[Shop-talk] Oil analysis - Blackstone

John Miller jem at milleredp.com
Sat Jun 25 22:53:50 MDT 2011


> 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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