I have been researching for weeks but still can't make up my mind. I really need the help of some Porsche/VW engine builders and tribologists.
Lots of specs have changed in the last 2 - 3 years for oil....Very hard to keep up!
I have several high performance flat tappet/solid lifter engines, Type 4/914 based and VW Type 1.
Most of the engines were built around '03/04 or earlier, before the big oil freakout and flat cam scare of that era.
My pride and joy is a 2270cc Type 4 with a Webcam 163/86b cam. This is in a '65 VW Bus
Back when I built the engine, oil was not such a problem and I believe I broke it in on straight Castrol HD30 wt (2004ish).
The engine only has ~400 miles on it and I changed the oil to Mobil 1 15w50 a few years ago.
I haven't inspected the cam, but I want to avoid any chance of damage.
Currently bought some Valvoline VR1 10w30 Conventional (~1400 Zinc/phos), but have not installed it yet.
I've been reading that the "best" oil is Driven DT50 15w50 for these engines, but can't find it locally.
1) Is the VR1 10w30 OK to use for now? (have not changed it yet)
2) Is Mobil 1 15w50 SN OK for my application? (Did I do damage so far?)
3) Should I wait and buy some Driven DT50, or should I go with Amsoil, Redline, or ?
4) With articles like the 540RAT blog, it makes me wonder how important ZDDP is for HP Flat Tappet applications? Lots of muscle car engine builders still swear by high ZDDP numbers...
Amsoil and Driven are mail-order only in my area. All other oils are available, Redline, and all auto parts store oils... Looking for the "best" protection for HT/HS in a High Performance flat tappet application. Keep in mind a HP VW engine can reach ~380F on the head temps under full load.
Thanks in advance!