Friday, Jul 24, 2009 at 20:25
This is an issue believe it or not and a topical one at the moment.
I have done some used oil analysis results on our 1 HD-T 4.2 TD cruiser in the past on
Mobil Delvac 1 fully synthetic that were less than glowing.
There are some old links I think back on the LCOOL site specifically about this issue.
I went searching for the old links just last night for a similar thread yesterday or the day before and couldn't find them, sadly.
Without the articles for backup proof I guess I will have to wing it and try to paraphrase what I read, so allow for the fact that there's some "chinese whispers" variation maybe between my recollection and what was actually in the two articles.
One day I will find those links and by then this thread will be archived!
So..
Our results with fully synthetic Delvac 1 were less that satisfactory.
Basically the report said there was high oxidization levels as
well as high sulphation and nitration levels.
The question the UOA's kept coming back with were "Is the unit operating at excess of normal operating temperature levels?"
Well that was questionable.......
A) It had always run cool since we bought it with 120,000 km's on it and now it was approaching 250,000 km's or so. Down in the city at lat 32 south, it still ran cool in winter.
B) we were now in the
Pilbara, in the monsoon season and it was 48C outside - in the waterbag in the shade - and even hotter on the road, NUTHING ran cool - not even the 80 series (but the gauge was only at half) when unladen at 100 kph highway speeds.
C) Once when towing the boat for 100 km's up there in summer the gauge actually went hot, - but we later found out when the trailer wheel fell off that a bearing was screwed so probably excess wheel drag wasn't helping the towing temps.
D) eventually we just said to hell with it and got a new radiator fitted and guiess what - the temps went back to 1/4 of the gauge, even when it was 40 outside!
So - in answer to the UOA place question about was the unit running at a normal or elevated temperature due to the elevated sulphation nitration and oxidisation levels - the proper answer was "probably not normal - probabaly hotter than we would have liked"......but it wasn't boiling it's head off either- just warmer than normal.
Was the oil no good for the cruiser, or was the UOA picking up the radiator issue BEFORE we had noticed any performance issues to indicate same?
Another compounding issue?
We have LPG diesel gas injection system installed, and THAT can also alter UOA results due to the higher running temps, when burning diesel andLPG together.
OK so - we know that
Mobil Delvac 1 wasn't doing the job for us, but in fairness to the oil - it MIGHT have been a deteriorating radiator problem, that was heating up the oil to the point it was oxidizing etc.
Its hard to be definitive with hindsight,maybe our failure to detect any issue with the radiator was why the oil results were coming back crook.
By then it was too late - Coz my eldest who now drives the 80 series,had given up on
Mobil Delvac 1 fully synthetic - as "not worth the drum it came in" and swapped to Pennzoil Diesel Longlife.
What the guts of the article we read about oils for these older Jap Turbo diesels was, that the engines are a different design to the lower revving USA made diesels, and as a result required adfferent type of diesel engine oil.
The article claimed that the Japanese diesels had the top ring of the Piston located further away from the top of the piston than the equivalent American designed built diesels.
This feature could result in a build up of soot between the top ring land and top of the piston that could lead to loss of compression and eventual engine failure IF a certain type of engine oil specified by the Japanese manufacturer wasn't used.
The Jap Oil Spec was very high in Calcium levels (above 3500 ppm) was required for the Toyota TD 4.2's to work properly long term.
The American oil manufacturers, by contrast had been reducing calcium in their oil, because of its effect on catalytic converters for strict California clean air regulations.
Their engines with the top ring closer to the top of the piston don't have the room for buildup of deposits and run generally cooler because they are bigger slower revving diesels than the smaller hotter running higher revving Japanese diesels of the variety in the 80 series 4.2 TD cruisers
The American oil companies, are replacing high calcium levels above 3500 ppm with Magnesium instead and it seems to be fine in their cooler running, slower revving, larger displacement engines, with the higher located top rings, thus shorter land spacing, and less deposits buildup.
Not so in the Japanese diesels that run hotter and have the older design larger ring land spacing and top rings located lower down the piston wall.
In the Japanese engines- the NORMAL operating temperature is beyond the thermal breakdown temperature of magnesium so the removal of calcuim and replacement with Magnesium isn't doing the same job and as a result elevated oxidisation levels were being noticed.
The problem today for owners of the 80 series 4.2 TD's is FINDING an oil with more than 3500 PPM of calcium.
It seems ALL the oil companys are reducing the calcium levels in their oils these days.
They are even "re formulating" the old oils to actively reduice Calcium levels
well below 3500 PPM - down around the 2000 - 2500 levels and adding magnesium - which we know is no damn good in our engine s- specially not iof you want to go for extended oil change intervals.
You might find a good Calcium level oil - like Pennzoil Deisel longlife that had 3500PPM calcium in its virgin oil analysis, BUT that's no guarantee that next month when you go buy the exact same 10 liter yellow pail of Pennzoil diesel longlife - that it will still have 3500 PPM calcium in it.
You see Pennzoil, might just have decided to re formulate that oil to comply with some new grading for newer diesels - and not told anyone about it!
Short of buying the oil new and sending a sample away to a Oil Analysis lab - how are you goingto KNOW for 100%whether your still getting a 3500 = PPM Calcium level oil that YOUR engine requires?.
I don't know if anyone can pull up this thread
http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=478127&nt=7&fpart=1
You might have to
sign up as a member at BITOG (Bob Is The Oil Guy) forums to view it but it was a whole list of oils that one old guy who ran a used oil analysis testing lab had tested virgin oils from many manufacturers to see just what was in them - so that when assessing the results of used oil analysis - he could take into account how much of any given element was in the clean oil in the first place when it was put into the engine.
The actual thread/post i getting on a bit now (%th JUne 2005) and the guy who posted it is now dead also - but at least you could check out your "favourite oil" to see how it stacked up (in this case for calcium levels).
Interstingly, your Dello 400 and even the fully synthetic Delvac 1 don't measure up in calcium levels of minimum 3500 ppm calcium - they are around 2900 or 2700 for Dello and for the Delvac 1 only 2100 or ~2300 ppm Calcium, a full 1000ppm below the Japaese oil specification for their diesel engines.
Shell rotella gets close at 3396 ppm calcium
Pennzoil at 3656 ppm also meets the calcium requirement.
But that was 4 years ago - are those oils still forulated the same now 4 years later?
Without someone doing the testing to fnd out - we the consumer have no other way of finding out!
For my money I like the Pennzoil long life diesel because it is over 3500 PPM calcium. (At least it was).
Unless you are testing your oil - with used oil analysis - how would any of us know whether our oil is or isn't doing a good job?
Cheers
AnswerID:
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