i know for solid cams.to add to oil? thanks

Do you know why solid flat tappet cams need zddp?

For the same reason reason hydraulic flat tappet cams need it.

Has nothing to do with solid or hydraulic and everything to do with being a flat tappet cam.

Yep what Supercuda said. Any flat tappet cam needs it. Ron

The EDM lifters do seem to help prolong cam life as well.

Rings also like ZDDP.

STP is a pretty good source of ZDDP.

My mechanic says you do.

This guy says you don't;
https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

Mobil1 says don't add anything to their oil because it screws up the additive package;
https://mobiloil.com/en/faq/product-faqs

Yon blogger sure is windy and I couldn't get through his love affair with his written word. Other than to find out that you need a certain amount, but not too much and that there are a lot of variables in cam life. Durrr

As for Mobil, here's what they say specifically about flat tappet engines.
"Mobil 1 Racing™ oils offer boosted levels of anti-wear protection (nominal zinc level of 1,850 ppm) for extra engine protection in highly loaded flat tappet engine designs."

My experiences: 440 with a mild hydraulic flat tappet and stock springs. I broke in the cam with comp's break in oil that had zddp in it. After the first oil change I never ran a special zddp oil in it again. The engine went 10k before teardown, and the cam+lifters still looked new.

360 also with a mild hydraulic flat tappet. Was already a running engine in a car I bought. I only ran cheap farm store oil in it, another 10k miles. Cam survived just fine. Sold car, its still running around.

My unprofessional opinion: if you have stock springs, and the cam is already broken in, it probably isn't a big deal to have a zddp oil.

However, if its an engine you have some money sunk into, the risk is hardly worth the savings. I just recently built a solid flat tappet Hemi with a little more aggressive valve springs and only run a zddp oil (VR1 10w30).

Yes you need it, however these days there are a variety of oils on the market with enhanced levels of zddp, aimed at guys like us. I would also say it depends on the cam and valve springs you've used. A stock cam with weak springs probably isn't going to notice any difference.

Ignorance rears its ugly head:

It's not a choice between oil that has zddp or doesn't have zddp. It's a choice of how much zddp is in the oil. I am not aware of a single commercially available motor oil that does NOT have any zddp in it.

The problem seems to be that 1200ppm and above is generally considered to be safe, while the latest blends are somewhere around 800ppm. Those are the SN oils. Over in the CD side, they have been reducing the levels as well, so it's not safe to assume that any Diesel oil has enough.

As mentioned above, if your cam is broken in and you are running nearly stock springs you should be fine with whatever.

If you are using big springs and a flat tappet cam you need to be careful.

Another thing to consider is tappet acceleration. Designers have really pushed the envelope closer to the maximum theoretical lifter acceleration rate for the different diameters. Faster acceleration means more force acting on the lifter/lobe interface. Add to this the fact that faster lifter acceleration requires more spring to control the valve and you have a very potent mechanism for cam failure.

One other thing to consider, and that's the consequences of using too much zddp in your engine. It is possible to have too much for a number of reasons.

I find the best information comes from the Joe Gibbs Racing Team. You can say what you want, they have had success and part of that is research. Read here: http://www.drivenracingoil.com/news/dro/training-center/articles/zinc-in-motor-oil/

I don't think there is any better information out there, or a better oil.

R.

The bottom line is this: ZDDP is an anti-wear additive that helps to prevent flat tappet cams from "going flat." If you're using flat tappet lifters (hydraulic or solid), you should probably use an oil with more than ~1000 ppm ZDDP, but less than ~1800 ppm ZDDP (above this threshold, ZDDP can cause corrosion inhibitors to become less effective). It really is that simple.

Yes as I run the EDM lifters also and I like them. Ron