Tuesday, Nov 25, 2008 at 14:08
RedBakk,
I've run used oil analysis on our 2 vehicles before and after diesel gas conversion. (A f250 7.3 PSD & A Landcruiser 8o series 1HD-T) Both are turbo diesels - the F trucks intercooled.
Dieselgas Australlia (Lovato) did both the conversions.
In neither case have the manufacturers claims of "cleaner oil" been proven true with the used oil analysis testing.
We performed the sampling and testing using identical samples sent to 2 different laboratories, one here in WA (Westrac equip) and one in the USA (Oil Guard).
Both vehicles showed increased soot in the oil after conversion - not a decrease.
Having said that, it needs clarification to be fair to Diesel gas Australia!
In their website they do mention somewhere that immediately after conversion - the LPG will have the effect of cleaning up the deposits in the engine that accumulated while it was running as a standard diesel.
As a result they claim soot levels in the oil will increase for the first 2 oil changes after conversion, not decrease.
They also recommend dropping the oil after the first 1000 km's after conversion then again at the next 5000 km's to get rid of the extra soot deposits that the LPG will bring out of the engine, and deposit in the oil.
They never mentioned this 1000km oil drop to us at conversion I only read about it afterwards so we never did the 1000km's oil drops because we didn;t know about taht requirement instead we did 2 x 5000km oil drops.
As stated Soot levels were up (not down) in Both vehicles results.
However...
The F 250 was also fitted with sub micron oil bypass filtering supplied by Oil Guard USA, that sposed to remove almost al the soot anyway - and the inceased soot levels actually remain after more than the first 2 oil changes - they are still up, and there are afew other oil issues with both vehicles that we don;t seem to be able to resolve...despite all the testing.
The "other issues" are increased Sulphation, Nitration and Oxidation levels in Both vehicles.
This appears to be a result of - the addition of the LPG to the burn cycle.
LPG engined vehicles like forklifts use a much different oil with much higher sulphated ash levels that standard diesel engined vehicles for good reason.
It seems that while the addition of LPG certainly gives increased economy and savings based on out test figures - that the oil companys themselves have not as yet formulated any oils specifically for Diesel gas blends vehicles.
I have been in contact with
Mobil in Australia about this issue because one of the oils we used that gave uisall these results is their premium fully synthetic Delvac one which costs about $20 a liter and is sposed to be good for extebnded oil change intervals, especially if you have sub micron oil bypass fltering to scrub your il clean of soot and other contaminants.
The testing resulyts showed no adverse wear metal results - it's justr that the oil has used all it's add pack of detergents etc in fighting the sulphation nitration and oxidation under hot Australian road use conditions - and isn't fot for any more than 5000 km changes based on the ressults in our vehicles.
Mobil say they have no plans to prodiuce any specific poil suited to diesle gas belnd engined vehicles- so it is up to users to find an oil that works with the gas if they want extended oil changes.
It might yet prove that the addition of LPGmeans you CAN'T run extended oil changes due to sulphation, nitration and oxidation issues.
It too early to tell - the jurys stil out on this issue of oil for diesel gas vehicles- the manufacturers have no helpfull adviceother than "use whatever the manufacturer of your engine recommends! Thats very helpfull when Used Oil Analysis proves even the best o f the bestDelvac 1 can't cope with diesel gas blend fuels!
It's an area the diesel gas manufacturers havent adequately supported their customers IMHO as an owner of 2 such converted vehicles.
There are other oil realted issues with respect to older Landcrusiers engines - that i won;t go into here since they seem to attract all manner of criticism...
What you do about converting r not is up to you,
All I'd suhggest after my experience is to do used oil analysis befiore and after converson andkeep good records of same.
I personally go to the trouble of graphing my results...
This is a UOA result from the F 250 before LPG & sub Micron Bypass filtering
Graphing various results trends
Unless you keep track and look for the trends - you are only really guessing about oils and that could be a bad risk to take with this new and unknown LPG diesel technology IMHO.
Some labs use different methods to analyse the samples also which makes comparison between labs results on the same samples difficult.
Some use infrared spectoral analysis for determining soot levels while others don't measure or report on soot at all!
Lastly - the info you get back from a used oil analysis is of little value if you don't have a virgin oil analysis to compare it too in the first place.
Howdo you know whether wear metal levels are up if you don;t know what those levels werein the clean oil you started with?
Thankfully that info can be found online if you know where to look.
You might for example worry if you got a result back saying wear metal for iron (fe) was 3ppm in your used oil analysis result - but if you knew the virgin oil had 2 ppm Iron Fe) in it when it was new- the extra 1 ppm wear metal of iron might not worry you so much!
Learning how to interpret used oil analysis results is a bit of an artform in itself.
My habit of testing the same oils in different labs at the same time even shows up some anopmoalies between labs on the same oil..
Theres always a possibility for shenannikins with UOA results....
Maybe they lost or mixedup the sample in the lab so gave you a copy of someone elses results!
Maybe newengine sales are down at the co this month and he sales guys need a bit of a helping hand so you get a dodgey result in the hope that you'll pannic and sell / trade your engine this month for a new onebefore the old one craps itself!
All I'm saying after the excercise in testing is - beware of the results you get, be prepaired to question them, educate yourself to be able to intepret them and keep good records (spreadsheet & graph them) to look for any trendsthat give clues to impending problems before they become serious issues.
Sorry the answer about soot isn;t an easy yes / no clearcut issue.
The truth is- theres more not known than is known on this particular issue.
The manufacturers of dieselgas technology aren't too happy that anyones actually looking as closely at their results as what I do - they would far prefer that customers wipe the dipstick on an old oily rag and say "yeah that looks cleaner than before"...
Take from the above what you will.
Cheers!
AnswerID:
336836
Follow Up By: Member - Redbakk (WA) - Tuesday, Nov 25, 2008 at 19:15
Tuesday, Nov 25, 2008 at 19:15
Flywest...you are a legend...thanks for all the info...much appreciated
FollowupID:
604579
Follow Up By: Flywest - Tuesday, Nov 25, 2008 at 20:20
Tuesday, Nov 25, 2008 at 20:20
You are more than welcome, its an interesting subject that I invested a lot of time Money and frustration into - the idea that someone else might benefit from that experience is one of the things motivates me to bother writing it all - and recording / analysing the results.
My other reason is that hopefully someone else with the same question at some point in the future will find the answers they seek via a search engine.
I do believe - that unless people bother to upload worthwhile info to the internet then it won't reach it's potential as a research tool
The other thing is - it helps keep the bastages honest as old Don Chip of the democrats was want to say!
The whole thing has got me too the point of believing that there COULD possibly be a small but growing market for sopmeone to specially blend an oil specifically for diesel gas conversion engines - since so far nothing from the major manufacturers seems to quite measure up.
You know - if the diesel gas conversion co's were smarter than they are - they would do this themselves and SELL theor happy customers their own special brlnd of diesel gas converted engine oil and add ongoing profits from their now once off conversion clients! ;o)
So far they don't seem to be quite that smart - I have a suspicion that all it might take, is to increase the sulphated ash content like they do for LPG powered forklift engines...
But there could be more too it and an industrial chemist could no doubt come up with better blends!
Another little gem I found out thats not often spelled out by the synthetic oil freaks...
Fully synthetic oils that derived from distilling esthers etc does have a lot of the claimed benefits in terms of uniformity.
Whats NOT spelled out is this.
It's a base 5 oil.
Yes - think Singer Sewing Machine Oil - i.e. thin - thin as
water!
Now - the interesting thing withthis thin oil - is that - its formulated for VERY cold US and European climates where they have sow and ice and on cold start ups tolerances are very tight and a very thin base 5 oil is great in that situation.
We in Oz with the exception of parts of the snowfields inVoc and part sof tassie etc generally have deserts and bloody hot temps.
In HOT conditions THIN oil ain't all that good at protecting your engine.
So - what do the companys add to the base 5 synthetic oil to make it behave like a heavier 15 - 40 base oil?
Well it;s an emulsifier - that is NOT UNLIKE the goo in your viscous clutch fan in it's properties, i.e. the hotter the oil gets the thicker the emulsifier gets. (Think it thru, as the fan clutch gets hotter, the special goo inside gets hotter & thus thickens & the cluth grips more and the fan spins faster, to cool the radiator more).
The emulsifier addedto the thin base 5 synthetic oil works the same way - the hotter the engine and oil gets the thicker the thin base 5 oil gets - such that it acts like a 15 - W 40 oil under typical Aussie conditions.
Thats all
well n good - I only have ONE concern about it!
Occasionally Viscous fans clutches fail - the goo leaks out or goes off / bad and stops doing it magic....and then the thermo fan thing is tossed out and a new one put in or sometimes just the goo replaced for new goo once it stops working asit should.
So if we start going for extended oil changes on this expensive $20 a liter fully synthetic oil, up to say 20,000 km;s on one oil change (with UOA testing) - whathappens IF - like the rest of the addpack - that special magic emusifier gets worn out used up or in some ways deteriorated by the aforementioned increased sulphation, nitration or oxidation effects of diesel gas conversion?
Well I guess your $10,000 or $20,000 intercooled turbo diesel engine is back to being lubricated in the heat of the Aussie desert by THIN base 5 (singer sewing machine) oil - at a time when it possibly needs a base 40 oil protecting it!
After the failure of Mobils Delvac 1 (and their subsequent re blending and repackaging re labelling) of the oil after they were advised of our results - I personallyhave a few reservations about recommending fullysynthetic oils for the moment - I remain to be fully convinced.
At $20 a liter the F truck takes 18 liters and the cruiser 12 - or 30 liters total ($600) for only 5000 km's (3000
miles)
Thats mighty expensive oil, if you do say 30 or 40,000 kms a year!
Specially when crude is back below $50 a barrel! ;o)
I could think of better things to spend say $3600 (5 changes a year at 30,000km's / vehicle) on what is essentially chemically derived base 5 singer sewing machine oil with magic thickener goo in it (emulsifier)! Especially 9 x 20 liter drums of it!
Good luck to those who go fully synthetic - been there done that, and it sucked big time.
Cheers!
FollowupID:
604598
Follow Up By: Member - Redbakk (WA) - Wednesday, Nov 26, 2008 at 10:44
Wednesday, Nov 26, 2008 at 10:44
Question...would a oil pressure gauge be or give some kind of indication on how the oil in the sump is preforming in regards to thickening or thinning ( viscosity) and also indicate that through operating temperature changes?
FollowupID:
604660
Follow Up By: Flywest - Wednesday, Nov 26, 2008 at 21:18
Wednesday, Nov 26, 2008 at 21:18
Indeed.
A working oil pressure gauge is a valuable assett in regards to monitoring oil pressure.
It should show any thinning of the oil, if the magic emulsifier in the fully synthetic oils were to be exausted or fail.
Theres another "quesionable" safeguard as
well.
Chlorinated parrafin - used in the tooling industry, sppecifically in cutting and working steel on a lathe etc
It has very unusual lubricating properties - in tha it is attracted to heat, rather than repelled from heat source like most oils.
In a run low oil situation, where any direct metal to metal contact occurs the chlor paraffin is attaracted by the heat of friction and lubricates that spot, hence why it is so efficient in the tooling industry for industrial cutting etc.
Bitron is a co that packages Chlor Parrafin for use as an oil additive.
I have reservations about using it in an internal combustion engine - because the chlorine when it blows bye the rings and enters the sump - along with the gasses of exhaust will form hydrocloric acid and eat away the calcium or magnesium detergents put in the oil add pack to combat acids that caiuse corrosion....
So - while it may protect from heat damage and wear it also might result in internal corrosion.
Where i think Chlorinated Parrafin perhaps has GREAT potential is in lubricating things like diffs and gearboxes etc where there is no combustion gasses present yet heat caused by friction CAN be a problem in a oil run low situation.
Cheers!
FollowupID:
604721