I see that I'm suppose to use high zinc oil for flat tappet engine, I saw on a site that you can use diesel oil for flat tappets as well, I believe diesel oil has other additives that are not for gas engines, anyone running diesel oil in their car?

7 hours ago, hdbob5454 said:

I see that I'm suppose to use high zinc oil for flat tappet engine, I saw on a site that you can use diesel oil for flat tappets as well, I believe diesel oil has other additives that are not for gas engines, anyone running diesel oil in their car?

Use shell rotella t4! Yes it is designated as a diesel oil now, but what you may not understand is all oils use to be the same formulation all could be used in either gas or diesel. The oil industry separated them around 2000 to save money on formulation cost. I only use shell rotella t4, but you can use any diesel formulated oil in your car. By far a better oil & by far more protection.

And Bob, last indian knows oil !!!!!!!

thanks indian I like to ask about things I'm going to try

4 hours ago, hdbob5454 said:

thanks indian I like to ask about things I'm going to try

That’s the way we all learn! What happened with the oil formulation is similar to oil viscosity ideology! Thinner is better! You know, 5w30, 0w15 & so on! All garbage! That ideology has been pushed by the powers that be for fuel economy! The problem with this is this! All these oil are multi viscosity oils! What does that really mean? It means @ 0 Celsius the first number is the viscosity & @ 100 Celsius the second number is the viscosity, but in between 0 & 100 the viscosity changes accordingly.

Put this way if you have a new OEM engine that the bearing specs are tight, but not that tight or the engine would seize. So 5w30 is ok 10w30 or 40 is ok. Because the oil isn’t a 40 weight till you reach 100C (aka 212F) & @ 212 I want 40 weight protection no matter the bearing specs! Also unless you are starting your car that has been sitting in 0 degrees all night the oil isn’t never @ 0 or 5 viscosity! I could go on, but you get the point.

Edited March 13Mar 13 by Last Indian

I have been running a diesel oil in the 5.3 liter LS engine in my El Camino for the last nine years - Shell Rotella T6 synthetic. Generally, 10W-30 or 10W-40. I have seen no ill effects and the Blackstone Labs oil analysis reports indicate the same.

I like the additives and detergent package in the Rotella and I will be changing to Rotella when the rebuilt LS 5.3 engine in my Catalina emerges from its break-in period.

Rick

3 hours ago, B52bombardier1 said:

I have been running a diesel oil in the 5.3 liter LS engine in my El Camino for the last nine years - Shell Rotella T6 synthetic. Generally, 10W-30 or 10W-40. I have seen no ill effects and the Blackstone Labs oil analysis reports indicate the same.

I like the additives and detergent package in the Rotella and I will be changing to Rotella when the rebuilt LS 5.3 engine in my Catalina emerges from its break-in period.

Rick

Ok, one last time, maybe. Diesel is the same formulation as it has always been; other than for updated formulation improvements, that happen periodically. All gas vehicles use to run the exact same oil!! The industry made a one time separation between gas & diesel TO SAVE MONEY! That’s all there is to it! You all got screwed by the oil companies! They did not lower gas engine oil prices! They just give you less. So no you are not going to see anything bad! Because the Rotella is basically the same oil you used forever before the change in 2000! Rotella t6 is a synthetic & t4 is conventional! If you change your oil every 3000 to 4000 miles you are wasting your money! The only advantage synthetic oil offers over conventional oil is shear stability for the long haul, but it still is subject to the same degradation of oxidation, fuel dilution, dirt etc. as regular conventional oil!

Hello Gary,

Yea, we all got screwed but not so much by the oil companies. Those companies were only responding to changes in requirements from the EPA. Gasoline motors and their catalytic converters could not tolerate the large amounts of additive package cadmium, molybdenum, phosphorus, zinc and sodium metals plating out on the catalytic converter metals thus decreasing the catalyst efficiency.

The oxygen sensors past where a catalytic converter would have been in the donor vehicle have all been tuned out of my El Camino and Catalina - both with a modern Gen 3 LS engine. Only the front O2 sensors for electronic fuel injection remain in these vehicles and I have edited out any other traces of catalytic operation such as Catalyst Overheat Protection inside the PCM operating system.

Thusly, nothing in the Rotella oil harms my LS engines and I think we agree. I see nothing bad about using a diesel oil.

Rick

ok good to know i was told not to run synthetic in a flat tappet motor but if the rotella has it i guess its ok.

7 hours ago, B52bombardier1 said:

Hello Gary,

Yea, we all got screwed but not so much by the oil companies. Those companies were only responding to changes in requirements from the EPA. Gasoline motors and their catalytic converters could not tolerate the large amounts of additive package cadmium, molybdenum, phosphorus, zinc and sodium metals plating out on the catalytic converter metals thus decreasing the catalyst efficiency.

The oxygen sensors past where a catalytic converter would have been in the donor vehicle have all been tuned out of my El Camino and Catalina - both with a modern Gen 3 LS engine. Only the front O2 sensors for electronic fuel injection remain in these vehicles and I have edited out any other traces of catalytic operation such as Catalyst Overheat Protection inside the PCM operating system.

Thusly, nothing in the Rotella oil harms my LS engines and I think we agree. I see nothing bad about using a diesel oil.

Rick

Rick, I presume you don’t know this because you undoubtedly haven’t read every post on FP, but I worked 40 years for the second largest additive company in the world. I work for the world headquarters on the corporate side of R&D in new product development. I got to literally work with every OEM manufacturer of automotive, truck, locomotive, farm, ship, etc. etc. plus all the oil companies & filter companies, including catalytic manufacturers of the world. We supplied nearly all the OEM auto makers in the world & a very large portion of the oil companies in the world. So, no what you implied was not the reason! Yes if you google this question, what you indicate is what will come back! But I was there! That was never the case! That was a ruse excuse to pacify the unknowing public. 

Think of this, if that were the case, why didn’t they make that change long before 25 years of catalytic use? Especially when engines & catalytic converters were much more prone to oil consumption & catalytic poisoning. You see, the additive package in engine oils are more than half the cost of the oil! Good quality oil, the additives are 35% of the cost of the oil. Add another 15% to that for testing! This is done by additive companies as well as the OEM or oil company. Then add another 10% for certification, done by both via the govt.. So you see, cutting 10% to 15% out of the 35% for a less effective additive package is a huge number for the oil company! Shortly after this separation of the two oils into their own categories the GF certifications started! That is another indicator of them knowing there would be issues from removing specific additives from the car formulations; & there were! Then in 2016 all the OEM automakers informed the additive companies that they were no longer going to invest any more money or time into new engine development. They were done! And the phasing out of ICE was in process.

5 hours ago, hdbob5454 said:

ok good to know i was told not to run synthetic in a flat tappet motor but if the rotella has it i guess its ok.

Bob, that’s fine. No harm in running synthetic oil! It will not harm a flat tapped motor, but let me ask you why? Why specifically do you want to run a synthetic oil?

Edited March 14Mar 14 by Last Indian

Iv'e had good luck running it in my bikes over the years and never know what dino oil is god, running the Lucas hot rod oil now I see it has high zinc, I never understood why running synthetic was not recommended in older motors, I thought the better oil would be the best choice just told by old mechanic not to use it.

2 hours ago, hdbob5454 said:

Iv'e had good luck running it in my bikes over the years and never know what dino oil is god, running the Lucas hot rod oil now I see it has high zinc, I never understood why running synthetic was not recommended in older motors, I thought the better oil would be the best choice just told by old mechanic not to use it.

Bob, first of all, zinc has a benefit in oil, but not as zinc per se! What is in oil is a chemical structured compound called ZDDP or zinc dialkyldithiophosphates! This is the wear additive that protects your friction points like your flat tappets. If you look at the specs for Rotella t4 & Rotella t6 they have virtually the same amount of ZDDP! Why anyone would tell you not to use an oil containing ZDDP would tell me they know nothing about oil chemistry! Which is probably most folks, sorry just true. People buy oil for all kinds of reasons due to misconceptions! But again, there is only one single benefit from using synthetic oil! It is a shear stable viscosity oil! That’s it! It is subject to all the same issues as a conventional oil. Ingested dirt, fuel dilution, carbon contamination, degrading additives like ZDDP! Yet it costs a lot more money.

Ask Kiwi, but I’ve done this before. ZDDP is an important additive, but one of the most important specs of an oil is its TBN! Hands down #1! The second most important spec is its TAN! These two specs will preserve or destroy your engine! I could run an engine probably twice as long as any one else & never change my oil & very seldom change my filter, just using these two simple specs! We have actually proved this more than once in our engine lab. Oil chemistry is very simple, but extremely complex! If that makes any sense to you.

Edited March 14Mar 14 by Last Indian

Man I love when The Indian man talks oil! It's always so informing! Thank you for sharing your wealth of knowledge sir.

Wrong way how are you? Always good to hear from you. Are staying busy? How’s the family?

You take care buddy!

One last thing I guess I should explain. What do I mean by shear stable? Synthetic oil are basically a Newtonian fluid, meaning under shear stress; that means being squeezed through bearing & orifices. Wiped up & down a cylinder wall & so on. That literally shears the oil that action in a conventional oil causes, at first to thin! Then as more shear takes place the oil starts to thicken. But in a synthetic oil the shearing action does not thin or thicken the oil! This reason & this reason alone enables extended drain intervals. Because the oil stays at a constant viscosity! But again as I said before that oil is still subject to all the other degradation that happens the conventional oil. So why do I want to keep running an oil in my engine that is suspect in every way except viscosity?!

Edited March 15Mar 15 by Last Indian

7 hours ago, Last Indian said:

Bob, first of all, zinc has a benefit in oil, but not as zinc per se! What is in oil is a chemical structured compound called ZDDP or zinc dialkyldithiophosphates! This is the wear additive that protects your friction points like your flat tappets. If you look at the specs for Rotella t4 & Rotella t6 they have virtually the same amount of ZDDP! Why anyone would tell you not to use an oil containing ZDDP would tell me they know nothing about oil chemistry! Which is probably most folks, sorry just true. People buy oil for all kinds of reasons due to misconceptions! But again, there is only one single benefit from using synthetic oil! It is a shear stable viscosity oil! That’s it! It is subject to all the same issues as a conventional oil. Ingested dirt, fuel dilution, carbon contamination, degrading additives like ZDDP! Yet it costs a lot more money.

Ask Kiwi, but I’ve done this before. ZDDP is an important additive, but one of the most important specs of an oil is its TBN! Hands down #1! The second most important spec is its TAN! These two specs will preserve or destroy your engine! I could run an engine probably twice as long as any one else & never change my oil & very seldom change my filter, just using these two simple specs! We have actually proved this more than once in our engine lab. Oil chemistry is very simple, but extremely complex! If that makes any sense to you.

yes!!!! Gary and I have had a very good chat about oil !!!

but Gary what i need to know now is where to find the cheap stuff!!!!!

petrol prices are at record highs here in nz .... are you sitting down ? $3.09 per litre this morning !!!!

And i am going to honest, this pisses me off. the knee jerk reaction and the money the middle man is making right now is bs !

the middle east farts and here on a little island at the bottom of the planet we pay more for all basic needs like food because of it. not impressed at all.

best i tuck my soap box away and go have some fun with my grand kids and the go kart ! its sunday afternoon :)

Edited March 15Mar 15 by 64 kiwi boni

4 hours ago, Last Indian said:

Wrong way how are you? Always good to hear from you. Are staying busy? How’s the family?

You take care buddy!

I'm well sir, thank you. It has been a pretty busy winter, I always think I'm finally going to have time to relax but then I find forgotten projects and neglected honey do lists. I know you know what that's like. Hope all is well with you and yours ol' buddy.

1 hour ago, 64 kiwi boni said:

best i tuck my soap box away and go have some fun with my grand kids and the go kart !

At $3.09 a liter I hope that go cart is electric!

15 minutes ago, Wrongway said:

At $3.09 a liter I hope that go cart is electric!

NEVER !!!!!!!!!!!!

my grandies are already trained to use ice !!!!!!!

Edited March 15Mar 15 by 64 kiwi boni

17 hours ago, 64 kiwi boni said:

yes!!!! Gary and I have had a very good chat about oil !!!

but Gary what i need to know now is where to find the cheap stuff!!!!!

petrol prices are at record highs here in nz .... are you sitting down ? $3.09 per litre this morning !!!!

And i am going to honest, this pisses me off. the knee jerk reaction and the money the middle man is making right now is bs !

the middle east farts and here on a little island at the bottom of the planet we pay more for all basic needs like food because of it. not impressed at all.

best i tuck my soap box away and go have some fun with my grand kids and the go kart ! its sunday afternoon :)

You have seen my work shop! That’s were the cheap (price) stuff is for me! All the same price! FREE!!

16 hours ago, 64 kiwi boni said:

NEVER !!!!!!!!!!!!

my grandies are already trained to use ice !!!!!!!

Ok! Were the hell is the roll cage & the fire suit?!

So I've been thinking and rereading this topic and now have a couple of questions, as I now realize I know NOTHING about oil and what the people selling it and google told me is crap. So please bear with my ignorance.

When I was driving trucks for a living, I was an owner operator, that means my trucks were mine, no company paid for my maintenance, PMs or oil changes. All I ran was Rotella. So, I was happy to hear that I could run it in my cars. As I understood from Mr. Indian in the past, I can run it in my GP (1968 428 less than 50mi since rebuild) without adding ZDDP. So I will be changing to the T4 10w-30 in my 2008 5.4L Triton also.

So first question, what are your thought on Lucas, or how dose Lucas oil stabilizer fit in? I always added 1 gallon with every oil change in my big truck.

Second question, I'm currently running straight SAE30 in my 428 as a break in oil. Is break in oil actually "necessary" or can I switch to T4 at any time?

On 3/24/2026 at 2:39 PM, Wrongway said:

So I've been thinking and rereading this topic and now have a couple of questions, as I now realize I know NOTHING about oil and what the people selling it and google told me is crap. So please bear with my ignorance.

When I was driving trucks for a living, I was an owner operator, that means my trucks were mine, no company paid for my maintenance, PMs or oil changes. All I ran was Rotella. So, I was happy to hear that I could run it in my cars. As I understood from Mr. Indian in the past, I can run it in my GP (1968 428 less than 50mi since rebuild) without adding ZDDP. So I will be changing to the T4 10w-30 in my 2008 5.4L Triton also.

So first question, what are your thought on Lucas, or how dose Lucas oil stabilizer fit in? I always added 1 gallon with every oil change in my big truck.

Second question, I'm currently running straight SAE30 in my 428 as a break in oil. Is break in oil actually "necessary" or can I switch to T4 at any time?

Wrongway, it would be hard to say what the chemistry is in the Lucus product. They would never reveal their formulations! That’s the Holy Grail for a chemical company. That is called “intellectual property” & when a patent is written they patent a process, not chemistry. But, by their description I would guess it has specific friction modifiers that are not typically in engine oils. I would also believe they are using a tactifier by their description of the product. Additionally they are more than likely using a seal swell additive. I would also bet that the product has a high TBN, probably a 15 to 20 TBN. These are the things that make or break an oil. Base stock is important, but not nearly as important is the additives & the quality of the additives. TBN helps keep an engine clean, it helps clean a dirty, varnished engine, it tends to help seals for the same reason. Seal swell has a softening effect on butyl rubber seals, keeping them more like new (valve seals, crank end seals, etc). A tactifier makes oil cling to a surface. So this not only helps in protecting parts while running, but also on startup! This would be their description of cling! There is no down side to running the Lucus product other than cost! Remember, all the things that are in it help the oil last longer! TBN declines as TAN increases! All the other additives decrease through oxidation, friction & excessive thermal exposure, which occurs in the bearings & valve train! Specifically the temperature in a bearing can be 50 to 100 degrees hot than the rest of the engine. This heat does several things. One the viscosity thins more than anywhere else. This effect kill film strength. Secondly it breaks the back of the oil! Though this is minuscule it adds to the decay of the oil. I could explain this further, but you get the point.

The SAE 30 question. Wrongway, that mentality has been replaced & no longer viewed as a good choice. So I would switch to the T4.

18 hours ago, Last Indian said:

Wrongway, it would be hard to say what the chemistry is in the Lucus product. They would never reveal their formulations! That’s the Holy Grail for a chemical company. That is called “intellectual property” & when a patent is written they patent a process, not chemistry. But, by their description I would guess it has specific friction modifiers that are not typically in engine oils. I would also believe they are using a tactifier by their description of the product. Additionally they are more than likely using a seal swell additive. I would also bet that the product has a high TBN, probably a 15 to 20 TBN. These are the things that make or break an oil. Base stock is important, but not nearly as important is the additives & the quality of the additives. TBN helps keep an engine clean, it helps clean a dirty, varnished engine, it tends to help seals for the same reason. Seal swell has a softening effect on butyl rubber seals, keeping them more like new (valve seals, crank end seals, etc). A tactifier makes oil cling to a surface. So this not only helps in protecting parts while running, but also on startup! This would be their description of cling! There is no down side to running the Lucus product other than cost! Remember, all the things that are in it help the oil last longer! TBN declines as TAN increases! All the other additives decrease through oxidation, friction & excessive thermal exposure, which occurs in the bearings & valve train! Specifically the temperature in a bearing can be 50 to 100 degrees hot than the rest of the engine. This heat does several things. One the viscosity thins more than anywhere else. This effect kill film strength. Secondly it breaks the back of the oil! Though this is minuscule it adds to the decay of the oil. I could explain this further, but you get the point.

Thank you, that makes logical sense.

18 hours ago, Last Indian said:

The SAE 30 question. Wrongway, that mentality has been replaced & no longer viewed as a good choice. So I would switch to the T4.

Awesome, with the little knowledge I thought I had on oil I have been concerned and wanting to change out the SAE30 but justa wasn't sure if I would be hurting anything. Thank you again.

So as normal I over think things and have a question. Please forgive me for asking a NON- Pontiac question. So, Mr. Indian, when I bought my Harley new in 2003, I was told to only use conventional oil in the engine until after break in. The reason I was given was that synthetic would not allow then engine to get hot enough to properly seat the rings. I always assumed that was BS but was never sure. I was also told that after break in IF I switched to synthetic not to do it all at once but replace one court of synthetic at a time during the next 4 oil changes and once I was running synthetic in my engine I could also run the same oil in my trans and primary. So, I also always used HD brand oil as the manual instructed. One day while at HD picking up stuff for an oil change, I got talking to their oil guy and asked him who made HD oil. He told me that Harley bought their oil from the cheapest vender, when the vendor contacts expired, they got new quotes and that became their new oil company. That was when I switched to Mobil 1 V-Twin full synthetic 20W-50 in all 3 of my box's and have used Mobile 1 in my bike ever since. Now back in the 80s and 90s when Shovelheads and Evo's where in Harleys I remember using the same oil in my truck and bike. I would literally buy 2 gallons of Trop-arctic engine oil and do both oil changes, 1977 F100 360ci and 1976 sportster 1100 cc at the same time. My bike now has an 88ci (1450 cc) air cooled engine, is there any reason why I couldn't use Rotella T6 in this bike? If I can, do you think it would also be safe to run it in the trans and primary?

Thank you for any knowledge you can pass on. Not sure if I can or will switch from my current set up but would like to have then knowledge and option to if the need arise.

6 hours ago, Wrongway said:

So as normal I over think things and have a question. Please forgive me for asking a NON- Pontiac question. So, Mr. Indian, when I bought my Harley new in 2003, I was told to only use conventional oil in the engine until after break in. The reason I was given was that synthetic would not allow then engine to get hot enough to properly seat the rings. I always assumed that was BS but was never sure. I was also told that after break in IF I switched to synthetic not to do it all at once but replace one court of synthetic at a time during the next 4 oil changes and once I was running synthetic in my engine I could also run the same oil in my trans and primary. So, I also always used HD brand oil as the manual instructed. One day while at HD picking up stuff for an oil change, I got talking to their oil guy and asked him who made HD oil. He told me that Harley bought their oil from the cheapest vender, when the vendor contacts expired, they got new quotes and that became their new oil company. That was when I switched to Mobil 1 V-Twin full synthetic 20W-50 in all 3 of my box's and have used Mobile 1 in my bike ever since. Now back in the 80s and 90s when Shovelheads and Evo's where in Harleys I remember using the same oil in my truck and bike. I would literally buy 2 gallons of Trop-arctic engine oil and do both oil changes, 1977 F100 360ci and 1976 sportster 1100 cc at the same time. My bike now has an 88ci (1450 cc) air cooled engine, is there any reason why I couldn't use Rotella T6 in this bike? If I can, do you think it would also be safe to run it in the trans and primary?

Thank you for any knowledge you can pass on. Not sure if I can or will switch from my current set up but would like to have then knowledge and option to if the need arise.

Wrongway,

The short answer is yes. Yet for the HD I would suggest Amsoil 20w50 synthetic! A far superior product! Since the bike is a low volume & protects multi-functioning parts that would be my suggestion.

Thank you sir, it is appreciated.