[TR] Starting a dry engine advice sought

[Randall]

> I've been told that Valvoline Racing oil has zinc in it.  
> It's odd that the newer cars don't require it.  In fact, why 
> is it important?

Lots of opinions, here are mine:

In a nutshell, it helps protect critical surfaces (like cam lobes and
lifters) in case the oil film breaks down (gets rubbed away by the relative
motion of parts).

The TR camshaft (along with many other performance cars) is actually pretty
aggressive in terms of force developed between the camshaft lobe and lifter
during high rpm engine operation. 

Newer engines either use roller lifters (to eliminate the rubbing between
lobe and lifter) or less aggressive camshafts (that are less likely to rub
away the oil film).

Honestly, I'm not absolutely convinced that the TR motor needs the extra
ZDDP.  But it seems clear that many older engines do (even those not
particularly high performance by today's standards); and it hardly seems
worth taking a chance by using a lower ZDDP oil.  (AFAIK, all modern motor
oils still contain some ZDDP, they just have lower amounts.  The oil
industry has been searching for a suitable substitute, but I haven't heard
of them finding one yet.)

-- Randall