Here is the oil chart from my 1973 Chevrolet Factory Service Manual.
67-81 GM viscosity chart
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Originally Posted By: jhellwig
Originally Posted By: maxdustington
SAE 30 above 5 celsius good to know, you can use SAE 30 for most of the year.
5W20 is odd but I think SAE 10 is even more strange. You could run straight grades year round if you wanted to throughout the 70s apparently.
It is 10w not sae 10. Two different things. Don’t ask me what it is but I just know it’s different.
SAE 10W is basically SAE 0W-8 without the extended cold-start performance, as the latter only differs by being a synthetic with high viscosity index (VI). It's amazing that it would be recommended for a classic car. In fact 0W-8 is probably thicker at 150 C.
There is an old study (1970s?) I linked a while ago that ran SAE 10 in an engine and no matter what they did, they couldn't fail the bearings. I'm not sure what is the viscosity difference between SAE 10 and SAE 10W, other than the obvious W cold-start rating. For example technically SAE 20W is allowed to be a little thinner than SAE 20. SAE 10 no longer exists.
Originally Posted By: maxdustington
SAE 30 above 5 celsius good to know, you can use SAE 30 for most of the year.
5W20 is odd but I think SAE 10 is even more strange. You could run straight grades year round if you wanted to throughout the 70s apparently.
It is 10w not sae 10. Two different things. Don’t ask me what it is but I just know it’s different.
SAE 10W is basically SAE 0W-8 without the extended cold-start performance, as the latter only differs by being a synthetic with high viscosity index (VI). It's amazing that it would be recommended for a classic car. In fact 0W-8 is probably thicker at 150 C.
There is an old study (1970s?) I linked a while ago that ran SAE 10 in an engine and no matter what they did, they couldn't fail the bearings. I'm not sure what is the viscosity difference between SAE 10 and SAE 10W, other than the obvious W cold-start rating. For example technically SAE 20W is allowed to be a little thinner than SAE 20. SAE 10 no longer exists.
Originally Posted By: Warstud
What the heck is a 20w20?
The farmer's co-op in my home town had it on the shelf in 1989-90. Farmland brand, at the service station and in the convenience store across the street.
I vaguely remember the guy who I helped overhaul my 1970 Pontiac 400 having me run it, either for the cam break-in or the first fill afterward.
What the heck is a 20w20?
The farmer's co-op in my home town had it on the shelf in 1989-90. Farmland brand, at the service station and in the convenience store across the street.
I vaguely remember the guy who I helped overhaul my 1970 Pontiac 400 having me run it, either for the cam break-in or the first fill afterward.
My Canadian 79 Malibu used 5W-30 year round according to the owner's manual. It gets up into the 90's F here. The plot thickens....
Originally Posted By: Warstud
What the heck is a 20w20?
The "20w" simply meant it had a cold viscosity (J300 spec, you know) measured in some standard device to simulate starting an engine.
Obviously a "20w" would be thicker than a "5w" when very cold; i.e., harder starting; your starter motor turns over more slowly cold.
Then, the "20" part is just another part of the J300 spec defined as a low-shear viscosity (how thick it is) at the temperature of boiling water by definition.
After all that, think how they made a 20w20 vs. a 5w20: A 5w20 needs more of the fragile VII chemicals, since you need thin base oils to meet the "5w" cold part, but it must still be thick enough to be a "20" at high temperatures. (Remember VII chemicals thicken a base oil at high temperatures without affecting cold temperature viscosity much.)
A 20w20 needs less VII, so its more stable over time at high temperature, high speed driving, made with thicker base oils to start with compared to 5w20.
What the heck is a 20w20?
The "20w" simply meant it had a cold viscosity (J300 spec, you know) measured in some standard device to simulate starting an engine.
Obviously a "20w" would be thicker than a "5w" when very cold; i.e., harder starting; your starter motor turns over more slowly cold.
Then, the "20" part is just another part of the J300 spec defined as a low-shear viscosity (how thick it is) at the temperature of boiling water by definition.
After all that, think how they made a 20w20 vs. a 5w20: A 5w20 needs more of the fragile VII chemicals, since you need thin base oils to meet the "5w" cold part, but it must still be thick enough to be a "20" at high temperatures. (Remember VII chemicals thicken a base oil at high temperatures without affecting cold temperature viscosity much.)
A 20w20 needs less VII, so its more stable over time at high temperature, high speed driving, made with thicker base oils to start with compared to 5w20.
Originally Posted By: Warstud
What the heck is a 20w20?
What the heck is a 20w20?
Originally Posted By: Dave1027
I think it's odd that they have 10w30 going past 100 degrees F but 5w30 only goes to 60 degrees? The first number is for cold engine. At operating temps, both oils are 30 weights.
the owners manual for my 2002 jeep is the same
I think it's odd that they have 10w30 going past 100 degrees F but 5w30 only goes to 60 degrees? The first number is for cold engine. At operating temps, both oils are 30 weights.
the owners manual for my 2002 jeep is the same
Originally Posted By: Chris142
Originally Posted By: Dave1027
I think it's odd that they have 10w30 going past 100 degrees F but 5w30 only goes to 60 degrees? The first number is for cold engine. At operating temps, both oils are 30 weights.
the owners manual for my 2002 jeep is the same
They have the same viscosity in the hydrodynamic-lubrication region (such as in the bearings) but not in the boundary-lubrication region (such as in the valvetrain and timing chain) where the viscosity-index improver (VII) no longer thickens the oil with the oil film nearly entirely squeezed out. There you need to look at the base-oil viscosity; hence, 10W-30 protects better with its thicker base oil.
Originally Posted By: Dave1027
I think it's odd that they have 10w30 going past 100 degrees F but 5w30 only goes to 60 degrees? The first number is for cold engine. At operating temps, both oils are 30 weights.
the owners manual for my 2002 jeep is the same
They have the same viscosity in the hydrodynamic-lubrication region (such as in the bearings) but not in the boundary-lubrication region (such as in the valvetrain and timing chain) where the viscosity-index improver (VII) no longer thickens the oil with the oil film nearly entirely squeezed out. There you need to look at the base-oil viscosity; hence, 10W-30 protects better with its thicker base oil.
Originally Posted By: oil_film_movies
Originally Posted By: Warstud
What the heck is a 20w20?
The "20w" simply meant it had a cold viscosity (J300 spec, you know) measured in some standard device to simulate starting an engine.
Obviously a "20w" would be thicker than a "5w" when very cold; i.e., harder starting; your starter motor turns over more slowly cold.
Then, the "20" part is just another part of the J300 spec defined as a low-shear viscosity (how thick it is) at the temperature of boiling water by definition.
After all that, think how they made a 20w20 vs. a 5w20: A 5w20 needs more of the fragile VII chemicals, since you need thin base oils to meet the "5w" cold part, but it must still be thick enough to be a "20" at high temperatures. (Remember VII chemicals thicken a base oil at high temperatures without affecting cold temperature viscosity much.)
A 20w20 needs less VII, so its more stable over time at high temperature, high speed driving, made with thicker base oils to start with compared to 5w20.
What makes it different from a SAE 20 ?
Originally Posted By: Warstud
What the heck is a 20w20?
The "20w" simply meant it had a cold viscosity (J300 spec, you know) measured in some standard device to simulate starting an engine.
Obviously a "20w" would be thicker than a "5w" when very cold; i.e., harder starting; your starter motor turns over more slowly cold.
Then, the "20" part is just another part of the J300 spec defined as a low-shear viscosity (how thick it is) at the temperature of boiling water by definition.
After all that, think how they made a 20w20 vs. a 5w20: A 5w20 needs more of the fragile VII chemicals, since you need thin base oils to meet the "5w" cold part, but it must still be thick enough to be a "20" at high temperatures. (Remember VII chemicals thicken a base oil at high temperatures without affecting cold temperature viscosity much.)
A 20w20 needs less VII, so its more stable over time at high temperature, high speed driving, made with thicker base oils to start with compared to 5w20.
What makes it different from a SAE 20 ?
Originally Posted By: Warstud
What makes it different from a SAE 20 ?
These days, in practice, I doubt there are differences between SAE 20, SAE 20W, and SAE 20W-20 oils sold out there. Technically they need to satisfy all tests described in the table above for both grades they claim.
What makes it different from a SAE 20 ?
These days, in practice, I doubt there are differences between SAE 20, SAE 20W, and SAE 20W-20 oils sold out there. Technically they need to satisfy all tests described in the table above for both grades they claim.
Originally Posted By: Gokhan
SAE 10 no longer exists.
The reason for this is to eliminate confusion in thinner oils. They came up with SAE 16, 12, and 8 instead. (See the table in the previous page.) SAE 10W and 15W remain.
SAE 10 no longer exists.
The reason for this is to eliminate confusion in thinner oils. They came up with SAE 16, 12, and 8 instead. (See the table in the previous page.) SAE 10W and 15W remain.
Appreciate the expertise Gokhan.
Originally Posted By: Gokhan
Originally Posted By: Gokhan
SAE 10 no longer exists.
The reason for this is to eliminate confusion in thinner oils. They came up with SAE 16, 12, and 8 instead. (See the table in the previous page.) SAE 10W and 15W remain.
There was NEVER an SAE 10 to "not exist"...nor was there an SAE15...and SAE 15W is a relatively recent invention along with 0W.
Oh, and 10W could never be considered a 0W8, so we are clearly on a roll.
Here's some (not all, I'm trying to get them all) J300s going back in time.
The "W" ratings are the MAXIMUM viscosities at cold temperatures...the SAE Grade is either a minimum or a range. in order to carry the 20W20 label, it needs to meet the maximum viscosity specs for 20W, and be in the range for a 20 grade.
first couple of charts are the modern ones, note that the "W" grades are at different temperatures.
Compared to the older ones that used 0F, and viscosity maximums, which were ultimately found to be not very good for predicting operation at temperatures below 0C, as the concept of wax formation and gelling wasn't understood or clear.
Note the absence of SAE10, SAE15, 15W, or 0W.
Last one is the oldest I've found...
Here's a CITGO monograde chart (they dropped 20W20 recently on a lot of their lines, but nearly every 20 these days would be a 15W, or 10W20 in reality, with an HTHS of around 2.9, same as the minimum for an ILSAC 30).
the 10W is clearly a 10W, not a 0W...
The CCS at -25C is 4,000, and using the doubling per 5C drop (even assuming no wax formation) couldb't cross into 5W territory....MRV is a different matter, but the MRVs are puffed up to allow for teh effect of VIIs at low shear rates...the CITGO 10W's MRV at 10,000 (-30C) is indicative of little to no VII action (should have none, as it's a monograde).
It's KV100 at 6.9 (note that it's graded only as a 10W...there is no upper range for a 10W, and there is NO SAE10 now or ever) could give it a 12, 16, or (just) 20...HTHS of 2.3 would make it probably a 16, possibly a 12.
So a 10W...is a 10W.
And likely in the modern parlance a 10W16, or possibly a 10W12, and not likely a 10W20...but definitely not a 0W8.
Castrol Tection
https://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/5AB64AFC2F7027E780257A4B003AF801/$File/BPXE-8WPPFA.pdf
Shell Rimula X
http://www.alba.al/files/products/GPCDOC_GTDS_Rimula_X_monogrades_2.pdf
Oh and for giggs, here's the equivalent in CAT T04, when they started to run away from J300 as it wasn't suiting their needs.
Their specification of a max viscosity at a minimum temperature makes a lot of sense...but they aren't dealing with the impact of VII plastics either.
Originally Posted By: Gokhan
SAE 10 no longer exists.
The reason for this is to eliminate confusion in thinner oils. They came up with SAE 16, 12, and 8 instead. (See the table in the previous page.) SAE 10W and 15W remain.
There was NEVER an SAE 10 to "not exist"...nor was there an SAE15...and SAE 15W is a relatively recent invention along with 0W.
Oh, and 10W could never be considered a 0W8, so we are clearly on a roll.
Here's some (not all, I'm trying to get them all) J300s going back in time.
The "W" ratings are the MAXIMUM viscosities at cold temperatures...the SAE Grade is either a minimum or a range. in order to carry the 20W20 label, it needs to meet the maximum viscosity specs for 20W, and be in the range for a 20 grade.
first couple of charts are the modern ones, note that the "W" grades are at different temperatures.
Compared to the older ones that used 0F, and viscosity maximums, which were ultimately found to be not very good for predicting operation at temperatures below 0C, as the concept of wax formation and gelling wasn't understood or clear.
Note the absence of SAE10, SAE15, 15W, or 0W.
Last one is the oldest I've found...
Here's a CITGO monograde chart (they dropped 20W20 recently on a lot of their lines, but nearly every 20 these days would be a 15W, or 10W20 in reality, with an HTHS of around 2.9, same as the minimum for an ILSAC 30).
the 10W is clearly a 10W, not a 0W...
The CCS at -25C is 4,000, and using the doubling per 5C drop (even assuming no wax formation) couldb't cross into 5W territory....MRV is a different matter, but the MRVs are puffed up to allow for teh effect of VIIs at low shear rates...the CITGO 10W's MRV at 10,000 (-30C) is indicative of little to no VII action (should have none, as it's a monograde).
It's KV100 at 6.9 (note that it's graded only as a 10W...there is no upper range for a 10W, and there is NO SAE10 now or ever) could give it a 12, 16, or (just) 20...HTHS of 2.3 would make it probably a 16, possibly a 12.
So a 10W...is a 10W.
And likely in the modern parlance a 10W16, or possibly a 10W12, and not likely a 10W20...but definitely not a 0W8.
Castrol Tection
https://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/5AB64AFC2F7027E780257A4B003AF801/$File/BPXE-8WPPFA.pdf
Shell Rimula X
http://www.alba.al/files/products/GPCDOC_GTDS_Rimula_X_monogrades_2.pdf
Oh and for giggs, here's the equivalent in CAT T04, when they started to run away from J300 as it wasn't suiting their needs.
Their specification of a max viscosity at a minimum temperature makes a lot of sense...but they aren't dealing with the impact of VII plastics either.
Originally Posted By: Shannow
Oh, and 10W could never be considered a 0W8, so we are clearly on a roll.
Wasn't it obvious that I was comparing their KV100, not their cold performance?
Regarding SAE 10, I saw it in a classic study, perhaps referenced in the Spearot book. However, it could be an error on the author's part -- I can't find it now, somewhere linked here, in which he failed to fail the bearings with it.
Oh, and 10W could never be considered a 0W8, so we are clearly on a roll.
Wasn't it obvious that I was comparing their KV100, not their cold performance?
Regarding SAE 10, I saw it in a classic study, perhaps referenced in the Spearot book. However, it could be an error on the author's part -- I can't find it now, somewhere linked here, in which he failed to fail the bearings with it.
I currently have a similar CHILTON Manual for a '67-'81 Firebird/Esprit/FORMULA/TRANS AM which says the same thing as does the Owner's Manual for my '80 FORMULA in my signature.
In the past, I also had a CHILTON manual and the OM for an '84 Charger/Turismo/Shelby Charger w/2.2L which was similar as well.
NOTICE The Statement:
* "5W20 oil is not recommended for sustained high speed driving".
This^^^ was before these 5W20 oils were stout enough for those older vehicles. Today, it's a different story, isn't it?
In the past, I also had a CHILTON manual and the OM for an '84 Charger/Turismo/Shelby Charger w/2.2L which was similar as well.
NOTICE The Statement:
* "5W20 oil is not recommended for sustained high speed driving".
This^^^ was before these 5W20 oils were stout enough for those older vehicles. Today, it's a different story, isn't it?
Originally Posted By: Shannow
Here's the recommnedation for the Chev Small Blocks (via Holden) in the late 60s.
Got to interpret it as a chart, as it doesn't look sensible at first glance
... which contradicts what you claimed about the nonexistence of SAE 10, as I see a SAE 5W-10 in there.
Here's the recommnedation for the Chev Small Blocks (via Holden) in the late 60s.
Got to interpret it as a chart, as it doesn't look sensible at first glance
... which contradicts what you claimed about the nonexistence of SAE 10, as I see a SAE 5W-10 in there.
Originally Posted By: Gokhan
Originally Posted By: Shannow
Here's the recommnedation for the Chev Small Blocks (via Holden) in the late 60s.
Got to interpret it as a chart, as it doesn't look sensible at first glance
... which contradicts what you claimed about the nonexistence of SAE 10, as I see a SAE 5W-10 in there.
Look at the 18C 0F line as well...I think it's a typo when gregories copied it for an aftermarket service manual.
The J300s that I used are actual SAE J300 tables...note NO SAE10.
Nice try.
Originally Posted By: Shannow
Here's the recommnedation for the Chev Small Blocks (via Holden) in the late 60s.
Got to interpret it as a chart, as it doesn't look sensible at first glance
... which contradicts what you claimed about the nonexistence of SAE 10, as I see a SAE 5W-10 in there.
Look at the 18C 0F line as well...I think it's a typo when gregories copied it for an aftermarket service manual.
The J300s that I used are actual SAE J300 tables...note NO SAE10.
Nice try.
Originally Posted By: Shannow
Originally Posted By: Gokhan
Originally Posted By: Shannow
Here's the recommnedation for the Chev Small Blocks (via Holden) in the late 60s.
Got to interpret it as a chart, as it doesn't look sensible at first glance
... which contradicts what you claimed about the nonexistence of SAE 10, as I see a SAE 5W-10 in there.
Look at the 18C 0F line as well...I think it's a typo when gregories copied it for an aftermarket service manual.
The J300s that I used are actual SAE J300 tables...note NO SAE10.
Nice try.
You're probably right. That chart looks totally rubbish.
Originally Posted By: Gokhan
Originally Posted By: Shannow
Here's the recommnedation for the Chev Small Blocks (via Holden) in the late 60s.
Got to interpret it as a chart, as it doesn't look sensible at first glance
... which contradicts what you claimed about the nonexistence of SAE 10, as I see a SAE 5W-10 in there.
Look at the 18C 0F line as well...I think it's a typo when gregories copied it for an aftermarket service manual.
The J300s that I used are actual SAE J300 tables...note NO SAE10.
Nice try.
You're probably right. That chart looks totally rubbish.
I see this is a case that eventually manufacturers do recognize the advancement in motor oils, but my guess is they only do after there tests. While they do, they don't extend the OCI on the older models. So if your driving around a 15 year old car, you probably have a OCI recommendation based on how oil was 25 to 30 years ago if not more. But worse than the manufacturers are the people. Some are still stuck on the 3000 mile oil change. Evidently, manufacturers were leaving that in the 70's already. I tell some people I am doing 10,000 mile OCI with my Toyota and they think I am going to ruin my engine.
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