yes...what you say is true......but it doesnt get much higher than that.....
it might get to around 110 degrees.......should be around 98 degrees.....
I think the essence of your reply is that the effort put into development of multigrade oils is rarely if ever needed in most places in Australia. The number of people who regularly have temperatures below 0C must be pretty small. On the other hand, the number of people who live where temperatures are often above 40C must be pretty high, especially if you look at temperatures on the road not in the shade. Viscosities you quote are at 100C, presumably the standard, but what is the typical oil temperature in an engine working hard on a hot day? Somewhat higher I suspect.Originally Posted by rick130
John
John
JDNSW
1986 110 County 3.9 diesel
1970 2a 109 2.25 petrol
yes...what you say is true......but it doesnt get much higher than that.....
it might get to around 110 degrees.......should be around 98 degrees.....
Interesting figures.....I assume you've got a specs guide for these and quoting from memory....I wonder if you've got the figures for Elf brand oils??....I'd be interested as to how they compare.....I'm using Elf 10W - 40 A3/A4, C2/C3 [I think that's right- from memory....] supposed to be for extended use.....do you know much about Elf's Fully Synthetic products?....are they as good as I was led to believe based on their extended service interval ratings, very low level of "leaving deposits/sludge/gunk" etc....recently approved/recommended by Euro manufacturers especially for those cars that tend to form and suffer from oil "deposits" [sludge/thickening/varnish etc - can't remember the correct term].....point is I'm hoping to avoid the V8's propensity for doing cams n other bits due to wear and deposits etcOriginally Posted by rick130
OOOOOPS!!!!.....I was tying to quote your longer bit, 'bout various oils' properties....but same Q's apply
Last edited by byron; 28th August 2006 at 08:11 PM.
Sorry mate... yeah, same thing...Originally Posted by DEFENDERZOOK
It was originally badged with the "light" in it and I just had a brain fart
Now just HPR Diesel 5
Cheers
Tomby
Most engines have oil temps around 90°-130° when operating in 30+ ambient temps. E.g. a mates range rover V8 sat at 110-120° for the entire trip from Brisbane-Canberra. Oil viscosity is normally linear, so if you know your normal engine oil temp, you can plot the viscosity vs temp data that Rick posted and work out the viscosities at your temps.Originally Posted by JDNSW
the only Elf specs I have are for their HTX race lubricants range, although I'm sure you could find the specs online somewhere.Originally Posted by byron
Fact is these days that any premium mineral/semi-synthetic/synthetic lubricant will do the job well, it just comes back to personal bias and who's pretty packaging/marketing cranks your handle the best.
Elf have a great reputation, as do all the major and quite a few boutique oil blenders/producers.
John, I'm surprised that I've never actually logged any engine oil temps, but what 'Zook and Ben have posted tallies with numbers I've seen bandied around from others that have. I believe 130* is the highest temp I've ever seen anyone admit to.
FWIW, it used to be the case 15 or so years ago that we tried to keep mineral race oils like BP Corse 30 below 100-105*, as above that they would 'collapse'. Around the same time I actually had Valvoline XLD 20W-50 suffer total viscosity collapse in one of my Jeeps on a 46* day driving along Richmond Rd. I thought I'd spun a bearing, the oil pressure crashed from 80psi to 30psi. I Let everything cool down for 20minutes, fired it back up and everything was back to normal. I started using Penrite after that, then threw the 'thicker is better' marketing out the window and went to synthetics after my experiences with them racing.
To calculate an oils actual viscvosity at higher temps, (or any temp in between) all you need is the viscosity at a known temp, eg. 100*C, it's viscosity index and plug the numbers into this handy little java powered calculator here (warning, it's a geocities site, so has pop-ups)
Temps below about -5* to -10* aren't really terribly accurate using an oils VI, as oil tends to behave in a non-linear fashion at this point down.
If you go to your local Caltex rep with the handbook specs of oils for your truck they have a database that tells you which of their oils are the same (or better) than those specified by lr handbook.
very $$$$ but never given me a drama.
also, try some 'moreys' fuel additive in the tank. almost zero smoke and a tad extra grunt. worth is for $20 for 1 litre which lasts for ages.![]()
No need for that, go to the Castrol, Caltex, Mobil, Shell or Penrite sites, input your vehicle details and they will tell you what is right.Originally Posted by DRUT
Castrol
http://www.datateck.com.au/lube/castr_au/
Mobil
http://www.datateck.com.au/lube/mobil_au/
Shell
http://www.shell.com/home/PlainPageS...lubematch.html
Caltex
http://www.caltex.com.au/products_oil_lubeguide.asp
Penrite
http://www.penrite.com.au/html/s02_a...&nav_top_id=61
BP
http://www.datateck.com.au/lube/bp_au/
And your anecdote above suggests that viscosity behaviour at high temperatures (including those sometimes reached) is also non-linear.Originally Posted by rick130
My main point was that most of the research effort into the management of oil viscosity has gone into achieving satisfactory performance at temperatures that are so low that they are totally irrelevant to almost everyone in this country.
This relates to one of my hobbyhorses - almost all car designers in the world live in cold climates (and those that don't slavishly copy the styling of those who do) so we end up with all those greenhouses guaranteed to reach inside temperatures in the fifties when parked in the sun. (The Defender is one of the best designs sold today from this point of view - but is slightly worse than the Series 2/3)
Although the effects are less dramatic it seems oil designers also live in cold climates.
John
JDNSW
1986 110 County 3.9 diesel
1970 2a 109 2.25 petrol
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