The Stovebolt Site Forums The Shop Area Engine Shop 50w motor oil?

I am getting ready to change oil in my 53 with a tired 216, and I asked at the FLAPS about 30W. It doesn't seem to belong to the standard assortment in Sweden, but they did have 50W. I bought 4 liters, but have not changed yet.
So the question - is it a bad idea to run straight 50W? I figure my alternative is to mix it 50/50 with regular 10/40.
Karl

In the beginning there were single weight oils. Single weight oils are thicker when cold and thinner as they heat up. So when the engine is cold you don’t get great lubrication and when it’s hot the oil thins out too much. So you chose a mid range oil as a compromise. Then multi-weight oils were invented. They act like a 10 weight when cold and a 40 weight when hot – the best of both worlds. Use the 10W-40W straight.

Agree!!! Your 10W40 would be an excelent choice for your 216, tired or not. The older straight weight oils were all they had when they built them.
DG

Gotta disagree with the above advice- - - -multi-weight oils don't change thickness according to temperature, they just lubricate like a heavier-weight oil as they heat up. The physical thickness stays at the lowest rating, which does not do a good job of cushioning parts with wide clearances. Try jumping onto a floor with a single layer of carpet on it from 10 feet up, or one with 3 inches of foam rubber- - - -which one will be more painful to land on? That's what's happening to bearings, etc. with a multi-weight oil. To prevent hammering of parts due to excess clearance in a worn engine, it needs the physically thicker oil to act as a shock absorber. I'd reccomend using about 2/3 of a crankcase full of 50 weight, and add a couple of quarts of 10W-30 or something similar in cold weather for better cold start lubrication.
Jerry

"The temperature range the oil is exposed to in most vehicles can be wide, ranging from cold temperatures in the winter before the vehicle is started up, to hot operating temperatures when the vehicle is fully warmed up in hot summer weather. A specific oil will have high viscosity when cold and a lower viscosity at the engine's operating temperature. The difference in viscosities for most single-grade oil is too large between the extremes of temperature. To bring the difference in viscosities closer together, special polymer additives called viscosity index improvers, or VIIs are added to the oil. These additives are used to make the oil a multi-grade motor oil, though it is possible to have a multi-grade oil without the use of VIIs. The idea is to cause the multi-grade oil to have the viscosity of the base grade when cold and the viscosity of the second grade when hot. This enables one type of oil to be generally used all year. In fact, when multi-grades were initially developed, they were frequently described as all-season oil. The viscosity of a multi-grade oil still varies logarithmically with temperature, but the slope representing the change is lessened. This slope representing the change with temperature depends on the nature and amount of the additives to the base oil.

The SAE designation for multi-grade oils includes two viscosity grades; for example, 10W-30 designates a common multi-grade oil. The two numbers used are individually defined by SAE J300 for single-grade oils. Therefore, an oil labeled as 10W-30 must pass the SAE J300 viscosity grade requirement for both 10W and 30, and all limitations placed on the viscosity grades (for example, a 10W-30 oil must fail the J300 requirements at 5W). Also, if an oil does not contain any VIIs, and can pass as a multi-grade, that oil can be labelled with either of the two SAE viscosity grades. For example, a very simple multi-grade oil that can be easily made with modern base oils without any VII is a 20W-20. This oil can be labeled as 20W-20, 20W, or 20. Note, if any VIIs are used however, then that oil cannot be labeled as a single grade.

The real-world ability of an oil to crank or pump when cold is potentially diminished soon after it is put into service. The motor oil grade and viscosity to be used in a given vehicle is specified by the manufacturer of the vehicle (although some modern European cars now have no viscosity requirement), but can vary from country to country when climatic or fuel efficiency constraints come into play"

Unless your rods and mains have .010" clearance don't ever use 50.

Is the oil really marked as a "50W"? Looking at the viscosity table in the latest SAE viscosity standard (J300) I do not see a 50W, only a 50. The viscosity of the 50 grade oil is probably at least slightly higher than you need at operating temperature, but may be a lot higher than needed at cold temperatures. The viscosity table does not even specify a value for low temperatures.

Hoyt

I have used 50W oil in engines that were about to die from bad bearings (low oil pressure). I do not know if the 50W helped any but I was desperate.

The label says
"Gulf Single G SAE 50
Gulf single G has been especially developed for use in older gasoline engines under conditions where a singlegrade oil is appropriate."
Now do I presume to believe that this product is appropriate for my bolt? Nay, but it might be. That is why I am asking. The manufacturer of my vehicle recommends straight 30W.

I just changed oil, and used Q8 10w30 for old cars and trucks with gas engines.

I used 10w40 in my old chevy with a 235, and the engine rattled a lot.
Changed to 10w30 and it calmed down.

I also talked to someone who said straight 50 oil.

As far as I'm concerned, 10w30 is the best choice so far.

/Ulf, Eskilstuna

might not be a good idea in winter or in cold temp...

The SAE has caused a lot of confusion by not adding a letter suffix to the viscosity grade number for the high temperature (100 and 150 degrees C) oils. I can't provide a link to the official SAE J300 specification, but the "SAE Viscosity" table in the Synlube link seems to be fairly complete. (Scroll down a frame and click on "SAE Viscosity"). Most of the notes have been left off, but the temperatures are degrees C, the kinematic viscosity is in centistokes, and the absolute viscosity is in centipoises (I think); mo more Saybolt Universal Seconds!

Note that the cold temperature grades (W) are 0W, 5W, 10W, 15W, 20W, and 25W. The high temperature grades are 20, 30, 40, 50, and 60. Thus, the only grade that can have the same number on both sides of the hyphen is 20W-20. When I srarted working in a filling station in the mid-fifties, we sold a 10W, a 30W, a 20W-20, and a 10W-30. When a customer asked for "a straight 20 weight" we sold him a 20W-20.

Autozone just mislabeled the Kendal Oil in the ad that Tim linked to; the Conoco-Phillips-Kendal website uses the appropriate SAE "W" and "non-W" grade designations.

The 1953 Chevy Truck Owner's Manual does not seem to be advising any oil with a higher viscosity than 20W-20. I would not want to use a 50 grade oil, especially in a cool climate.

Hoyt

We have milder winters in Sweden than I ever suffered from back in Minnesota. One might say I moved here for the pleasant climate, but that is an exageration.
It seems that a number of members are running 30W. I thought of trying a little of the same. Maybe I won't. The 50W was the only straight weight oil in the store. I can always use it in the lawnmower...

Hoyt,

I understand your point about 50W.

"When you see a W on a viscosity rating it means that this oil viscosity has been tested at a Colder temperature. The numbers without the W are all tested at 210° F or 100° C which is considered an approximation of engine operating temperature. In other words, a SAE 30 motor oil is the same viscosity as a 10w-30 or 5W-30 at 210° (100° C)."

Sorry about adding confusion to this discussion.

It was straight SAE 50 oil that I used to use in the late 60s and early 70s.

And, I think I also used a "multi-grade" SAE 50 oil (before the "W" grading was around) for the same reason (higher oil pressure in an old engine). This oil was recommended to me by my brother-in-laws dirt track "pit crew" around 1970 for use in my worn-out 1948 216.

I wonder how many of the self-appointed "experts" here have actually run SAE 50 oil in anything? I ordered it by the case from one of the sponsors of my race car, and saved the slightly-used oil we drained out of the round tracker to use in my street vehicles. All of them had well over 100,000 miles, some closer to 200. For several years, I never bought any oil for any of my cars, and got excellent engine service and really good oil pressure.
Jerry

good tip, never thought of that when we were dirt track racing... just used it in the car...........

I just couldn't bring myself to dump premium-quality oil with less than 50 miles on it- - - - - -I guess I'm just a cheapskate at heart! We changed oil in the race car after every second week at the track during the racing season, from May to October, and it held 9 quarts.
Jerry

Everyone needs to remember that the low pressure engines use drip oiling on the timing gears and that's a mighty small line running to the rockers for cold 50 weight to push through. While thick oil has it's place I wouldn't run it in my '38. Many folks say 10w-30 is fine and while I admit to having used it in the past in my '38 I prefer 15W-40. I once read a technical paper that claimed multi-viscosity oil's viscosity modifiers morf into a single viscosity over a few heat/cool cycles. I don't remember the exact figures but a 10-30 would end up equivalent to about a straight 20 weight over time. Was the author full of beans? Beats me but it's something to think about when mulling over what oil to use.

SAE 50 would be a bit too thick for an older non pressurized engine, SAE 30 is the best bet. I will not use a multi viscosity oil in older engines. And for that matter there are some engine manufactures that recommended against a multi viscosity oil.
Multi vis is good for brand new cars.
Multi vis oil the base oil is the low number like 10W-30 is a 10 weight oil, with viscosity index improvers to make it similar to a 30 weight at temperature. Remember lots of newer engines have such things as antifriction lifters etc and can handle the newer low vis oils with no EP additives.