasket for my dinky 1 GM Yanmar single cylinder diesel cost $120 AUD!
The real virtue of any Ford series engines is that parts (other than marinised parts such as exhaust manifolds etc.) should be readily available.

Note the good advice and warnings from North Coast Joe.

[captlloyd]

Originally Posted by acem

That sounds awfully high priced to me. I work on non marine diesel engines. You can rebuild most small diesel engines for much less than $10K. That would not include removal and installation.

If a head job on a marine diesel pays $5-40K i need to change professions.

Thx-Ace

Absolutely. I’d definitely find another mechanic, preferably a non marine type as that engine is a very basic engine, any diesel mechanic can work on it or rebuild it. If you have any mechanical ability at all you could pull the head yourself and then hire a mechanic to reinstall. I’m sure you would be talking less than $2000.

[auskiwi]

Sounds way to expensive, ran Leymans for years in my Charter boat, cheap and easy to maintain. Just replaced the complete head assembly with new on a Cummins 6BTA, with labour came to less than $10k, where are you, someone may be able to recommend someone who knows these motors.

[Madehn]

taking off the head is not that hard and can be done much cheaper than your mechani is quoting but first take a look at the rockers when it is running- see what is moving and what isnt-you might try this first-if the valve is just sticking, an old trick from my hot rodding days was to dilute the oil down with transmission fluid and run the engine BRIEFLY at very low power-- that has freed up some valves on older big block gasoline engines when i was building street machines- sometimes it worked sometimes it didnt- of course change the oil immediately afterwards. - i cant remember the ratio but i want to say we used a couple quarts of tranny fluid to replace 2 of the 5 quarts of oil- might want to see what other people on the forum with more diesel experience have- i dont THINK it would be harmful if done moderately -- i also like the spraying of penetrating oil or solvent on the valve stems idea--most of the time when valves stick it is carbon coked onto the valve stems-- as long as the valve doesnt stick hard enough to bend a pushrod or stay low enough to hit a piston head things can usually be fixed without all the effort-just my opinion- your engine-- good luck

[Wulf]

Originally Posted by Scrimshaw4

I definitely would not pull the fuel line and crimp it. The pressure to the injector is VERY high and would probably blow fuel thru a crimp. If your going to bypass a cylinder, which could lead to rough running (vibration related issues to the engine, mounts and shaft), you should mechanically close off the end of the line with some form of non-destructive butt cap fitting. JMHO

No, no, no, no. Please, no.
Either crimping the line or plugging it is just setting yourself up for an expensive HP fuel pump failure. Fuel is non-compressible. Whatever is being pushed to the injector needs to be redirected back to the fuel tank if you’re intent on cutting fuel to a cylinder, else you will very likely damage your high pressure fuel pump in short order.

Oh, on a side note...5K to do a head job...I’m coming out of retirement...

[wilsod3]

Originally Posted by jakkum

I had a sticking valve in a Mercedes engine. Figured out which one it was and with the piston down, pushed it further than the cam did. Result is that the carbon built up is scraped off a bit. Tha. Sprayed pen. oil on the valve stem and pushed again and repeated till I had the idea it was free.
Than started the engine and ran it slow and sprayed again now on all stems one by one. Put the cover back on and Bob was my buy uncle.

Yes! I’ve hired myself a mechanic for cash and we are going to try that procedure today! D

[wilsod3]

Originally Posted by Wulf

No, no, no, no. Please, no.
Either crimping the line or plugging it is just setting yourself up for an expensive HP fuel pump failure. Fuel is non-compressible. Whatever is being pushed to the injector needs to be redirected back to the fuel tank if you’re intent on cutting fuel to a cylinder, else you will very likely damage your high pressure fuel pump in short order.

Oh, on a side note...5K to do a head job...I’m coming out of retirement...

Ha ha! Yes - my mate who is gun mechanic was horrified by this idea too. Called it a very “cowboy” move... going to try and unstick valve. But... if I was a cowboy: what if I jury rigged a hose from the injector line back into the fuel tank? Crazy?

[CassidyNZ]

I’m just curious. How do you know it’s a stuck valve. Here’s why I ask such an apparently stupid question.

If a valve sticks open, two causes are possible. First one is massive carbon build-up on top of the valve head which interferes with the valve seat/port and holds the valve fractionally open.

Second one is the valve stem has partially seized in the valve guide. This would normally only happen after standing for extended periods. But here’s the thing - in this condition the valve is likely to go to its fully open position, pressed there by the valve train (camshaft, pushrod) and it will stick there. Two likely scenarios exist - one, the piston will hit the valve which I think is probable on the Lehman engines, two, the pushrod will jump free when the cam releases it.

In both events the engine will clatter at a scary level. You don’t mention any scary noises coming from the engine? In fact you don’t provide any symptoms (noises, misfire, vibration). It’s a simple job to remove the rocker cover and have a quick look. If you have no clattering noises, I would be doubtful that the problem is a stuck valve.

[wilsod3]

Good point. Just removed the rocker. Push rod totally bent!