Just saw an add for Rislone - an 'additive' that restores the proper amount needed in older [flat tappet] engines!
4 to 1 on an oil change, probably great insurance!
Available everywhere, but didn't see a price.
Don't know if it's new, but I'll be looking for it on my next oil change!

 

Sounds good to me, but do you know how much ZDDP in PPM you end up with when mixed with 4 quarts of oil?

Shell Rotella T 15w-40 has 1200 ppm as is off the shelf. Inexpensive, good oil in my opinion. Both my vehicles use it.

 

Rotella T in all my flat tappet engines too.

 

I use the rislone ZDDP additive, about $11.99 to 4 qts of oil. Been using it a year now.

 

i use gm EOS(the stuff they quit making). i add 1 oz per quart of oil, maybe a little more, in all my vehicles.


bill

 

Instead of an additive, I use Kendall GT-1 High Performance motor oil in my flat tappet engines. It is designed for flat-tappet cams and has higher levels of ZDDP. I have used it in my high-performance air-cooled Volkswagen (high compression, high lift cam) since 2004 with no issues (6,600 miles to date).