Turbo Overrun (Runaway) 1HD-T (2 Viewers)

[Cutrex]

...and, out of curiosity, how much oil is 'a little too much oil'?

 

[sunrk]

On the note (about positive air shutoff) how do you actually achieve that with an 80? With a snorkel perhaps clogging the intake, or dumping a Co2 extinguisher's contents, will do it by 'smothering', but without a snorkel the factory intake is inacessible in an emergency situation like a runaway.

 

[Landseer]

The idea that overfilling the engine oil increased the oil pressure and led to the runaway seems questionable. The oil pump on these is a positive displacement pump meaning it pumps a set volume of oil with every revolution - more oil in the pan isn't going to increase the oil flow rate, or the oil pressure. If you overfill the pan enough that the crankshaft starts hitting the oil you can start aerating the oil (foamy oil) which will lead to a lower volume of oil getting pumped and lower oil pressure. If the crankshaft is splashing oil into the cylinders maybe enough oil could make its way past the rings to cause the runaway?

Hope theres no major damage to the engine.

 

[MyModded80HDT]

The idea that overfilling the engine oil increased the oil pressure and led to the runaway seems questionable. The oil pump on these is a positive displacement pump meaning it pumps a set volume of oil with every revolution - more oil in the pan isn't going to increase the oil flow rate, or the oil pressure. If you overfill the pan enough that the crankshaft starts hitting the oil you can start aerating the oil (foamy oil) which will lead to a lower volume of oil getting pumped and lower oil pressure. If the crankshaft is splashing oil into the cylinders maybe enough oil could make its way past the rings to cause the runaway?

Hope theres no major damage to the engine.

So essentially you are saying that it was total coincidence that after I overfilled the sump that the turbo seal failed?

Not disputing your input, I can only put it down to be the cause. If it was coincidence then my luck ain't good. I'll put some pics up later, so far there has been a lot of oil in all the places it shouldn't be

 

[nickolai]

I regularly dump the whole 10L container into mine. I also doubt the overfilling theory.

I would:
Drop the oil and inspect.
Borescope down the glow plug holes if you can find one
Pop the cross-over pipe off and inspect down the intake, could also pop the rocker cover off and inspect cam.

If no schrapnel and the oil is clean then I'd run it again, likely do a compression test to see what that uncovers and then go from there.

 

[mudgudgeon]

So essentially you are saying that it was total coincidence that after I overfilled the sump that the turbo seal failed?

Not disputing your input, I can only put it down to be the cause. If it was coincidence then my luck ain't good. I'll put some pics up later, so far there has been a lot of oil in all the places it shouldn't be

You may never know the cause.

You'd have to add a lot of oil to block the HDT oil return at the crank cradle. If it was blocked, I can see oil backing up in the drain line being an issue.

 

[mudgudgeon]

These engine are built STOUT!

The valve clearance at stoopid rpm would be a worry as they are an interference engine. ( No clearance between pistons and valves if timing is wrong)

Also, the forces on the crank increase massively with every 1000rpm.

If you're tight on cash, do everything you can to inspect and test before trying to fire it up again.

You might be lucky.

 

[MyModded80HDT]

You may never know the cause.

You'd have to add a lot of oil to block the HDT oil return at the crank cradle. If it was blocked, I can see oil backing up in the drain line being an issue.

Would nearly 5L too much do it? I dumped the oil, filled a 13L pan, then got another litre and a bit. I ran the oil through a fine mesh strainer, no shrapnel or major swarf!!! Ran a kitchen magnet off a bulldog clip as I poured it into the empty jugs I have from last service, didn't pick up anything more than some really fine dusty metal. So that's a good thing I'm thinking.

 

[MyModded80HDT]

Never been in this situation - but - I'd recommend inspecting the oil first. As in - drain the thing fully into a new container. It's quick and easy. If you've got shrapnel, you know right away you're talking full rebuild. No way around it.

If no sign of shrapnel, send it away for analysis maybe? People here talk about Blackstone state-side. Never used a service like that, but might be worth it in a case like this. While waiting for that, and if there's no shrapnel, I'd probably try turning it over by hand as the next easy thing. If that works, and it feels good, I'd probably also drop the pan and/or flush the engine through with a bit of diesel, and see what comes out. I'd do all that before you go down the rabbit hole of pulling and rebuilding things, and definitely before you try and start it back up under its own power. If all signs look good though, and the oil analysis doesn't flag something catastrophic, maybe consider from there whether you start and drive, or tear into it further. It's not a foregone conclusion it's toast, it could have survived.

Diesel runaway is scary. Never experienced it first hand. Probably isn't possible under the 1HZ I'd imagine unless you inject something like nitrous into the intake. Didn't diesel runaway cause the Deepwater Horizon disaster?

So I dumped the oil, filled a 13L pan, then got another ~1.5L out of it. Definitely overfilled. Ran it all through a fine mesh sieve, no shrapnel or shavings, did a magnet pour over as I emptied the pan into the clean jugs, no shavings just a tiny bit of dusty filings.

It's a bit too late for no teardown, I had left the oil in until today, I'm pretty happy that there isnt any shrapnel. Just need to wait for my mate to get home from work to help me manoeuvre the exhaust manifold etc out as I'm a useless cnut and can't get it out on my own for some reason.

Because I'm 20k out from 100k service I ordered new big end kit amd timing belt, I'll drop the sump tomorrow and pray there isn't any surprises.

 

[MyModded80HDT]

...and, out of curiosity, how much oil is 'a little too much oil'?

I think 5L plus probably is too much

 

[MyModded80HDT]

These engine are built STOUT!

The valve clearance at stoopid rpm would be a worry as they are an interference engine. ( No clearance between pistons and valves if timing is wrong)

Also, the forces on the crank increase massively with every 1000rpm.

If you're tight on cash, do everything you can to inspect and test before trying to fire it up again.

You might be lucky.

Yeah something tells me there isn't any massive damage to the block or bottom end, but i dont want to take any chances. As you said, it could be all top end damage, guide rods, valve stems etc. Maybe even cam damage.

I've ordered all the spares I think I will need, and already have a heap of stuff like gaskets etc. If it turns out the block is ****ed or it doesn't fire up at least ill have new kit and spares for the replacement motor.

 

[cody c]

I am also hesitant to think that over filling caused the run away, but hey you never know.

There was some speculation in another thread once that there was some sort of "hydro-lock" damage to the piston or con rod from the bottom side from an over filled oil scenario (full to the top sort of thing) where the con rod maybe couldn't handle shear force pulling down on the piston with it against lots of oil. I guess technically it could push oil past the rings and start burning oil but I don't think it would be atomized enough for combustion, and it would be maybe only the worst compression pistons creating that not all 6.

My best guess is that your turbo blew the oil seals and that's what caused the runaway, I've heard of that happening from a couple sources. but your air intake post turbo should be full of oil if that's the case.

It is possible that something happened to the injection pump causing this, which, if your intake isn't full of oil would be the next suspect I would think. Most IP's have a diaphram that controls amount of fuel based on ambient vs. manifold pressure, perhaps the potential cause as well, I've had issues with the diaphram component on my 6BT but it under fueled and not over fueled.

On the note (about positive air shutoff) how do you actually achieve that with an 80? With a snorkel perhaps clogging the intake, or dumping a Co2 extinguisher's contents, will do it by 'smothering', but without a snorkel the factory intake is inacessible in an emergency situation like a runaway.

Usually a positive air shutoff is right next to the intake manifold on a diesel engine, its essentially just a butterfly valve with a cable linkage to shut the air off. So you could install one if you wanted. To kill airflow with a snorkel, youd want to knock the top cap piece off the snorkel and put a block of wood or similar over it, but like I mentioned earlier you may have better luck flattening a rubber intake hose somewhere with channel locks or something.

In the O&G industry in Alberta its often a requirement to have positive air shut off for all equipment on site, some of the wellsites and drilling rigs etc have potential for gas leaks and the thought is that some engines can have enough fuel in the air to keep running when shut down in emergency, so it became a requirement, but I've never heard of it happening first hand. Runaway diesel engine is the most likely scenario to have it IMO.