CL-4 oil for new GM crate engines ?

[Larry B. Seaney]

I have read many threads about the benefits of using CL-4 oil in our older engines. I am in the process of putting a new zz383 in my C2. The literature that came with it says to use 10W-30. Is it advisable to use CL-4 15W-40 in this new engine? Will using a 15W-40 weight oil void my GM warranty?
THanks
Larry

[Dennis B.]

Re: CL-4 oil for new GM crate engines ?

Larry,

I have the zz383 in my 66. When I broke in the engine I used 10w30 with the GM EOS break in additive added. Ran that for 500 miles. Dropped that oil and repeated 10w30 with EOS for the rest of last years driving season. Changed the oil again before winter storage with 10w30 Castrol. That is what is in it now. With the limited driving these cars get I think non diesel oil will be fine. Just my $.02. By the way that motor pulls like a mule and runs like a scalded dog.

Dennis

[Clem Z.]

the ZZ383 has a hyd roller cam

so camshaft break in is not required. i would stick with GM recommendations on the engine oil to make sure you do not cause any warranty problems

[Duke W.]

Re: CL-4 oil for new GM crate engines ?

The desired viscosity range, particularly the "W" (winter) rating is a function of the lowest typical anticipated cold start temperature. All of your owner's manuals should have a chart showing the acceptabel viscosity range as a function of starting temperature range. In general, modern cars recommend lower viscosity ranges as a sop to EPA fuel economy ratings.

So what do you estimate?

You can also buy CI-4 (not CL-4) oil 10W-30, but I've never seen it stocked in the popular outlets in California. Maybe colder areas carry it.

Eventhough this engine has roller lifters, the richer additive package in CI-4 may be beneficial, and there is no catalyst to be concerned about.

Duke

[John L.]

Re: CL-4 oil for new GM crate engines ?

My New Holland TC30 Tractor calls for 10w-30 diesel oil. You can buy it at any New Holland Dealer.

[Donald M.]

Re: CL-4 oil for new GM crate engines ?

Duke, I just thought I'd toss in a little info I read in the owner's manual of my 2006 Malibu Maxx. In the oil section it specifically says "do NOT use ANY other weight oil but 5W-30" There is no "anticipated temperature" chart, just "use 5W-30". I was told by a knowledgable friend that the insistence on 5W-30 is due to the extremely close bearing tolerances of the new engines. On a cold start, the thinner oil gets to the bearings faster. Makes sense to me.
BTW, 10W-30 CI-4 oil is very hard to find. I managed to locate a supplier after much searching and writing the manufacturer (Chevron).
Don

[Duke W.]

Re: CL-4 oil for new GM crate engines ?

Be careful of "told by knowledgeable friends" statements without any evidence to back it up or some analysis on your part. Many folk's "knowledge" is based on other than objective science and engineering. The first thing you should do is find the OE bearing clearance range for your Maxx.

From the 1963 Corvette Shop Manual, the range of main bearing clearance is .0008-.0034" and .0007-.0028" on the rods. That's a VERY broad range. If anything, new cars probably have a much tighter range within these ranges due to more precise machining, and within these ranges, looser clearances will usually reduce friction.

Some modern high viscosity range spark ignition engine oils, like 20W-50, do not meet the current SM specification because SM places limit on viscosity range for "fuel economy" reasons. Go check out any on-the-shelf 20W-50 and you will likely find it is labeled "SL", which also means if has more ZDDP anti-wear addtive than SM oil since the SM spec places a limit on phosphorous, which limits ZDDP concentration.

The industry has agreed on a set of oil specifications for MODERN catalyst equipped spark ignition, but this specification, SM, IS NOT necessarily best for a vintage engine or even a modern engine that will be placed in a non-catalyst vehicle.

If you have a modern car, especially one under warranty, follow the manufactureres oil specification(s) recommendation, but don't apply this to a vintage car apriori.

For a vintage vehicle, even one with a modern crate engine, use the oil viscosity-temperature chart in the owner's manual, and avoid using SM oils due to their marginal additive package. Use either a SL or CI-4 oil.

Duke

[Clare Carpenter]

What does EOS stand for?

As in GM "EOS" break-in additive? Also, just to clarify the point further, oil refiners have agreed to a new standard for oil to be used in modern engines, one's equipped with catalyst ignitions convertors. Was this done for emission purposes?

Because of limits on phosphorus, there is also a limit on the anti-wear additives ZDDP for SM standards and thus these oils aren't the best for flat tappet cams in vintage engines. Do I have that assumption right? Duke, you mentioned a "modern" engine in a non catalyst ignition equipped vintage vehicle should also use SL or CI-4 oil due to better anti-wear additives. If that is the case then it appears long term engine protection is being sacrificed for emissions on new cars, or what? Thanks for the clarifications.

[Duke W.]

Re: What does EOS stand for?

"Engine Oil Supplement" - it has a high concentration of ZDDP - zinc dialkyldithiophosphate. It is recommended ONLY for engine breakin.

It is generally believed that some additive combustion byproducts including phosphorous compounds can degrade catalysts. Since emission control system/component warranties will be extended in future years, automoitive OEMs in conjunction with the the oil industry have agreed to a reduction in ZDDP.

Modern engines have fewer sliding surfaces. Even most DOHC engines have roller rocker arms, so less ZDDP is needed in many parts of the engine, however, the one boundary lubrication condition where modern and vintage engines are the same is ring reversal at the top of the bore.

Time will tell whether a reduction in ZDDP leads to more rapid wear at the top of the bore on modern engines.

You can be assured of lower long term sliding surface wear in a vintage engine if you use an oil with a high dose of ZDDP, which is why my number one recommendation is CI-4, and in most cases catalyst degradation is not an issue.

Duke

[Clare Carpenter]

Thanks for the details, now I get it. EOM *NM*