E.O.S (Engine Oil Supplement)

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Does anyone know what really is in EOS? I understand it has ZDDP, moly and other good stuff in it. Can it be added to a synthetic engine oil? Will it blend well in synthetic or blended oil? Since the amount of ZDDP in OTC PCMO has dropped and is continuing to drop wouldn't it be wise to add EOS to the oil to increase the anti wear properties of OTC PCMO?

Tim C
 
The E.O.S sold in Canada is now
AC DELCO ENGINE OIL SUPPLEMENT
part #992869. I bought a 500 ml.
bottle a few weeks ago and put
half in my BMW with synthetic oil.
I've used it in the past in other
cars and always heard good things
about it. Since my car is being
stored, I felt the added zinc will
coat the engine parts and reduce
start-up wear. This additive is
designed to reduce break in wear,
reduce camshaft lobe scuffing,
reduce valve train noise and eliminate
lifter sticking. I don't think it
contains moly. On the bottle it states:
contains petroleum distillates,
naphthenic oils and zinc dialkly di
thio phosphate and other residual oils.
This should be a great additive for any
engine.
 
The last time I saw a bottle of the EOS the label said specifically not for extended use beyond break-in . Unless it's been reformulated I personnaly would only use it for it's intended purpose . Actually while on topic I would only use it to help run in a cam with heavy spring pressure on the nose and then get it out of there to avoid possible risk of gunking up the ring pack .
 
I don't believe that EOS has been reformulated. I think they could not sell it as an engine oil supplement because the required levels of ZDDP have been reduced in recent years because of the supposedly toxity of ZDDP. I think GM changed the labeling for liability purposes. The EOS that I purchased yesterday from the Chevy dealer is still labeled as a GM product with a part number of 1052367. It does not list the ingrediants, all it says is, Contains: Petroleum oil (Engine Oil Supplement).

Tim C

Tim C
 
The MSDS for the GM Engine Oil Supplement (PN 1052368, 1052367) manufactured by Ralph Shrader Inc., lists ingredients as:

1.31% (by weight) Zinc
1.19% (by weight) Phosphorous
2.14% (by weight) Calcium
3.44% (by weight) Sulfur
0.17% (by weight) Nitrogen
Balance Motor Oil

If you use a quality oil, why would you need this?
 
quote:

Originally posted by doyall:
0.17% (by weight) Nitrogen

If you use a quality oil, why would you need this?


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Because it would be cool to have an oil that fizzes when you open the bottle
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You would only need about 1/10 of a can of this stuff. The add pack exceeds the current limits of Phosphorus and Zinc by 10X.

EOS was originally used for the breaking-in of the older V8's.
 
Had to revive this thread...I tried some today in my 3800, and it instantly made it seem smoother and quieter. I'm using Pennzoil High Mileage 10W30 in it right now. I normally run Schaeffer's, but I was way overdue for a change, and this worked in a pinch. I thought it couldn't hurt to throw a can in since I planned on changing the oil in less than 1000 miles anyways. It's pretty impressive as far as additives go. I've never really had one that made such an instantaneous difference before.

The can also claims it works to quiet ticky lifters and valve train noise. Any explination as to how or why it does this? A buddy of mine who runs a machine/speed shop told me to try this in a car with valve train noise and it would most likely fix it.
 
But for the sulfer, it looks like it would be a good additive, but as MolaKule says, about one-tenth of a can. Perhaps half that much even. But forget about it. That sulfer is surely not good in the long term.
 
I use the stuff for assembly lube on all the notors I build. And I add a can for the first start up and camshaft run in. So far I belive it is great stuff. I have never used it on motorcyle engines though. I have allways been afraid it would mess up the clutch pack. And I'm hard enough on them as it is.
 
So no long term use. I have a few projects ope motors that are soon to be fresh .010" over, valves, head mill work. I plan to run dino in one, ams ope oil in other three. Initial run-in fill will be travellers sae30 diesel all fleet, i have RP assembly lube to,.

Ken
 
I have used GM EOS and its equiv (look up SLOB) in lots of motors over the years long term. The HDEO oils used to have higher ammounts of ZDDP before they reduced it around the time of the launch of cat converters in big rigs. The thought was too much of the heavy metals could plug the cats up, especially in a motor with oil blow by.
Yes, it's great for cam and engine break-in, but also is helpful for solid lifter and older pushrod, and air cooled motors full time.

Rotella T used to have much more zddp, adding a little of one of the additives brings it back up to the levels of the good old days. But, I use it full time in my tractors, race cars, and air cooled engines, and not in my modern daily drivers, as they don't need it, and because of the cat plugging possibility.
 
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