Re: [Amc-list] 1967 232 six with 122K miles- grade of oil?

[adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)]

" From: Tom Jennings <tomj@xxxxxxx>
" 
" There's also "high mileage" oils, in 10W-30, that are probably a good 
" idea. They contain more zinc than other oils, and some contain seal 
" softeners (like stool softeners for old cars :-) Costs a bit more than 
" the cheapest crap oil, but probably worth it. Oil's not a thing to cheap 
" out on.

good point!  i forgot about this.

current oils actually have a much-reduced zinc level from the oils of
even 10 years ago.  the old level had been set by sae experimentally
based on observed wear, and it's the oil our engines were designed
for.  it's not as critical after break-in as at break-in, but as tom
says, don't be penny-wise and pound-foolish.

zinc levels were 'high' up to api 'sm' and 'ci' ratings; they've been
cut almost in half because zinc supposedly poisons catalysts and only
flat-tappet pushrod engines [rare now] need it.  maybe this is why
mopar finally dropped the 4.0, even though the 3.7 has been a problem
child?
________________________________________________________________________
Andrew Hay                                  the genius nature
internet rambler                            is to see what all have seen
adh@xxxxxxxxxxxxxxxxx                       and think what none thought
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