5w 20 Facts or Fiction?

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quote:

Originally posted by Rickey:
And I do take issue with those that represent 20wt as a panacea,without fault,infallable,and universal.

It's very easy to take issue with a straw-man figment of your imagination. I don't know of anyone here who represents 20wt as you have described.
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Side leakage? A bigger pump? Rickey your sure know how to keep a thread open. Your statements try to defend your disinformation. As you see it not working.

How bad is it not working? Well you got a Jr Gearhead saying you are wrong. Now lets talk about this Jr Gearhead. I knew from the start that I was a know nothing, so for the past 4 years I been studying people smarter then me. Now I don't understand every thing but I can see the difference between science and **.

Now is a thinner oil aways better? No, but you be shocked how a good xw-20 is better suited for many applications. If oil flows better, hot oil can more quickly be cooled cooler oil from the sump, and less risk of thermal breakdown. Ricky where you go WRONG is by imaging a MYSTICAL WEDGE of OIL. In a ICE there are number of places metal on metal connect happens normally, like the piston rings. If a piston ring does not scrape oil off the piston walls, how do they work?
 
Straight 20W oil took my 1954 Ford V-8 to 140,000 miles by 1959, when I traded it. It did not smoke, was still quiet, and the mechanical valve lifters had required no adjustment since the original one at about 2,000 miles.

I got this car new in '54, a gift from my Dad when I graduated high school at age 17, and used, or abused, it until I was 22 in 1959. It never used an appreciable amount of oil, and it did not get very frequent oil changes.

If the 20 weights of the 50's were OK, shouldn't the 20 weights of today be just as good?
 
quote:

Originally posted by XS650:

quote:

Originally posted by 1999nick:
Straight 20W oil took my 1954 Ford V-8 to 140,000 miles by 1959, when I traded it. It did not smoke, was still quiet, and the mechanical valve lifters had required no adjustment since the original one at about 2,000 miles.

I got this car new in '54, a gift from my Dad when I graduated high school at age 17, and used, or abused, it until I was 22 in 1959. It never used an appreciable amount of oil, and it did not get very frequent oil changes.

If the 20 weights of the 50's were OK, shouldn't the 20 weights of today be just as good?


Why not, it was good enough for a 46 Chrysler.
46 Chrysler lube requirements


Could it be because oil temperatures ran lower then? I had oil temp gauges in some 50s and 60s vintage cars and they usually ran under 200 F oil temps, while modern cars usually run over 200 F.

A 10 to 15F temperature change is about the same true viscosity change as going from SAE 20 to SAE 30.
 
XS650,

I really enjoyed the part about using 10 wt for break-in and the part about diluting your 10 wt oil 1:10 with kerosene if the temps were expected to go below minus 10 F.
 
quote:

Originally posted by GMorg:
XS650,

I really enjoyed the part about using 10 wt for break-in and the part about diluting your 10 wt oil 1:10 with kerosene if the temps were expected to go below minus 10 F.


Some piston engine military aircraft used to dilute their oil with gasoline if they were going to have to let them sit in extremely cold weather. They had the occasional engine fire cooking the gas out of the oil when they started them later too.
 
I have read here or another post about 10 PSI oil pressure for every thousand RPM would indicate the correct oil viscosity. I kind of think my motorhome towing an 8000 lb trailer on the flat highway in overdrive at about 2300 rpm would destroy the engine if it only had about 23 PSI oil pressure. In all engines cruising down the highway in overdrive wouldn't it be better to have about 60PSI vs 20? I have read all the charts and links on this thread. In all of my vehicles oil guages (except dune buggy)(some do not have numbers just L and H), the guage may drop slightly at idle but moves up and does not change from about 1000 to redline. One has 5-30, 2 have 10-30, one has 15-40. The dune buggy currently with 15-40 does fairly closely follow the 10 PSI per 1000 rule. It's getting 20-50 before next season.
 
Every one is partly right the crank will run 'off center" as the oil wedge pushes over and a thicker oil will move the wedge some also BUT the total clearence in the bearing does not change and the dif between a high vis oil and a low vis oil is also midigated by "leakage" out the side of the bearing as the wedge moves the crank more leakage,is present and oil pressure/flow drops and crank will "try" to center kinda self limitng.

It is all small differences and IMHO boils down to other peramiters such as cold temp start up flow, ANY hydrodynamic regime is GOOD nothing touching.

""Oil at the wedge can also act as a solid under extreme pressure""

Not true the angles of wedge formation will not allow oil to be trapped thus EHL will not form
in a Plain bearing, gear teeth and roller bearing yes but crank or rod NO.

bruce
 
I've gotten very good UOA's on the wife's car with both Motorcraft and M1 5w and 0w-20's. Low wear metals are low wear metals.
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It has Pennzoil Platinum 5w-20 now which I will drain this week and send to Blackstone with 5k on it.
I bought Pennz Plat 5w-30 that I'll put in for summer and see how that compares.
 
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