What oil do YOU use?

[ZekeTheSneak]

Always ran Castol High Miliage 20w50, I was watching GRZ on spike tv and stacey was explaining that engines are designed for the weight of oil that they recommend before the engine is ever even built. After hearing that I will never run anything other then conventional 20w50 in my m20.


Now on the other hand my forester XT gets full Motul synthetic, damn boost

[smooth]

The guy who wrote the first article I posted uses Chevron Delo 400 Synthetic 5W-40
(not the LE, which is CJ-4; less damaging to cats at the expense of wear protection) in his '88 BMW.

He tested a range of 20w-50's due to request and concluded that AMSOIL High Performance Synthetic 20W-50 Motor Oil (CI-4/SL may damage cats) was the best (and one of only two x-50 oils, the other being Brad Penn *I think, but it's hard to tell because he tries to refrain from recommending or dissuading an oil based on branding*) he found with excellent anti-wear properties.

The author of this article is writing about Porsche (and VW) engines:

Failure to use the right oil, use proper filtration, or observe proper changing intervals can affect the performance of even the best motor oil. This also includes changing the oil too often (needlessly bad for the environment and your wallet) or not often enough. Against conventional wisdom, engine wear decreases as oil ages to a certain extent, which means that changing your oil more frequently actually causes engine wear; these findings were substantiated by studies conducted by the auto manufacturers and petroleum companies, leading to standard drain intervals increased from 3,000mi/3 months to 5,000-7,500mi/6 months in most domestic vehicles, using mostly non-synthetic oils. Based off of extremely long drain intervals recommended by most European manufacturers, some in excess of two years and 20,000 mi, some users have found it best to reduce those intervals by half or even a quarter. Porsche for the 2008MY has reduced their extended drain intervals significantly to one year/12,000 mi, which is actually less miles than Porsche recommended back in the 1990s with 964 and 993 based aircooled 911s. Based on UOAs provided to us by our customers, new Porsche owners should consider reducing their drain intervals further to no more than 9,000 mi or one year and some shops recommend changes every 5,000-6,000 mi or six months (an interval we run in all our vehicles).

-- http://www.lnengineering.com/oil.html

One of his points is that increased potential catalytic converter damage is less expensive than costly Porsche engine rebuilds. He notes that pre CJ-4 era oils did not result in widespread reports of reduced cat longevity.

[Holland]

A lot of great info in this thread, although I do have to throw in on the synthetic argument. It's probably not worthwhile to run in a DD, but I don't see how it could be pointless. It's not like after 1990 engine tolerances just magically increased detrimentally. Synthetic in theory should fill the finer crevices in our engines and do their job better.

I do agree though that we change our oil often enough that the oil doesn't have a chance to break down and filter changes are super important.

I always laugh at those 10k synthetic commercials, no filter can last that long and it isn't mentioned to the general public.

[smooth]

But it was made in the 80's. Just cause its synthetic doesnt mean extra protection. Am i right anyone?
I dont think in 1991 everyone switched to synthetic. Its just more "popular" now and ppl think it will make things run better. It was explained to me that it makes things too slippery and can allow oil to get through seals or past piston rings. Plus in all my old reciepts i neversaw synthetic
But hey, it could just be prefence. Im not trying to start a debate that goes nowhere so if someone with ACTUAL oil knowledge could settle this thatd be great. Ive always wanted to have a definitive answer or an answer with facts so i could justify using the regy. other than a hunch

I don't currently use synthetics because my engine is a sieve and I believed that would exacerbate the issue. This article, however, claims that's a myth. I'm going to follow the recommendations and test it myself. Hopefully I'll remember to post an update in this thread in about 6 months.

http://www.gress.org/Home/Cars/TrackTales/DIY/OilingSystem%20Improvements/Oil%20Debate/Corvair_oil.pdf

takeaways:
* relying on viscosity ratings without looking at the data sheets can produce results ranging from uselessness to damaging

* oil and car engineers/manufacturers have different goals than owners/drivers

* BMW's recommendations in the 80's have minimal relevance to modern oil choices
(other than understanding the specifications our engines were designed to operate within)
-- that is, maximum protection will occur once we determine the best modern oil that will meet or exceed the design specifications rather than dumping any 20w-50 in our crankcases

* modern high detergent oils clean the sludge around seals thereby allowing them to shrink back to their original sizes and seal *better* (not worse)

* if you do nothing else, "If you want the maximum valve train protection, look for an oil that is certified CH-4/SL or CI-4/SL without CJ-4."

[E30ruben]

Synthetic mobil.. Whatever o'rielly had in their computer for my 318

[sofargone561]

what do guys recomend for a high hp built turbo m20 etz block with build 885 head? i live in the VERY south east so cold here is 85 i need somthing the preferms great under high stress and high heat

the car a track car no DD but will acosianly be taken out on weekends if that helps at all...

[JRKOUPE]

My first Beamer. I am running castro gtx 10w30. Not a fan on synthetic on older cars.

bimmer....bmw car...

beemer..bmw bike..

beamer..??????? no idea...lol

[NigelStu]

Valvoline VR-1 20w50 (conventional) for daily driver and storage/testing/general use on the Chump car.

Amsoil Dominator 20w50 for the races.

[Killacortes]

If I had a brand new m20 I'd use synthetic too but I dont

[E30Kaiser]

Mobil 1 15w50 in the summer so far, this winter i have started using 0w40 after noticing 15w50 being sluggish in the winters, has done great so far. I will tell you when my stroker blows up or not if it was a good idea.

Also to all you guys that are anti-synthetic because "It wasn't used back then" http://www.youtube.com/watch?v=gHmMlU8Q-V8 repost but still valid.

[Killacortes]

Autozone special 20w50. On my cleaned m20 with 224k on the block

[Hey_You]

I use whatever is on sale, and thick enough weight. Maybe once I finish my build it will get better treatment, but who wants to spend lots of money on a stock m10 oil change? Not I my friend, not I.

[85e325]

Anybody use Royal Purple??? I have heard A LOT of mixed reviews about that stuff

[dnguyen1963]

More good info. For us not-so-scientific, could it be said the higher Z and P levels might be a "side affect" of oils designed to have good lubrication properties and less of the detergents that might harm older motors?

I know they're not there by accident, but more likely left there for processing reasons.

Crude oil coming into refinery could be from anywhere in the world. I doubt that the oil industry monitor the amount of elemental metals in their products because it is costly prohibitive to remove ppm level contamination. Therefore, from batch to batch, the amount of elemental metals will be different. Further processing by other companies to make different types of commercial oils can create more confusion. Cheaper brand, like those of Walmart, reports only the amount of elemental zinc. Other companies report the amount of zinc derived from ZDDP that they added to their formulation and not the total. The bottom line is that we should buy oil from a reputable brand and change oil religiously. Have you guys noticed how many different brands are used in these posts? All the cars are operating fine using these many different types of oils. If we perform statistical analysis then the final answer is that it does not matter which type of oil you use. The frequency of oil change and how well we take care of the car are more important.

[BrandonG]

15w40 all day i use mobil one oil and filter did the same on my aba in my vw and it ran strong forevor :) btw my m20 has 300k and runs like a champ ;)