Wow you guys are great, what an informative thread this turned out to be! On a different note, my builder said I could get away with 10w30 safely I really like Amsoil stuff as I get a discount also, so I was thinking about Amsoil Dominator 10w30 once I'm broken in. Good choice?

 

Heavier weight oils are fine if the rod and main bearing clearance is on the looser side of things. I run Redlne 5W30 with clearances of .0025-.0030 and my oil pressure nears 70psi cold and around 50psi at hot idle so I really do not see the need to run a thicker more restrictive oil in the LSX build.

 

NO!!! He was adamant about not EVER using it. He said for track/racing, yes. For street/strip use, just change the Dino oil every 2,000 miles, and I'd be fine. I used it for 1,000 miles for break in, Mobil1 0w-40 from then on......

 

For a regularly street driven car I would suggest the AMSOIL Signature Series 10W-30 (ATM),
The narrower spread compared to 0W-30, or 5W-30 requires fewer Viscosity Improvers
which has slightly better anti- shear properties.
As well as the detergents and additives required for the street.
Save the Dominator Series for the track.
Head of AMSOIL Technical Development gave me that recommendation at the Direct Jobber Convention
in October 2019.

 

10W-30 for summer and 5W-30 in the winter.

 

Amsoil Dominator 10W-30 has a higher High Temp, High Shear (HTHS) rating than Mobil 1 FS 0W-40 (3.6 cP vs 3.5 cP) so it would actually withstand more abuse. I'd be happy with that oil in your application. While that oil is marketed as a "racing" oil, it still contains a standard DI additive package with a TBN >7 so there's no issue with using it for typical 3-5k mile / 1 year intervals.

Ugh... I don't even touch conventional. With the weaker performance parameters, you're starting at a disadvantage when it comes to formulating and have to blend in additional anti-oxidants and viscosity modifiers. You'd also have to use pour point depressants to give it some sort of cold start function, and increased anti-foaming and anti-aeration additives. Then you'd have to adjust levels of anti-wear, friction modifier, extreme pressure, and detergents to ensure there's still synergy as AOs and VMs tend to work counterproductively to AW and EP additives. Basically, it makes it a real PITA and still get stuck with an inferior product in the end. There's just no advantage to it. That painful process is most of the reason why conventional is only a few dollars less than synthetic retail price, but only lasts about half as long.

 

MORE truth in lubrication... and why dino oils' days in the sun are over...

 

I built my engine (L96) for my 65' Cutlass and from day one I have used Quaker State Ultimate Durability 5W30. Great price and its on the shelf at your nearest Wal-mart. They will more than likely have 10W30 as well.

Look up articles from 540Rat. He goes into great detail on oils that he tested and Quaker State Ultimate Durability had good reviews.

https://540ratblog.wordpress.com/

 

Case in point: 5W30 Amsoil Signature Series.

 

So final outcome is I went with Amsoil Dominator 10w30 for after the break in. For break in I'm using Lucas 30w break in oil

* On a side note, this car is not a daily. Not a very frequent weekend car either due to my work schedule, etc. Not driven in winter months either.

 

I still believe in Dino oil to help with ring seating. In fact, some builders run non-detergent Dino oil for the first 400-500 miles, then change to synthetic. I guess everyone has their own theories.....

 

I can see that. Basically you use a simple oil that does a so-so job of protecting the innards, so the rings get bedded in faster than with a good oil that might hinder that process. In which case dino oil is ideal.

 

540rat is the laughing stock of the oil world. Please don't take any advice from his blog.

His "film strength" measurements are bogus because the equipment that can measure it that accurately doesn't exist. An SRV is the closest thing you'll get and even it has a 30,000 psi margin of error. What he's doing is running the oil in a scar rig, observing the scar by eye, and then pulling a number out of his ****.

Also, actual oil film strength isn't relevant to engine oils anyway. It's a gear oil spec. It doesn't matter if an oil has 60,000 psi or 120,000 psi film strength when the most demanding applications on Earth (Top Fuel) see just 40,000 psi bearing load. Most common commuter cars are 5,000-8,000 psi with performance engines being closer to 10,000 psi.

Conventional is still ideal for break-in. I should've specified that I was referring to oils for regular use outside of break-in. That said, a break-in oil can be made using group III synthetic with no viscosity modifiers that performs on par with conventional for break-in. It's just more expensive and no advantage to it so conventional for break-in it is.

 

I learn something new everyday. I am still a fan of the Quaker State Full Synthetic.

 

540rat aside, it is likely a decent oil.
Though I do wonder what Poly's opinion of it is. Can't have too much GOOD knowledge!

 

Scar tests are B.S.... Wanna know one funny thing about that "Scar Rig" setup some "oil testers" use? You own, right now, a substance that will kick the **** out of any oil on the market at preventing wear on one of those rigs, and its cheaper than motor oil.

Ready for it? Shampoo. Head-and-Shoulders is a more effective "scar test" lubricant than any engine oil you can buy. Do NOT put shampoo in your engine. All that the Scar Test setups prove is which engine oil would make the best grease.

I've said it before and caught some flak for it, but really, your oil choice is your last line of defense, especially at high RPM or in racing. No super oil will prevent you from spinning bearings if your clearances are wrong, or prevent your lifters from collapsing. If the engine is built right with oil and windage control, proper oil pump, and all the rest a small variation in oil choice will not matter much.

 

Kawboom, what you said makes a TON of sense! LOL @ the shampoo result! Good stuff!

 

It's a decent shelf oil. It's Pennzoil Platinum in a different jug.

I mostly agree with this. No oil is going to bandaid or fix poor machining and/or assembly.

There are benefits to certain oils over others depending on the application. You likely would never see the difference on the street though some oils (of the same grade) have shown better fuel efficiency in controlled, steady state testing. It's mostly in strict racing applications, where you're chasing every last 0.5 hp you can get, that you'll see differences. I helped deliver an oil formula earlier this year for a professional racing team that was average +7 hp better than the old oil.

There can be other effects that oil has on the engine and power, again typically only in extreme racing applications. I've seen engines want less spark timing or more spark timing with changes in the oil used. I've seen air/fuel ratio changes as well. The reason why that happens though starts flirting with proprietary information.

 

Poly (I hope you don't mind this short version..), you most certainly are in a very interesting line of work. And it is appreciated!
Always good when you can drop by.

 

Is it worth it to use synthetic oil?

Synthetic oil is more expensive than conventional oil but offers superior protection for your car's engine. Synthetic oil provides more effective protection for your car, may even prolong the life of your engine.

What happens if you put conventional oil in a car that requires synthetic?

Answer. Synthetic oils typically provide better protection than conventional oils, but switching back and forth between full synthetic and conventional oil will not damage the engine.

Should I switch from conventional oil to synthetic?

Myth: Once you switch to synthetic oil, you can never switch back. This is one of the most persistent myths about synthetic oil—and completely untrue. You can switch back and forth at any time. In fact, synthetic blends are simply a mixture of synthetic and conventional oils.

Is it better to use 5W-30 or 10w30?

5w30 provides better lubrication compared to 10w30. It is best suited for private vehicles and light-duty diesel and petrol engines, while 10w30 is more suitable for commercial vehicles and other cars with heavy load engines. With all of the options available when it is time to purchase motor oil, how do you decide what to buy? Should you go for a particular brand? Or a certain type? Is conventional oil just as good as synthetic? Is one grade of oil better than another? And what does “grade” even mean? Let’s take a look at some commonly asked questions about motor oil and see if the answers can clear up some confusion.

When it comes to motor oil, what is a “grade”?

To start with, we should clear up some confusion over motor oil (also called “engine oil”) terminology. Motor oil grades are a scale developed by the Society of Automotive Engineers (SAE) to describe the viscosity of oil. Viscosity is the ability of a liquid to resist flow - how thick it is. Oil grades relate to an oil product’s performance at operating temperature (about 212 degrees Fahrenheit in your engine). You might be familiar with terms such as “30-weight” or “10W-30” oil. Those numbers refer to the grade. The higher the number, the thicker the oil. The lower the number, the thinner. Thinner oils flow faster than thicker oils, and engineers design engines to work with a certain grade of oil.

For all practical purposes, the terms “grade” and “viscosity” refer to the same thing with motor oil. So does the term “weight”. Each of these words are used interchangeably when people talk about motor oil. So, SAE30 oil is also 30-weight, and both describe the oil’s viscosity or thickness.

What is the difference between “straight-weight” and “multi-weight” (multi-viscosity) oil?

Many years ago, straight-weight motor oils were common. Straight-weight oils are lubricants that have a set viscosity, a single grade. SAE50 is higher viscosity (thicker) than SAE40, and so on. Straight-weight oils come in a wide range of viscosities.

But your car operates (ostensibly) in a wide range of temperatures. When your engine is running at operating temperature, it does not matter too much if it is summer or winter. The engine is still warm and so is the oil. But if your car has been sitting all night, the difference in temperature can be very different from one season to another.

Why is this important? Because oil gets thinner as it heats up. Or you could say it gets thicker when it cools down. Say your engine needs 30-weight oil when it is running at operating temperature. Well, 30-weight oil will work perfectly well when your engine is warmed up. But when you go to start it on a cold winter morning, that 30-weight oil is considerably thicker and has a hard time moving when you turn the key.

Enter “multi-weight” oil. These products are one grade or viscosity (or weight) when cold and another when warm. You have seen 10W-30, 5W-20, and the like. The first number refers to the grade when cold and the second when warm. Actually, the oil itself is the lower grade and contains additives that make it resist thinning out as it gets hot, thereby making it work like a higher-viscosity oil. So, 5W-20 is a 5-weight oil that acts like 20-weight when warm.

What does the “W” stand for in a multi-weight oil?

So the numbers represent the oil’s grades when cold and when warm. But what about the letter “W”? Simple. It stands for “Winter”.

When might it make sense to use straight weight oil (SAE30) rather than multi-weight oil (5W-30)? Straight-weight oil has one potential advantage over its multi-weight cousins. Because it does not contain viscosity improvers (the additives that allow a low-viscosity oil to perform as a higher-viscosity oil), straight-weight oil has better shear protection. Shear is the breakdown of viscosity during operation, especially when an engine is running at high RPMs. Some muscle cars with older engines might benefit from straight-weight oil, unless they are driven in the cold, in which case the benefit of a multi-weight oil outweighs the improved shear resistance. Most engine wear occurs not when the engine is hot, but on startup when the engine is cool. If you drive a classic, you might consider straight-weight.

That said, straight-weight oil is never recommended for an engine that calls for multi-weight oil.

Is thicker oil better for an engine?

There are some circumstances where drivers have used thicker oil in an engine. If, for instance, clearances between engine components have increased, gotten sloppy, a thicker oil can help to fill the void. Within reason, thicker oil maintains a better lubricant film between moving parts. Some have even used thicker oil in a leaky engine to prevent oil from seeping out.

But really, thicker oil is not good for your engine. Not when “thicker” means higher viscosity than the manufacturer recommends. Your engine was built to specific tolerances - spaces between the moving parts. So the recommendation for a specific grade of oil is deliberate. The oil needs to be able to coat those surfaces, but it also needs to be able to flow into all of the tight spaces in a modern engine that has been engineered to be smaller and lighter weight, and with tighter tolerances. The best grade of oil for your engine is the grade recommended by the manufacturer.

Is it okay to switch grades of motor oil, say, from 5W-20 to 10W-30?

With that in mind, some manufacturers suggest only one grade of motor oil for use in a particular engine, while others set a range of grades based on the climate in which the vehicle is driven. If that is not the case with your car, stick with the manufacturer’s recommendation.

How about 5W-30 instead of 5W-20?

Again, although both of these examples are 5-weight oil when cold, they have different properties when warm. Using oil that is thicker than recommended may lead to a decrease in fuel economy, a higher load on your engine, and even a shorter life for your engine. Conversely, using thinner, lighter-weight oil than recommended can cause excessive wear and shorter engine life.

Compliments of the worldwide web which every one who decides to post on here has access to. I don't know of a single factory built LS engine that ever needed anything more than 5W30 or 10W30 oil but I do know an old timer who's been running Castrol 20W50 since the day he bought his truck new. Oil pressure was good but it always ticked a little at start up. Now wouldn't you think the 20W50 had something to do with it?

Out of this entire thread the one thing that stands out in my mind about oils is that. "He who is without oil shall throw the first rod"