The Mrs got me this old quart of Pennzoil 10W40 for Christmas. Anyone have any idea what Z-7 is? Maybe this is from the glory days of catless cars and the Z is for zinc?

 

I use Valvoline's high zinc racing oil in the Z. Perhaps this is where it came from.

 

 

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53 minutes ago, Reptoid Overlords said:

The Mrs got me this old quart of Pennzoil 10W40 for Christmas. Anyone have any idea what Z-7 is? Maybe this is from the glory days of catless cars and the Z is for zinc?

Can't really answer your question regarding Z-7, but here are pictures of what I found at an estate sale over the summer. SAE30, with zinc.

Sad to say there were 3 cans of R12 there, should have picked them up for those who haven't done the R134 conversion yet.

 

There's an explanation of Z7 here:
https://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=4017

I liked it better when there was some mystery.

Well there it is. I even looked through bobistheoilguy but somehow missed that. You're right, it's not as big as I thought it would be.

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2 hours ago, Reptoid Overlords said:

Well there it is. I even looked through bobistheoilguy but somehow missed that. You're right, it's not as big as I thought it would be.

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I'm thinking of going to Rotella T4 and it seems I read you are using that.  Would you reccomend?   I've read until my eyes bled and think that for a street car that to be the best bang for the buck.   Thanks for any advice.  Cliff

After some deep thinking, errr drinking, I remember it was @gwri8 that uses Rotella.  Maybe you do as well?  I'm going to get the 2.5 gal jug for my two Zs.

I haven't used shell rotella. I've been using Valvoline's VR1 10W30 conventional oil. As far as I can tell, the high Zinc responds to pressure in the engine, therefore being most effective at the places where pressure is at the greatest. I only occasionally beat the car, normally shift at 3k rpm, and mix freeway /city driving. Maybe add 1/4 of a quart every 3k miles. Original rings(as far as I can tell), valve seals about 2 years old now.

 

I'll never claim to truly understand from a chemistry perspective how it works, but all my research leads me to believe it's good. But thats not to say shell rotella, or even just plain old O'Reilly's dinosaur oil are just fine. People seem to have high opinions of the high detergent rotella oils. I'd like to know how it goes if you try it.

 

I've still got years of service left in the engine in the car now, with a backup built on deck. I'm always wishing I had the means to test the oils on my own.

 

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