Rotella is typically known as a Diesel spec oil.  I run their 5W40 T6 (full synthetic) in my 6.0 and it was a game changer in terms of cold weather performance.  Start ups, etc. are MUCH better with the T6 than with either 15W40 or 10W30 conventional.

I wouldn't run it in hopes of anything being improved in an engine that is already performing well.  Like Bearing Bob says, they used to recommend Diesel oil for engines with flat tappet cams because it contained the proper zinc concentration for years after it was pulled from the gasoline spec oils.  That came to an end quite a while back now, but that doesn't stop people from parroting information they heard years ago and think is still valid. 

Otherwise I think Rotella is a good product, but IMO its MUCH more important that you change the oil regularly than what exactly the oil is.  I certainly wouldn't change oils from one brand to another of the same weight and type and expect anything from it.

The builder MAY use Rotella because he gets it at a better price/or bulk ('Buck' if UR from Ala.) delivery.
Y'all know my feel'ins about oil brands......for the most part it all comes outta the same hole. Changing it (and the filter) every 3000 miles.... you could prolly use Crisco oil and be OK!!
6sal6

6sally6 wrote:

The builder MAY use Rotella because he gets it at a better price/or bulk ('Buck' if UR from Ala.) delivery.
Y'all know my feel'ins about oil brands......for the most part it all comes outta the same hole. Changing it (and the filter) every 3000 miles.... you could prolly use Crisco oil and be OK!!
6sal6

From where.....??
 

MS wrote:

I ran Rotella T 15-40 in my 427 until that lifter broke. Now I am back to using Valvoline conventional.

Something about the shear properties of Rotella being not optimum for higher bearing speeds in a gas engine...

I don't think a shear issue is what you may have experienced.  Oil shear is when the oil is reduced in viscocity due to use.  Oil analysis has shown that Diesels, particularly those with HEUI injection systems are particularly hard on oils in this respect.  After say 3,000 miles OA reports will often show a 40W oil has been reduced to 30W.  Part of this has to do with how the oil achieves its intended viscocity.  The principle way oil companies achieve viscocity is the use of an additive, so what's really happening isn't that the base oil is breaking down, rather the additive is being consumed.  The degradation and elimination of additives is the principle reason for changing modern oils at intervals well below that at which the oil itself is degraded. 

Due to the inherently greater propensity for Diesel engines to shear oil the Rotella series is one of the best oils on the market in terms of preventing this.  I don't think oil shear is an issue with Rotella.  However, there are several different additives used to thicken oils.  Possibly the additive used in the Rotella is not ideal for higher engine speeds.  It doesn't have anything to do with shear, but the difference between say a polyurea thickener and a lithium complex thickener is significant in respect to operating speeds.  Most Diesels are only running in the 3,000-4,000 RPM range, whereas a performance gas engine is going to be considerably higher.  By contrast the bearing loading in a Diesel is much higher than in a gas engine, albeit at lower RPM. 

This is the primary reason I was never a fan of using Diesel oils in a gas engine.  Oils are formulated for intended use.  Diesel engines and gas engines operate under very different conditions.  Truth be told I knew almost nothing about oils until I owned a Diesel.  The amount oils are discussed on the Diesel forums, technical information available, pages of OA, etc. makes how much gas engine guys worry about their oil look like we don't care at all.  Its amazing how interested in oil you get when its responsible for a set of injectors that cost $2,000-$3,500. 
 

I don't know if anybody here every check a forum called BOB THE OIL GUY. A lot of good info. I have used Wally World brand oil for 20 plus yrs in everything  Not because it's cheaper than name brands and I being thrifty also. It is a good oil and test highly recommended with the best of them.

I'll pass this along. for what it's worth. I have an engineer bud that builds gear boxes in huge printing presses. They run around the clock, and live abused lives. Longevity is their life blood. So to the degree their boxes were failing, that meant, down times, calls for service and unhappy customers. He was tasked with finding the best lubricant for preserving the metal-on-metal interfaces. Everything was on the table. And like engineers tend to do, he designed a reproducible test for comparison

We are in St. Louis. There is a company here named Lubri-Loy that produces a product called Revive. It is an oil fortifier. It doesn't coat parts, it modifies oil. Adding this "fortifier" to anything they tested produced what he called "shocking improvements". He made the mistake of using it in newly assembled engines and they had trouble wearing the parts in. They had to use oil absent the modifier for the initial starts.

My bud found it miraculous enough he won't hardly run anything without this additive. It doesn't matter what weight oil, it improves it all. It even improves the synthetics. It's pricey. The company doesn't seem to be looking for customers like me. They want industrial orders. But they produce quantities for folks like us. One ounce per quart, poured right in with the crankcase oil. I suppose most folks would have to do their own tests to trust something like this. I'm shooting my mouth off without any particular personal testing. But he was so impressed with the stuff I'm sold on it. Thought I'd share it here if you care to explore...

https://www.reviveoil.com/Articles.asp?ID=156

Lance

RV6 wrote:

I think I'll go back to using Wolfs Head if I can find it.
 

Wow, Wolf's Head oil, I used to buy that in the 2-gallon size when I had a Vega that burned a quart every 100 miles.
 

For what it's worth I've had good luck with Valvoline's "Racing" 10W-30. Believe it or not Walmart has the best price, way better than Summit! Even at that price it still hurts the pocket book every 8 qt change and because my 427 is running E85 I change mine sooner than if I was on pump fuel.

https://www.walmart.com/ip/Valvoline-VR1-Racing-SAE-10W-30-Motor-Oil-1-QT/196957962