[fyrffytr1]

I use 10-30 Valvoline race Oil in my 67 GTO. A friend who runs big block Chevelles told me about a product he uses in them made by Rislone, called Nano Prime so I put a bottle in my GTO. The car runs quieter and smoother than it ever has. You only add it once a year.

[Heybuck]

Different countries I know but for my 2 cents, but on the recommendation of my engine builder, I have ONLY used 10w-30w Diesel in my Pontiac since I've had it. Done 40 thousand miles on the rebuilt engine and its smooth and as quiet as the first start. Plenty of zinc in diesel oil to cushion any cam wear.

We can buy 91, 95 or 98 RON fuel here. I use 98 in the Pontiac and have never used any form of additives in the oils or fuel.

Works for me.

[GT182]

I don't understand why anyone uses diesel oil on their gas engines. It's for diesel engines not gas. I used it at one time in my 79 Formula and it ruined the engine bearings. That's one of the reasons I only use Valvoline. You might think your doing your engine a big favor but it the long run you aren't. And I've heard that from a number of retailers and those that have used it.

Sorry for the rant but I hojnestly found out the hard way.

[Fullsize455]

Originally Posted by GT182

I don't understand why anyone uses diesel oil on their gas engines. It's for diesel engines not gas. I used it at one time in my 79 Formula and it ruined the engine bearings. That's one of the reasons I only use Valvoline. You might think your doing your engine a big favor but it the long run you aren't. And I've heard that from a number of retailers and those that have used it.

Sorry for the rant but I hojnestly found out the hard way.

All that sounds good to the totally uninformed who are unfamiliar with engine and fluid bearing design, but is of course totally false. Diesel oil did not ruin your bearings, nor has it ruined anyone else's.

Diesel engine bearings are no different than gasoline engine bearings, and oil intended for diesel engines is not fundamentally different than oil intended for gasoline engines. There are additive packages that differ somewhat, but they are absolutely interchangeable with no risk of damage. Now, using a high-zinc diesel oil in a modern car with a catalytic converters and sensitive O2 sensors may cause problems with those parts, but it will do no harm whatsoever to the engine itself.

Now, diesel oil is designed for the much harsher environment of a diesel crankcase, and is thus more robust. It also has to deal with more soot contamination and diesel fuel dilution than a gasoline engine oil. The additives and properties that result are beneficial in gasoline engines as well. Conventional diesel oils are not designed for prolonged high RPM, nor prolonged high temperature use, so something like Rotella T would not be suitable in any serious race engine that sees serious track time, but it is absolutely acceptable and in many ways better for everyday road usage.

Your anecdotal story of ruined bearings obviously neglects to mention some other serious factor that was the primary reason for your bearing failures, because the oil wasn't it. So long as you were using the proper viscosity oil of course, and changing it at proper intervals.

My own anecdotal evidence includes using Shell Rotella T 15-W40 extensively in numerous old carbureted pushrod engines over the years, including nearly 50k miles on the already high mileage 455 in my '71. I used nothing but Rotella T in that engine from the moment I acquired it with 193k on the clock. When I tore that engine down at 241k miles, it was still a good runner, had good oil pressure, bearings looked perfectly fine, and I have no doubt it would have continued to run for many tens of thousands more miles. Same goes for numerous other pushrod engines that I have used it in and have put tens of thousands of miles on. Never had any sign of trouble from any of them.

But of course, just like so many things in life, people love to fall back on their one-time singular piece of anecdotal evidence, having done no additional research on the subject, and present it as a definitive argument. Anyone that understands fluid bearing design and has some knowledge of automotive engine oils would never make such a foolish claim that "diesel oil ruined their bearings the one time I used it", because that is of course absurd.

So there, there's a counter-rant. I've been fighting the ridiculous myths about oil for years, but they persist because people love sticking to their anecdotes and blaming someone else, because it's easier than accepting reality sometimes.

[68 461 Bird]

Originally Posted by Fullsize455

Conventional diesel oils are not designed for prolonged high RPM,.

What do you consider prolong high RPM? On a long trip (3-5 hours) at 65 to 70 mph, my engine is at 3200 RPMs.

[Fullsize455]

Originally Posted by 68 461 Bird

What do you consider prolong high RPM? On a long trip (3-5 hours) at 65 to 70 mph, my engine is at 3200 RPMs.

That's fairly high for a diesel engine, but I wouldn't consider that high RPM. You can't ignore the context of my post, which was referencing race usage vs. street usage when talking about prolonged high RPM usage. 3200 RPM at a steady, low throttle cruise is not hard on an engine. Routinely giving it full throttle to redline is much, much harder on it, and diesel oil would not be approriate for that kind of abuse.

[68 461 Bird]

Originally Posted by Fullsize455

That's fairly high for a diesel engine, but I wouldn't consider that high RPM. You can't ignore the context of my post, which was referencing race usage vs. street usage when talking about prolonged high RPM usage. 3200 RPM at a steady, low throttle cruise is not hard on an engine. Routinely giving it full throttle to redline is much, much harder on it, and diesel oil would not be approriate for that kind of abuse.

Thank you for your reply and was not ignoring the context of your post. I was mainly asking your opinion if you thought a steady 3200 RPM was considered too high for the diesel oil on a street driven classic. I have been using the ZR1 Vavoline 20W-50 in my street driven classics, wasnt sure if I should switch over to diesel oil or not.

[TedRamAirII]

One issue is that "Rotella-CK" is not the Rotella that everyone's engine builder has used or recommended in the past. When it was rated CH, CI or CJ that's a entirely different oil than it is now, they dropped the "S" ratings, only the name is the same. Its all spelled out on the ratings on the side of the bottle. Reading the bottle of any motor oil, "APPROVED FOR" is different than "Recommended" or "Meets or Exceeds". So, if its safe for Cat Converters, it maybe isnt good enough for our Pontiacs. Every oil company has continued to remake and substitute their additive package to help auto/truck manufacturers meet emission specs. What is the latest, greatest oil....today?

[geeteeohguy]

Originally Posted by GT182

I don't understand why anyone uses diesel oil on their gas engines. It's for diesel engines not gas. I used it at one time in my 79 Formula and it ruined the engine bearings. That's one of the reasons I only use Valvoline. You might think your doing your engine a big favor but it the long run you aren't. And I've heard that from a number of retailers and those that have used it.

Sorry for the rant but I hojnestly found out the hard way.

All due respect, as an automotive master tech with over 40 years of experience, this is not the truth. Look it up....do the research. The worst oil you can run in a street driven flat tappet engine today is RACING OIL, which lacks the additive packages needed to fight corrosion, acid build up, dilution, etc. Plenty of failed bearings on the street using that stuff. Been running Rotella and Delo for 12 years or more, and thousands of miles. When I tore down my '67 GTO in 2011 for a reseal at 90,000 miles on the rebuild, the bearings looked like new, as did the rest of the engine.

[78w72]

Originally Posted by GT182

I don't understand why anyone uses diesel oil on their gas engines. It's for diesel engines not gas. I used it at one time in my 79 Formula and it ruined the engine bearings. That's one of the reasons I only use Valvoline. You might think your doing your engine a big favor but it the long run you aren't. And I've heard that from a number of retailers and those that have used it.

Sorry for the rant but I hojnestly found out the hard way.

where do people come up with this stuff?! diesel oil is 100% compatible with & rated for gas engines. at least look at a bottle & the specs it has before posting crap like this. it did not & physically could not damage your bearings in any way, shape or form!

same goes for the comment on here that diesel oil isnt designed for "high revs"... its made from the same base stock oil as any other off the shelf conventional oil & will handle 2000 or 7000 rpms just the same.

the misinfo being spread out there is amazing!

[Ram Air IV Jack]

Originally Posted by 78w72

where do people come up with this stuff?! diesel oil is 100% compatible with & rated for gas engines. at least look at a bottle & the specs it has before posting crap like this. it did not & physically could not damage your bearings in any way, shape or form!

same goes for the comment on here that diesel oil isnt designed for "high revs"... its made from the same base stock oil as any other off the shelf conventional oil & will handle 2000 or 7000 rpms just the same.

the misinfo being spread out there is amazing!

The word "compatible" means one thing, the words "approved or recommended" mean another. Please remember that!! I've heard stories on both sides of this debate concerning diesel oil being used in gasoline engines. One thing that is pretty certain is using a quality oil made for gasoline engines, the "starburst symbol" you see on most oil containers, will be fine and won't hurt anything. As far as the diesel oil debate, it is personal choice and what people are comfortable with. There is one good debate though. Since diesel engines are not designed for high revs, you do wonder if diesel oil would provide adequate protection in a gasoline engine pushing 5k to 6k+ revs! I can see an argument there.

[78w72]

Originally Posted by Ram Air IV Jack

The word "compatible" means one thing, the words "approved or recommended" mean another. Please remember that!! I've heard stories on both sides of this debate concerning diesel oil being used in gasoline engines. One thing that is pretty certain is using a quality oil made for gasoline engines, the "starburst symbol" you see on most oil containers, will be fine and won't hurt anything. As far as the diesel oil debate, it is personal choice and what people are comfortable with. There is one good debate though. Since diesel engines are not designed for high revs, you do wonder if diesel oil would provide adequate protection in a gasoline engine pushing 5k to 6k+ revs! I can see an argument there.

i use compatible to convey its rated & approved by the manufacturer for both diesel & gasoline engines... thats what the API rating means! remember that! & its recommended by anyone that knows about oil or engines in general... rotella-t has been recommended by engine builders for decades with zero problems. ive been using diesel oil in my classic pontiacs for 10+ years!

yes there are "stories" about diesel oil, just read this thread or many of the other threads on here & other forums... complete udder nonsense!

you must be the guy that posted the "high revs" thing earlier, where did you come up with that concept? a story you heard? there is no argument for that at all... diesel oil uses the same base stock oil as any other normal oils, therefore it can & will work exactly the same as "gasoline" oils. seriously, oils are not designed based on rpms, if it has an api rating it is "designed" for any normal rpm range. please show me where you got this "not designed for high rpm" mumbo jumbo.

edit: actually scratch that last part, if you seriously think or believe thats true, then its not worth wasting any more time on it. carry on.

[mgarblik]

Every thread on every forum involving cars or trucks and oil/additives will end up just like this. There is lots and lots of money at stake and it's in the best interest of all the manufacturers and retailers to keep it that way. Opinions are strong, anecdotal evidence rules the day. Two things to help guide you through the mess. API, American Petroleum Institute, SAE, Society of Automotive Engineers. In a very generic sense, API rates quality, SAE rates viscosity. API S ratings are for spark ignition engines, C ratings are for compression ignition engines. Some conventional oils and some synthetics carry API quality ratings for both S and C applications, some do not. Oils listed for "high mileage" are allowed slightly more ZZDP in the chemistry than the latest S rated oils with the DEXOS designation. Oils sold as synthetic blends are impossible to qualify IMO. A semi-synthetic oil blend can be 10% synthetic up to 90% synthetic, there is no standard. It would be in the best interest of profit to keep the % low. I have been in this business almost 50 years, still waiting to see my first engine failure CAUSED by the engine oil. Oil can contribute to engine failure, sure. Try and prove it!. My advice FWIW, use the correct SAE viscosity for your application. Use full synthetic oil for the best possible engine protection. Use the API S or C rated oil for the approximate age/mileage/ design of the engine. Use any major, recognized brand of oil you like. NO ADDITIVES OF ANY TYPE are needed after break-in of a new engine if the above guidelines are followed. (full disclosure) My race team is sponsored by Valvoline, I use all Valvoline lubricants.

[Fullsize455]

Originally Posted by 78w72

i use compatible to convey its rated & approved by the manufacturer for both diesel & gasoline engines... thats what the API rating means! remember that! & its recommended by anyone that knows about oil or engines in general... rotella-t has been recommended by engine builders for decades with zero problems. ive been using diesel oil in my classic pontiacs for 10+ years!

yes there are "stories" about diesel oil, just read this thread or many of the other threads on here & other forums... complete udder nonsense!

you must be the guy that posted the "high revs" thing earlier, where did you come up with that concept? a story you heard? there is no argument for that at all... diesel oil uses the same base stock oil as any other normal oils, therefore it can & will work exactly the same as "gasoline" oils. seriously, oils are not designed based on rpms, if it has an api rating it is "designed" for any normal rpm range. please show me where you got this "not designed for high rpm" mumbo jumbo.

edit: actually scratch that last part, if you seriously think or believe thats true, then its not worth wasting any more time on it. carry on.

Right, because you know you don't have an argument. You're not arguing based on facts or established science, you just came up with something that sounds right to you and think it's an argument. Trouble is, gut feelings and reality are not always one and the same.

Prolonged high RPM operation results in much higher oil temperature, and motor oil breaks down exponentially faster with heat. No, of course the oil does not know the engine RPM, it is simply affected by the conditions under which it is used. High RPM and frequent heavy throttle break down oil much faster than regular street driving at lower RPM. This is the kind of common sense that you don't have to be a scientist to understand.

Even those with even the most basic understanding of the differences between oils know that synthetic oil has far superior ability to deal with heat, thus it is almost universally better at dealing with higher performance engines than a typical conventional oil. Since we're talking about stuff like Rotella and Delo, we're talking about conventional oils here. Yes, there absolutely are differences between different oils' ability to handle higher RPM operation. If you think otherwise just because you think oil isn't a tachometer, I can't help you.

If you want facts, you do research and read information from as many sources as possible. If you want to be stubborn and never learn anything new, you come up with something that sounds good in your own head and you stick to it regardless what anyone else says and whether or not it's true. Fact is, the science involved with motor oils is widely studied, widely understood and available for anyone who desires knowledge to persue and understand, most people just don't care, because they think they already know all there is to know. That's why every thread about oil always devolves into these dumb arguments and disagreements, where endless myths are spewed, misinformation runs rampant, and in the end nobody is any better off than they were before we started. Most people are just too stubborn to bother learning anything new, especially when their daddy told them something different 40 years ago, and we all know daddy was always right!

[TedRamAirII]

Originally Posted by Ram Air IV Jack

The word "compatible" means one thing, the words "approved or recommended" mean another. Please remember that!! I've heard stories on both sides of this debate concerning diesel oil being used in gasoline engines. One thing that is pretty certain is using a quality oil made for gasoline engines, the "starburst symbol" you see on most oil containers, will be fine and won't hurt anything. As far as the diesel oil debate, it is personal choice and what people are comfortable with. There is one good debate though. Since diesel engines are not designed for high revs, you do wonder if diesel oil would provide adequate protection in a gasoline engine pushing 5k to 6k+ revs! I can see an argument there.

How does the oil know how many RPM's its going?

[78w72]

Originally Posted by TedRamAirII

How does the oil know how many RPM's its going?

oh it knows, diesel oils have a super high tech nano robot that can detect when the oil is above 3000 rpm, & then, the oil completely fails & causes catastrophic engine failure!


I have been in this business almost 50 years, still waiting to see my first engine failure CAUSED by the engine oil.

the first ever failure is documented in this thread & it's true because he said so... he used diesel oil & it ruined his bearings! because you know, diesel oil will do that in a gasoline engine!