You will get many opinions on a question like that, I use Brad Penn semi-synthetic racing oil my 427ci small block

"The Brad Penn® Penn Grade 1® Racing Oils contain the higher level of anti-wear (ZDDP – zinc dialkyldithiophosphate) and enhanced film strength so critical to proper high performance engine protection. The Penn-Grade 1® oils “typical” 1,500 ppm Zinc (Zn) and 1340-1400 ppm Phosphorus (P) content provide the needed anti-wear protection to critical engine parts, such as piston/cylinder walls, roller cams under heavy valve spring pressure and especially those that employ a solid “flat tappet” type system."

Oh yeah I forgot, it's a green color !

 

Subdriver & jb78L-82, after reading and posting on this forum for over two years now those were the most matter-of-fact and informative pieces on the eternal dino-vs.-synth debate that I've yet seen-VERY well done. While woefully unable to compete with either of you on the technical side of this matter, I will once again offer that for the most part this is still a get-what-you-pay-for debate. I run cheap diesel oil in my C3; it hasn't wiped a cam or bearing yet and I don't 'spect it will as long as I can continue to find oil with ZDDP in it. For me, the synthetic argument is basically a cost-no-object game-in real terms, you're just not going to realize four times the benefit for the four-times+ cost of synthetics over cheap diesel oil. If you just gotta have the best stuff, then you're gonna have to pay-period.

 

Interesting posts. Unfortunately, oil cans/bottles don't have their ingredients on the label. The best way to decide on what oil is to go by experience. And, what to look for in a oil is to reduce friction and keep the passages clean...almost all oil advertised for the engine application will work in varying degrees. And, the old adage is true...you get what you pay for. If you use $3 per quart oil then you rarely get better friction reduction or cleanliness than a $5 per quart oil. Racing oil seems to be the best, but will cost you almost $10 per quart and needs to be changed about every 1,000 miles or when it gets dirty, and it does such a good job that it gets dirty fast.

Hence, oil manufacturers who have an investment in their brand name provide an oil that exceeds the requirements for a standard 3,000 mile or 6 month oil change schedule. The rule of thumb I always used was to change the oil at the change of seasons or unless it looked dirty (could not see through it). But, recently car manufacturers are saying that some engines can run for 7,500 miles before an oil change. But, keep in mind that they are talking about new engine designs. Most of us are using the old design which has less tolerance.

So, my suggestion is to use what was originally designed for the engine that you have. If you have the original engine then use the original oil. If you have an engine that has a new design then use the new oils.

 

Thanx for the kind comments! Hopefully, some folks will rethink their opinions on the subject although I doubt it based on my previous experience with this issue and other subjects that leave room for interpretation. You are absolutely correct with your analogy that generally you get what you pay for! As with most things, though, you pay a significant cost premium for an incremental benefit which is one of the reasons that a synthetic like Mobil 1 is actually a terrific deal since at Walmart the last time I bought oil, Mobil 1 15W-50 Racing was $23 for 5 quarts versus Shell Rotella 15W-40 at $16 for 5 Quarts, which is a difference of $1.40 per quart more for Mobil 1 or $4.60 per quart for Mobil 1 versus $3.20 for Shell Rotella. $8-$10 per quart for some of the other synthetics is another story completely. Really peanuts when you use 5 quarts over the course of a year's driving for me.

 

You're quite welcome for the compliments-you guys may yet persuade me over to the Dark Side. Personally, my biggest issue with synthetic oil (specifically, Valvoline 10W-40) aside from the added cost was that it had a mysterious penchant for....disappearing. This in a car ('94 Isuzu Rodeo) that previously had shown NO oil usage issues. 2000 miles after switching to synthetic the oil level light came on, and there was none showing on the stick-it had gone through 2 1/2 quarts. Pulled the plugs, no signs of oil fouling. Checked underneath, nothing to indicate that 2 1/2 quarts had leaked out all over the bottom of the car. VERY spooky. Went back to mineral oil, no more problem. I would be very interested in whatever info you guys might have about Disappearing Synthetic Oil Syndrome. I know, Isuzus aren't real cars- I've long since repented....

 

Birdsmith,
Thanks for the kind comments as well.

As for the question on the disappearing Valvoline, I'd suspect that the oil left via the exhaust, probably due to a combination of blow-by and/or high volatility. This gets back to the point I was trying to make above, that all synthetics are not the same due to variances in basestock and additives and that drawing parallels between one brand an another may be inappropriate.

 

Wow! No idea on this one. My 78 vette L-82 4 spd with 3.70 gears revs like a mother on the highway and uses zero Mobil 1. My 2001 Grand prix that had dino oil up to 50,000 and then I switched to Mobil 1 5W-30 for the last 50,000 miles with 5,000 mile oil change intervals uses zero oil as well. 1994 Mustang GT 5.0 also uses zero Mobil 1 between changes. Totally spooked. Did you use the correct weight oil for that engine and year?

 

By the way, for all the dino oil lovers out there, just came back from Costco and they have Shell Rotella T 15W-40, 3 gallons for about $31. Great price! You see I am not all bad!

 

Im a oil nut myself and done some pretty in depth studies to satisfy my choice, Royal Purple. I buy it by the 5 gallon container. Use it with a mobil one oil filter and forget about wear.

 

Honda motorcycle oil, 10w30, has all the additives for flat tappets.
15w40 Diesel oil is to thick for my taste.

 

soooooooooo.. with all of this said the best oil for the 1978 l-82 that is stock with 25000 miles that i just bought would be??? dino, syn or diesel? the sticker says it has 10w40 in it now.. i don't know a whole lot about motors , rollers or flat tappets. also what octaine gas? i looked in the book but just saw to use unleaded fuel,

 

in my big Cat. I just dropped an Edelbrock ZZ4 435hp/435tq in my '71 vert, and for what it cost me, I want the VERY best! Right now it has the break in oil still in it. What should I go to next? I expect high temps,etc.,especially in the summer.A Corvette is a heat machine to begin with.I am definitely all ears!

 

I put Mobil-1 in my Lawnmower, not the car!

 

You should really try milk - tastes even BETTER!

 

Now there's a TRUE rebel - one of the few places it is NOT recommended!!

 

Royal purple also has a new line of break in oils as well.

 

I want to use a truly synthetic oil. Should I use AMSoil,Royal Purple or Mobil 1?

 

Clearly biased, but I'd recommend AMSOIL SAE Synthetic Premium Protection 10w40.

This bias comes from my own review of hundreds of used oil analysis reports on the oil forums, my own used oil analysis reports and some others of forum member cars who have taken samples for me, and some comparative testing (particularly in motorcycle oil and gear lubes - AMSOIL hasn't done that in-depth of an automotive engine oil yet, but I drew my own parallels).
Cadillac CTS-V Used Oil Analysis – Mobil 1 5w30 vs AMSOIL 0w30
Corvette C5 Used Oil Analysis Report – AMSOIL SAE Synthetic 10w30
Used Oil Analysis Comparison: German Castrol 0w30 vs AMSOIL Series 2000 0w30
AMSOIL Motorcycle Oil “White Paper” (1 MB pdf file)
AMSOIL Gear Lube “White Paper” (2 MB pdf file)

 

My lawnmower is where I have noticed the benefits of Mobil 1 the most.
Going on 15 years with only 3 oil changes, abusing it as a small branch mulcher too in very dusty, sandy conditions. Doesn't even use any oil at all and always starts 1st pull. Runs like new.
Don't use it in the old vettes though.