[Shop-talk] Oil grade selection

[Steven Trovato]

That's what I thought too.  I asked about this back in May over on 
the HAMB board.  This is what I was told:

"...the Big Three have used roller cams in their V8s since the mid to 
late '80s, at least the designs that actually use tappets/lifters.

A sliding tappet...there are a couple of definitions of this, but the 
common one would be an OHC-style engine, generally where the "tappet" 
as such is the actual end of the rocker arm...no separate pushrod or 
lifter. A more common term is "follower".
.
.
.
At any rate, since OEM followers/sliding tappets do not need cam lobe 
taper, the point of contact is larger and has much less loading in 
terms of PSI as compared to conventional flat tappet designs."

Here's the whole thread if you are 
interested:  http://www.jalopyjournal.com/forum/showthread.php?t=263632

-Steve Trovato
strovato at optonline.net

At 03:36 PM 10/22/2008, Doug Braun wrote:
>The ZDPP articles I have read have said that modern
>engines are not affected because they have roller
>tappets instead of flat tappets.  But obviously not
>all (or even most) modern engines have roller tappets.
>
>Does anyone know what the articles really meant?
>
>Doug