The Stovebolt Site Forums The Shop Area Engine Shop Synthetic Oil

A while back I watched a program, maybe power block, were they did a demo using conventional oil to lubricate engine bearings. They had a electic motor which rotated a bearing in a oil bath which worked fine. They then took the bath out to see how long the bearing would survive and in minutes the bearing seized. They then did it with a synthetic oil (I think it was quick purple). When taken out of the synthetic oil the motor ran the bearing under pressure for more than five minutes. The interviewer asked the mech. how long would it take for the bearing to burn. He stated maybe an hour or more. MY qestion is , is it better to use synthetic oil in my 235 dipper or is conventional the way to go? The Mech. stated that synthetic oil coates bearings and if at some point your engine is starved for oil, the coating will increase the longevity of your motor. Is this correct?

That demonstration has been around for at least 50 years, touting various types of miracle lubricants. I saw my father embarass a salesman to the point he packed up his sample case and left the shop, by freeing up one of those stalled load machines by squirting a little bit of Coca-Cola onto the rotating assembly. It's called a "P.T Barnum Special"- - - - -there's a sucker born every minute!

Synthetic oil is basically vegetable oil with some trick additives instead of oil that's pumped out of the ground. It's no better, or worse than what we've been running for the past 100 years. Keep it the right thickness for the job, and change it regularly- - - - -mineral or synthetic doesn't make much of a difference!
Jerry

I hate arguing when Hotrod Lincoln is posting. I look forward to his posts and I find them reliable. I do believe in the use of synthetic oils in the cold temps of South Dakota. But for your old truck, I'm not so sure it would be beneficial or cost effective.

I found this article which does seem to make sense to me.

Here is the link:
http://car-reviews.suite101.com/article.cfm/synthetic_oil_vs_conventional_motor_oil

Here is the text:


Dealerships, auto repair shops and fast lube facilities will often recommend using a synthetic oil when a vehicle is brought in for an oil change or routine vehicle maintenance. Naturally synthetic motor oil is much more expensive than conventional oil, so before making a decision, find out the differences between synthetic and conventional motor oil and what it mean to a cars engine.
What is Conventional Motor Oil?
Conventional or regular motor is processed from crude oil out of the ground. The crude oil is separated at the oil refinery. The thicker oil is used for applications like roofing tar and asphalt. The thinner oil is used for applications like gasoline and engine oil, among other applications.
This oil becomes the base stock for the oil. Engine oil base stock refined from crude oil contains small amounts of natural contaminants that can’t be removed from the base stock used in processing engine oil.
What is Synthetic Motor Oil?
There are two components to synthetic motor oil:
1. Base Stock - Unlike conventional motor oil, synthetic motor oils base stock is artificially created or synthesized. Because of the higher purity of synthetic oil, the properties of synthetic motor oil can stand up to heat much better before breaking down than conventional motor oil. Synthetic motor oil can also withstand colder temperatures better than conventional motor oils. This a huge benefit when an engine is first started in cold weather.
2. Performance Additives - Beside the base stock, performance additives are added to both conventional and synthetic motor oils. According to Castrol, the performance additives used in synthetic motor oils are engineered with special additives that help to fight off sludge and mineral deposits that are naturally caused in combustion. Performance additives in synthetic motor oil provide superior protection in extreme driving conditions like extremely cold or hot temperatures.
Pros and Cons of Using Synthetic Motor Oil

Pros
• Synthetic motor will increase the life of an engine
• Longer oil change intervals, because of viscosity breakdown
• Better for extreme driving conditions, especially extremely cold or hot weather.
Cons
• Synthetic motor can cost up two three times more than conventional motor oil.
• Should be used in the beginning of the engines life (after 5,000 miles preferably) not if the vehicle already has a lot of miles. .
• Probably should not be used when the vehicle is brand new due to engine break in of the factory oil in many new vehicles.
Is Synthetic Oil Better Than Conventional Motor Oil?
There’s no doubt that synthetic oil is better than conventional motor oil. Since synthetic oil is made with smaller molecules and less impurities it’s just a plain better lubricant. It’s especially better for today’s modern engines that have tighter tolerances and smaller oil passages that need a super lubricant. Car manufacturers are requiring that synthetic oil be used more and more. Most new vehicles are at least required to use a synthetic blend.
If synthetic oil is used, it’s advisable to use it after the engine break-in period. If the vehicle has a lot of miles, it’s not recommended that synthetic oil be used. If someone plans on keeping a vehicle for a long time, using synthetic oil is a good idea. On the other hand, if someone gets a new vehicle every year, why have the added expense of synthetic oil.

Well Jerry, on this one I gotta disagree with ya. Not so much the on the demonstration, but the boys building engines at the top swear by synthetic oil. I've read many articles (non advertisements) from Indy, Nascar etc engine builders who all claim that there is much less wear in the engines using synthetics. My nephew is still running the midgets and most of those guys say they see the same results. There is just to much legitimate testing reports that shows that the synthetics are superior.
If I weren't getting 100 miles to the quart I'd probably be using it too. In fact if I ever get around to pulling the short block down this winter (running out of time now) I’ll probably start using synthetic instead of the Rotella-T after it’s broke in and my oil consumption stabilizes.
Denny Graham
Sandwich, IL

I have to respectively disagree also Jerry, I highly respect your truck savvy but synthetic oil is not vegetable oil and the additives are far from trick.

There are unreliable test methods than can be easily manipulated (portable one arm bandits) and then there are industry standard (ASTM and SAE) tests that are performed on all oils and synthetics outperform petroleum oils in every catagory.

I would also assume that if you run any engine on synthetic or conventional and you run any engine short on oil, you will damage the bearing surfaces.

As far as the demonstrations go, I have not seen one yet that isn't a "sales" tool for a specific product, and tend not to believe them or rely on them completely.

I remember one demonstration where the guy ran the engine without any lubricant in it for 5 minutes. He adamantly wouldn't run an engine with "straight" oils for any length of time. I asked him to run the "treated" engine without its oils until it stopped to see how long it would last. It lasted 18 minutes and some odd seconds. The salesman rejoiced that it was a miracle that the engine ran that long.

Shoot, we had contests when I was in high school to see how long an engine would run after draining the conventional oils. I remember 21 minutes and 34 seconds on one of them because I sold the winning ticket to my buddies father.

I started using synthetics on my tractor when in sub zero temps the oil filters would blow. I noticed that after I switched, not only have I never blown another oil filter, but the oil pressure stays consistant when the engine starts cold or is running at operating temp.

I don't use synthetics on everything however. Many times I don't get the miles on the vehicle to warrant synthetic use in them. I use synthetics in my newer vehicles that I drive every day, and my tractor of course.

I'm not sure which demonstration is being referred to, but I still have the kit that my father used in the early 50's to sell lubricants for Continental Oil. Continental was one of the licensees of zinc which at that time was still under patent. If the kit wasn't enough to impress customers, I personally would crawl under the particular GMC pickup he was driving and drain all 8 quarts of oil into a wash tub. He would drive about 100 yards and return and I would pour the oil back in. There was no trickery involved. None of his competitors would dare try this. Zinc coated wear surfaces for 50 years until it was required to be phased out. I use synthetic in all my gasoline engines as well as my Mercedes Diesel. I do not use it in my Cummins 14 liter engines because I feel the 15W40 which I sell is more cost effective. They hold 48 quarts. These engines go over a million miles on 15W40. Why put in more expensive Oil. I'm not sure where the vegetable oil idea came from either.

I feel sure that Chevrolet would not use synthetic oil in a new Corvette delivered from the factory if it wasn't up to their requirements. I am not sure though how it would work in an old design engine that was not equipped with an oil filter, or one that operated on a bypass design instead of full flow.

Interesting debate. It was just a thought as I was draining my new/old 53 this morning as it was minus 21 C. The old oil was black but still flowed. Also, on the program they dyno'd three named top oil brands vs. quick purple synthetic and the syn. put out 3-5 more horsepower. For now, Im going to stay with the convensional oil. If and when I rebuild the motor, I will prob. change to synthetic. Another consideration is Slick 50 which is a 50 50 mixture which I used in our trucks in the high arctic, worked well on those -40 days...

I have a 56 GMC with a 316 or 317 pontiac engine. When the truck was in Use( last plates and last use are 1975 plates) we used mobiloil special. I think in the 50's and 70's mobiloil contain ed zinc. My question the truck has just been started up again after all those yrs. and what kind of oil should I use?

GM does have an additive in about a 4 0z container that may contain Zinc. Shell rotella has been suggested. All adviced appreciated..tom

Rotella

Interesting comments, guys, and I don't have a problem with the use of synthetics on modern engines with clearances down in the fractions of a thousandth, and alloys that have virtually no thermal expansion. It's just not worthwhile nor wise to run that type of oil in a 50+ year old engine designed for 30 weight mineral oil. The very first use of synthetic oil that I'm aware of was on jet turbine engines, and the dead-end type lubrication with no return to a central sump meant that the oil was eventually consumed by the engine. A free-flowing lubricant that burned in the exhaust stream with little or no ash was needed, and synthesized oils based from vegetable products were eventually developed. These oils were later fortified with additives to make them compatible with reciprocating engines, and suitable for recirculating oil systems. I'm still partial to a high quality, high-detergent mineral oil with a straight viscosity for 1940's or 50's designed engines. Regular oil changes and reasonably good filtering will still be of more advantage to these engines than some trick-compound oil, at least in my decidedly biased opinion!
Jerry

I love your opinions Jerry....biased or not they hold weight with me.

I too am leary of the "demonstrations" one see's on TV and elsewhere but I reject the idea that synthetics are vegtable oil. That stuff is squeezed out of soybeans, cotton seeds, rape seed, and god knows what else. Synthetics are the result of molecular trickery in the labratory and some great German chemists. I use it in damned near everything I own..all 84 cylinders and swear by it.

The first use of the synthetics I'm aware of was by the people who seemingly invented them or at least always get the credit for it; the Germans in WWII who ran the Wermacht on them for 3 years . Now that was a test I'll accept. They worked on the BMW built inverted 12 cylinder aircraft engines. Proof enough for me.

If you guys are really interested in the pros and cons of various types and brands of oil and lubricants, filters and such check out the forums at www.bobistheoilguy.com

Most of the information is geared to newer vehicles than most of the ones we're dealing with (newer being a relative term), but lots of interesting reading, anyway.

Syn oil has been around for a long time, being used by our military planes in WW 2, and the benefits of Syn oil can't be argued unless you want to weigh the benefit against price.
Along with the previous mentioned benefits Syn oil excels in lubricity because the molecules are all the same size where as in mineral based oils they differ in size.

As all ready mentioned, Would GM spend the extra money putting Syn oil in Corvettes coming off the line if there wasn't a beneficial reason for doing it.
I have been using Syn oil in my best cars since the 80's and have had excellent results, and I run it in two Kohler motors as well.
I don't run it in my tractors, not yet, because of price and because I have a huge stock of mineral based oil to use up.

The question of using it in an old Stovebolt motor has come up before and it is my opinion... There is not enough to gain to justify the cost. Greater tolerances in those motors,along with the fact that most are not a new motor makes the choice of a mineral oil adequate, provided you keep clean oil in the crankcase.
Dirty polluted oil is the main enemy to an engine.

I can find no reason not to use Syn oil if you can find the correct viscosity, and want to pay the extra for it.

Dan

A CORRECTION.....Syn oil goes back to our military jets flown in the 50's. But hey, that's still a long way back, sorry bout that .
Dan

Misunderstanding on synthetic oil's origin is understandable when one remembers that the early WW II synthetic oil was just that... a man made lubricant based on vegetable oil.... and it was a necessity due to regular oil shortages.

Agriculture Canada was one of the key player in designing/discovering a very high performance vegetable oil for high output engines in particular torpedo engines.

The oil was based on the "rape seed" which later became socially unacceptable and was renamed "Canola oil".....CANadaOilLow Acidity...... and now it is sold as a low cholesterol oil for French Fries.

So next time you eat Fries and fell like going like a torpedo you will know why...

The later "synthetic" oil was created in labs from petroleum based oil particularly for the oil hungry jet engines.... and later used for gas engines in extreme cold conditions in Alaska.

Synthetic oil has a lot of advantages but on old totally rebuilt 235/261 good old fashion HD Diesel oil like Rotella is probably best for the solid lifters and looser tolerances....

Rotters in Ottawa have migrated to HD Diesel oil and now add Zinc additives for safety.

That being said I have driven 100s thou miles on two Ford Diesel with 0-40 synthetic and it makes one H**l of a difference on cold morning when it dips to minus 30 F..... yet the same oil performs well after 8 hours at 75mph on the 4 lane highways. At 4 gallons per oil chages it is costly...but so is repairing the diesel.

And I still buy and use straight 30 non-detergent in my single cylinder make&brake engines... thats' what they were designed for..... sludge is welcomed as it seals the oil leaks...!!!

Bob C.
Ottawa

Didn't know that jet engines were 'oil hungry'! I know radial engines are. Check the gas and fill the oil!