Rizlone ZDDP additive

[secondchance]

Originally Posted by ittlfly

Is that the Rislone brand you are using or something else?

No. This is what I have been using.
http://www.eastwood.com/zddp-plus-oi...e-4-fl-oz.html
2 oz fater an oil change.

[Marc Haibeck]

The LT5 was designed for API SG oil. It is noted on the oil filler cap of the 1990 to 1992 engines. SG has .12% ZDDP. This is also specified as 1200 ppm ZDDP. Modern oils like Mobil 1 10W-30 have .08% ZDDP. They are removing ZDDP because it can reduce the efficiency of the catalytic converter. In the future they might remove more ZDDP.

This is a minor issue with the LT5 because the smaller valves have lower loads on the lifters. The LT5 load on the lifter at full lift is 248 lbs. The L98 with flat tappets has a lifter load of 375 lbs.

I have observed that the lifters wear more than the cams on the LT5. On the LT5 the main concern is lifter wear. Camshaft sprocket wear is also a factor. ZDDP is used to protect these parts.

The easy way to address this is to use an oil that is formulateded for older design engines with flat tappets. The Amsoil AMO product and many other products are available. These products have .12% ZDDP. Too much ZDDP can cause a problem too. The .12% level was used from about 1965 to about 1995 and is well proven.

Amsoil AMO is priced about the same as Mobil 1 if you sign up as a Preferred Customer. Since Amsoil AMO is a higher quality lubricant than Mobil 1 you could go an additional 1000 miles more than you would with Mobil 1.

If you want to save a few dollars you could use GM EOS as an additive for modern oil. About half a bottle of EOS will increase nine quarts of .08% ZDDP oil to about .12%.

If you are subject to emissions testing, modern oil might be right for you. Longer catalyst life might be as important and less lifter wear. Lifter wear due to reduced ZDDP seems to me to be a minor issue on the LT5.

[USAFPILOT]

How about the Mobil 1 Extended Performance?

[Marc Haibeck]

Until about six months ago Mobil 1 stated that their 15W-50 product was for "engines with flat tappets". I can?t find that statement on their www site today. Now they are listing the High Mileage product as having "extra anti wear additive". I can?t find where they document exactly how much. I would want to know what the specification is before trusting it. The Extended Performance product does not have either of the above claims.

[4-cam]

Mobil 1 product guide[ATTACH]1369

[Marc Haibeck]

That's a very useful document. Thank you for supplying it.

According to the list the 15W-50 Mobil 1 product still has the full ZDDP EP package. I think that a 50 weight viscosity is too high for an engine with less than 100k miles. Except for the higher parasitic friction loss it would probably work well.

[bdw18_123]

I notice that the Mobil 1 High Mileage product is listed as having 1100 ppm of zinc. Since that is only 100 ppm less than the required 1200 ppm, would this work ok for the LT5?

It doesn't seem like 100 ppm less would make much of a difference. That 15w50 is really high viscosity and although my LT5 does have 140K on it, I'd still rather use the regular viscosity if I could.


Or how about that 5w40 diesel truck oil? It's got the 1200 ppm of zinc. Would it work in the LT5, or is it's formulation too significantly different?

[ittlfly]

Originally Posted by Marc Haibeck

That's a very useful document. Thank you for supplying it.

According to the list the 15W-50 Mobil 1 product still has the full ZDDP EP package. I think that a 50 weight viscosity is too high for an engine with less than 100k miles. Except for the higher parasitic friction loss it would probably work well.

Thanks Marc for you input....