STP oil additive with Zinc - opinions, please ....

[mtnmankev]

if you are running a flat tappet cam and not adding zinc you are simply rolling the dice. yes some will get lucky and get long service on straight conventional oil, i was not so lucky. my engine builder proposes using rotella t4 and in addition i add 4 to 6 oz. of lucas cam break in lube with every oil change. the lucas is not expensive and adds a lot of zinc. i do not recommend this procedure if you have a cat as that is the reason the zinc was removed from motor oil in the first place.

The county I live in doesn't have emissions testing or requirements for a cat, so NONE of the vehicles I drive have one.
And after reading that too much zinc can be bad for an engine, I plan to add a little bit each oil change and hope the level is close enough to correct.
I just won't run cheap oil, it's either Valvoline or Castrol GTX for my money.
Affordable and I have always had good success with them.

 

[DoubleDingo]

I'm a firm believer in heat cycles protect the cam lobes. If you drive your vehicle a lot, and use good oil in the early stages of the cam's life, the heat cycles harden the steel, and thus using conventional oil is enough. A vehicle that is driven very seldom needs more protection as they never get the heat cycles to properly harden the steel. I may be wrong, but I think I am on to something with long heat cycles = good for your engine.

 

[Ricko1966]

The cam is work hardened which is why the first 20 minutes of the cam life are so critical.But it still needs all the help it can get to live along life lots thus the dzzp.I used a mixture of stp and 30 weight motor oil for decades as assembly lube, not some home brew but a mixture recommended by a top engine builder.When I ran out I called stp to try to get the answer does stp still have the same amount of dzzp it's always had? All I could get was a carefully worded response of yes stp has dzzp.Does it still have the same amount yes stp has dzzp.So that is no longer what I use for assembly.I did call I think it was shell ,about oil recommendations for flat tappet cars,and was surprised to learn how many different oil companies are the same company with different names.Their rep said use Castrol racing oil, or t4 rotella even though its marketed as a diesel oil it has high dzzp content and is good for flat tappet engines,so it's my go to oil.

 

[SquareRoot]

I may be wrong, but I think I am on to something with long heat cycles = good for your engine.

And the wife...just saying.

 

[DoubleDingo]

And the wife...just saying.

Yes, yes indeed