engine oil for C3 smallblock

[Thomas O.]

Is Shell Rotella (sorry about name brand) 15w 40w oil ok for use in a 73 small block. I have heard that this oil contains the needed additives for the older 350 ci engines.

[Donald L.]

CI -4 *NM*

[Duke W.]

Re: engine oil for C3 smallblock

Rotella is just one of MANY oils certified to the API CI-4 service category, which contains a better additive package including more ZDDP anti-wear additive than current spark ignition oils designated SM, which are designed for modern, not vintage engines.

Walmart sells their own house brand CI-4 that is packaged by one of the majors, and I think it's Chevron, so it's the same as Chevron Delo.

Buy oil by the API service category, not brand. Look on the package labeling for the API "donut" and service category. If it's CI-4, it's the "good stuff" regardless of brand, and the only differentiation is price.

Duke

[Anthony S.]

Re: engine oil for C3 smallblock

Tom,

A friend has been looking doing alot of homework into what oils are best for older engines. He has been an auto tech & manager for 30 years.

Most of todays oils are designed for roller cams and do not have the amounts of sulpher & zinc found in older oils. These additives are also less emmissions friendly.

Shell Rotella T is his choice for enghies with flat tapppet cams. However, a can of MOA additive or STP Oil Treatment will help increase the sulpher & zinc levels and add shear strength (sticks to parts) to the oil.

Good luck,

Anthony

[Duke W.]

Re: engine oil for C3 smallblock

If you use CI-4 oil you don't need any supplemental additives, and I strongly advise against them as does every automotive OEM on the planet.

I'm not a service tech or shop manager - just a retired automotive and aerospace engineer that has discussed this issue at length with current engineers from both the major automotive OEMs and oil companies. I also have some familiarity with the various API tests to certify oil to the two major current standards.

Shell must have some marketing clout because all I ever read on internet discussion boards is Rotella.

It's not the ONLY CHOICE!!! Motor oil is a generic product and there are a couple of different types - S and C. Buy CI-4 or CJ-4 (NOT SM) for your vintage cars, and forget about the brand name.

Duke

[Ray G.]

Re: oilC3 SB. ECHO Duke, from a retired shop owner

Hello;
Rotella (15W40) is an oil of choice(truckers) for sparkless ignition.
Additives except the Generals "EOS" have a tendency to gum up internals(rings). Some are fine IF the engine is run through a complete heating/cooling cycle(15 miles) each time it is driven.
The best lubrication is Dukes recommendation changed by milage and time. Whichever occurs first.
Dukes technical knowledge is phenomenal.(Not that he needs me to say that.)
Ray

[Tom S.]

Re: oilC3 SB. ECHO Duke, from a retired shop owner

I agree with the above post's. I prefer Chevron Delo, but any of the CI- OR CJ oils are fine. Duke has researched this more than anyone I know,he is very well educated on this subject.And others as well I might add. Tom