Several things I have read tells me the oil makers stop putting zinc about 1995. A good INDY recommend that I when I change oil to add zinc oil additive. I got mine at O'Relilys'. Any one have knowledge or a comment. I use Castrol 10w40 with half 10w50.

 

You'll probably get lots of opinions

Personally I don't think it's necessary. I sold my X300 last year with 171k miles and the engine was sweet as a nut and quiet as a mouse, and used only 1 qt of oil every 4000 miles, and I never used any additives...zinc or otherwise. To be honest, I just used whatever engine oil was on sale that day and changed it every 5000 miles.

If you decide to go ahead and use the zinc pay attention to the concentration as too much might harm the cat converters....which is why zinc was phased out to begin with.

Others will chime in

Cheers
DD

 

The Zinc (ZDDP) is a still there, just in lower quantities than the good ol' days in order to protect the cat cons as Doug mentioned.

It's pretty much a non-issue, except on OHV engines with non-stock cam profiles.

 

i know its important in old cars with flat tappets, and cams with flat shoulders and no ramps on the cam lobes, such as my dad's 1928 Alvis. I use Penrite oil in that, which is formulated with higher Zn levels for old engines.
I doubt it matters in X300 AJ16 engines, but it probably wont do any harm, either.
Experts like Doug or Andy Stodart may give better advice.

 

Hi Ak,

Little slow getting back. Where do you get Penrith oil? I need to either use an oil like that or a additive in my 1929 Model A Ford. I wasn't even aware of this Zn issue until I visited a friend of mine that is an engine rebuilder of the old school. Don't want to screw up the old A bone any more than the X300.

Thanks for the input.

 

A little slow responding guys. Thanks for the input. Guess the old X300 will keep doing just fine the way it is.

Thanks again.

 

Very simple. Look for oil that's rated API CJ4 and choose the viscosity you need. Walmart has it under their own label or Shell Rotella if you like brand names.

This oil has all the ZDDP any street-going engine would require.

 

I think Penrite is an Australian brand.
With the huge Vintage car movement in USA, it should be easy to get a high-Zn oil. I'd ask your local Model A club as a starter