No two engines are exactly identical, and no two engines owned by two different people will be operated and cared for in exactly the same way.

4000-5000 mile change intervals are not necessarily bad, it all depends on the application and how you use the engine. You can't know for sure if a given change interval shows above normal wear for a specific application without a UOA; even 3000 miles might be too long in extremely severe conditions and/or with low detergent racing oils.

It's not good data because there are too many variables (different engines, hand built, different climates, unknown usage and care pratices, etc.) in your examples. These are not documented by anything more than your claim that "people you know using synthetic oil with stroker LSx engines have failed sooner than yours". That's not a statistic or a trend, it's anecdotal at best. Where is the proof that these engines would have lasted longer with conventional oil of the same grade and same change interval? To potentially show any real evidence of your theory that synthetic, by itself, leads to higher engine wear, you'd really need to do back-to-back UOAs on the same exact engine used under the same conditions.

Perhaps more people just happen to use synthetic in the first place, and therefore more engines that fail (but that would have also failed with conventional) just happen to have synthetic in them. Or perhaps some people are expecting too much of the synthetic and not changing it as often as they should be for the application (which would be equally harmful if you were running conventional for too long). Other reasons could include using the wrong grade for the application/climate (since the majority of wear in a street engine occurs at a cold start), combined with living in colder climates that make cold starts even more difficult. Abusive usage pratices could also be a factor (60k "hard miles" can wear things out much quicker than considerably more "easy" miles). Point being, there are a ton of variables in your examples and absolutely nothing that actually proves your claim that, overall/in general, conventional oil is superior to synthetic.

My advice to anyone looking for real answers about oil is to vist a site like bobistheoilguy.com, and to begin doing UOAs on their specific engine to see what works best.

 

Can you explain why some on here claim that their camaros and trans ams came out the factory with mobil 1 and some have oil caps with mobil 1 5w-30 printed on them? Not disagreeing with your above statement, just curious.

 

The SLP cars (SS and Firehawk) had an optional "synthetics" package that could be ordered when these cars were new. It was not Mobil 1 brand though, but rather Castrol. Here is a picture of the label applied by SLP to an SS that was ordered with this package:



Other than this, there was no option for a factory synthetic fill for the F-body LS1s. The Mobil 1 caps can be easily installed on F-body LS1s just the same as C5s.

 

Yea I assumed someone could easily just get a Mobil 1 cap and install it. But I seen a few guys on these oil related threads defend the synthetic oil by claiming they came out the factory with Mobil 1 and even had Mobil 1 on the cap.

 

That is absolutely true, when speaking of the LS1s in the C5s. But it's the same LS1, and therefore it would be absurd to claim that LS1s weren't "designed" for synthetic oil.

 

i use mobile 1 10w 30 on my ls1 z28

 

It's FINE, as is their Ultra.

Some people on here just DO NOT understand how motor oil works, nor it's VERY varied functions which DO depend on type/grade/add packs/base stocks/viscosity indexes/TBNs/etc.

Will an engine outlast the rest of the car with timely conventional changes?
ABSOLUTELY!

Will that engine possibly perform better, quieter, cooler, with MUCH LESS start up wear (especially in the cold) with a high quality, high viscosity index SYNTHETIC oil?
EVEN MORE ABSOLUTELY!!!

 

EXACTLY!!

The ONLY difference between our f body LS1s and the ones which went into the y bodies (NOT the LS6es in the Z06es, of course) was the intake manifold not having an EGR inlet, the exhaust manifolds were different, and maybe the cam was slightly different a few years, THAT'S IT!
Otherwise, they could have come off of the same exact line, using the same exact materials/seals/gaskets/etc.

 

The problem is that all of the naysayers and those who only listen to the 'old timers'/old engine builders on here will of course say that whole site is BS.

AS IF their "oil is oil" builders/old timers know more about oil/lubricants than the many actual tribologists on that site.

 

I always love oil threads. Always read something new sometimes good. I use M1 10-30 since day 1 I have been thinking about getting some zinc additive, my changes are religious.

 

Common synthetic oils are nothing but a marketing ploy. I don't think they really protect any more than the common conventionals. Now if you're talking about synthetic racing oil, that's a whole different ball game. But the fact that GM put m1 in the vettes but not the exact same motor in f bodies tells me there can't be anything too special about the synthetic oil.

 

Maybe so, but the Mobil 1 0W-40 IS a great oil, and much better than any of their other offerings.

And YES, there IS a difference when speaking of Red Line, Motul, some Amsoils, Torco, LAT, Joe Gibbs Driven, etc. over the 'on the shelf at Wal Mart', group 3 synthetics, even if people think they do not protect any better, or cause any less friction/wear than conventionals.

I would still take M1, or especially Pennzoil Platinum, Ultra, or Quaker State Ultimate Durability over any of the conventionals, or even semi-synthetics of the same or other companies.

 

I used to sell those decals/caps "back in the day" to forum members -- they were a GM part.

As RPM mentioned, the C5 LS1 (and perhaps GTO?) had the Mobil1 with those caps, but the Camaro/Firebird just had conventional with a generic cap.

 

Yea I actually ran across those caps on WS6Project the other day.

All I wanna know is why did GM put synthetic in the vettes but not in the camaros with the exact same engine? If synthetic is so superior, then why would GM not spend the extra money(what like maybe $10 a car?) to put synthetic in the camaros/TAs? If synthetic is so superior, then why wouldn't GM perform the SIMPLEST task to increase the longevity of their engines? I'm not being sarcastic at all. If anyone has an opinion or answer to those questions, I'm very interested.

I don't think synthetics are bad by any means. Sure maybe SOME of them "protect" better. But there is nothing wrong with conventional oil. AGAIN, NONE OF THESE ENGINES WILL EVER FAIL DUE TO OIL BRANDS/SYNTHETIC/CONVENTIONAL.

Clean, correct weight oil changed at the correct intervals is all you have to do.

 

GM got paid. By Mobil. The "average" F-body owner is probably not the target demographic for a synthetic oil change whereas a Corvette owner probably is.


The economics of auto manufacturing (slim profits) are such that every little penny counts. Save 100 pennies on some of the tens of thousands of parts on every car that a company like GM makes, and you are talking real money...

 

My 02 SS I run Royal Purple religiously. And my 02C5Z i run Redline becuase of the higher zinc content, allows rings to seat better. It isn't a big fan of RP like the SS, but thats the nature of a Vette.

 

If that's the truth, than it really supports my theory.

All GM had to do though was add in the cost of the synthetic oil to the price tag of the f bodies. Nobody would've noticed an extra couple dollars.

 

Maybe so, but I also think part of the motivation was that they wanted to make it seem like the Vette was more 'upscale' and exclusive by using M1 as the factory fill.
We are lucky that they even decided to put the same LS1 in our rides (albeit lower rated on paper only), since many y body owners were probably more than upset over that, despite it being almost 'tradition' at this point going back to the 1st and 2nd gen f bodies.

It seems that the General is even unwilling to do this nowadays since the ZL1 only gets the LSA, and NOT the ZR1's LS9 (although the base SS gets the C6's base LS3), and ONLY now that there is a new C7 y body, and engine name/design for it LT1), have they decided to put an LS7 into an f body (Z28).

 

You would be surprised at the internal politics that go in to this. The minute you have the engine department asking corporate finance to allow them another $10 expense, the interior designers ask for more, the body designers ask for more, and the finances snowball.

In the end, the consumer pays what the market will bear and what the perceived value of the vehicle is. There is minimal linkage to what the car actually costs to build. In fact, auto makers often loose money on some models of car every time they sell one. Any dollar saved goes to the shareholders.

Your point above about regular oil above is correct. The oil spec (met by synthetic and non-synthetic oils) and oil change intervals in the owners manual will get the hardware past the warranty periods and design life without issue. Any extra benefit from a "better" oil would pay off for those of us pushing the car past its design life. (Which is pretty much everyone on this site with an F-Body at this point.) Although... "pay off" is a relative thing. Money wise, I've probably sunk more money in to synthetic oil than I would have spent to rebuild the engine at 100K.

 

So you think you would have to rebuild the engine around 100k if you used conventional oil instead of synthetic?