Need advice on "correct" oil for overhauled 37 engine

[drdon]

Ok experts. What is the best oil for this 37 Dictator engine, recently completely rebuilt but not yet run. I hear any quality

multi grade detergent, Classic Car Oil from Indiana, 30 W only, synthetic, and don't forget the ZDDP. So what do you all

think and recommend. Getting ready to go on this.

In addition, one web site recommended loosening the oil pressure pipe from the back of the oil pressure instrument, wrapping it

in absorbent, and cranking the engine to get the pipe full of oil. I sure don't know about this. PS: instruments were completely rebuilt a couple of years ago by Bob's Speedometer in Michigan.

[Gary_Ash]

The original shop manual says SAE 30 weight for summer use, 20 weight for winter, and 40 weight for hot summer and high speed. But, we have to remember that these are recommendations before multi-weight oils with detergents and when few cars had oil filters. The theory was that non-detergent oils would react with the crud in the oil and precipitate it into the pan. The oil got changed every 3,000 miles to get the sludge out of the pan. Even my old 1972 VW bus was designed to run this way, no oil filter.

I think modern multi-weight oils with detergents will work OK, especially if you have cleaned the engine during a rebuild and now have a filter in place. It is true that bypass filters don't take 100% of the flow all the time, but they do efficiently filter the oil over an hour or so and remove the crud. It's only at the moment of start-up that they might not pick up a big particle, but how would the particle have gotten into the pan at the instant of the previous shut down anyway? So, good quality 10W-30 ought to work just fine. They may not have high levels of ZDDP but they do have other, more modern stuff. Most of us are not going to drive an old car 100 hours a year, nor push it at high speed. Your 1937 engine is never going to develop temperatures or engine speeds where synthetic oils would make a difference.

As for the oil pressure gauge, it isn't necessary to fill the capillary tube all the way to the gauge. If there is a little air in it, it just gets compressed by the oil and transfers the exact pressure to the gauge. We don't really even need to worry about "thermal transpiration", a theoretical effect if the oil temperature is much hotter than the gauge itself. As I recall, the basic engineering laws are:

1. PV= nRT - the basic gas law relating temperatures and pressures

2. f=ma - Newton's law about force, mass, and acceleration

3. E=IR - the basic principles of electricity

4. You can't push on a rope - an analysis method for mechanical structures in tension and compression

5. Crap flow down hill - the final law that covers all civil engineering and organizational management problems.

[Spinneyhill]

If you use a diesel oil, CI, there is plenty of zinc. CJ has less but would probably be OK too.

[drdon]

Spinnyhill: I hear that the CJ-4 has lower zinc than the CI-4. I can't find any definitive answer. For now, I looks like either a multi weight oil with added ZDDP will be the way to go, or the CI-4 by itself. Thanks for the answers.

[Stude Light]

I agree with Gary but personally I run the straight weights. The multi viscosity oils have an additive package that shears down closer to the base stock (i.e. 10W30 will shear down closer to a 10 weight oil over time). If you don't believe me, compare the 10W30 you use in your lawn mower after one season to brand new 10W30. Drain it cold and do a flow comparison with new oil. The used stuff pours more like water.

For cars with partial flow filters (or no oil filters), just change your oil a bit more. It is best to change it once a season to reduce moisture concerns, so I use mineral oil and don't bother wasting money on the synthetics as I don't need 10k mile oil changes. And like Gary mentioned, these old engines aren't making lots of power and heat so they don't need the more expensive oils. The mineral oils today are vastly superior to the pre-war oils and do a great job in all but the most severe applications.

My last comment, skip the ZDDP, no need to waste your money. I did the research......

http://forums.aaca.org/f126/28-president-8-a-301944.html (towards the end of this thread)

Scott

[Spinneyhill]

My comment was based on Richard Widman's paper here: http://www.widman.biz/Corvair/English/Links/Oil.html

[Spitfire8]

Don: In my President, I use Chevron Dello 400, straight #30. This is a non-synthetic diesel oil containing 1200 ppm ZDDP (just to be safe). I buy a box containing three one-gallon containers from my local auto parts store at reasonable price.

To avoid a "dry" start on a new motor, I'd remove the spark plugs (faster spinning), ground the coil secondary and turn the motor with the starter until I saw movement on the oil pressure gauge. Bill.

[drdon]

I finally talked to my overhauler, who I trust totally. He said Valvoline Racing Oil, straight 30W, (I thinkVR-1). Available at local parts store.

Plenty of ZDDP. He frowned about the diesel oil, said it had some other "things" in it he didn't like. He was adamant about making sure,

regardless of the oil you choose, that you insure you have the correct amount of ZDDP in it. So, off to the parts store for VR-1. Thanks all.

[Buffalowed Bill]

From what I have read over the years, Stude Light is right in a multi viscosity oil will, over time, have a tendency to shear. I don't agree that you can really feel the difference in thickness virgin vs used. Unless it would be the used oil feels thicker. From what I have read used oil has a tendency to get thicker over time, unless it is adulterated with gasoline. This is because of the particulate matter that it will pick up during the combustion process. Maybe SL has mowers with an oil filter, but I don't, and it would have to be a lot more high end mower then anything that I own to have seen. An argument for multi vis. oil, is that most engine wear happens on start up when the engine is cold, and when the MV oil does its best work, and not after warn up. Engine oil has a tendency to shear at the top of MV molecular chain. The farther apart the number are the more propensity of the oil has to shear at the top end of its chain 10W40 shears more then does 10W30, but all MV oils do a better job of reducing engine wear then do single grade oils.

[Spinneyhill]

I don't know what "shearing down" over time means, as stated by Stude Light. Nor do I understand what Buffalowed Bill is talking about with "a tendency to shear at the top of the MV molecular chain". I am not sure how these statements are squared away against oil changes at 15,000 km (9,000 to 10,000 miles). Is it time that degrades the oil, or usage, i.e. the number of times it has been sheared in a boundary layer, such as in the bearings? I would expect the carbon chain molecules the oil is made up of will be damaged with use. As the damage increases, the effectiveness as a lubricant (= an boundary layer fluid separating the metal parts) reduces. Is that "shearing down"?

I will be using a 10W30 CI oil in my 1930 DC Dodge, which has a bypass oil filter. I will be changing the oil at 1000 miles. Any talk of "shearing down" is, basically, irrelevant, I would think. The oil should be barely dirty at that distance.

Richard Widman's paper (reference in my previous post) shows and provides discussion of the viscosity vs. temperature curves of a number of oils, as well as how the various SAE classifications (SL, SM, CI, CJ etc.) relate to the ZDDP contents of the oil. Essentially, you want an oil that is not too thick at startup that does not become too thin at high temperature. That is the idea of multigrade oils: the first number is related to the viscosity at low temperature (Winter or W), the second at high temperature.

[Stude Light]

Hi Spinneyhill,

To create a multi-viscosity mineral oil you start with base stock oil and compliment that with an additive package. The additive package consists of long polymeric chains which just means they have repeating molecular patterns to create a long molecule. These long molecules (chains) get cut up with use, especially in an engine. That is what is referred to as shearing down. After the chains get cut up enough, the viscosity gets closer to the base stock (for instance 10 weight in 10w-30). For most of us, we'll be using our vintage cars in the summer and changing the oil often (1000 miles or less) - no cold starts or extended usage. Whether you like straight weight or multi-viscosity, the oils of today are so vastly superior to the oils used before the Second World War that no matter what you choose will work perfectly fine and give your engine plenty of protection. My suggestion was just an opinion on not to waste a bunch of money on specialty oils or additives. Recall that our pre-war engines have fairly low compression ratios, pretty wimpy valve spring forces and the horsepower to cubic inch ratio is low. If you want to buy specialty oils or additives to make you feel better about what is your engine you aren't going to hurt anything. Between my research, discussions with lubrication engineers and the data provided through the SAE papers I'm convinced on using current production straight weight mineral oils only. When it comes to this subject, to each their own.

I mention pre-war oils…..there was a lot of engineering and improvements in oils to meet the demands of the high performance aircraft engines used in the war. This carried over into the post-war automotive era.

Buffalowed Bill - reference to difference in "sheared down" oil was just doing a room temperature pour test with used MV oil vs virgin MV, the used stuff always seems like it pours more like water after being used.

Scott

Edited February 8, 2015 by Stude Light (see edit history)

[Thoffs]

I was told by an old Studebaker man that you should use straight 30 wt. non detergent oil in my Rockne, and he said to put about 4 oz. of Marvel Mystery oil in every tank of gas. He said if you do that you won't have any problems with that flat head six engine. Hope that helps!

[Guest colt45sa]

Just an aside about motor oil weights. My Dad traveled a great deal in his work. He purchased a '56 Power Hawk with very few miles on the odometer from his local friend/Studebaker dealer. We lived in New Jersey so we had a pretty good temperature range between the hottest summer day and the coldest winter day. The Hawk had its oil changed every 10,000 miles using 10 weight oil. The filter was changed every 3,000 miles. At 170,000 miles the car used a quart of oil every 1200 to 1500 miles; the valve seals needed replacement, so Dad traded the car in ! So much for light oil in winter and heavier oil in summer. You see, the engine is water cooled so when the engine temperature reached 180 degrees, it didn't know weather the ambient temperature was hot or cold.

[drdon]

What great replies from a number of people who know their oil dynamics a lot better than I ever will. Thanks all.

In retrospect, since this is a frame up restoration, this vehicle probably won't see more than a few hundred miles the

rest of my life. Not sure what I was worried about. It will be kept in a heated area in dry Western Colorado, not driven

in rain or snow, and probably outside temperature is not a factor since when it is started it will already be 70 degrees. '

Good food for thought for those who have restored their vehicles to be daily drivers but at the prices CE's are getting

up to now, to daily drive this would not be smart I think. Again, thanks to all who took time to improve my oil knowledge.

[Guest colt45sa]

Just an aside about motor oil weights. My Dad traveled a great deal in his work. He purchased a '56 Power Hawk with very few miles on the odometer from his local friend/Studebaker dealer. We lived in New Jersey so we had a pretty good temperature range between the hottest summer day and the coldest winter day. The Hawk had its oil changed every 10,000 miles using 10 weight oil. The filter was changed every 3,000 miles. At 170,000 miles the car used a quart of oil every 1200 to 1500 miles; the valve seals needed replacement, so Dad traded the car in ! So much for light oil in winter and heavier oil in summer. You see, the engine is water cooled so when the engine temperature reached 180 degrees, it didn't know weather the ambient temperature was hot or cold.

I would also add that the basic job of motor oil to 'lubricate'. It actually has two other jobs; to cool, and to clean. It is 'not' a cushion to keep parts from slamming against one another. That being said, it you have an engine that has severe wear, a heavier motor oil may help to prevent you from hearing a bunch of pounding, banging noises and reduce consumption. I'm mostly talking about engines that have a pressurized lubrication system as opposed to a 'splash' system. If rebuilding, you might make sure that you refer to the manufacturer' engine specs and stay within tolerances. Check this out and win a beer with a trivia question. "What weight motor oil do NASCAR teams run during time trials?" The answer is 0W-5 ! Remember, motor oil is a lubricant, not a cushion ! When 0W-5 weight motor oil was first introduced, it enabled Formula engines to reach higher RPM's and create a significant increase in horsepower.

[Stude Light]

Agree. Lower viscosity means less drag and windage losses so you get more hp out of the engine and you are more competitive....of course the NASCAR teams have good sponsors and rebuild the engines quite often.