quote:

ORIGINAL: marquisvns
I have had a lot of engines in for new bearings this year, not only Kingtech's but all makes and the alarming thing is that the time run figures are way under 20hrs.''

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ORIGINAL: marquisvns

Negative, DTE is no longer an approved oil for our engines as we have bearing failure reports from Australia, however none from the US.

I must say, this is all a bit confusing!!

Phil quotes “It will NOT mix with any other oil that is Synthetic ester based. It will form a white sludge that will block and damage the engine and components.” Meaning as far as Phil is concerned mixing mineral with synthetic (even if it is only remanets in the tank) is a no no.

Kingtech have used this as an advice to drop DTE light but Kingtech have now released a Tellus 32 mineral oil blended synthetic oil at an 80/20 ratio??

Mobil Jet II has a viscosity of 27.6 (@ 40^o c) Dte Light is 32 cst which is exactly the same viscosity as Tellus 32.

Tellus 32 is just a dumb arse hydraulic oil (I know as I sell thousands of litres of the stuff), DTE light is a Steam turbine circulating oil.

Mobil Jet II has a flash point of 270^o , Tellus 32 flash point is 210^o , DTE Light flash point is 218^o .

Phil is a smart dude who knows his stuff, but I just can’t understand why Kingtech would remove DTE light and replace it with Shell Tellus 32 claiming it is better where in real life it is the same if not worse than the DTE light.

And oh yeah, before you start with the blending stuff, both oils have the same anti oxidization, anti foam and air release agents in them, in fact DTE light is designed to operate in environments up to 150^o  c where all standard hydraulic oils start to breakdown and suffer shear from 110^o  c and up.

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ORIGINAL: marquisvns

Negative, DTE is no longer an approved oil for our engines as we have bearing failure reports from Australia, however none from the US. This came from Phil Celima, who has extensive petroleum engineering background, here's what he has to say:

"Over the past year the use of DTE light in jets has increased and unfortunately so has bearing problems. 
The issues with using DTE are: 

It will NOT mix with any other oil that is Synthetic ester based. It will form a white sludge that will block and damage the engine and components. If using or swapping over to DTE it is essential to ensure that no remnants of the previous synthetic oil remains in the tank. The tank and fuel system should be thoroughly flushed with pure kerosene first.

Another problem with DTE is the oil is a higher viscosity, the problem here is that with a higher viscosity the flow through the lubrication orifice is lower.
You can raise the mix from 4-5% to 5-6% there is enough range in pump limit to cope with this. But ideally the lubrication orifice needs to be 1 gauge bigger.

I have had a lot of engines in for new bearings this year, not only Kingtech's but all makes and the alarming thing is that the time run figures are way under 20hrs."