0W40?

[DRM500RUBYZR-1]

It is extremely difficult, nearly impossible, to prove something cannot possibly happen.
However, that does not mean that it can or will.

The Zinc and ZDDP content of the 0-40 is higher than most of what is often currently being used in these and other older engines.

Religion, politics and yes, oil, are very often controversial subjects.

Mobil One has been around since 1976.

While I understand it's formula has had to undergo changes, for mostly political reasons, i.e. Reduced exhaust emission requirements for catalyst longevity, that does not mean that it destroys engines.

I continue to favor Brad Penn for my LT-5, but I would not hesitate using Mobil One 0-40, and may even switch to it on my next change.

You may call me a Heathen, but I do have faith in companies such as Mobil and their products.

I do not believe or expect that this will change anyone's opinion, and that is OK.

Use whatever, as you wish.

Be happy!

Marty

[AirbusDriver]

Beaky Buzzard once said....you can't fool me because, I'm a moron. With that said, I'll rely on others. My 90 is scheduled to go to Haibeck and whatever he recommends is good enough for me.

[Hib Halverson]

Playing the devil's advocate...

LT5s with stock valve train don't need that level of zinc and phosphorous (which was formulated with pushrod valve gear in mind) because the cams act directly on the tappets. There are no pushrods and no rocker arms. That means less mass and since there is less mass, even the stock 1G LT5 valve springs have significantly less tension than valve springs in pushrod engines, thus the pressure over the nose is less and...there is less need for the extreme pressure additive ZDDP.

I no longer have Mobil 1 data sheets going back to the 90s so I can't quote facts, but I'm not convinced that all the factory fill oil used back then has 1200-1300 PPM phos.

[grahambehan]

Hib, there comes that "Beacon".

Graham

[Matt B]

Apart from the ZDDP discussion wouldn't it be interesting to to know about the positive effect of high viscosity oil during cold start? That's where engines are supposed to have the highest wear. At least according to what I read about it.

My personal experiences are:
- with those super thin oils the chance of leaking dramatically increases the thinner they get.
- the best way to get great engine performance and lifespan is to treat it well. Proper brake in (which unfortunately the least uf us can control in their 30 years old ZR-1), patient warm up & plenty cool down phase, high quality fuel and regular/frequent oil chances make engines purr like kitten. No oil can offset poor usage - but good habits can, to a certain degree, offset a poor oil.

My 1995 Audi S6 4.2 still consumes no oil, doesn't smoke at startup or during hard acceleration, runs smooth as silk and pulls like a freight train (though compared to the ZR-1 I have to say: like a steam train). I tried many different oils in this car over the last 22 years of ownership (with strict annual oil change). 0W30 was the thinnest. But I always treated the engine with love and care. I don't claim that this is the ultimate way to success but at least in my case (includes all my other cars) it worked well.

Back to my question above: how much would 0W instead of 5W or 10W support a well lubricated engine start and thereby reduce wear?

[secondchance]

I hear LT5 valve tension being less than that of typical push rod engine. However, shouldn't we also enter higher RPM into this equation?
I had used Mobil 1 products for years in my 94 ZR-1 (as well as long departed 91 ZR-1) until I found out that Mobil has quietly reduced the Zn and phosphate content and eventually turned to Amsoil.
For me with less than 5,000 miles being put on my 94, a bit of hassle and cost once a year in exchange for a peace of mind is well worth it.
Below link should take you to the latest Mobil 1 oil specifications.
https://www.mobil.com/lubricants/-/m...pecs-guide.pdf

[CamP]

Rotella T6 5w40 is a good option if you're looking for a 40wt synthetic oil with a lot of zinc.

[spork2367]

Originally Posted by Paul Workman

Every time this question comes up, some are quick to say they have tried it in their motors w/o any issues. But, lubrication issues seldom pop up until considerable run time has occurred under typical wear scenarios or under stressful scenarios.

I dunno 'bout Uz, but I can't afford to experiment with my engine - too rich for my not-so-deep pockets. Therefore, I would prefer to see some comprehensive, scientific testing and comparisons between historic results with a former recommendation lubricants and the new product (good as it may be!).

Our LT5s are flat tappet motors and rev limits are ~ 7100 rpm to 7500 rpm (in some modifications). And, the ZDDP of the oils recommended at the time they were being built (by Mercury Marine), the zinc/phosphorous levels were in the ~1200/1300 ppm - to accommodate the demands of those (LT5) engines.

However, air pollution mandates resulted in reducing (in part) the ZDDP levels. And, offsetting the reduction of reducing the ZDDP, flat tappets gave way to roller tappets and rocker arms, etc.; both roller tappets and rockers are still in use today. My point is: aren't we comparing apples to oranges here? That isn't to say that this or that GM oil recommendation will spell trouble for our first gen LT5s. But, it remains to be seen if the new oil recommendation can bridge the gap between the specific application (roller tappets/lower rpm vs. flat tappets/high rpm) requirements.

Your mileage may vary. But, as for me - I'll stay with the "Kool-aid" until something else proves to be better...hopefully in an application other than MY LT5! Just sayin'

The ONLY reason 0w oil was created was to reduce emissions and increase fuel economy, primarily during a vehicles warm up period. Anyone who says anything else is drinking the corporate kool-aid from the auto manufacturers. I spent years at a company that built air cooled aircraft engines that were used in environments with starting temps well below zero and places with starting temps well above 3 digits. We've done our research and operate in a market devoid of emissions regulations (for the time being). Zero weight oils were created in Japan for emissions and fuel economy. You know, the country where it was cheaper to buy a new car than to continue to run a car with 55k miles due to emissions and other restrictive requirements like the "shaken" law.

There is no measurable benefit to 0w oils on start up unless you are comparing them to straight 50 weight or gear oil. Sorry. The car manufacturers and the government are trying to dupe you.

Run what the manufacturer recommended originally or slightly heavier depending on driving conditions and style. That recommendation came from before the environmentalists became so woke and figured out how much money was in it. While additive packages have improved, there is no magic to oil manufacturing from the 90's until now. It is almost exclusively driven by CAFE and emissions laws.

My 2011 Subaru Forester came with 0w 20 oil from the factory and the timing chain clattered like none other at startup until I switched to a heavier oil.

[Dynomite]

Originally Posted by AirbusDriver

Beaky Buzzard once said....you can't fool me because, I'm a moron. With that said, I'll rely on others. My 90 is scheduled to go to Haibeck and whatever he recommends is good enough for me.

I think Haibeck is still going with Amsoil 10W-40 on his web site 👍
"Amsoil offers their AMO product. I believe that it provides the best protection. It has the full EP additive package. In addition it is 10W-40 viscosity. The higher viscosity offers more film thickness, which adds to EP protection."

Let us know if that has changed 👍

I just got a case of Amsoil 10W-40 delivered today 😁😁

[Matt B]

Originally Posted by spork2367

The ONLY reason 0w oil was created was to reduce emissions and increase fuel economy, primarily during a vehicles warm up period. Anyone who says anything else is drinking the corporate kool-aid from the auto manufacturers. I spent years at a company that built air cooled aircraft engines that were used in environments with starting temps well below zero and places with starting temps well above 3 digits. We've done our research and operate in a market devoid of emissions regulations (for the time being). Zero weight oils were created in Japan for emissions and fuel economy. You know, the country where it was cheaper to buy a new car than to continue to run a car with 55k miles due to emissions and other restrictive requirements like the "shaken" law.

There is no measurable benefit to 0w oils on start up unless you are comparing them to straight 50 weight or gear oil. Sorry. The car manufacturers and the government are trying to dupe you.

Run what the manufacturer recommended originally or slightly heavier depending on driving conditions and style. That recommendation came from before the environmentalists became so woke and figured out how much money was in it. While additive packages have improved, there is no magic to oil manufacturing from the 90's until now. It is almost exclusively driven by CAFE and emissions laws.

My 2011 Subaru Forester came with 0w 20 oil from the factory and the timing chain clattered like none other at startup until I switched to a heavier oil.

Very interesting post. Thanks!