I'm not a lubrication engineer either, but in making up the flat-tappet oil thread I exchanged a great deal of email with a bunch of them

The guidance universally was that generally diesel oil was designed to address the needs of a very different usage and combustion cycle - specifically dealing with soot and ash that is a byproduct of burning the heavier, less-refined diesel fuel and dealing with often very extended idle time and different metallurgy of the diesel engine.

All of them noted that they wouldn't recommend diesel oil for a gasoline engine, although all declined to provide specific, detailed rationale. Interestingly, they all noted that using gasoline-specific oil in a diesel engine is an absolute NO and had been cited in several fleet failures.

So in the end I came away understanding that a) the additive packages were different and b) if I was going to post a sticky with guideance for others I would take no chances at all and only provide information I felt 100% comfortable with.

Again, in the end everyone needs to make their own decision. From where I sit, there are readily available and reasonably priced alternatives for flat-tappet cams such that I can't see a reason to experiment to save a few bucks.

 

On the other hand, I am familiar with many owners who have used Rotella or similar in their Corvettes and other vintage cars for many many years without issue. The accumulated time and usage period would have revealed any short comings of the aforementioned oils, so I believe there is no 'experimentation' going on.

Their reasons for doing so was a combination of commonality (one oil that suits all vehicles) and availability, nothing to do with saving a few bucks. I use it because of the availability factor.

 

The challenge is that a lot of ZDDP additives are of uncertain and unverified heritage - lots of no-name-brand stuff out there. Many have 10,000+ PPM zddp - and this amount has been known to create combustion chamber deposits with extended use. Additionally, virtually all the oil manufacturers I spoke with provided strong guidance against using additives with their oils.

I tested EOS at about 4800 PPM ZDDP (<- corrected after review) - still quite a bit for daily use. I use EOS for initial engine break-in, but that's it.

The decent synthetics will take an oil change interval of 5,000 miles or so...which while doesn't bring the price down to dino oil levels, mitigates it to some extent.

 

But, of course flat-tappet cam wear doesn't happen in 10 minutes - it happens over time. And those vintage cars may not see the level of street use or miles that will show it up in the same timeframe as those that drive their Corvette regularly, or drive it hard, or have agressive aftermarket valvetrains. And I take it these individuals aren't doing regular oil analysis to determine if wear is happening?

Of the oils on the sticky, other than Amsoil most have no difficulties at all finding most of them at the local parts store.

We have different perspectives of the level of risk associated with the choice, and we're clearly not going to close the gap I see the choice as higher risk - so for those folks that are willing to accept this risk - real or imagined - for convinience and/or a few dollars per qt - go for it

 

Making multiple assumptions simply to dismiss the other person's assertions really is not conducive to holding a beneficial conversation. See ya.

 

Mike, you seem to be so busy trying to be "right" that you can only see one answer.

Your assertations, as I see them, is that "Duke" from NCRS says it's OK. Additionally, you claim anecdotal evidence based on people running the oil, including yourself, that it's "fine"...yet when I ask about doing oil analysis, you decline to comment. These aren't assumptions on my part - simply a perspective that you may not have from your comments.

So I agree there's not a lot of use in continuation of this discussion. Use whatever oil you like, which has been my guideance from the outset.

 

While I didn't mean to start a heated discussion of various oils I was just asking about the Amsoil AMO. I guess some points were made each way. FWIW I put the AMO in this AM before the oppressive heat and humidity kicked in.

 

Rick, it just becomes a sensitive subject for some You should see some of the emails I get regarding the sticky =:-*

Key point is that we can be 100% confident you made a good choice, with no disrespect to the other choices out there

 

 

No- I'm simply standing by my post way above:

Which you took issue with:

To which I provided proof of my claim. You (and the other poster) for whatever reason are making every effort to dismiss this. So, let's not point fingers over being determined to be right by seeing only one answer. N'kay?

 

Gosh, Mike. And I provided a rebuttal to your proof.

One of us has to stop, so I'll be the better man and be the one

 

I for one have used Rotella in my L-48 for the last 2-3years since putting in a higher lift cam. Recently I dropped in a 383 stroker.
Pulled the L-48 apart just to see how things were (maybe to sell).
The cam was f****d.
Now lots of things can go wrong ,I know. And I'm not blaming Rotella,
but I'm going to find the best oil I can - AMSOIL- and use it. I probably won't put it in my everyday drivers, but the vette is certainly getting it. Just my 2 cents. You need to do what you need to do.

 

I know. The diesel engine generates a lot of soot. If you change the oil in a diesel it turns dark in a couple hundred miles. This soot in the oil leads to engine deposits so the diesel oil formulations use a lot more detergent in their additive package (this is the calcium in your analysis). Detergents help reduce internal engine deposits. They also reduce the bonding of the sacrificial layer of phosphorous to the internal parts such as lifters and cam lobes. This is fine for a modern diesel engine but not what you want in a flat tappet gasoline engine. A lot of the SM and new SN rated 10W-30, 5W-30 gasoline engine oils are also going to higher detergent additive packages and again, this is fine for a modern roller cam gasoline engine but not what you want in a flat tappet engine. The triple protection Shell refers to is Moly, Boron and Phosphorous. All reduce friction and wear but only Phosphorous will bond to the metal and provide a sacrificial layer that will withstand the extreme sliding pressure (over 200,000 PSI in a stock engine) generated at the cam lobe, lifter interface. This extreme pressure is not reproduced anywhere in a roller engine or a modern diesel. If the phophorous don't bond that point is not protected.
The Amsoil AMO 10W-40 is an excellent choice for a flat tappet chevy engine. Modern Rotella is not.

 

We build alot of circle track racing enigne and have used AMSOIL in all the engines and our customers like the results they have seen over the years when there engines are tore down.


Rotella has gone down hill over the years, But we do buy 15/40 CENPECO which has 1580 PPM of zinc. I also use it in my 07 Peterbilt when the Rotella went down hill.

I build alot of high performance enignes and we see using AMSOIL pays off in the end. Then you have guy that work at the chevy dealer ship LOL

 

I try and determine which oil has the desired Z & P for my flat tappet engine. During my investigation, several years ago, I found Valvoline VR1 fits the bill.

I have been running this oil for 6 or 7 years, both in the 350 and the 383, without problems. It costs about $4 a quart at the local NAPA. I see no need for boutique oil that costs about twice as much.

 

I had a 86 Z-28 with a 383 that I used to drag race. I initially ran Castrol GTX racing oil in it. Every other time I would race the car the oil would need to be changed. After a year of that I switched over to Amsoil and it would last the whole season no viscosity loss. I started putting it in my daily drivers and got the same results. I ran a turbo 350 trans in the car when I had the local speed shop build me a custom tranny I asked them about Amsoil for transmissions. They said they used to have to teardown and rebuild a tranny after 150 passes. Once they went to Amsoil they toredown a tranny after 300 passes and there was virtually no wear. It is worth it to me pay more for the protection. As Virgil in the old Fram commercials would say "You Can Pay Me Now or You Can Pay Me Later".

 

VR1 certainly has sufficient ZDDP (around 1400 ppm) but generally racing oils aren't the best choice for daily driver use as the additive package isn't intended for extended change intervals - racing oil is changed after every race/run...not every 3,000 miles

 

And not surprisingly, the author of the article I linked to above completely disagrees with your assertions above and dismisses it as yet another story that has just added to the confusion. He spent his
entire career as an automotive engineer concentrating on this on similar subjects, as did his father before him.

Why don't you guys all pick a mutually agreeable location and meet up face to face to sort this out once and for all.

For interest's sake, I did go back to the person who supplied the oil sample report up above. He's been using Rotella exclusively since the 1960s including in NEW C2s and C3s that had the snot beat out of them 'cause they were 'just cars' back then. One of them was an L88 that saw considerable track duty, BTW.

There's a string over on the C2 section where various people are extolling the virtues of Rotella- even one guy who mentioned it was factory recommended for a Ferrari he once owned. Have fun guys, I've said more than enough already

 

Similar results found reguarding Amsoil in fleet use. My father in law was instramental in starting Oswego Drag raceway in the 50's, built and raced there for over 20 years, was a machinist and mechanic, owned his own machine race, repair shop and rebuilt diesel and farm tractor engines. He was the most knowlegable hands on mechanic I ever knew and the most honest guy you would ever meet. He became an Amsoil dealer in the early 90's and was a dealer until he passed away a couple years ago. He sold to a couple large trucking fleets. They found greatly reduced long term wear in the entire driveline and noticably improved fuel mileage in large commerciel semi trucks traveling over 100,000 miles a year along with extended oil change intervals overall cost for routine maintainance was reduced and major overhaul intervals greatly extended. I used Shell Rotella exclusivly for over 20 years and was very satisfied with it. Never an oil related failure until 2006. Wiped my cam, Did a lot of research, listened to my father in law and changed over. He was smart and right. My results were phenomenal.
I broke in my wifes new Aveo. Swiched to Amsoil 5W-30 and increased fuel mileage from 32 MPG to over 34 MPG. Engine runs smoother and oil change intervals are over doubled. It is cheaper than conventional oil when this is taken into account.

 

I used rotella since the 70's for well over 20 years. You still don't get it. It is not the same formulation, not even close. What worked in the past is not what works today. Cat and Ferrari used to require it to maintain your warranty, not anymore. Why? because it is a different formulation. Duke Williams is well respected but is retired and was never a lubrication or additive engineer. Things have changed. Here is some info for you. I know you are never wrong in anything you say ever but try to have an open mind.

What about detergency? I don’t know if I’ve said it in TDR before but, “Diesels love detergents!” High detergent content oils can sometimes interfere with the additives responsible for valve train wear protection.

The above is from John Martin. Here are his credentials and what he has to say about the new formulation Shell Rotella T CJ-4 oil.(scroll to bottom.)


To examine the changes to lube oils we contracted with a “hired gun,” John Martin, formerly
(25 years of service) of Lubrizol Corporation.
For those not familiar with Lubrizol,it is one of a handful of companies
that make and sell the additive package that goes into the finished
product, the one gallon lube oil jug.
More on John’s credentials: He holds several patents and has
published many industry-related technical articles. he is a past
Chairman of the Cleveland Section of the Society of Automotive
Engineers (SAE) and both a Recognized Associate and a Silver
Spark Plug (their highest honor) of the Technology and Maintenance
Council of the American Trucking Associations. He is a recognized
lubrication consultant to both the racing (NASCAR and NHRA) and
trucking industries.
We were fortunate to have John’s article addressing the CJ-4 lube
oil specifications. Then in Issue 55 John wrote a three page article
that debunked several lube oil myths.
Last issue we blindfolded John and sent him oil analysis data from
eight unused lube oils and asked him to comment. Astutely he
picked the CJ-4 oil out of the bunch, identified the Exxon/Mobil oil
by its unique blend of additives, and used price logic to determine
the lube oil from Wal-Mart. He didn’t hold anything back when he
stated, “I wouldn’t cross the street for a free crankcase of oils 3
(the Exxon/Mobil Delvac 1300 Super CI-4 plus) and oil 4 (the Shell
Rotella T that meets the new CJ-4 specification) unless I was running
a fleet of busses or garbage trucks.”