running off of engine oil (run away)

[jtduncansr]

Kubota D1105 3 cylinder in a lawn mower will run away if I let it. It cranks and runs without turning on the fuel. It has 350 lbs. per cylinder compression. Does anyone have a clue as to why this is happening?
I lowered the engine oil to the add oil dot, did not help one bit.
A little history, this pos came to me with a broken crankshaft, which wiped out the bearing cases. I installed a set of good cases, a reground crank, new rod and crank bearings, new rings after I broke the glaze on the cylinders, which measured with in wear tolerance, and all new seals.
Right now I am thinking that I might pull the engine and try a different brand of rings.

 

[MOOTS]

Can’t help you, but am in for info.

 

[85Hokie]

Is this turbo charged by chance?

 

[North Idaho Wolfman]

This is the first one that I've ever heard of that will run without fuel, sounds like you have the perfect engine!
Seriously sounds like you put the rings in upside down if anything.
Kubota's are not know for run away issues.

 

[jtduncansr]

Can’t help you, but am in for info.

That is good, that is how we all learn.

 

[jtduncansr]

That is good, that is how we all learn.

Not turbo. That is often a source of oil when the seal blows.

 

[BruceP]

It cranks and runs without turning on the fuel.

I understand what diesel-runaway is... but I am not convinced your issue is the rings.

I have heard of turbocharger seals and even valve-stem seals allowing oil into combustion-chamber.... but never heard of the rings causing runaway.

Please elaborate... Specifically what do you mean by "without turning on the fuel".

If I were you I would try some things to ENSURE it is not getting fuel thru the injectors. before assuming it is burning engine-oil. Something as simple as stuck fuel-shutoff solenoid could be your issue. Perhaps try loosening up the high-pressure injection lines to make sure there is no injection taking place.

 

[xrocketengineer]

No diesel expert here but, would it make sense to remove the injectors and use a swab to see if there is any oil in the combustion (pre?)chamber?

 

[D2Cat]

Are you sure the fuel line is not allowing fuel into the IP? If it's oil, as you suggest, how do you regulate the engine RPM? Did you block of the air intake to get it to quit running? Did it ever run wide open, like it was going to disintegrate?

 

[GeoHorn]

Does it smoke? What color?

 

[kubotafreak]

Had a little run in similar to this. I had cleaned a stuck fuel injection pump once on a super series kubota. I got the thing running and it would go to full throttle. I had the control unison rings on the pump backwards. So the thing started at full throttle. Diesel engines will suck fuel out of the line if there is any way possible(through the lift pump/shutoff valve). So unless you have the fuel line disconnected it probably has the strength to pull it. On another note, if you hadn't touched the pump, it could be the governor springs. That is a mechanical injection system. It is all ready to go without much help. All the key on is a magnet for the shutoff, and a little lift pump.

Think simple, you probably have something else wrong in the engine. I would not condemn your rebuild from the sound of your experience. I say gov./rack control or injection pump.

 

[lugbolt]

there is only a few ways it can run away

is it smoking horribly while running away? If yes, is it oil smoke? If yes, it is indeed likely running on it's own lube oil

if it's fuel smoke, you have an injection pump problem.

typically oil-related runaways, there's only 2 or 3 ways oil can get to the top end. Turbo, rings, or PCV. We can rule out the turbo since yours ain't got one. Rings or crankcase vent. remove the intake manifold and look at the intake ports in the head. If you see a bunch of oil in the ports, you have a crankcase vent issue, or entirely too much oil in the crankcase which would vent, and if the vent is routed from valve cover to the intake like most of them are, that's where it'll vent to--into the engine (hence one major downfall of the closed crankcase ventilation system). IF it were rings, typically you'd have low compression--which you have. 350 psi is only 20 psi above the service limit, if I remember right. Most that I have been around are 500+ when running properly. Some of the newer ones are 600+.

So with that, I'm thinking that you have some sort of piston ring or piston issue. Inspect your pistons carefully for cracked or broken ring lands-I have seen this somewhat commonly with engines that have ingested starting fluid, carb cleaner, gas-rag, or other artificial starting devices. You also obviously want to inspect the rings themselves, make sure one ain't broken, and make sure they're installed in the correct orientation. There is a top ring and a 2nd ring, they are different, and they have a specific way to be installed. I have never put them in upside down to see what would happen, but I have seen low compression and excessive oil usage from cracked or broken ring lands which could lead to runaway if the conditions are right.

 

[GeoHorn]

there is only a few ways it can run away
...typically oil-related runaways, there's only 2 or 3 ways oil can get to the top end. Turbo, rings, or PCV. ...

Or defective valve-guides, head gasket or cracked head.

 

[lugbolt]

Or defective valve-guides, head gasket or cracked head.

Explain.

Only reason I ask is because I've never seen it, nor have I heard of it on a Kubota. Typically cracked head is a result of overheating. Similar with failing head gasket.

 

[GreensvilleJay]

I have a BUDA 4BD153 in my forklift. The 'blowby' is soooo bad, I've plumbed the valve cover into the air intake...solved the mess on the engine and pool of black on the floor. In a perfect world, I'd pay the 5K to have the engine rebuilt but... step 1 ,remove battery is easy, step 2, remove counter balance weight. THAT's a bit harder. 4000# cast and I ain't got a red 'S' suit !

 

[GeoHorn]

Explain.

Only reason I ask is because I've never seen it, nor have I heard of it on a Kubota. Typically cracked head is a result of overheating. Similar with failing head gasket.

Think of the ways engine oil can get into the intake path. (Neighbor’s Deutz had two cracked valve guides that would pass so much oil it would run.... barely.)

 

[jtduncansr]

I understand what diesel-runaway is... but I am not convinced your issue is the rings.

I have heard of turbocharger seals and even valve-stem seals allowing oil into combustion-chamber.... but never heard of the rings causing runaway.

Please elaborate... Specifically what do you mean by "without turning on the fuel".

If I were you I would try some things to ENSURE it is not getting fuel thru the injectors. before assuming it is burning engine-oil. Something as simple as stuck fuel-shutoff solenoid could be your issue. Perhaps try loosening up the high-pressure injection lines to make sure there is no injection taking place.

Thank you. You are correct as to your question about turning off the fuel. The owner has installed an electric fuel pump, which I did not turn on.

 

[85Hokie]

Thank you. You are correct as to your question about turning off the fuel. The owner has installed an electric fuel pump, which I did not turn on.

So...... if the pump does not run - fuel still can be pulled into the IP !!!

On BX machines - many fuel pumps quit and the engine will run fine, until it get lower than about 1/2 tank.

Unhook the fuel LINE and see if it still runs............

 

[BruceP]

if the pump does not run - fuel still can be pulled into the IP !!!

My point exactly!... My electric lift pump quit and my tractor ran just fine.... until the tank got low on fuel.

This is the reason why I asked the OP to specify what they mean by "without turning on the fuel".

 

[jtduncansr]

More info, thanks to all of you for your input. I have disconnected the injector lines and it will not run. Put them back on and it runs wide open. I removed the side throttle plate and can move the rack which makes no difference on it's running.
The smoke is mostly light gray.
I did not disassemble the head, I checked the combustion areas for cracks. Could be valve seals in combination with fuel. Once the engine starts on diesel it may take off on oil from the valve seals.
The crankcase vent dumps to atmosphere and when it is running there is not much venting out of the valve cover with the cap off.
I do not now how hot it got when it broke the crank, but based on the discoloration of the bearing cases they got plenty hot.