Runaway diesel engines

[MVDarlin]

I had a WOT runaway at the dock with my 120 Ford Lehman port engine. It hsd about 3,800 hrs. It ran for about 6 min. Smothered air intake with a coat to stop it. It was caused by diesel displacing 30 wt oil in the injector pump. Complete rebuild required. $10,000 in Mazatlan Mexico. I also had starboard injector pump rebuilt.

[grantmc]

Originally Posted by Briis

Just to illustrate my previous text on how much smoke and noise there is for those who haven't experienced a runaway diesel yet:

https://youtu.be/fJIcxMJevII?si=fDBlf3gp3DejtCvY

That video presents my own first hand experience. The smoke and the noise are horrific. It was a small Isuzu truck and the cause was that the oil had been over filled by an idiot. It ran for about 3 minutes and was a complete write off.

The video paints a clear picture of why the suggestion that you should put a rag over the air intake is bs. All you want to do is want to do is watch from a safe distance.

[skipperpete]

I saw a similar thing with an overfilled 8V92 GM, a new oil change guy didn’t know that there was a 15 minute wait between the first start after an oil change and the second dip, he just shut er down, re dipped and topped up the level before the coolers and filters had time to drain back into the oil pan. Two stroke engines act differently to 4 strokes if overfilled and while this one DIDN’T have a spectacular overspeed, it did produce epic quantities of smoke and had to be stopped with the emergency shutdown....... the normal solenoid shutdown couldn’t stop it. No damage to the engine but an early end to the greasers employment. Interestingly it took a lot of cranking to get that GM to fire up after the incident.

[skipperpete]

Originally Posted by MVDarlin

I had a WOT runaway at the dock with my 120 Ford Lehman port engine. It hsd about 3,800 hrs. It ran for about 6 min. Smothered air intake with a coat to stop it. It was caused by diesel displacing 30 wt oil in the injector pump. Complete rebuild required. $10,000 in Mazatlan Mexico. I also had starboard injector pump rebuilt.

Yeah, you really have to keep a close watch on the cambox oil level on the Ford Lehman’s those Simms minimec pumps need to have the oil changed every time the engine oil is changed. The early engines had a cambox drain tube and you could see the diluted oil dripping into the catch can as the leaking plungers overfilled the pump housing, Mercedes Bosch injector pumps were another one that did this. Leaking plungers is an early warning, the canary in the coal mine.

[skipperpete]

And another destructive diesel overspeed...... last night heading north to Brisbane on the Gold Coast highway there was a car in the emergency lane belching out huge volumes of smoke so I pulled over to see how well or badly this might pan out. This was a 4WD with a V8 Diesel engine and it was absolutely screaming with intense clouds of grey smoke that effectively stopped 4 lanes of 110kph traffic. Like the abundant YouTube videos it raced at a constant crazy high rpm and then bogged down to a rattling stop, but here’s the thing I didn’t expect..... the smoke smelled sweet, not like the familiar burnt oil “death smell” from a seized bearing .... and not black smoke like injector pump runaways.... this was light grey. I can only guess that it was full synthetic oil from a broken turbo shaft and until the very end was a combustion product , not related to seized or red hot bearings, bloody spectacular though. I’m pleased to report that at no time was I tempted to put my hand over the intake, discharge a fire extinguisher into the engine or even approach the car.
Yeah, not marine related but it was the first car incident like this that I’ve seen up close and personal.... not on YouTube. Today I had a look on line for any video footage of the event and was amazed to see numerous reports of car fires on this bit of freeway and one report of an engine runaway in surfers paradise.
This was a common rail engine, Toyota V8, fairly new and in about 7 minutes.... completely buggered. The car itself was seemingly unharmed , no fire broke out and no bits of engine flew off the engine and I’m really surprised that the DPF didn't block up solid and shut the whole thing down. The lady driving it was ...unhappy and totally bewildered about what had just happened.

[Jacana]

Had a 3gm30 where a mechanic decided to remove injector pump unnecessarily while replacing leaking o - ring on outlet.Upon restarting it went from a cold start nothing to an absolute racing engine which took about 30 seconds to stop .He then sent pump to specialist to be re - calibrated cost was about $800 .Engine started and ran well for about 7hrs using 1/2 a litre of oil after that then gave a big rattily sound and seized.The marine workshop owner offered to remove rebuild and replace all at no charge (had done 12000 hrs ) .l decided to buy a new 3ym30 and they did all the work for free .Which was good of them.Runaway apparently caused by rack not aligned when originally replaced injector pump.
And yes heat ,smoke and noise was incredible .

[skipperpete]

Originally Posted by Jacana

Had a 3gm30 where a mechanic decided to remove injector pump unnecessarily while replacing leaking o - ring on outlet.Upon restarting it went from a cold start nothing to an absolute racing engine which took about 30 seconds to stop .He then sent pump to specialist to be re - calibrated cost was about $800 .Engine started and ran well for about 7hrs using 1/2 a litre of oil after that then gave a big rattily sound and seized.The marine workshop owner offered to remove rebuild and replace all at no charge (had done 12000 hrs ) .l decided to buy a new 3ym30 and they did all the work for free .Which was good of them.Runaway apparently caused by rack not aligned when originally replaced injector pump.
And yes heat ,smoke and noise was incredible .

That’s a sad end to a great little engine, all that needed to be done by the mechanic was to crank it over with the injector pipes still loose and operate the stop control to see if it cut off the fuel before attempting a startup. He could also have tried using the decompression levers, this might have damaged the valves and pistons a bit but this was an emergency so definitely justified.