[DML] Corrected: Cam Wear cause (Soft Camshafts)

["content22207" <brobertson@xxxxxxxxxxxx>]

Through the miracles of modern technology, this post was truncated
prematurely. Should have read:

> For some reason this rumor is endemic in the DeLorean community and
> simply refuses to die (quite ironic when you consider DeLo usage
> accounts for only .8% of total PRV production). There is no 
difference
> in camshaft composition between various B27/B28 applications, nor 
to
> my knowledge between various Peugeot, Renault, and Volvo aps. The 
only
> TSB Volvo ever printed on the subject was to substitute 10W30 oil 
over
> the previous 10W40 spec (retroactive to the beginning of PRV 
usage).
> Thicker oil has a tendency to gum up camshaft/rocker arm orifices.
> Note that the rocker arm orifices are located at the camshaft 
lobes,
> not the valve stems -- probably the source of characteristic valve 
noise.
> 
> Volvo's words Re: camshaft wear (circa 1985 -- after the TSB,
> footnoted as a supplement to my particular manual):
> "Damaged (worn) rocker arms and/or camshafts may be due to one or 
more
> of the following causes:
> - Incorrect quality or grade of oil. It is important that the 
correct
> oil is used and that it is changed sufficiently often with regard 
to
> driving conditions.
> - Contaminated oil. May be caused by camshaft grindings, coolant,
> fuel, etc.
> - Insufficient oil supply to rocker arms."
> 
> That last point is especially important if timing chain tensioners 
are
> fully extended -- oil will simply flow past them back into the pan,
> never reaching the camshafts.
> 
> Consider this: If later production camshafts were so superior, why 
is
> premature wear still a concern in 1985?
> 
> Bill Robertson
> #5939
> 







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