[Shop-talk] Oil analysis - Blackstone

[Bob Spidell]

You are correct, of course.  I was thinking of roller cams when I wrote 'hydraulic' (shouldn't post so late at night, I 
guess).

Thanks for setting that straight.

Bob

On 6/25/2011 9:53 PM, John Miller wrote:
>> 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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-- 
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Bob Spidell           San Jose, CA            bspidell at comcast.net

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