Oil fault in Beta engine.

[forelle541]

A friend has just had a rather unfortunate problem with his engine in a boat that he was selling. The engine would not start, always started first turn. Injector, pump, etc etc all checked no fault. He noticed that the oil was black considering the hours that had been done since the last oil change, he changed the oil. He left the oil overnight to settle then was surprised to find the next day that it had split into a clear liquid and a black plasticky stiff fluid, note no emulsifarcation. The engine reluctantly started but did not run well, when he drained the oil it had gone the same way. He could not risk selling the boat with the dicky engine so fitted a new one and away it went but we still wonder what caused the oil to split, the oil was two separate brands. The only thing so far is that Ehtol Glycol can cause strange things in oil but his coolent was not low.

Any clues?

 

[pvb]

He could not risk selling the boat with the dicky engine so fitted a new one ...

That sounds a bit extreme to me!

 

[forelle541]

No just did not want the engine letting anyone down.

 

[pvb]

But the engine itself can't affect the oil. Just flushing it and filling with fresh oil should have been OK.

 

[forelle541]

The only answer he could think of was contamination from the coolant, from a porous casting or dodgy core plug, obviously out of warranty as 12 years old. If he was keeping the boat it would have been different but as it was going to a new owner he had to make a decision.

 

[pvb]

The only answer he could think of was contamination from the coolant, from a porous casting or dodgy core plug,

But you said the coolant level wasn't low.

 

[forelle541]

Certainly never needed topping up, but where else could the contamination come from?

 

[cryan]

First and foremost, if your friend is in the habit of buying a new engine because of dirty oil please direct him to my website where we have a range of engines from £2000 - £50,000 all with beautifully clean oil from new.
Several things can affect oil. Temperature, contamination, manufacturing flaws, etc. the first case is usually to just recharge the sump with new oil incase the first lot was just a dodgy batch. Then if it happened again the second step would be to take a sample and send it to the manufacturer ie Shell. They will test the oil and tell you what has happened you can then figure out why.

 

[forelle541]

He is now in the process of getting the oil tested. The boat had to go to offset his next one and he new the buyer. As I said he did change the oil to a different make and it went the same way. If all you do to a shot engine is change the oil and then sell it then buyer beware!

 

[pvb]

As I said he did change the oil to a different make and it went the same way. If all you do to a shot engine is change the oil and then sell it then buyer beware!

I think that's uncalled for - you don't know the engine's "shot" and, as I suggested, flushing it and putting nice fresh oil in might have solved the problem. However, I still think that putting a new engine in is a bit extreme but, hey, it's only money I suppose!

 

[vyv_cox]

There seems to be a lot more here than contaminated(?) oil. The fact that the engine would not start cannot be a consequence of a problem with crankcase oil, suggesting that maybe there is a problem with diesel fuel reaching the crankcase? Presumably when the oil was changed it was done cold, so are you certain it was all removed? Why was the engine left 'to settle' after the oil change? Did it still refuse to start at the time? I'm not sure that diesel fuel running onto crankcase oil would divide into two phases but I guess it would if run in slowly enough. My first investigation would be the fuel lift pump diaphragm, followed by the injection pump.

 

[VicS]

There seems to be a lot more here than contaminated(?) oil. The fact that the engine would not start cannot be a consequence of a problem with crankcase oil, suggesting that maybe there is a problem with diesel fuel reaching the crankcase? Presumably when the oil was changed it was done cold, so are you certain it was all removed? Why was the engine left 'to settle' after the oil change? Did it still refuse to start at the time? I'm not sure that diesel fuel running onto crankcase oil would divide into two phases but I guess it would if run in slowly enough. My first investigation would be the fuel lift pump diaphragm, followed by the injection pump.

I read that as allowing the drained oil to settle, rather than allowing the refilled engine to settle.

I think diesel fuel and engine oil will mix quite well. Certainly wont separate or remain in two layers after draining.

Water ingress must be involved but Ive no idea what effects ethanediol antifreeze will have.

Might do some experiments later.

It will be interesting to hear the results of the oil examination.

 

[forelle541]

I will post anything we find out, the only thing I have found so far is black mayonnaise caused by concentrated antifreeze but I am not convinced this is what he has.

 

[VicS]

I will post anything we find out, the only thing I have found so far is black mayonnaise caused by concentrated antifreeze but I am not convinced this is what he has.

OK done some experiments, but not really conclusive

A couple of sample of engine oil ( Castrol GTX Diesel) some diesel oil, some antifreeze ( Halfords non OAT type) and the water to dilute it:-

Diesel gently added to engine oil but not mixed:-

Easily mixed by swirling. Completely miscible as expected:-

Antifreeze dilluted to 50%:-

Added to the oil:-

and mixed by swirling. I was surprised how readily the oil and diluted antifreeze emulsified. I am more used to oils that dont easily emulsify and quickly demulsify when then do:-

For comparison oil and water similarly mixed. They emulsified as easily as oil and antifreeze:-

After an hour or so It appeared that some solid was settling at the oil/antifreeze interface. I will look at that tomorrow.

Sorry about the quality of some of the photos. I was concentrating on the science and rather ignoring the photography.

 

[Seadawg33]

Thanks very much for that post very informative. I would be curious to see the same experiment done with used or dirty oil. I had a problem on a Yanmar engine that ended up with the engine creating oil and then the oil level would get as high as the breather tube for the valve cover and start smoking. If I turned the RPM's lower it would last a long time but when I checked the oil it was emulsified like your examples. In the end it turned out to be the Injection pump but what a nightmare to track it down.

 

[VicS]

I dont have any uncontaminated used oil I'm afraid.

Something seems to have gone wrong with the picture sizing...... sorry about that ....still learning about the "new"Photobucket.

hopefully now fixed

 

[davidej]

I had a problem on a Yanmar engine that ended up with the engine creating oil and then the oil level would get as high as the breather tube for the valve cover and start smoking.

No engine can "create" oil. Something else must be getting into the sump and mixing with the existing oil. It can only be diesel or water/antifreeze and it should be easy to distinguish between the two - look at the photos of the experiment