Change in oil additives?

[Joe L.]

Re: Change in oil additives?

Michael-----

Shell Rotella is available in 10W-30 viscosity. It's also available in single viscosities of 20, 30, 40, and 50. The Rotella synthetic is available in 5W-40. That ought to be perfect for older car applications of all kinds and types---the best of all worlds.

[Duke W.]

Re: Change in oil additives?

CI-4 oils are also rated SL, but I don't think they will meet SM due to the ZDDP issue. SM if fine for modern engines, but not for vintage engines.

Duke

[mike mccagh]

Re: Change in oil additives?

jop: the LT5 cats on our 41 Willys lost their contents by my cutting the cans open and me removing Mr Monolith. after i got the willys cats apart, i relaized the monolith crumbled easily. When i recently decided to loose the cat contents on the ole 61 Farm Use LT5, i simply removed the cat back exhaust system and with the aid of a crow bar, poked around and broke the monolith into small enough pieces that allowed the shop vac to suck out the crumbled pieces. Kinda riminded me of "pithing" a frog brain or the frontal lobotomys that were in vogue for schizophrenics in the 30's and 40's. regards, mike

[Gary #41345]

Re: Change in oil additives?

So after all of this has been said and done by some and not by others...what is the best oil for my 66 SB here in the northeast "Shell Rotella 10W-30 viscosity"?

[George J.]

Re: Change in oil additives?

I'm assuming from the above discussions that the most widely available diesel is the Shell Rotella brand, either the 10W-30 or the synthetic 5W-40. Does this sound correct? Duke, what about a '98 BMW M3? What about Mobile 1, do they make an equivalent? Thanks this sounds like a very important issue that everyone should be clear on.

George

[John L.]

Re: Change in oil additives?

Michael and others -- If you have a New Holland dealer nearby, they also sell a diesel oil in 10w-30 grade. It is the recommended oil in some of their newer diesel tractors.

[Mike McKown]

You gotta' watch what you buy here.

My nearby Case International dealer also sells 10W-30 diesel oil. The additive package in it is different than Rotella T. This stuff costs quite a bit more. It is called "Heavy duty diesel oil". Check your labels.

Case bought out New Holland.

[Duke W.]

Re: Change in oil additives?

The viscosity grades sold probably vary depending on the part of the country you are in with colder regions (during the winter) having lower viscosity grades than the typical 15W-40 that is carried in California.

There are a zillion "Mobil 1" products. Google on the name to find the complete list and study the data sheets.

Don't get hung up on brands. What you should look for is the API service classification "CI-4" on the label, and select a viscosity range that is suitable for the lowest typical cold start conditions (see your owner's manual).

The primary advantage of a synthetic base CI-4 is wider viscosity range (5W-40 for example instead of the 15W-40 mineral oil blends), which is okay for sub-zero cold starts and longer service intervals due to the greater oxidation resistance. But if you only drive your car a few hundred to a few thousand mile a year during the warmer periods of the year and don't cold start it below 10F a 15W-40 mineral oil based CI-4 is ideal. The key is the typical lowest temperature COLD START. If the crankcase got down to -30F with 30W oil, it's no big deal as long as you don't attempt to start it.

BTW, GM owner's manuals of the era say that straight SAE 30 is okay for typical cold starts at no less than 40F.

Duke

[George J.]

Thanks Duke *NM* *NM*

[Henry S.]

Re: Change in oil additives?

WOW, I am new here and the oil subject is very interesting. From what I see here this has to be one of if not the MOST informative boards I've ever been on. I recently joined NCRS when we purchased our first Corvette (64 Covertible). Since then we have also bought a 91 ZR1 and 90 Covertible. All this within a year and a half. Trying to get all this corvette information into my brain in such a short peoriod of time is like cramming for an exam. It's not easy for a 50 year old. I must say the people (corvette) I have met young or old, rich or poor are the most genuine people I have ever met. Our only regret is not buying one sooner.

Enough rambling, now for the question and I hope it doesn't sound stupid after all the discussion. Dr. Duke what oil should I use? 64 is 327/300 auto (70,000 miles), 91 ZR1 (12000 miles), 90 (9000 miles). Thanks for your help. Sincerely, Henry Shoot

[Michael H.]

Chevron Delo

Thanks Joe. Found a link to a Chevron site that lists all of their locations in the country that carry Delo in quantity. There's one just a few miles from me and they have the 10W30 I'm looking for, in addition to straight 30W.




http://www.chevron.com/products/prod...heretobuy.shtm

[Duke W.]

Re: Change in oil additives?

I would hope from my previous posts that you know the answer, but I would recommend a mineral oil based CI-4 (for both), in a viscosity range suitable for the lowest typical ambient cold start - look at the owner's manuals. If it's no less than 10 deg. F, then a 15W-40 would be just fine.

Since the cars have low mileage for their age, I would assume that they see low annual mileage accumulation, and if so, an annual oil change is suitable. If you store them during the winter, change the oil just before storage and then again prior to the next storage.

Use Zerex G-05 antifreeze in both, SAE 80W-90 GL-5 gear oil in the '64 trans (assuming it's a manual) and axle, along with the GM 1052358 additive if it's Positraction. I recommend axle and transmission oil changes every 60K miles or every 30K for Positraction. I bet the '64 could use a change at this point as I expect the fluids are original Antifreeze should be changed every 2 years if you are a maintenance fanatic or at least every four years. Again, you should within reason, follow the owner's manual recommendation, and pay particular attention to the TIME limitation.

See your ZR-1 owners manual for the recommended transmission and axle oil specs.

Lastly, I recommend DOT4 brake fluid even though DOT3 is acceptable. I flush/change brake fluid every two years, but if you live in a dry climate (like the SW desert) four year intervals are probably okay.

Duke

[James G.]

Re: Change in oil additives?

Late for comment, but here goes:
I worked for SHELL OIL for 7 years, then was a SHELL, UNION 76 AND CHEVRON Dealer for 26 years. I learned that ROTELO and DELO were the best products. Duke, you have all at 100%. Also, during the 80's when Corvette had the GTP cars, a switch to Chevron Delo gear oils saved many transmission and axels on all the racers in that series. Toyata specified Delo for many years in their drivelines under SEVERE DUTY.

[Joe L.]

Re: Change in oil additives?

Duke-----

I've not really researched this EP issue for the recent gasoline service motor oil ratings. However, it would seem to me that if the zinc-based EP additives have been reduced in concentration or eliminated altogether, then something else must have replaced them to provide equivalent (or better) EP protection. With respect to the need for EP protection, modern engines are not all that much different than vintage engines. It is true, of course, that many modern engines do have roller lifters. That does eliminate ONE of the significant "sliding metal surfaces". However, it does not eliminate ALL of that type of situation in the engines. Plus, there are some modern engines that don't use roller lifters. Many OHC designs don't use roller followers. So, there's still PLENTY of requirement for an EP additive.

Beyond that, the most current gasoline motor oil service rating generally supercedes all previous ratings. In other words, you can use an "SM" rated oil for cars originally requiring "SL", "SJ", "SH", etc., although the CONVERSE might not be true ( e.g. an "SL" motor oil might not be approved for an engine requiring "SM"). It's hard to believe that the manufacturers would strip out all EP protection and, at the same time, say that these oils are fine for use in older applications that definitely did need EP protection.

Of course, it's possible that something else replaced the zinc EP additive and this replacement folks don't consider to be as effective as the zinc compounds for EP protection. Generally speaking, though, modern motor oils provide much better wear protection than the old motor oils. In fact, that's one of their strongest suits. Without extremely effective EP additives, they would not be able to provide better wear protection than old motor oils.

I'm not saying, at all, that it might not be wise to use an oil primarily rated for diesel service. Personally, I'd be reluctant to use them if they were not dual-rated for gasoline service. However, all of the ones that we're discussing are so-rated. Whether or not they ever achieve an "SM" rating is fairly irrelevent (unless one is talking about using them in a VERY late model car that requires an "SM" oil).

[Joe L.]

Re: Change in oil additives?

George-----

Except for the cold weather start issue, I don't really think that the viscosity is much of a concern, at all. Here's why: all multi-weight oils are an oil of the LOWEST viscosity rating of their range. Viscosity modifiers are added to the oils so that at higher temperatures they ACT like a higher viscosity oil. They are not going to ACT like a 40 weight oil unless the temperatures and other conditions require them to ACT like a 40 weight oil. So, why would someone want, say, a 10W-30 oil in their engine (which "tops out" acting like a 30 weight oil) when conditions get to the point where a 40 weight oil would be best?

I really like the idea of the Rotella synthetic 5W-40. That pretty much gives you the entire "usable range". The 5W base oil will also not only provide better cold start (assuming one needs that) but, more importantly, it should provide improved fuel economy. Lately, that's become more important than it used to be.