[linden_gto]

i have been running Rotella in my porsches for years. always happy with it. running VR1 in the gto, though - even though i considered rotella.

[ponchjoe]

Rotella 10w40 here.

[Doug Hopkins]

Originally Posted by Doug Hopkins

Kauffman recommended Rotella T-4 15W40 on my engine. Over 300 passes with zero issues, but I 've heard the T-4 formula had been changed. Was thinking of switching to Rotella T-6 Synthetic 5W40. Any thoughts?

I was really wanting input on the use of the Synthetic 5W40. Read a few reports that claimed to be better than Mobil 1 which I use in my Bonneville GXP and 6.0 Chevy truck with good success.

[PurelyGTO68]

Originally Posted by Doug Hopkins

I was really wanting input on the use of the Synthetic 5W40. Read a few reports that claimed to be better than Mobil 1 which I use in my Bonneville GXP and 6.0 Chevy truck with good success.

We have a fleet of about 140 trucks at work. Over the years we have done several different oil studies and used labs to check the samples. We found that standard CJ-4 oil is very good. We can run it in our work trucks for about 15,000 miles between changes. We didn't see any measurable difference with synthetic oils. If we use Rotella as an example, T4 is dino oil, T6 is synthetic and T5 is a blend. All three types lasted about the same amount of time according to the lab results. The determining factor was breakdown of anti foaming agents which is important to high pressure oil systems (26k-30k psi).

In your engine, you don't have anything near that sort of pressure so the next point of concern is polluted oil from cylinder blow by. If you have ever removed the oil fill cap from a running diesel engine, you would see that diesel engines have a much larger blow by issue compared to gasoline issues.

Since diesel oil is designed for very high pressures, it's shear strength is excellent. That is why it works so well with high lift flat tappet camshafts/lifters. Diesel oil is also very good with crankcase vapors so it makes a great choice for classic car engines.

So, my personal opinion is that you are wasting your money with synthetic diesel oil but feel free to use it if you prefer....it will do a good job (but so will standard T4 for that matter)

Our fleet operates in Arizona and California where we have mild winters in most of the places we work. However, we did see evidence that synthetic engine oil performed better than dino oil in the northern parts of Arizona during the winter months. The injectors in our 4.5 and 6.0 liter PowerStrokes really liked the synthetic oil better when temps were 30 degrees or less. So it it's cold where you live, then you might see a benefit with the synthetic oil.

Hope this helps.

Sent from my XT1585 using Tapatalk

[Doug Hopkins]

Thank you, very good information.

[Sirrotica]

You'll lose some oil pressure with the T6, I just switched in my 6.5 TD (260,000 miles), and I lost about 5 lbs of OP with the switch. I don't see any negative problems after the switch. The faster flow in the winter, plus less drag on the starter and batteries starting the engine cold, plus an overall better quality oil are the reasons I switched. Although I haven't had problems with the turbo bearings I figure I should keep top shelf synthetic oil to keep them intact as long as possible.

I never run diesel oil in any of my gas engines, just Penzoil Platinum synthetic in everything from my wife's Vibe (260,000) miles, to my LS2 GTO (127,000 miles). I also run a Frantz by pass oil filter system and the oil never gets changed in anything under 25-30,000 miles. I believe that the synthetic is more acclimated to extended oil changes as the dino oil gains viscosity numbers as it ages, where synthetic is no where near as prone to get thicker the longer it's in the engine.

The by pass oil system preserves the oil remarkably well by keeping it much cleaner throughout it's life than a full flow filter is able to do. I just figure the synthetic has better, more structured molecular chains owing to it's longer life and better lubricity.

Since my philosophy is to just keep the oil as clean as possible with superior filtering, as opposed to letting it get saturated with solids by inefficient filtering, I want oil that is engineered for longer extended oil changes. I like to run my stuff as long as possible without lubrication related failures.

[Dragncar]

This is one of the most overblown topics of autos/racing. The most important thing about oil, is changing your oil. Not the type/brand. Sure, the weight matters depending on where you live. But people will talk on this subject to no end. For the most part, oil is oil. Use the one for your application and change it regularly.
Why do so many people get hung up on brand loyalty, because thats what people do. Not that it matters in reality.
The most important thing about changing your oil is the additives go away after a period of time and people continue to use it. Whatever the additive package is, anti foam.. is gone. No one wants to put in 10-40 and it become 10WT only on a hot day. I had a boss who did not change his oil when he should. Let equipment go for years without changing oil. I told him he should run straight 30 WT. Its always 30WT. Lets just say he always seems to have maintenance issues.
And this stuff about synthetic. Its ALL dino oil. There is no lab made oil that companies make so we can put in our cars. There are no giant vats of man made chemicals that gets mixed with other chemicals and out comes "synthetic" oil. Its just a higher refined dino oil with the best additives.
All oil containers have the label that says what the oil is. You know, SG, SI ect. Now THAT is what the oil is and everything else written about it means nothing. Engineers put the oil through the device that says what it is, has to meet the specs so that it is what the label says.
To me, there are no 10,000 mile, 15,00 mile oils. That is just a way for car companies to bring down the cost of yearly maintenance. Same way car companies all seem to recommend super thin 5-30 or even 0-30 oils. No way they protect better. But they will take the overall MPG of a fleet of vehicles down slightly and with the the BS regulations Washington has on them I understand why.
Sure, for what we do stuff like Brad Penn is a good choice. Its specifically made for our hobby.
But I do not run anything close to it. And I have never blown up a engine or even spun a rod bearing in my life.
I have run Wal Mart oils and now run 15-40 Delo because I have access to it. But I always run it with a QT of Lucas in my oil. Good stuff in my opinion. It clings to metal. You can even pull your distributor and there is this this slimy film on it. I call it protection.
My Tundra, I do run "synthetic" 10-30 just because it is the nicest vehicle I own. But it is the Wall Mart 17$ for 5qt variety. It has the exact SFI label as Mobil 1. So it is the same oil. What do you want to bet it came out of the same refinery. I know it was at least a peer refinery. Just like products such as dog food, charcoal, car batteries came from the same factory but with different brands.
Now my beater/work rig 98 Honda Civic. It almost never gets new oil. I take the oil out of my race car that has been in it for 4-5 races and save it for the Honda. It has well over 200,000 miles on it and running like always. Getting ready to rebuild the A/C, brakes, timing belt,water pump and CV joints. Worth more to me as a reliable, good MPG with working AC than the 800$ its worth. Keeps miles off my Tundra too.

[Tom Vaught]

I went thru a couple of Fuels and Lubes classes in college and then later worked with the Research Lab Guys and "Outside" BP Oil Guys on oil analysis of our oils during and after extended dyno testing.

A Lot of what Dragncar has posted fits with the info I have received over the years.
Michigan is not the desert and I don't drive in the winter time. I bought the oil I bought because of the "additives" that were good for the camshaft grinds I run, PERIOD.

Tom V.

[Dragncar]

Last time I looked at a bottle of old school STP Oil Treatment it said zinc on the ingredients. My dad used to break in cams with it. Worked.

[dragracerx2813]

I run Rotella in the race car. I also add a quart of ZDDP. The key to any oil ,is to change it when it is time to change it and use a good oil filter. I don't care what brand oil you use, just change it! That all you need to do! Just change it when you should!

[Tom Vaught]

Originally Posted by dragracerx2813

I run Rotella in the race car. I also add a quart of ZDDP. The key to any oil ,is to change it when it is time to change it and use a good oil filter. I don't care what brand oil you use, just change it! That all you need to do! Just change it when you should!

You are putting 4 bottles of this stuff (or similar stuff) in your oil every time you do an oil change?

Tom V.

[Half-Inch Stud]

I apparently don't give a crap about my freshly rebuilt 455+060, been putting synthetic 5-20w, 10-20w, dunno who's brand, and got a leak at the oil mount.

Seems to drive good for commutes, and Lowe's runs, dog park, but no drag racing because the flat hyd cam in it now idles too good so it ain't performing no 12.2's or better.

No ZDDP, no 1050(for now), just slapped the Q-JET on it& and will again check the plugs soon after a highway run with a clean shut off.

Otherwise, thinking to part out the great running 68 GTO & get a sissy Pontiac (99 Firebird Black T-Tops with a 6 CYL) for a couple grand.

I guess the oil spots on me garage floor motivated this post.

[dragracerx2813]

Originally Posted by Tom Vaught

You are putting 4 bottles of this stuff (or similar stuff) in your oil every time you do an oil change?

Tom V.

I only put one bottle . Sorry my mistake.

[Tom Vaught]

No problem, I read that and said WOW! The stuff costs $8 for the 4 oz bottle and you are adding $32 more dollars to each oil change. You got more $$$ than I got.

I think I paid $7 a gallon for the High ZDDP 15w40 Diesel Oil from Farm Fleet years ago.
With-in a year, the government had mandated a 1/3 of the ZDDP vs the stuff in the oil I bought. But I have enough for the Solid Flat Tappet Camshaft engines I will build.

Tom V.

[dragracerx2813]

Originally Posted by Tom Vaught

No problem, I read that and said WOW! The stuff costs $8 for the 4 oz bottle and you are adding $32 more dollars to each oil change. You got more $$$ than I got.

I think I paid $7 a gallon for the High ZDDP 15w40 Diesel Oil from Farm Fleet years ago.
With-in a year, the government had mandated a 1/3 of the ZDDP vs the stuff in the oil I bought. But I have enough for the Solid Flat Tappet Camshaft engines I will build.

Tom V.

To be honest with you I don't really think I need to add the zddp to the Rotella . But I know they have cut back the amount that is in Rotella , so I figured it's better safe than sorry. If I was running a roller cam I wouldn't add it.

[Tom Vaught]

Rotella today I BELIEVE is mandated to be 800 vs the older stuff that was 1350 to 1400.
Some claim with a flat tappet camshaft you need 1000 (Chebby websites). Don't think 800 is going to cut it as there have been posts mentioning failures of flat tappet camshafts with any lift to them.

Tom V.

ps lots of discussion on the web on this topic.

[455firebird1969]

5 qt Rotella T 15/40, 1 qt Lucas oil stabilizer, one pt STP every oil change in my Poncho (changed every 60-70 passes). 10 qt Rotella T6 15/40 in my Duramax every 25K (with a bypass filter). 6 qt 5/30 Mobil 1 in my LS1 Formula every 5k. 6 qt 5/30 Walmart brand Dino in my wife's Toyota every 5 k. Napa/wix filters on everything but the Duramax, it gets Amsoil filters.

Toyota has 283k miles
Duramax has 191k miles
Formula has 160k miles

Current Poncho engine is still fresh with about 125 passes on it. Last Poncho engine went 7 years over 1000 passes using napa brand 10/40/Lucas/STP

Synthetic out performs Dino in high temp conditions, and has a longer life if kept clean. IMO (the way I understand it)

[dragracerx2813]

Originally Posted by Tom Vaught

Rotella today I BELIEVE is mandated to be 800 vs the older stuff that was 1350 to 1400.
Some claim with a flat tappet camshaft you need 1000 (Chebby websites). Don't think 800 is going to cut it as there have been posts mentioning failures of flat tappet camshafts with any lift to them.

Tom V.

ps lots of discussion on the web on this topic.

Yeah with a flat tapped you really need to add the ZDDP. I have seen a few cars have problems without it.

[Dragncar]

In a perfect world I would have a 55 gallon drum of the old Rotella or Dello.
I suspect that the new oils of that type with a qt of Lucas and a can or two of STP would get the job done for flat tappets.

[beemergary]

Start out with Rotella and switch to Amsoil. My 1984 Peterbilt with a Caterpillar and close to 1 million mi. runs like a fine tuned machine. Never been apart. Must be something in that diesel oil.