Oil for my engine?

[Sören]

Yes, I know, "what oil to put in my Engine?" is probably one of the most asked qustions :-)

But, anyway, can't find info so I wonder what oil to put in my 1969 472" Engine.

Only drive at summer, no cold starts.

[Cadillac Jim]

I would look on my oil filler cap for the grade, which is probably 10W-30, and only use oil with the starburst symbol or API "doughnut" on the (plastic) can (from MotorOilMatters.org):

Since motor oil additives that provide engine protection have been reduced since your car was designed to protect the life of catalytic converters, I would not go over 6,000 miles between oil changes under any circumstances, and would consider 3,000 miles to 4,000 miles a good idea. Whatever the absolute maximum oil change interval in your owners' manual says, cut it in half. You can use oil analysis services such as Blackstone Laboratories (CLICK HERE) to determine what the actual life of the oil is, if you care to do that. Areas of your engine that are affected by this change in oil formulations include your timing chain, the distributor/oil pump gear, and the cam lobes and valve lifters.

Follow this advice and you will be honoring the design intent of the manufacturer and allowing for composition changes in engine oil since 1972. Beyond that, there are people here and elsewhere who will give you much other advice. I have found over the years that offering any advice on oil invites endless posts on the subject. So, at the risk of further inviting many divergent opinions, I will offer one bit of advice regarding going beyond the minimum requirements for engine maintenance. You might consider synthetic oil. It is purer than dino oil and will have be better for your engine at very low temperatures (winter starting) and very high temperatures (pistons, exhaust valve guides, etc.), absorbs less moisture and is far less likely to produce sludge, etc.

[KHE]

I would recommend Shell Rotella 10W-30 for your car. The Rotella oil is a diesel oil and it has additional anti-wear additives vs. the gasoine 10W-30 oil has. The additional anti-wear additives are what your engine needs since it does not have roller cam followers and since it has a distributor.

[Cadillac Jim]

With the Shell Rotella, you can use your owner's manual for oil change intervals.

[Sören]

Have information here in Sweden that Rotella is not on the market in my country.

Shell says that Rimula R5 LE 10W-30, a HDDEO-oil, should be "the same"

[Göran W]

Sorry, wrong language but local adwise!

Sören, prova det här: http://www.granngarden.se/product/motorolja-turbo-super-20-l

Vet inte vad frakten blir - beror på var du bor. Klart jämförbar med Rotella. Med årligt byte bör du klara dig i tre år så det blir inte dyrt.

For all English speaking: Your starburst symbol does generally not apply in Sweden.

[Cadillac Jim]

Yes, the starburst symbol is obsolete, as are the cardboard cans that featured it on the lids, but some oil featuring it is still out there. I included it because when I did a web search, it was still featured as a logo in use to flag motor oil certified for use with gasoline vehicles.

[KHE]

Have information here in Sweden that Rotella is not on the market in my country.

Shell says that Rimula R5 LE 10W-30, a HDDEO-oil, should be "the same"

The 10W-30 diesel oils (Rotella, Delvac, Delo, etc) are recommended for your car since it does not have roller lifters and it has a distrubutor. All that requires extra anti-wear additives in the oil. If all that is available is the SN grade oil, I'd add a few ounces of GM Engine Oil Supplement to the crankcase to make sure there is enough antiwear additives in there.

[Z15]

He is outside of the USA (Location:Sweden) so our spec's mean little.

Buy the best 10W-40 engine oil you can find.............

[Cadillac Jim]

If you buy regular 10W-30, don't go over half the oil change mileage specified as the maximum in your owner's manual. GM does recommend an additive that adds ZDDP, as KHE mentions, but I don't know the part number. You can also use cam break-in additive, used to add ZDDP to oil when you have a new cam and lifters with flat tappets.

[hjb981]

The starburst symbol is, as far as I know, mostly about protecting the emissions control systems of modern cars. In other words, it has less relevance for an engine that does not have a catalytic converter. If price is not a concern, the oils from Redline offers a lot of oils with high levels of ZDDP (the traditional anti-wear substance that is used in lower concentrations today compared to before to protect catalytic converters). This oil is available in Sweden (or cheaper from online retailers in Europe, for example: http://www.opieoils.co.uk (I have not used Redline or Opie myself)). I have confirmed the higher levels of ZDDP in Redline's oils by reading on their website, MSDS documents and by asking them directly by email. This includes some oils that are marketed as being suitable for applications requiring SM or SN classified oil.

Just for the record: there are starburst-labelled oils available in Sweden (imported from the US, for example Amalie), but they are not the most common ones. I have not found any such oils in 10W-30, however. For some reason, 5W-30 and 10W-40 are very common in Sweden, while 10W-30 is harder to find (and the ones I have been able to find have not had the starburst symbol).

In Europe, a different system, ACEA (http://www.acea.be/images/uploads/pub/070308_ACEA_sequences_2007_LD_and_HD.pdf), is used, partly in parallel with the American API system. The ACEA grades can be quite confusing: for example, A1/B1 and A5/B5 both have low HTHS viscosities, while A3/B3 has a higher HTHS viscosity. HTHS stands for high temperature high shear, and this value is more representative for the situations in places like the valve train than the "normal", kinematic viscosity, denoted by the oil weight equivalency at 100 degrees C / 212 deg. F (30-weight in a 10W-30, for example).

An oil with a higher HTHS viscosity will retain the oil film under more severe conditions (higher mechanical pressure and temperature, e.g. in the lifters), and thus rely less on wear additives such as ZDDP. Therefore, the same amount of ZDDP should last longer in an oil with a higher HTHS viscosity. The best oil from an anti-wear perspective should be one with both a high HTHS viscosity and a high dose of anti-wear additives (ZDDP, for example). Many modern engines are constructed differently to reduce the need for ZDDP (to protect emission control systems) and be able to run with low viscosity oils with low HTHS viscosities (to reduce drag in the engine and hence improve fuel economy). For that reason, it is important to be informed when choosing oil for an older engine.

If you really like to read about oils, have a look at this: http://www.widman.biz/uploads/Corvair_oil.pdf. It is a document written by a Bolivian oil guy with a passion for Corvairs, and contains a lot of reasoning about what one should think of when choosing engine oil for older cars.

[Cadillac Jim]

The PDF document at the second link in your post is very interesting but it does not have any handles that I can find to cross over from things like 10W-30 or 5W-30 without going to similar definitions of the numbers in the API technician standards and reports; page 5 is the most informative to me without looking up other references. The third link, apparently to a classical link to a forum post by a oil guru and Corvair enthusiast in Brazil, great credentials for high-performance oils in old cars, is a dead link; widman.biz moved or deleted the page.

The 1997 Cadillac factory shop manual gives two API oil grades for early Northstars, 5W-30 and 10W-30, and specifically says not to use other grades such as, specifically, 20W-40, ever (page 0B-3). I would think that for a 1972 iron big block that a good grade of 10W-30, or, from the linked PDF document of European standards, a good C2 oil for gasoline engines. If the cat is not there, then, as you say, an A1/B1 or A2/B2 oil seems to be a good match to American requirements.

[Z15]

AMSOIL Z-ROD 10W-30 Synthetic Motor Oil Modern Technology For Classic Cars would be ideal but I doubt you can find as its not distributed in your country..

[hjb981]

Just to make sure there is no misunderstanding: The correct viscosity should be used at all times --- the European system (ACEA) does not replace the viscosity system, but rather the API quality ratings (for example SJ/CH). Engine oils are rated for viscosity (for example 10W-30) whether the API quality rating or ACEA quality rating is used. In other words, there is no cross-over between the ACEA grades and viscosities, just as there is no crossover between API quality ratings and viscosity. All European oils that I have seen have the viscosity printed on the bottle, and they often have both the API and ACEA quality/service ratings, and sometimes also some manufacturer-specific standards.

The link to Richard Widman's oil document was incorrect because my explanation of the link was incorporated in the URL by accident. The last line of my previous post should have read:

If you really like to read about oils, have a look at this: (http://www.widman.biz/uploads/Corvair_oil.pdf). It is a document written by a Bolivian oil guy with a passion for Corvairs, and contains a lot of reasoning about what one should think of when choosing engine oil for older cars.

[Cadillac Jim]

Thank you for fixing the link, this is a magnificent article. Although references aren't given to books and papers at the end, the company has run its own tests and massive amounts of data from those tests is given here. There isn't much on synthetic oils but there is enough. Some of my favorite highlights on the list of conclusions about 2/3 of the way down the document:

Remember that the correct viscosity is your primary consideration. Increasing it beyond what it should be will cause more wear and heat. Reducing it below what is needed will cause additional bearing wear. Read your manual and use the “preferred” viscosity or the lowest viscosity that covers your temperature range.

We should recognize that the 10W-30 in the Corvair manual is probably a general recommendation for the weather ranges in the US. That is a huge range. If you are constantly driving in high temperature areas, your oil temperature is probably higher than “normal” so an oil such as a 10W-40 would give you the same start-up protection, and would be in its proper viscosity range between 105° C and 120° C instead of 95° C to 105° C. Making that a 5W-40 would give you better startup protection at the same time. But don’t use 5W-40 or 10W-40 oils that are not 100% synthetic or good semi-synthetic (note the shear of polymers above)

Shear strength of the base oil is more important than a few parts per million of ZDDP. Synthetics will give the best protection, with Group II oils next. Try not to fall for the group I oils. This is not always easy to identify, although in the USA group II is now more of a norm than an exception.

If you want the maximum valve train protection, look for an oil that is certified CH-4/SL or CI-4/SL without CJ-4. If the CH-4 or CI-4 comes before the SL, that is fine. Oils that are only SL certified have much less anti-wear additives.

You do not want the API starburst. That is what tells you that it meets all the reduced phosphorous levels for catalytic converters.

Forget the myth that you can’t switch over to synthetics in an older engine. Any formulation on the market today is totally compatible, and the better formulations will not only give you better shear protection and cold weather protection, but will clean up the sludge around the seals, allowing them to be softened to their normal size by the oil.

Forget the myth that synthetics cause leaks. The formulations of decades ago were pure PAO (group IV) that had poor solvency and tended to shrink seals. All of today’s formulations have esters or other ingredients that make them totally compatible with the seals, and the better ones will actually reduce leaking after a couple thousand miles.

Don’t believe the myth that you can break in a rebuilt engine with synthetic oils. The argument that new cars come with synthetics so you can break in a rebuilt engine is totally false. None of us has the same work conditions, torque wrench calibrations or parts that the factory has. Use high quality mineral oil until the consumption stops; then switch to synthetic if you want maximum protection. Note: The use of Chrome or Moly rings in your rebuild will extend the break-in period. Don’t switch over to synthetics until oil consumption has (basically) stopped. [Here I would go with the supplier's recommendation. Some reman suppliers like Jasper do have the "work conditions, torque wrench calibrations... [and] parts that the factory has." So, ask before you put the first oil fill in a dry engine.]

Near the bottom of the last page:

Can I use a 5W-30?

Yes: Particularly in colder climates, and especially with synthetics. For the reasons I mentioned on page 28, a good synthetic SAE 30 can be labeled 5W-30 and 10W-30 (That does not mean all SAE 30’s are 5W-30, but a 5W-30 is a 30). With mineral oils, I’d say only if they are the best. The cheap stuff might shear down. [A good synthetic 5W-30 is very much the same as a 10W-30 over the temperature range of the 10W-30, but flows better on startup. Not so for cheaper oils, particularly after the first 1000 miles or so; read the whole article.]

This is the first time in a long time that I have learned something I actually believe, that I didn't know before, from just one article. The last time was when I did some research about things brought up in the oil wars of five or six years ago and I looked up viscosity curves of different oils over temperature and found that Mobil 1 5W-30 surpassed dino oil 10W-30 in that it's "best" temperature range was wider and it flowed better at lower temperatures, as well as had other good properties like maintaining film strength at high temperatures and flowing at very low temperatures, not absorbing water very much, etc. and most of those links are down. At that time, the only 5W-30 oils that I saw curves on that looked good for my 1997 ETC were Mobil I and Amsoil.

The big surprise to me is that only a very few oils are approved for Corvair owners. Corvair engines were air-cooled 2.3, 2.4 and 2.7 liter flat-six pushrod engines that included a turbo version, so demands on oil over temperature are very high for this engine. The author of this article (and principal maintainer of the web site, apparently) owns and drives a restored 1960 Corvair, and older cars are common in Latin America, particularly US cars. Hence his interest in applying the resources of his retail oil supplier company to provide information for use by owners of older cars, particularly Corvairs, in their selection of engine oils. Much of what he says is directly relevant for the 1993-1999 Northstar, and the majority of what he has to say is informative for any automobile owner.