i've been using the pennz synthetic in my 06, i cringe every time i pour 5w20 in there but thats what it calls for and thicker oil has been heard to mess up the variable cam timing.

and yeah, 300's are pretty much indestructable - 200's and 250's no so much =(

 

If you prefer a true Full synthetic oil, consider some of the Amsoil oils that have high levels of ZDDP:
https://www.amsoil.com/dealer/techse...t%20Tappet.pdf

fwiw, I run the AMO in my 4.0 L Jeep engine (cam failures common in them w/ wrong oil) and the RD30 racing in my Stang 302.

 

Wow, this is the first time I have ever heard this mileage recommendation. I've asked the question many times in the past and was always told 2000 miles was fine. Oh well, back to the drawing board!

 

I use Valvoline VR1 SAE40 in the winter and SAE50 in the summer. Love the additives. It make me feel like I am using a real oil. Crazy you have to use a "racing oil" to get the stuff you need. It is perfect for my car, but over kill for a modern vehicle, IMO (I use the QS10W30 in most everything else). I change the oil twice a year (Oct. and March) unless I am tearing into it. Mileage is not really an issue for me.

 

What about you have roller cams versus tapplets? on new engines?

 

I have a roller cam, lifters, and rockers. I still run the oil with all the additives I can get. Yes, it is more important for flat cams, but what is good for the gander...

As for new engines, what do you mean? New as in modular motor w/overhead cams or new as in fresh 351W?

 

There is a good reply on this "flat tappet/oil" subject in the January Mustang Monthly in the reader reply section. They recommended a few oils that still had zinc. They also said you could use any of the major brands of regular oil if you changed it every 1000 miles. That would suit me better cause my 351C oil seems to get pretty dirty by then (driven about once a week). I even tried using Mobil1, it is dirty at 1000mi too, seems like a waste of $$. Use regular dino-oil and change it very often, engine stays real clean.

To answer the previous post: with roller cams you can use any modern oil, the problem is with the flat tappets on cars older than 1989.

 

Has anyone used Royal Purples Break In oil? Or their regular oil in their stangs?

 

While you don't absolutely need high zinc oils in roller engines, it's still good for other parts of the engine (like thrust bearings).

71Mach, oil is going to be 'dirty' looking no matter what brand or type it is. Synthetic doesn't keep crap from accumulating in the oil, it just lubricates better and doesn't turn to sludge like normal oils do. If you drive hard, your oil is going to be dark, synthetic or not. 3k change intervals are good for most cars, old or new.

 

Are there any readily available in normal stores additives to replace the missing ZDDP in the newer oils?

I know about ZDDPlus but its not sold in normal retail outlets. Just seems to me if this was such a big problem for older cars, someone is sure missing out on a GREAT marketing opprotunity.

i looked at a number of additives on the shelf at the auto parts place and none of them said anything about zinc or zddp levels. Just lots of great promises.