Just my experience, but on my last engine rebuild, my lifters were toast,
having traded much metal with the cam lobes. I'd run exclusively Valvoline
synthetic, an otherwise fine oil except for the zinc content. Now I'm running
Valvoline 20-50 racing oil. So far no problems, but we'll know for sure at the
next tear down.
Terry Smith, '59 TR3A
New Hampshire
> On September 5, 2018 at 1:59 PM Randall <tr3driver@ca.rr.com> wrote:
>
>
>
> > 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
>
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