> By all accounts, a non-issue unless you're running a pushrod engine
> with solid, 'flat' lifters. There are reports of premature cam
> failures on this type of engine, but I haven't heard of any problems
> with hydraulic lifter or OHC engines (which is pretty much all newer
> engines).
No, any 'flat-tappet' - that is, mechanical or hydraulic lash adjustment
but non-roller lifter sliding on cam lobe - engine is at risk from
reduced ZDDP levels.
As are some OHC motors, typically those running stiffer-than-stock
valvesprings with aftermarket cams on bucket or other sliding-type lifters.
There's lots of good reasons to build your engines with roller-type
valve actuation hardware where possible, and this is just another.
IIRC API SJ was the last really 'good' oil, SL had half the ZDDP, SM was
halved again from SL, and I now see an SN and I have no idea what it's got.
John.
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