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#3242219 - 01/08/14 07:28 PM Re: CJ-4 oil for older flat tappet engines.. [Re: Ponch]
Gokhan Offline


Registered: 12/29/10
Posts: 1547
Loc: Los Angeles, California
I think we all agree that a CJ-4/SM oil is usually OK to use in a gasoline engine, assuming the recommended viscosity is available. As I said earlier, I used Mobil Delvac 1300 Super 15W-40 CJ-4/SM for many years in my small gasoline engine. The main drawback was excess drag on the engine, making idles, especially cold idles, rougher and the fuel economy a little less and light-throttle power a little less. The excess drag is caused by the high viscosity (internal friction of the oil) and higher surface friction of the oil in comparison to an ILSAC GF-x (Energy/Resource Conserving) oil.

My main point in this thread is that, after educating myself reading the SAE Lubricant Reference and a couple of other references, higher ZDDP limit in CJ-4 oil (1200 ppm P vs. 800 ppm P in ILSAC GF-x oil), is not to make a CJ-4 oil more wear-protecting than a GF-x oil. It's only to make up for the detergents and dispersants in the CJ-4 oil. If you have 1200 ppm P, it's effectively much less because of the detergents/dispersants in Cx-4 oils. There is a lot of buzz on the Internet for using Cx-4 for flat tappets because of high ZDDP, but they are ignorant of this very important technical reason why the ZDDP is higher in diesel oil. That's my main point and I didn't realize this myself until I read the references.

I do agree that CJ-4/SM oils pass the gasoline-engine wear tests Sequence IIIG and Sequence IVA and they should usually be OK in a gasoline engine.

Also, the issue regarding primary vs. secondary ZDDP, the latter of which is far more potent as an antiwear additive, may be somewhat less of a concern, as nowadays they seem to mostly use a mix of the two and the mix seems to have similar potency of secondary ZDDP alone. (In the past diesel engines used only primary ZDDP because of better thermal stability of it.) So, perhaps, this is not too big of an issue but then it may also be. Some gasoline-engine oils may take more advantage of higher secondary-ZDDP ratios in the ZDDP mix than diesel-engine oils can accept.

Garak, you pointed out that the detergent levels have been decreasing in Cx-4 oils. However, notice that ZDDP levels have also been decreasing. The reason why they used more ZDDP in CI-4 was to make up for the rather high concentration of detergents in CI-4. The reason why some of the CJ-4 formulations use even less ZDDP is because they use even less detergents. So, someone shouldn't get sucked into a CI-4 oil for flat tappets because it has more ZDDP, as it's only to make up for high detergent content. In fact, the wear-protection requirements in CJ-4 or stricter than in CI-4.

What's also very important is the dispersants in diesel oil. CJ-4 in particular has a very high concentration of dispersants as CJ-4 has unprecedented soot control. These dispersants are ashless (metalfree) and they don't show in specs or VOAs. They are called succinimides. They also fight against the ZDDP films. See this very recent (September 2013) scholarly article (full text not available for free):

Abstract: Recent years have seen an increase in the concentration of dispersant present in formulated engine oils, while the concentration of antiwear additives has been progressively reduced. However, it is known that the presence of dispersant can, in some cases, detract from the performance of antiwear additives in lubricant blends. In this article, the influence of three succinimide dispersants on the film formation and wear-reducing properties of a secondary zinc dialkyldithiophosphate (ZDDP) has been studied. Both posttreated and non-post-treated dispersants reduce steady-state ZDDP tribofilm formation to a certain extent depending on the dispersant concentration. At very high dispersant concentrations, ZDDP film formation is suppressed almost entirely. This can be restored only marginally by increasing ZDDP concentration, which implies that the absolute dispersant concentration rather than the dispersant : ZDDP ratio controls the impact of the dispersant on ZDDP film formation.

Addition of dispersant to ZDDP also caused an increase in wear rate for all three dispersants tested. For one succinimide reported in detail in this article, it is has been shown that the wear rate increases approximately linearly with dispersant concentration and is largely independent of ZDDP concentration over the P weight percentage range studied.


So, moral of the story is that don't get sucked into heavy-duty (CJ-4, CI-4, etc.) oils just because of their high ZDDP content. Their high ZDDP content is only to make up for high concentrations or dispersants and detergents found in diesel oils. You won't get the same potency of a given amount of ZDDP in a diesel oil as you would get from the same amount in a gasoline oil with less dispersants and detergents. Effectiveness of ZDDP is greatly and inversely affected by the amount of dispersants and detergents in oil, and diesel oils have a lot of dispersants to control harmful soot.
_________________________
1985 Toyota Corolla LE, 4A-LC engine, ~ 257,000 M
Toyota (by ExxonMobil) SN/GF-5 0W-20 Synthetic
Toyota 90915-YZZF2 filter, 90430-12031 drain gasket

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#3242239 - 01/08/14 07:48 PM Re: CJ-4 oil for older flat tappet engines.. [Re: Gokhan]
Gokhan Offline


Registered: 12/29/10
Posts: 1547
Loc: Los Angeles, California
Originally Posted By: Gokhan
So, moral of the story is that don't get sucked into heavy-duty (CJ-4, CI-4, etc.) oils just because of their high ZDDP content. Their high ZDDP content is only to make up for high concentrations or dispersants and detergents found in diesel oils. You won't get the same potency of a given amount of ZDDP in a diesel oil as you would get from the same amount in a gasoline oil with less dispersants and detergents. Effectiveness of ZDDP is greatly and inversely affected by the amount of dispersants and detergents in oil, and diesel oils have a lot of dispersants to control harmful soot.

In addition, more generally than for flat-tappet engines, I also don't see much of an advantage of using a CJ-4 oil (heavy-duty engine oil) in a gasoline engine in general, as there are a vast variety and number of gasoline-engine oils, more tailored and better tested toward gasoline engines, using gasoline-engine specific additive packages. A CJ-4/SM oil will probably work OK in most gasoline engines given the availability of viscosity, but then why use it just because it's OK to use, as it's not optimized for gasoline engines but for diesel engines?
_________________________
1985 Toyota Corolla LE, 4A-LC engine, ~ 257,000 M
Toyota (by ExxonMobil) SN/GF-5 0W-20 Synthetic
Toyota 90915-YZZF2 filter, 90430-12031 drain gasket

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#3242255 - 01/08/14 07:58 PM Re: CJ-4 oil for older flat tappet engines.. [Re: Garak]
Gokhan Offline


Registered: 12/29/10
Posts: 1547
Loc: Los Angeles, California
Originally Posted By: Garak
With respect to my Infiniti, "luxury car" or not, its oil specifications are very modest. It calls for SM/GF-4 in North America, with a bit wider range elsewhere. Generally speaking, the engine isn't calling for anything too terribly specific, like a certain phosphorous or SAPS content.

In that case, why not use a cheap conventional 5W-30 GF-5 or perhaps a cheap fully synthetic 5W-30 GF-5 in your Infiniti? Your car (smoother idles) and your wallet (less money spent on fuel) will both thank you. Do you really need to run xW-40 in it (racing it etc.)? I can understand that you can get the Delvac 5W-40 cheaper than the Mobil 1 0W-40 or similar if that's the case.
_________________________
1985 Toyota Corolla LE, 4A-LC engine, ~ 257,000 M
Toyota (by ExxonMobil) SN/GF-5 0W-20 Synthetic
Toyota 90915-YZZF2 filter, 90430-12031 drain gasket

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#3243013 - 01/09/14 03:56 PM Re: CJ-4 oil for older flat tappet engines.. [Re: Gokhan]
Garak Online   content


Registered: 12/05/09
Posts: 11363
Loc: Regina, Saskatchewan, Canada
As mentioned already, I wouldn't call an HDEO interchangeable with a break in lube, a pure racing oil, or VR1. It is, however, another very good option for various circumstances. I wouldn't recommend that someone building a performance engine go and grab it and use it for break in. On the other hand, I'd have absolutely no hesitation about using it in my F-150. Additionally, 15w-40 got a lot of use in the old Audi, as it was the widest recommended viscosity. People who do have flat tappet high performance engines should be cautious, particularly at break in. But, the guy driving an old slant six or a Ford 300 doesn't need to go and buy a racing oil or VR1 20w-50.

In older engines, too, there are other things we have to consider. An older engine can benefit from detergency, either from an HDEO or a modern GF-5 oil. In carbed applications, fuel dilution is certainly a possibility. In my F-150, it was terrible before the rebuild and carb replacement. To maintain operational viscosity, I had to use 15w-40 (for the summer) or a non-ILSAC PCMO (MaxLife 5w-30, non-ILSAC at the time). Otherwise, the oil light would come on.

While not all carbed engines were as terrible, we have to be cautious when comparing a carbed example versus a modern fuel injected system. The introduction of fuel injection probably did more to extend OCIs than most other advancements. We shouldn't underestimate the issue of fuel dilution; look at some of the DI examples we see today.

When it comes to detergency competing with anti-wear, we see oil companies trying to strike a balance. This is nothing new. After all, break in lubes and racing oils have little to no detergency for a reason.

Note the GF-5 oils aren't exactly light on the detergency. I would say that few of us here are equipped to determine whether a GF-5 or an HDEO or a racing oil has the best anti-wear properties for a given situation, unless that situation is really obvious (i.e. GF-5 in a new flat tappet race engine is silly, and race oil in a taxi is pretty foolish). Generally speaking, though, to determine which (between a 5w-30 SN/GF-5 and a 10w-30 HDEO) would provide the best anti-wear in my F-150 or (between a 5w-30 SN/GF-5 and M1 0w-40 and Delvac 1 5w-40) my G37 would require a serious undertaking.

I'm aware of the fuel economy issues when comparing a GF-5 rated lube (such as a 5w-30) versus something like a 10w-30 HDEO, 5w-40 or 15w-40 HDEO in something like my G. And yes, it's false economy to choose a thicker, yet cheaper grade. But, that's not exactly what it's all about. Walmart Canada is nuts, and I mean certifiably insane, and sometimes it's necessary to vote with one's wallet. Imperial Oil seems to reward HDEO purchasers, and again, it's necessary to vote with one's wallet.

For idle and performance, I don't notice a difference between the HDEO and the PCMO. I've already gone through the fuel economy in another thread here, not to show that there's no difference, but to show that it's unnoticeable. Yes, it's there. Yes, I would agree that it costs me more gas. But, from an operational perspective, I wouldn't notice an oil switch unless it were 20w-50 in our -40 or something similarly odd.

With respect to ILSAC type lubes, I have nothing against them. I used about 500 bottles of QS conventional in a 1981 Impala over the years alone. That's one taxi out of many. My LTD went half a million kilometers and only saw QS and GTX. My Town Car was similarly treated. I simply had some Delvac 1 ESP in stock, and tried it. I may want to run some UOAs for the heck of it. I may want to stick with it, given the pricing. Of course, my mixing phobia is well known here. If I have Delvac 1 in there, I have to stick with it until I'm sick of it. wink

But, I hold no illusions. I would have an exceedingly difficult time proving that this choice is "better" than Formula Shell, PYB, QS, M1, Mobil Super, Valvoline, GTX, or whatever alternative we wish to pick.
_________________________
Plain, simple Garak.

2008 Infiniti G37 coupe - Mobil Delvac 1 ESP 5w-40, Hastings LF113
1984 F-150 4.9L six - Quaker State GB 10w-30, Wix 51515

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#3411795 - 07/01/14 03:46 PM Re: CJ-4 oil for older flat tappet engines.. [Re: Gokhan]
dgcamero Offline


Registered: 01/17/10
Posts: 16
Loc: Barbecue, NC
Originally Posted By: Gokhan
Originally Posted By: Gokhan
Originally Posted By: widman
DO not add ZDDP. You have no idea how badly you are screwing up particular formulations, upsetting their additive balance and adding deposits to the engine. And if you go too high, you will have cam galling and other problems.

I agree on this.

Flat tappets require extreme-pressure (= antiscore) additives such as moly more than ZDDP, which is not an antiscore but an antiwear additive. So, what you really need is an oil with a good balance of ZDDP and moly. I don't think too much moly makes too much of an harm other than more engine deposits but too much ZDDP will certainly result in less protection against wear after a certain optimum value of ZDDP. This could be as high as 2500 ppm P but don't take chances with aftermarket additives. There are also different types of ZDDP and the one used in your oil is optimized against other additives.

Once again, my recommendation for temperatures above 20 F is Mobil Delvac 1300 Super 15W-40, which has about 1000 ppm P and also has the extremely potent trinuclear moly. For lower cold-start temperatures, use Mobil 1 Turbo-Diesel Truck 5W-40 if you want premium protection. A cheaper alternative would be Rotella 5W-40, and an even cheaper alternative would be Delo 5W-40.

Also note that Non-ILSAC (non-GF-5) SN oils are exempt from the 800 ppm P ZDDP maximum limit. This means xW-40 and xW-50 SN oils have no ZDDP maximum limit. Also, high-mileage SN oils of any viscosity have no ZDDP maximum limit, as they are not GF-5. ZDDP maximum limit is imposed by the "Resource Conserving" (of the GF-5) designation, not the SN designation by itself.

This said, Mobil 1 0W-40 SN is a great alternative for flat-tappet engines. It has about 1000 ppm P (of ZDDP), which is similar to CJ-4 oils, and (probably) has trinuclear moly, the most potent kind of moly. It also has another advantage against CJ-4 oils: It's tailored more toward gasoline engines. This is unlike CJ-4 oils, which are tailored more toward diesel engines.


I don't know if I recommend the SN Mobil 1 0w40 in a flat tappet anymore. My last oil in my boat was an older batch of SL Mobil 1 0w40, and the oil pressure held phenomenally above the magic 100 degree C mark (after a long pull the oil gets up to about 220 F and sits there), but the newer SN held pressure so poorly above that limit that I immediately drained it out and wasted $25 of oil...replaced it with Delo 15w40 and the pressure holds fine...ymmv of course, and this is in a PCM Windsor 351 GT40 engine.
_________________________
'07 GTI 2.0T FSI, '98 ML320, '95 Ski Nautique PCM GT-40

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