Oil Questions.....

[Monstar]

So, I have read many of the posts regarding synthetic oil vs. dino, appropriate change intervals, and when to switch to synthetic... ... and I have a couple more questions.



1. ) Is breaking in the engine not "wearing" it in? If not than what is it?



2. ) Assuming the synthetic oil lessens wear why not switch @ the first oil change?



3. ) By following cummins recommendation of not switching until the engine is broken in, are we trading long term durability (in the sense of decreased wear) for short term mileage improvements?



4. ) Am I missing something about synthetics? I have never used them much, as most of my car knowledge relates to pre-1930 cars.



Thanks.

 

[Boonieman]

I am by no means an expert, but here's what I think. Breaking in an engine is the same thing as wearing it in. Putting in synthetic prevents, or extends, the break-in period because the oil is "slicker" and prevents the metal surfaces of the moving parts from mating and wearing together. The theory is that once these moving parts have achieved their desired wear, or break-in, then it's OK to use synthetic to slow further wear on the engine's moving parts. It also is supposed to improve fuel economy somewhat due to reduced friction of the moving parts. There are as many opinions on this subject as there are people and it's been beat to death. As for me, I'm going to use a good quality oil, change it and the filter at a reasonable frequency, and keep my air filter clean. In my mind, if I do this my Cummins engine will far outlast the rest of the components on the truck.

 

[rbattelle]

As for me, I'm going to use a good quality oil, change it and the filter at a reasonable frequency, and keep my air filter clean. In my mind, if I do this my Cummins engine will far outlast the rest of the components on the truck.

Amen. I run Mobil 1 synthetic in my wife's car (Civic) because the sump capacity is less than 4 qt. I don't want to buy 3 gallons of full synthetic for my truck, so it gets dino oil, changed every 3000 miles.

 

[PKnoerzer]

The machine surfaces in the engine aren't actually smooth, and have a pattern of grooves on their surfaces from the manufacturing process. These may be microscopic, but they're there. The break in process ideally laps these surfaces together so they are smoother by wearing down the peaks of these grooves.

Synthetic oil protects these surfaces from wearing in properly because there is not enough friction. One possible effect of this is excessive blow-by caused by the rings not making a good seal with the grooves on the machined cylinder surface.

The opposite can happen if an engine is run hard before it is broken in. Since the loads are carried by the peaks of the grooves in the machined surfaces, the load and friction is concentrated on a smaller, more fragile surface. Instead of the peaks wearing down gradually in microscopic amounts, the surface tears away in larger chunks accelerating wear.

This is probably more than you wanted to know, but I don't know a simpler way to explain.

 

[LightmanE300]

I personally think the theory that synthetic doesn't allow engines to break in properly is a bunch of poopy. If that's the case, then why do ALL MB, BMW, VW/AUDI, Porsche, Corvette, Vipers, and many others come filled from the factory with synthetic?? I think this is an antiquated theory about using dino oil in the beginning, that has been perpetuated by Cummins.

 

[rbattelle]

The machine surfaces in the engine aren't actually smooth, and have a pattern of grooves on their surfaces from the manufacturing process. These may be microscopic, but they're there.

Molybdenum Disulphide is meant to improve this.



And here's a VOA (Virgin Oil Analysis) of Valvoline Premium Blue 15w-40, which is the factory fill.



[I'm not disputing anything PKnoerzer said, just adding to the info]

 

[amsoilman]

I personally think the theory that synthetic doesn't allow engines to break in properly is a bunch of poopy. If that's the case, then why do ALL MB, BMW, VW/AUDI, Porsche, Corvette, Vipers, and many others come filled from the factory with synthetic?? I think this is an antiquated theory about using dino oil in the beginning, that has been perpetuated by Cummins.

I do beleive these manufacturers run these engines to break them in before they leave the factory. This is why they come factory filled.



Wayne

amsoilman

 

[Pawpaw]

I personally think the theory that synthetic doesn't allow engines to break in properly is a bunch of poopy. If that's the case, then why do ALL MB, BMW, VW/AUDI, Porsche, Corvette, Vipers, and many others come filled from the factory with synthetic?? I think this is an antiquated theory about using dino oil in the beginning, that has been perpetuated by Cummins.

Cummins specifically states it's for ring-to-cylinder wear-in. It makes sense to me because none of the vehicles you mentioned above have 18:1 compression ratios.



Not trying to start anything here, just hoping to add to the discussion.



Bob

 

[WNowlan]

1. I am not an expert but, The explantion given by PKnoerzer is correct. The Synthetics tend to be a lower viscosity oil (5W) versus a dino (15W), in the ring area the oils perform at the lower number not the 40. This is due to temporary shear loss of the VI improver. This is especially true with a POA versus what we are now seeing with Group III socalled synthetics...



2. The Moly found in the Cummins/Valvoline is actually used as an antioxidant. To prevent premature oil thickening due to oxidation.



Like it was mentioned earlier, you would delay the seating of the rings. It will cause higher oil consumption if the rings do not seat properly. It is true you should try to pull as much as possible with these egines to expirence a good breakin. The increased fuel economy is a direct result of the combustion chamber sealing and produces a more complete burn.



I hope this helps.....

 

[amsoilman]

1. I am not an expert but, The explantion given by PKnoerzer is correct. The Synthetics tend to be a lower viscosity oil (5W) versus a dino (15W), in the ring area the oils perform at the lower number not the 40. This is due to temporary shear loss of the VI improver. This is especially true with a POA versus what we are now seeing with Group III socalled synthetics...

Synthetic oils and petrolium oils that are rated as a 15W-40 have to measure the same Viscosity! They are not different in any way when it comes to Viscosity, as long as they are of the same grade, ie. VISCOSITY.



Multi-weight oils (such as 15W-40) are made possible by adding polymers (VI Improvers) to oil. The polymers allow the oil to have different weights at different temperatures. The first number indicates the viscosity of the oil at a cold temperature of 40 C. ,while the second number indicates the viscosity at operating temperature of 100 C. The temperatures that they are measured at are the same regardless if petrolium based or synthetic based.

At cold temperatures, the polymers are coiled up and allow the oil to flow as their low numbers indicate. As the oil warms up, the polymers begin to unwind into long chains that prevent the oil from thinning as much as it normally would. The result is that at 100 degrees C, the oil has thinned only as much as the higher viscosity number indicates. Another way of looking at multi-vis oils is to think of a 15W-40 as a 15 weight oil that will not thin more than a 40 weight would when hot. In the ring area, I would say it would be very hot.



Wayne

amsoilman