History lesson- 20w-20 motor oil

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When I was a kid riding minibikes and dirt bikes I remember this viscosity of oil was popular and widespread (I think). What were it possible applications and benefits? This dates to the early 1970's if I remember correctly. With my current limited knowledge of lubricants, that weight oil seems kind of silly given the types of motors in wide use in those days. Thanks for any comments.
 
I also remember seeing a 20W-20 viscosity oil way-back-when. I reckon it was a "winter-ready" 20-weight oil. Don't know what it was used for.

Yeah, I thought it was rather a strange designation.
 
quote:

Originally posted by blupupher:
Wouldn't a 20w-20 oil be the same as a straight 20 weight oil?

This topic has been discussed before. I found it easily with a search. I believe the 20W-20 had significant pour point depressants and was near 30wt. on the upper #. Better cold properties than a straight 20 weight. Maybe not far from a cheap 10W-30 of today when new as far as pour point.
 
Way back 25-30 years? the W grades were pour depressed and the Vis grade designations had not fully encorporated the new Multi grades that were just coming out back then they were new and suspect till proven out. Also all the new style cold test machines were not avalable and pur point was the olny test.
bruce
 
20w20 was actually a very popular grade of oil throughout the 50s and 60s. In fact, I think 20w20 was factory fill in most GM, Ford, and Chrysler engines up until the late 60s.

NB: A 20w20 oil is a straight 20wt, but unlike other SAE viscosity grades, 20wt has both a low temp and high temp spec, thus it can be labeled as "SAE 20w," "SAE 20," or "SAE 20w20."
 
quote:

Originally posted by bruce381:
Way back 25-30 years? the W grades were pour depressed and the Vis grade designations had not fully encorporated the new Multi grades that were just coming out back then they were new and suspect till proven out. Also all the new style cold test machines were not avalable and pur point was the olny test.
bruce


You said it better than I did. I think some of the 20W-20 had some very low pour points, that today would get a 10W or 5W at a temp. where straight 20W would be solid. Different rating method at that time.
 
quote:

Originally posted by haley10:

quote:

Originally posted by blupupher:
Wouldn't a 20w-20 oil be the same as a straight 20 weight oil?

This topic has been discussed before. I found it easily with a search. I believe the 20W-20 had significant pour point depressants and was near 30wt. on the upper #. Better cold properties than a straight 20 weight. Maybe not far from a cheap 10W-30 of today when new as far as pour point.


Oh, I see. I guess it makes sense. They just make a 20 weight oil that is both at the low and high end of the "20" limit.
 
It's still available.

TropArtic® Single-Grade Motor Oil (20W-20)

Typical Properties: Values are representitive of current production
SAE Number Grade
------------ 20W-20
Stock Number
67270
API Gravity
30.0
Flash Point, COC, C (F)
222 (432)
Pour Point, C (F)
-30 (-22)
cP @ 10 C (+14 F)
2500
cSt @ 40 C (104 F)
59
cSt @ 100 C (212 F)
8.5
Viscosity Index
115
Sulfated Ash, %
0.85

Some cars owners used straight 20 weight in the winter ..straight 30 weight in the warmer months.

Straight 20 weight appears to be, at least from some venders/blenders a 20w-20 anyway. Now I'm not the sharpest tool in the shed ..so I could have missed this obvious point, but since one of the ways of making a multi visc is taking a 10 weight base oil and then adding VII to make it appear to be a 30 weight @ 100C ..then a straight 20 weight already is a 20W to begin with ...just being itself.

The search function is on the blink temporarily.
 
quote:

Originally posted by haley10:

quote:

Originally posted by bruce381:
Way back 25-30 years? the W grades were pour depressed and the Vis grade designations had not fully encorporated the new Multi grades that were just coming out back then they were new and suspect till proven out. Also all the new style cold test machines were not avalable and pur point was the olny test.
bruce


You said it better than I did. I think some of the 20W-20 had some very low pour points, that today would get a 10W or 5W at a temp. where straight 20W would be solid. Different rating method at that time.


Pour points have nothing to do with the rated viscosity of an oil. ExxonMobil's heavey UltraSyn PAOs in the 100 cSt range have extremely low pour points (-30C), but are also very "thick."

A typical straight 30wt has a pour point of -20F. Pour point is 5F above the point at which a chilled oil shows no movement at the surface for 5 seconds when the container it is in is turned horizontal. That means a 30wt will "pour" at -20, nevermind that it might take an hour to empty the bottle. As for pumping at -20...forget it.
 
GManII,you are correct. Don't think they spec'd MRV and CCS back then. So they didn't imply any more accuracy than was measurable. Pour point is not as relevant as it may seem. I agree.

[ July 31, 2005, 04:18 PM: Message edited by: haley10 ]
 
THANKS ALL! Great explanation. The body of knowledge here is incredible.
(Alright enough a**kissing) Peace
 
Just keep in mind the number of "loose" engines that ran on 20W oils in the old days. Those 20W oils were not up to par with the 20W oils of today. Why are we concerned about a new engine being speced for a 20W oil?
 
A 20wt oil's cold flow spec is at -15C, with a max vis at that temp of 9500 cP. How the oil performs at lower temps is irrelevant, as is the pour point, from the standpoint of meeting the cold flow specs for 20w.

I personally wouldn't use a straight 20 (or a 20w40 or 20w50, for that matter) if I expected overnight lows to dip below 20F.
 
quote:

Originally posted by Chris142:
Funny how this thread showed up today. I was at Carquest this morning and they have 5 qts of Pennz 20w-20 on the shelf.

It's very dusty, faded and rated "SF".


Buy them. They could become collector's items.

offtopic.gif
I just bought a can ot 10w30 Veedol rated API Service MS DG DM. That predates the S designations. Wonder how old that would be?
 
Hi,
SAE20W-20 lubricants were recommeded for many US cars for MY1941

This viscosity was a factory fill for VW for many years (SAE30 was the alternative). Porsche used the same viscosity but only as an HD oil
It was a very popular viscosity for English cars too - Ford, Rootes Group and BMC to name a few

A "notary" in this district recently died and in the wind up (I am a volunteer with the local Historical Society-Musuem) we discovered a stash of old oils and containers. A full gallon one is labeled "BP-Energol 20w-20 HD-MS"

Regards
Doug
 
quote:

Originally posted by bruce381:
Way back 25-30 years? the W grades were pour depressed and the Vis grade designations had not fully encorporated the new Multi grades that were just coming out back then they were new and suspect till proven out. Also all the new style cold test machines were not avalable and pur point was the olny test.
bruce


I agree entirely with Bruce’s explanation. Remember, he is speaking of 1970’s Grp I solvent refined base oils that had a relatively high wax & aromatic content. Pour point depressants have a significant effect on this type of base oil.

The SAE 20 grade did(does) not require any type of cold temp rating.

Today, a 20W rated oil, 9500 cP @ -15C, is the equivalent of a 4250 cP requirement at -10C, the temp from the 1997 revised SAE J300 chart.

So today, a 20W-20 at -10C/14F is the viscosity equivalent of a very good 5W-30 rating of 4250 at -30C/-22F.
 
quote:

Originally posted by Blue99:
So today, a 20W-20 at -10C/14F is the viscosity equivalent of a very good 5W-30 rating of 4250 at -30C/-22F.

You are so wrong it's not even funny.
rolleyes.gif
 
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