TheSamba.com :: View topic - 20w-60 multigrade oil question

Sun Jun 04, 2023 3:58 pm

Good morning from Brisbane.
Two months ago I bought a 1972 super beetle which is basically standard.
I have been using 20-60 multigrade oil and using my VDO oil pressure gauge as a viscometer of sorts note that oil pressure at start up is around 40 lbs/sq. inch at idle and when up to operating temperature drops to around 10 lbs./sq.inch.at idle.
I realise oil viscosity drops with increasing temperature so I presume hot 20w-60 grade has lower viscosity than cold oil of the same spec.judging by the oil pressure drop as per gauge. If this is the case and 20 weight oil flows well to prevent metal to metal contact surely the same oil supposedly with viscosity now equivalent to 60 weight is thinner than 20 ( at start up) and can then bathe bearings just as well.If my thinking is correct the theory that thicker oil reduces flow to bearings (when hot) is flawed.
All I am saying is that if cold 20 weight is ok then so is hot 60 weight wrt bathing bearings.What do you fellas think?

Sun Jun 04, 2023 4:02 pm

Unless it's a severely worn engine, you need thinner oil.

Sun Jun 04, 2023 4:11 pm

Good gawd, isn't that one step below gear oil?, I didn't even know they made it that thick.

As Glenn says unless it's super worn out 10-30 is about as thick as a properly functioning oil relief system can handle to work as VW designed it.

Sun Jun 04, 2023 4:20 pm

busdaddy wrote: Good gawd, isn't that one step below gear oil?, I didn't even know they made it that thick.

As Glenn says unless it's super worn out 10-30 is about as thick as a properly functioning oil relief system can handle to work as VW designed it.

But, but, but, all the pro engine builders (GEX Lol!) recommend running 20-50wt. oil in their engines. :D

I typically use 30wt. and never over think it.

Sun Jun 04, 2023 5:00 pm

20w-60 is the recommended oil in Australia.Read Rob (VW resource) who states viscosity of hot 20w-60 is the same as monograde 40 weight that vw recommended before clever oils,no one has answered my theory as yet , worth thinking about instead of following the leader who may or may not be right.
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Sun Jun 04, 2023 5:33 pm

I thought we all answered your question, that goo is far too thick for any VW engine regardless of what temperature it is outside. The only thing tar like that will accomplish is a constant bypass of the oil cooler because it fools the system into cold mode (even in tropical climates), but if you will sleep better at night dump it in and drive, let us know how it works out long term.

Sun Jun 04, 2023 6:15 pm

Busdaddy, the "goo" is less viscous at running temperature than 20weight is at start up, is it "goo" also?
This oil is recommended and used widely in Australia for aircooled vw,it is manufactured to a very high standard by one of the leading oil companies, if you are lucky it may become anvailable in America and become the gold standard.
My only answer I am seeking is simply if 20 weight is safe for start up why then isn't 60 weight at operational temperature if it has LESS viscosity,my car runs cool so I confident the oil cooler is being perfused as it is designed to do.

Sun Jun 04, 2023 6:41 pm

chookhen wrote: Busdaddy, the "goo" is less viscous at running temperature than 20weight is at start up, is it "goo" also?
This oil is recommended and used widely in Australia for aircooled vw,it is manufactured to a very high standard by one of the leading oil companies, if you are lucky it may become anvailable in America and become the gold standard.
My only answer I am seeking is simply if 20 weight is safe for start up why then isn't 60 weight at operational temperature if it has LESS viscosity,my car runs cool so I confident the oil cooler is being perfused as it is designed to do.

chookhen wrote: .What do you fellas think?
We all think it's too thick. But you seem to disagree and are looking for everyone to say YES.

Sun Jun 04, 2023 6:42 pm

chookhen wrote: Busdaddy, the "goo" is less viscous at running temperature than 20weight is at start up, is it "goo" also?
Yet it still remains thick enough at operating temp to fool the bypass system into "start up" mode.

Thick oil isn't dangerous to pumps and bearings in the same way modern cars are, cavitation isn't quite so serious with VW's. But the bypass system isn't smart, it counts on thick viscosity when cold and super runny when at operating temp to flow correctly and cool the oil. Many "experts" recommend the thick stuff because the don't fully understand the way it works and only watch the pressure gauge, then they get perplexed by high temps and start changing other things like oil pump sizes and upgrading coolers, it's a slippery slope.

Try the thin oil, you'll be surprised.

Sun Jun 04, 2023 7:56 pm

Glenn I am only interested in the question I asked, seems according to Rustavenger that professional engine builders use 30w-50 which flies against all replies so far, I am happy to use the 20w-60 as recommended in Australia but will try a thinner oil next change as suggested by Busdaddy, my question was born only out of interest and I welcome all imput, still however I am non the wiser,we are all entitled to our own opinions, some borne out of experience others out of interest.
Busdaddy my oil cooler gets hot to the touch and dip stick quite easy to hold after a run and there is no hot engine smell thus presumably oil relief valve is operating as designed and thus I conclude oil viscosity wrt cooler is ok?

Sun Jun 04, 2023 10:16 pm

https://autoexpert.com.au/posts/qa/which-engine-oi...ngineers.)

This article says 20w60 is similar to 20w40 and 50 oils.

Mon Jun 05, 2023 12:43 am

Your question is........ complex sounding
But it's basically
why don't most engines use 60 weight oil

you guys can handle this.
Just list the pros and cons.

It's just like everything else, not too thick, not too thin.

Most engines are not hot enough or loose enough or loaded enough to benefit from 60 wt oil, so it just will be slowing them down and making them run hotter.
The oil getting thinner when it gets hot and flying away out of the hot parts..... is part of what makes it work good. This lets fresher cooler oil come in.

But if you look at the SAE J300 specifications it is just minimums and maximums, and this does not actually tell the whole story of what the ACTUAL viscosity is at the temperature you ARE running.

We have HAD the technology to been able to make wild splits like, 5-60 for many years, 30 years at least, and the reason is it hasn't taken off is most of the time it doesn't work better or have better bang for the buck.

Mon Jun 05, 2023 12:49 am

Hi bnam
Thank you for your reply and the attachment which states Penrite 20w60 is an API graded oil compatible with SAE grades20W40 and20W50.
As i understand these grades are all suitable for ACVW engines.

Mon Jun 05, 2023 1:41 am

Hi Modok,

Thank you for your response which is at least balanced, I'm pleased that at least the 20W60 is ok, it has a good load of zinc too but I take your point that it doesn't have a great bang for buck and isn't any better than the better known players.
Probably Australia's most prolific builder recommends 20W50 in all his customers and his own cars, any well known brand particularly if on special, interestingly doesn't mention Zinc at all so possibly not required.
I'll try his recommendation next oil change and bet the car does't feel the difference.

Mon Jun 05, 2023 9:55 am

I stopped arguing and trying to reason with all the 20w50 or bust people. It's just not worth it, and it IS their equipment. Hey, running that thick guarantees bypassing the oil cooler... GREAT way to drop the viscosity so it sort of works and doesnt smoke bearings etc. :lol: :lol: :lol:

Mon Jun 05, 2023 11:26 am

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

Try reading with an open mind.

Mon Jun 05, 2023 1:05 pm

that is a very interesting read. Tech Article 69 is about Aircooled Engines, FYI. Ironically, I run the preferred A/C oil in my 911 - 20/50 VR1 Racing oil.

Mon Jun 05, 2023 1:44 pm

All you folks that live in the USA need to understand that oils in other parts of the World have different standards than here in the USA. They may also be graded differently.

To the OP, you need to listen to the folks in your country about the oils produced in your country and the standards accepted in your country.

Mon Jun 05, 2023 3:55 pm

Firstly MuzzcoVW read the article tcoop1100 has attached with an OPEN mind.
tech
2. tcoop1100, thanks very much ,540RAT -Tech Facts ,not myts is the best article I have ever read regarding motor oil Engineering, as he states many people fail to understand that oil becomes thinner and thinner as temperature gets hotter and hotter and 20w-60 is much thinner at operating temperature than it initially is at start up,it gets THINNER not thicker ,this was my thinking from the outset, seems all you 10-30 guys are advocating the worst possible weight oil for their cars.
3.Franklinstower..if it's good enough for your 911 it is good enough for my poor little dub!

Mon Jun 05, 2023 5:32 pm

For what it's worth I've run GTX or VR-1 20w-50 in my cars for many years and thousands of miles with none of the dire consequences some of the 10w-30 guys keep predicting.

What irks me is that there are other methods and experiences that are valid and have value but some here seem to think only their way matters and go out of their way to denigrate anyone who questions the conventional wisdom or tries something different and has success with it.

Chookhen mentioned more than once that his motor works well with the 20w-60 and yet some here can't seem to accept that at face value.

Unless you can prove empirically with data and test results that something doesn't work then you're just pissin' in the wind. :D