More oil stuff and zinc additive

[gary124sport]

There is zinc in the multi-vitamin that I take. Maybe I should give my car a couple the next time I change the oil. I've been using Mobil-1 15W-50 synthetic for about the last 30 years and 130,000 miles. The engine is getting tired but will still pull to the red-line in 5th gear. It has over 150,000 miles on the engine (over 265,000 on the car). It has been basically untouched - meaning the head has not been off or even re-torqued and the oil pan has not been off since 1980 when I installed it. Should I switch from what I'm doing and add this additive? Has the formula of the Mobil-1 15W-50 adversely changed? I have almost all of the parts I need for a refreash of this engine. When I (or should I really say Alvon and I) tear into this and if there is no obvious signs of wear on the valve shims should I switch?

[wachuko]

There is zinc in the multi-vitamin that I take. Maybe I should give my car a couple the next time I change the oil. I've been using Mobil-1 15W-50 synthetic for about the last 30 years and 130,000 miles. The engine is getting tired but will still pull to the red-line in 5th gear. It has over 150,000 miles on the engine (over 265,000 on the car). It has been basically untouched - meaning the head has not been off or even re-torqued and the oil pan has not been off since 1980 when I installed it. Should I switch from what I'm doing and add this additive? Has the formula of the Mobil-1 15W-50 adversely changed? I have almost all of the parts I need for a refreash of this engine. When I (or should I really say Alvon and I) tear into this and if there is no obvious signs of wear on the valve shims should I switch?

That is what I use for my Porsches... and yes, the formula changed. I was going to say to stay away from it due to the reduced levels of zinc... but it looks like it changed again...

http://www.mobiloil.com/USA-English/Mot ... _Guide.pdf

Back with 1300ppm of Zinc...

I still have a few boxes of the original formula and with oil changes every 15K miles in the 911 I had not looked into this for awhile... looks like it is safe to use it again in my cars when the current stash runs out.

Also a nice article:

http://www.lnengineering.com/oil.html

... Even current "re-introduced" formulations are not the original formulations many shops and owners were used to. Aside from reduced Zn and P levels (now restored in certain products), many products with "adequate" Zn and P still use high levels of Ca detergents, well documented in various SAE publications as known for causing more wear than Ca/Mg or Ca/Mg/Na detergents, as previously used in oils like Mobil 1 15w50, back when it was API SH/SJ rated and prior to reformulation ...

Many Porsche repair shops have acknowledged that these newest SM and CJ-4 motor oils are not sufficient for protecting any Porsche engine, including newer water-cooled ones ...

So, just to be on the safe side, we should not be using it for our classic cars....

A bit confusing really...