The real oils

[jeffro ra28]

25w 50 i think it is.
Temperature isnt really a problem as all these engines are running pure alcohol.

[30psi 4agte]

25- w50 sounds good. do you know what sort of bearing clearences they use? what type of cars are they?
You say temps not a prob cause they burn alcohol but correct me if im wrong alcohol burns cooler hence some turbo cars running methanol not using an intercooler.

[jeffro ra28]

Well im not entirely sure on bearing clearances exactly, i usually consult my boss when it comes to that, I know we run different size bearings in the block then the cap if it is an alloy block.

Correct, Alcohol is actually a refrigirant. When sitting still, ice usually forms ontop of the blower hat. On an NA engine full temp at idle the intake side of the cylinders heads are colder then room temp. But a healthy EGT temp at full noise is about 1100F.

The NA engine package we offer are mostly ALL alloy Small block chev sprint car type engines that turn around 8500 rpm and 700-750hp. Usuing the cylinder heads that we make. We have used them in sprint cars marine and drag cars. The blown engines are of similar make just with different geometry etc.

[jeffro ra28]

Oh btw, i mean the issue with mineral oil not handling high temps in reference to temperature is not an issue. Becuase they run so much cooler hence less the need for synthetic oils.

[30psi 4agte]

Yeah cool i didnt think i had that right but couldnt quite understand what you meant.
Cheers

[Joorsh]

I don't know how accurate this is, but I've also heard that a rapidly blackening oil isn't necessarily a bad thing. Again this is all second hand info, but I've been told that aside from lubrication and cooling, another purpose of the oil is to remove contaminants from the engine. So if your oil is turning black, then it can mean that it's doing its job. It's picking up all the cabon and gunk from your engine, and dumping it when you do your oil change. I don't know about you guys but I'd rather flush that crap out of there, than have a nice clean oil and leave it stuck in there. Obviously the flipside of this is that there is a point where the oil you are using is just too thin, and is being burnt up and hence turning black.

Personally, I'm not entirely convinced on the whole "black oil can be a good sign" thing. I'm wondering if anyone here can give us some actual technical info on this, and not just "nah that's wrong" or "yeah that's true"? Some references and technical articles would be especially nice if anyone has them handy. Oil topics come up every second day, but it's rare that anything of value or merit is actually said.

[mullett]

I can give you some basic tech info. The 'blackening' is the carbon deposits in the oil. If it's picking this up out of your engine, I guess it isn't all a bad thing. That being said, if it wasn't picking it up, it should mean your engine is clean. A couple of oil changes after going to a very good semi-synth, my oil is coming out clean: it's picked up all the crap and now the engine is clean. Alot of what blackens the oil is parts of it being overheated, for example the oil which is sprayed onto the bottom of the pistons. This is damn hot, and burns the oil, blackening it, after this that particle is effectively useful only as a carrier to other particles of oil. Oil does breakdown under mechanical stress and heat, thus the reason you need to change it. Gearbox oil, which isn't under such heat, lasts a lot longer, to the point where many new cars are coming with sealed gearboxes (never change the oil).

RM.

[30psi 4agte]

well put.
you do have a point about the black oil removing carbon and stuff but personally i like my oil to come out as clean as it goes in! id be lucky to do 1000km before a change but that just me!

[Joorsh]

So assuming that your engine is in near-perfect working order, a black oil indicates oil breakdown, and you should probably switch oils?

[mullett]

jeez man, if you're doing that you could run supercheap generic oil....no matter what you're doing to it, a decent semi-synth should last 5000km (unless it's a purpose built racecar)

RM.

[30psi 4agte]

Guess you could say its a bit of a purpose built racer!

[Toobs]

So assuming that your engine is in near-perfect working order, a black oil indicates oil breakdown, and you should probably switch oils?

Black oil in a turbo car is pretty normal as a certain amount of blowby is inevitable.
The only time you will really get "clean" oil back out the sump after 5,000kms is if you have no blowby and a really clean engine.

If you want to know how your oil and engine are really performing send a sample to get analysed.
Most of the larger logistics companys analyse the oil from their rigs to check that the oil is doing it's job and that the engine is not wearing excessively... these guys run drain intervals that would worry the sh!t out of your average enthusiast (greater than 50,000kms is not uncommon)

You can get your oil analysed by places such as:
http://www.als.com.au/oils/introduction.asp
or through the larger oil manufacturers (e.g. Castrol, Ampol/Caltex, Shell, BP etc.)

Costs from about $30 for basic testing to several hundred for more in depth testing (usually reserved for larger mining equipment)

[Nark]

Ressurrecting an old thread since it's the same topic.

I found this link.
http://www.technilube.com/sections/comps/synth_diff.htm

It's an interesting read. In short:

From the information given to me last, EVERY synthetic on the market today has converted over to this Group III (hydrocracked) oil, with the exception of most of the Amsoil line, Mobil 1, and a few other specialty oils, usually more difficult to find.

[jonchai]

I'm wondering if anyone here can give us some actual technical info on this, and not just "nah that's wrong" or "yeah that's true"? Some references and technical articles would be especially nice if anyone has them handy. Oil topics come up every second day, but it's rare that anything of value or merit is actually said.

I agree with this quote and + rep for it. Earlier comments about Mobil 1 being crap "Because its too thin and drains to the sump causing noisy start-ups" is not a valid reason to claim the oil is crap. If Porsche & Lamborghini's (spelling) can recommend such an oil from factory...it is a mighty big claim to say its crap oil. I'm biased....i use Mobil 1..and highly recommend it. however...i too have no scientific back-up. i can only merely recomending having used it since rebuilding the engine, putting it through track-days and have had no problems with it what so ever

[Adam_Cressi]

Highly recommend Royal Purple.. since SAS whacked some in the 2jz when they did one of the turbo's... its feels like it runs smoother.. and it might be just me, but it feels more responsive