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Mobil 1 15W-50

xjman96

NAXJA Forum User
Location
ok
I have checked my regular sources for Mobil 1 15W-50 (high ZDDP)
and I cannot find the 5 quart containers like I used to.
Are they pulling it off the market?
 
I saw a noted posted on the oil shelf at Wal-Mart that said Mobil is having trouble keeping up with demand on some of the synthetics.

I try to keep a couple of bottles ahead...

I haven't had any problems with the 15w50, but I've been thinking of trying a lighter weight. By the way, the 50 doesn't mean the oil is viscosity 50, it means it acts like a 50 weight oil would at 250 (?) degrees F. (I'm not sure about the exact temp.) When 50 weight is heated to 250 degrees it gets quite a bit thinner.
 
Amsoil has ZDDP, so does Valvoline, and I believe Pennzoil Platinum does too (only pennzoil I would ever run.) all > mobil 1
 
Amsoil has ZDDP, so does Valvoline, and I believe Pennzoil Platinum does too (only pennzoil I would ever run.) all > mobil 1

"THE LAST TWO NUMBERS HERE ARE THE PHOSPHORUS LEVEL THEN ZINC LEVEL
AMO 10W-40 Synthetic Premium Protection 1265 1378"

You are absolutely right and I thank you. That's what I'm getting.
 
What you can do as well, is have your oil tested at a lab. I used to work for Oil analysis lab, inc. located in Spokane, Washington. Having your oil tested can tell you SO much more than just looking at or smelling your oil. Their site is www.oillab.com It is a small independantly owned place, many large companies send their oil to them for testing.
 
"THE LAST TWO NUMBERS HERE ARE THE PHOSPHORUS LEVEL THEN ZINC LEVEL
AMO 10W-40 Synthetic Premium Protection 1265 1378"

You are absolutely right and I thank you. That's what I'm getting.

You don't need that much ZDDP on a low compression engine that is fully broken in--more like 800.
 
You don't need that much ZDDP on a low compression engine that is fully broken in--more like 800.

from what I understand the requirement for higher ZDDP levels is the fact our engines are flat tappet, as opposed to a roller cam.

preventative medicine
 
What you can do as well, is have your oil tested at a lab. I used to work for Oil analysis lab, inc. located in Spokane, Washington. Having your oil tested can tell you SO much more than just looking at or smelling your oil. Their site is www.oillab.com It is a small independantly owned place, many large companies send their oil to them for testing.

I agree that oil analysis is very useful. In my case I see no reason to bother. My engine has around 176K miles, works well and I doubt that I would do anything to it regardless of the analysis. When it breaks, I'll fix it.
 
The 50 number is not the concern. The 15 is kind of thick for start up, when 80% of your wear occurs. ZDDP helps the flat tappets and cam wear longer, but ours are not highly stressed. 800 should be enough. Using additives to get over 1500 may cause problems with buildup.
 
from what I understand the requirement for higher ZDDP levels is the fact our engines are flat tappet, as opposed to a roller cam.

preventative medicine

Correct. This is why we can't use SM (SN?) oil - because the ZDDP has been lowered so much that the "antiscuff" properties are just plain gone and you end up scrubbing out your cam lobes and tappet feet!

Most newer engines are using rollerised tappets (cam-in-block) or rollerised followers (overhead cam,) and don't have that problem.

The organometallics have been reduced because the poison the catalyst bed when they get into blowby gasses and burned.
 
I haven't had any problems with the 15w50, but I've been thinking of trying a lighter weight. By the way, the 50 doesn't mean the oil is viscosity 50, it means it acts like a 50 weight oil would at 250 (?) degrees F. (I'm not sure about the exact temp.) When 50 weight is heated to 250 degrees it gets quite a bit thinner.

15W-50 acts like a 15W oil at low temperatures. The modifiers prevent it from thinning as much with heat so that it acts like a 50W oil at 100°C (212 °F).

Typically oils are rated be viscosity at 0°C and 100°. Still 15W50 is a fairly thick oil. I wouldn't use it if you see cold start temps well below freezing.
 
So if I put in a new set of roller rockers, this concern is completely eliminated (essentially)?

No - because you'll still have flat tappets. You need rollerised tappets (preferably along with rollerised rockers - at least the pivots and tips, if not fully rollerised) in order to do away with a lasting need for organometallics.

A shaft-mounted rocker might reduce the need, due to the larger bearing area than the pedestal-mount pivots. However, I'd rather have a roller bearing there, and a roller wiper at the valve tip. The pushrod seat isn't necessary; but as long as I'm dreaming, I'd like a pony...
 
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