ZDDP Opinions

I have a spare bottle since I sold the 944. I bought it since, supposedly, the '44 benefited from adding it to any oil you would buy. Not sure what I'd use it on now.

Anything with a flat-tappet camshaft.

Add it to anything that uses oil. Really the only reason they reduced/eliminated the use of ZDDP in most engine oils was that in worn out engines that used oil that additive would get burned in the engine and go out the exhaust and reduce the efficiency of the cat. The EPA thought that this was a bad thing and the change was made. Of course since most engines today use some form of "roller lifter" the need/requirement for this additive is nearly zero. You get some in oils spec for diesels as they are longer lived engines and many still are in use and have flat tappets in them.

I still have a old 1988 Ford van with the 5.8L engine. That engine didn't get roller lifters until the mid 90's and only the last 1-2 years of production. I still add a ZDDP additive to the oil or use diesel oil. But since I only change the oil once a year (I have gone longer) it's not an issue. It sees less then 4K miles a year.

It's been a while since I've hung out on bobistheoilguy, but isn't Molybdenum the "better than ZDDP" hotness?

Bobistheoilguy is an easy site to get sucked into.

I tryed the additive in my wagon when i first got it and had issues with it so i just run rotella. Trying to explain zddp to people who drive old cars with original motors is like pulling teeth.

If you ever build an engine with a radical camshaft, you'll kinda want the stuff for initial break-in and perhaps even continuous use.

The basic problem was flat tappet lifters, strong valve springs and steep cam lobe ramps. The combination was/is too much for the lower zinc content.

Pretty much anything under that will be ok without it.