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Engine oil series 90

Started by KD, January 20, 2012, 07:09:53 PM

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KD

Whats the best engine oil to use and what viscosity for my V-16?
Ken D
Ken Dennison

1935 Auburn S/C Cabroilet
1940 Cadillac V16 7 passenger Imperial Sedan (9033)
1929 Ford Closed Cab Pick Up
1960 Austin Healey Sprite

Mike Josephic CLC #3877

#1
My old books tell me that Cadillac recommended SAE 30 weight during this
time period for summer, SAE 20 weight for winter.  The modern equivalent
would be a 10W-30 type for year around use.  Any major brand oil that's
API certified should be fine.

As for the V16, I'm not aware of any special oil requirements but for something
as rare as you have, I would advise you to seek other opinions especially
from owners of such cars.  Also, if you have a shop manual or the authenticity
manual that's a good resource to check.

Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

Tom Magdaleno

Mike, My understanding of oil viscosity is that a 10w-30 is a 10 weight oil with the heat resistance of a 30 weight oil.  I'm not sure if an old engine that usually had loose tolerances from the factory needed the 30 weight for the heat resistance or for the oil pressure (take up the space in the tolerances and maintain pressure).  I would err on the side of caution and run heavier oil like 20w-50 along with some Lucas zinc additive. 
Tom
'38 Cadillac V16
'71 Buick Riviera
'65 Chevy Truck
'56 Packard Super Clipper

Mike Josephic CLC #3877

Tom:

Your understanding is not correct.  The functioning of the viscosity additives
in multigrade oils is rather counter-intuitive.  That is, they are formulated to
thicken when getting hotter and thinner when getting colder -- the opposite
that one would normally think of.

Therefore, a 10W-30 oil acts like a 10 weight when it's very cold outside and
like a 30 weight when its hot outside.  That's why back in 1955 or so Cadillac
recommended to switching to a multigrade, instead of doing the "30 weight
in summer and 10 or 20 weight in winter" ritual.  It's in the shop manual.

An oil like a 15W-50 or 20W-50 is not a suitable oil for our older cars as it
is not thin enough (cannot be the correct viscosity) because of its additive
package.  It cannot provide sufficient lubrication protection for the bearings
especially in cold weather.


Mike
1955 Cadillac Eldorado
1973 Cadillac Eldorado
1995 Cadillac Seville
2004 Escalade
1997 GMC Suburban 4X4, 454 engine, 3/4 ton
custom built by Santa Fe in Evansville, IN
2011 Buick Lucerne CX
-------------------------------------
CLCMRC Museum Benefactor #38
Past: VP International Affiliates, Museum Board Director, President / Director Pittsburgh Region

Tom Magdaleno

Ok, thanks Mike, I had it backwards.
Tom
'38 Cadillac V16
'71 Buick Riviera
'65 Chevy Truck
'56 Packard Super Clipper

RayPayne

Ken, I recommend Lubriplate Super HDS. It contains 800 ppm ZDDP. I use SAE40 in my '31 V12. You can get it by mail from Restoration Supply Company at 800 306 7008. They are very knowledgable about all kinds of lubricants. Ray Payne.

KD

Ken Dennison

1935 Auburn S/C Cabroilet
1940 Cadillac V16 7 passenger Imperial Sedan (9033)
1929 Ford Closed Cab Pick Up
1960 Austin Healey Sprite

MB49Caddy

Quote from: RayPayne on January 24, 2012, 12:08:41 AM
Ken, I recommend Lubriplate Super HDS. It contains 800 ppm ZDDP. I use SAE40 in my '31 V12. You can get it by mail from Restoration Supply Company at 800 306 7008. They are very knowledgable about all kinds of lubricants. Ray Payne.

Thanks Ray, I am going to give them a call too. Talking oil is like talking drinks. Everyone likes different ones but it is important to stay within a range to not screw up the lump under the hood... ;D
"Sir, my concern is not whether God is on our side; my greatest concern is to be on God's side, for God is always right." - Abraham Lincoln

waterzap

#8
Mike is correct. A 10W-30 oil has the same viscosity as a 10 weight oil when it is cold (W = winter) and 30 weight oil when it is hot. Cold and hot are relative, but they measure oil viscosity at very low and very high temps. Probably much lower and higher than you would start your classic car in, or let the engine heat up to.
That is the basis of multigrade oils, but its not very intuitive.

When you dump out some multigrade oil when the oil is cold, you will see that it flows harder (more viscosity) than when it is hot, so you might think, what is going on. Should it not get thicker with heat? Not quite.

Think of it as two oils. I am just going to make up some numbers. The numbers you see on the oil is not viscosity numbers. If I remember correctly, they came up with these numbers almost a hundred years ago. Looking at how long a certain amount of oil takes to travel a certain distance. Any oil made today is vastly superior to anything they made when these old cars were made.

Say we have a 30 weight oil.
At 0 degrees, the viscosity might be 1000 (thick). When the oil heats up (say 200F) and the engine gets to operating temp, the viscocity goes down, say to 500 (thinner)

Now let’s look at the 10 weight oil.

At 0 degrees the 10 weight oil will be thinner than the 30 weight oil, say 700. This is great. Thinner oil flows more easily.
However when the engine heats up, the 10 weight oil gets even thinner. Much thinner than the 30 weight oil. Now we have an oil that only has a viscocity of 300, which might not be enough to keep the engine parts separated.

So to recap. The 10 weight oil will have a viscosity of 700 at 0F, and a viscosity of 300 at operating temp.
The 30 weight oil will have a viscosity of 1000 at 0F, and 500 at operating temp.

When we start up, we want a thin oil, so we would like to have a 10 weight oil at 700 viscosity. However the 10 weight oil thins out too much with heat. So viscocity modifiers are added to the oil. Now when warmed up, the oil will act like a 30 weight oil. The 10W30 oil will still thin out. However at operating temp it won’t thin out as MUCH as a straight 10W oil. It will only thin out as much as a 30 weight oil.

Straight 30, 10W30, 5W30 oils will all be the same viscocity at operating temp, ie 500. Now of course you might think, why not just choose a 5W30? Great low temp, and keeps good viscosity at higher temps. That is true, but a 5W30 oil will have more viscosity modifiers and less base stock than a 10W30 oil. SOME synthetics I dont think use these modifiers. They are engineered to be different oils at different temps. But even with synthetics there are some that are more synthetic than others.

In my Northstar engine they specifically say not to use 5W30 oil except in certain conditions. A 10W30 oil is required because the viscosity modifiers apparently burn and cause carbon deposits (as I understand it). Also if the modifiers are used up, the oil will become a 5 weight oil and will not give adequate protection at operating temps.

Having looked at oil viscosity charts, it seems there is a BIG difference between the cold numbers (W) of at 10W30 vs. a 15W40.
The hot numbers (second number) aren’t that much different for whatever reason. So at startup the 10W30 will flow much easier than the 15W40. But once the engine is hot, they are both very similar.
In practice, with cars that are garage kept and it never gets that cold. A 10W and 15W oils will be very similar. A 20W oil will be thicker, but if the garage is warm, there once again might not be a big difference between the 20W and the 10W oil. At -30F, that’s a different story altogether.

Once the engine is at operating temps, the 20W50 oil is now a 50 weight oil. It is still thinner than when you started  the car up, but not as thin as it would have been with a 20W30 oil for example.

Personally. I use good old Delo 15W40 for almost everything except the Northstar. That gets Rotella 10W30.
As I usually don’t drive most of my cars when it is cold, the 15W is a non issue. The 40 adds a bit of viscosity when the engine is hot.

https://cglapps.chevron.com/msdspds/PDSDetailPage.aspx?docDataId=339444&docFormat=PDF

The Delo has 1300 ppm zinc and 1200 phosphorus as per the Chevron site.
Most engine and engine component manufacturers recommend zinc and phosphorus content of more than 1,200 PPM for break-in, so I am more than comfortable with those numbers for my cars.
Leesburg, AL

"Cadillac Kid" Greg Surfas 15364

Not to "muddy" this thread, but basic fluid dynamics tells us that the dominating cause of kinematic viscosity in liquids is molecular cohesion.  Multi-viscocity lubricants are "chock full" of magic compounds that modify molecular cohesion with changes of temperature, and it is not just a matter of thicker and thinner.  In an automobile engine the "viscosity" that counts is the ability of the lubricant to provide a film between bearing surfaces that will not be "squeezed out" by pressure and/or temperature.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-