David McFall - 5w-20 article

[1 FMF]

here's my question,
from Molakule's post on the Engineer's Edge Educational site, it states fluid film thickness varies inversely with the load- when the load increases the film thickness decreases, so to what horsepower/torque rating is a 5w-20 engine oil good for, at temperatures of 200F, 240F and 280F ?

Ford wants to make 5w20 backward compatible with their whole fleet. What about marine engines? I have a 1993 351w motor, rated 285hp, in the boat. I've run synthetic 5w30 in it in the fall, would 5w20 hold up in that, why or why not?

"Ford recommends those who can't find 5w20 to use 5w30 but to switch back to 5w20 the next oil change."

What do all the people who said you can't use 30 wt in an engine calling for 5w20 or it'll damage the engine say now ?

 

[Steve S]

quote:

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Originally posted by 1 FMF:


What do all the people who said you can't use 30 wt in an engine calling for 5w20 or it'll damage the engine say now ?

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They think they know. What else can I say

 

[Terry]

Dial up is inhibiting my ability to read the article.

From our own testing, using, and concerted efforts with formulators and engine builders, the final formulation/molecular structure of the lubricant is more important than the blanket SAE 100C vis clean, at determining durability and longevity in a given engine.

One reason why synthetics were such a rage 30 years ago when I started in this business.

With better add packs and extremely stable group II/III or higher blends just about every SAE ?w-20 graded lube offers excellent protection in about any gasoline engine.

Focus on the macro lube capability not one aspect.

Most of you have been using a 20 vis @ 100c lube for years and just didn't know it until now ! Your bottles of 10w30/5w30/10w40 all sheared so severely until 7 or 8 years ago when add pack and formulating was stepped up quality wise.

 

[G-MAN]

quote:

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Originally posted by Terry:
Most of you have been using a 20 vis @ 100c lube for years and just didn't know it until now ! Your bottles of 10w30/5w30/10w40 all sheared so severely until 7 or 8 years ago when add pack and formulating was stepped up quality wise.

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And let's not forget that 20w20 was factory fill in most Detroit iron in the 50s and 60s.

 

[AEHaas]

In my testing of motor oil viscosities in the early 1970 most multi-viscosity 30 wt. oils rapidly thinned down to a 10 or 20 wt. oil. (mostly a 10 wt.) Many cars lasted several hundred thousand miles.

Therefore, todays 20 wt. oils are actually thicker than yesteryears 30 wt. oils. The reason these newer oils work so well may just be because they are in fact thicker, overall, compared to earlier 30 wt. oils during the run inside your engine.

aehaas

 

[zlippery]

If a 20 wt. oil flows better than a 30 wt. this would mean better startup lubrication especially the lower the outside temperature is. If cost and increased mpg is not a factor and engine longevity is than which grade would be best? Assuming the optimum operating vis is approx. 10 cSt at the normal operating temp (100 C). If one will not be racing / abusing the motor in any way than should one be more concerned with the viscosity of the oil at startup - ie 40 C, at normal operating temp - 100 C or at the high shear temp 150 C ? There are oils which are better at startup ie Vis of 40 plus cSt but at the high temp / shear they are between 2 and 3 cSt vis. Others are better at the high end. If 90% of wear occurs at startup then we would be better off using the 5w20 or the 0w20. So what happens 2, 5, 10 years later? If the 0w20 offers better flow at startup would we have to switch over to a 0w30 and 0w40 etc. wt as time increases and oil pressure decreases ? What is happening inside the engine if flow is better at startup using a 0w20 vs a 0w30? If the 0w20 offers better protection at startup what happens over time to affect the oil pressure? Which engine would lose oil pressure and show more wear over time given all else is equal, the one using a 0w20 or the one using the 0w30. Should we be leaning towards the 0w20's or 0w10's (if they were available) or should we lean towards the 0w30 and 5w20/30's ? Just thinking out loud. I cannot sleep lately thinking about these things!

 

[Blake Sobiloff]

zlippery, I've been thinking about the same things. In particular, I've seen how quickly oils are sheared down in a motorcycle with lubrication shared by the engine and transmission. I'm left wondering if the manufacturers are OK with oil shearing down from a 50- or 40-weight down to 30- and 20-weights? Are the engines designed to run well, with minimal wear, at the lighter weights? Just what is the optimal weight?

I'm afraid I don't have an answer, though. I'm currently trying to find a 40-weight multi-grade that won't shear, hoping that that's the best.

 

[Lumberg]

I think that when running oils with a lower than recommended viscosity, some way to supplement with lots of moly is a must.

 

[Big O Dave]

I was thinking the same thing, Lumberg. I'd put a bottle of VSOT in there.

 

[Lumberg]

That VSOT is some seriously good stuff. it's pretty thick though. I presume it wouldn't raise the viscosity at either end of the spectrum though?

 

[MolaKule]

Just remember people, thicker doen't mean better.

Recommend you make a mix and then send to Terry Dyson before putting into engine to make sure your viscosity is within spec. That way, you'll also know the what the final add package will look like.

 

[M Smith]

Bill in Utah and ToyotaNSaturn - I can easily understand your concern with the recommended 5W-20 oils and the apparently qualified "150,000 mile statement." It took me quite awhile, too, to "accept" the 5W-20 "concept," but I think I finally have. I recall having a difficult time accepting the Ford-recommended 10W-30 for my 1970 Torino; I insisted on using at least 20W-40 (remember that oil viscosity?).

If it still concerns you then give the 5W-20 a try and take intermittent oil samples. After all, it isn't as though a few oil change intervals using 5W-20 is going to forever ruin your engine. If it shows levels of wear that concerns you then you can easily switch to something more viscous. That's the rationalization I had to come to in order to take the "5W-20 plunge" with my mother's 2001 Honda.

 

[ToyotaNSaturn]

M Smith, I ran PZ Synth GF-4/SM to 2900 miles recently (in the UOA section) to give it a shot. Other than this being an older car and that it's prone to consuming oil to begin with...this was not the ideal experiment. It ran fine in the car and provided protection at the same excellent rate as other oils I've tried.

I was thinking about running PZ 5w-20 dino for the remainder of the winter, but I'm going to leave the Havoline 10w-30 SL HM formula in the crankcase. This will tell me if there is too much fuel dilution from cold idling warmups. And it will be about a 7000 mile OCI, all of winter.

Testing on 5w-20 oils will resume in spring.

[ December 31, 2005, 10:21 AM: Message edited by: ToyotaNSaturn ]

 

[SirEager]

Guys I'm sure you miss the best parts of the new thinner oils they pump and flow better.

Motor tolerances are tighter then ever before, this is a good thing. A thinner oil flows much better pass these smaller gaps.

I'm sure they are better writings but AEHaas (correct me if I'm wrong) http://63.240.161.99/motoroil/ really nailed the point home. The author states that his Ferrari is running 5-20w in FL's heat. Let me ask you how many men are confident enough to do that to a 60+ grand car and then brag about it. That is CONFIDENCE!


Now you all are focusing on the 150,000 mile testing. That is when they STOPPED testing. (Testing to 150,000 miles is not cheap 300,000 would be worst) So is the motor going blow up after they stop test? No! More likely the motor will have tolerances closer to a motor designed for 5-30 weight oil. Every car I owned made after 95 the motor was the MOST durable part of the car.

As long as your 20w oil meets the Ford spec WSS-M2C153-H or better. I would not worry.

 

[GMorg]

AEHaas wrote: " The reason these newer oils work so well may just be because they are in fact thicker"

So, thinner is better because it is thicker than use to be. And, thicker is poorer because is is thicker than use to be possible. The label on the bottle is the problem. Viscosity at 2K miles has changed!

 

[XS650]

quote:

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Originally posted by SirEager:
Guys I'm sure you miss the best parts of the new thinner oils they pump and flow better.

Motor tolerances are tighter then ever before, this is a good thing. A thinner oil flows much better pass these smaller gaps.

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I believe you actually mean "clearances" not "tolerances".

Which clearances are significantly smaller than they were in similar engines 10 years ago? Examples with numbers please.

 

[SirEager]

No I meant manufacturing tolerances. Better manufacturing tolerances allow clearances to be tighter.

quote:

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Motor tolerances are tighter then ever before, this is a good thing. A thinner oil flows much better pass these smaller gaps.

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XS650 the statement above is not based on comparisons of motor clearances over the years. So feel free to attack me on this.

Instead my statement is based on a number of sources the including the writings of AE Haas, my experiences as a consultant in a manufacturing environments, and the simple fact that ford states that oil starvation can happen if you go thicker then 5w-20.